Cubic bipryamid cobalt-doped iron oxide nanoparticles and methods for making and using in hyperthermia treatment

Abstract

Disclosed herein are embodiments of a nanoparticle suitable for use in providing hyperthermia treatment. The nanoparticle may be a cubical bipyramid cobalt-doped iron oxide nanoparticle. Also disclosed are compositions comprising the nanoparticle. The composition may further comprise a polymer and / or a targeting moiety. Further disclosed and methods for making the nanoparticle and the composition, and embodiments of a method for using the nanoparticle or a composition thereof. The nanoparticle may be useful for treating cancer, endometriosis, or ectopic pregnancy.

Description

[0001] 245-112651-02 09 / 12 / 25 OSU-24-52 CUBIC BIPRYAMID COBALT-DOPED IRON OXIDE NANOPARTICLES AND METHODS FOR MAKING AND USING IN HYPERTHERMIA TREATMENT CROSS REFERENCE TO RELATED APPLICATION This application claims the benefit of the earlier filing date of U.S. provisional patent application No.63 / 694,599, filed September 13, 2024, which is incorporated herein by reference in its entirety. INCORPORATION OF ELECTRONIC SEQUENCE LISTING The Sequence Listing is submitted as an XML file named “Sequence.xml,” created on September 9, 2025, 9,227 bytes, which is incorporated by reference herein. FIELD The field of this disclosure generally relates to nanoparticles and compositions thereof, methods of making the nanoparticles and compositions, and methods of using the nanoparticles and compositions in certain medical applications, such as medical hyperthermia treatment. ACKNOWLEDGMENT OF GOVERNMENT SUPPORT This invention was made with government support under Awards R01 CA237569, R01 HD101450, R01 HD112007, and R37 CA234006 awarded by the National Institutes of Health. The government has certain rights in the invention. BACKGROUND Magnetic hyperthermia has emerged as a promising experimental clinical modality for cancer treatment. It leverages the ability of magnetic iron oxide nanoparticles, directly injected into the tumor, to generate heat upon exposure to an external alternating magnetic field (AMF). Achieving therapeutic intratumoral temperatures, typically above 44°C, is essential for cancer growth inhibition and potential eradication. However, conventional magnetic nanoparticles used in clinical trials exhibit moderate heating efficiency. Consequently, there is a critical need in the field of magnetic hyperthermia for the development of nanoparticles with significantly enhanced heating capacity. SUMMARY Disclosed herein are aspects of a cobalt-doped iron oxide nanoparticle having a cubical bipyramid shape. The nanoparticle may comprise from 2 atom% to 10 atom% cobalt, from 25 atom% to 55 atom% 245-112651-02 09 / 12 / 25 OSU-24-52 iron, and from 35 atom% to 75 atom% oxygen, such that the total amount of cobalt, iron and oxygen is 100 atom%. And / or the nanoparticle may have a formula CoxFe3-xO4Formula I where x is from 0.1 to 0.8. Also disclose are aspects of a method for making the nanoparticle, comprising providing an octagonal cobalt-doped iron oxide nanoparticle; combining the octagonal cobalt-doped iron oxide nanoparticle with a first cobalt compound, a first iron compound, and a first surface capping agent in a first solvent system to form a first mixture; heating the first mixture to a first temperature for a first time period; and isolating the cubic bipyramid cobalt-doped iron oxide nanoparticle. Additionally, aspects of a composition comprising the nanoparticle are disclosed herein. In some aspects, the composition comprises a cubical bipyramid cobalt-doped iron oxide nanoparticle as disclosed herein, and a polymer. The nanoparticle may be encapsulated in the polymer. And / or a targeting moiety may be conjugated to the polymer. Also disclosed are aspects of a method for making the composition. In some aspects, the method comprises forming a solution or suspension comprising the nanoparticle and a first organic solvent; forming a mixture comprising the solution or suspension and a polymer in a second organic solvent; and isolating a composition comprising the nanoparticle and the polymer. A method for using the nanoparticle or a composition thereof also are disclosed herein. In some aspects, the method comprises administering the nanoparticle, or composition, to a subject in need thereof. The method may be a method of treating cancer, such as ovarian cancer. In some aspects, the method is a hyperthermia treatment method. The foregoing and other objects, features, and advantages of the disclosure will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures. BRIEF DESCRIPTION OF THE DRAWINGS FIG.1 is a schematic illustration of the two-step seed-and-growth thermal decomposition synthesis of cobalt-doped iron oxide nanoparticles (Co-IONPs), including 3D models of the resulting octahedron and cubical bipyramid morphologies. In step 1 (seed formation), octahedron Co-IONPs are shown with their hexagonal

[0111] and rhombohedral

[0110] projections enclosed by {111} facets. In step 2, these octahedral nanoparticles are used as seeds for the further growth of cubical bipyramid Co-IONPs, 245-112651-02 09 / 12 / 25 OSU-24-52 which are primarily enclosed by {111} facets along the

[0110] projection and {100} facets along the

[0100] projection. FIG.2 is a HAADF-STEM image of Co-IONP seeds illustrating the structural and compositional characterization of octahedron-shaped Co-IONPs. FIG.3 is a HAADF-STEM image of Co-IONP seeds with the dashed circle delineating an individual octahedron Co-IONPs in a rhombohedral projection. FIG.4 is a HAADF-STEM image of Co-IONP seeds with the dashed circle delineating an individual octahedron Co-IONPs in a hexagonal projection. FIG.5 provides bright-field TEM images of octahedron-shaped Co-IONPs observed at different magnifications. The octahedron Co-IONPs highlighted by a white circle show its hexagonal projection, while the nanoparticles highlighted by a dark-blue circle show its rhombohedral projection. FIG.6 provides high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images of octahedron Co-IONPs observed under different orientations with their corresponding high-resolution TEM (HRTEM) images and Fast Fourier Transform (FFT) patterns. FIGS.7A-7C are representative EDX elemental maps of iron (FIG.7A), cobalt (FIG.7B), and oxygen (FIG.7C), illustrating the elemental composition of octahedron Co-IONPs. FIG.8 is an EELS spectrum of octahedron-shaped Co-IONPs, with the inset table providing the atomic percentages of Fe, Co, and O in synthesized nanoparticles. FIG.9 provides a comparison of XRD patterns for octahedron (seed, lower) and cubical bipyramid (growth, top) Co-IONPs. FIG.10 is an SAED pattern of Co-IONPs, confirming crystalline spinel structure. FIG.11 provides bright-field TEM images of cubical bipyramid-shaped Co-IONPs at various magnifications. FIG.12 provides representative HAADF-STEM images of Co-IONPs at various magnifications. Dashed circles delineate individual cubical bipyramid Co-IONPs in hexagonal (top right and bottom left) and cubic (bottom right) projections. FIGS.13A-13F provide a 3D geometric model of a cubical bipyramid (FIG.13A) along with three different 2D projections: square or cube (top view) (FIG.13B, top), hexagon (side view) (FIG.13B, middle), and hexagon (diagonal side view) (FIG.13B, bottom); multi-modal characterization of the cubic projection of cubical bipyramid Co-IONPs (FIGS.13C-13F, top): HAADF-STEM micrograph (FIG.13C top), HRTEM image displaying lattice fringes with 3.0 Å spacing, corresponding to the (220) planes (FIG.13D,top), FFT pattern (FIG.13E, top), and 3D model of the cubic projection along the ^100^ zone axis (FIG.13F, top); analysis of the hexagonal (side view) projection of Co-IONPs (FIGS.13C-13F, 245-112651-02 09 / 12 / 25 OSU-24-52 middle): HAADF-STEM micrograph (FIG.13C, middle), HRTEM image revealing lattice fringes with 4.9 Å spacing, attributed to the (111) planes (FIG.13D, middle), FFT pattern (FIG.13E, middle), and 3D model of the hexagonal (side view) projection along the ^110^ zone axis (FIG.13F, middle); and analogous analysis of the hexagonal (diagonal side view) projection of Co-IONPs (FIGS.13C-13F, bottom): HAADF-STEM micrograph (FIG.13C, bottom), HRTEM image (FIG.13D, bottom), FFT pattern (FIG.13E, bottom), and 3D model of the hexagonal (diagonal side view) projection along the ^110^ zone axis (FIG.13F, bottom). FIG.14 is a high-resolution HAADF-STEM image of a cubical bipyramid-shaped Co-IONP showing both {111} and {220} planes. FIG.15 provides TEM images from the growth experiments 1 (left) and 2 (right) illustrating the spherical Co-IONPs prepared using the developed two-step seed-and-growth thermal decomposition method, excluding 1,2-hexadecanediol during the growth phase (left), and a TEM image of truncated octahedron Co-IONPs prepared using the same method, including a 2-hour slow nucleation step at 210°C during the growth phase (right). FIG.16 provides EDX elemental maps of iron (left), cobalt (middle), and oxygen (right), demonstrating the elemental composition of cubical bipyramid Co-IONPs. FIG.17 is a representative SAED pattern of cubical bipyramid Co-IONPs. FIG.18 provides a representative HRTEM image (left) and the corresponding HAADF-STEM image (right) of cubical bipyramid Co-IONPs reveal the surface oxidation and roughness, with the thickness of the oxidized surface being depicted with white dashed lines and an arrow. FIG.19 is an inverse FFT image of Co-IONPs representing the formation of vacancies (dotted circles) on the surface of a nanoparticle. FIG.20 is a schematic diagram of the unit cell of Co-IONPs illustrating surface oxidation, which leads to the formation of oxygen-occupied sites within the unit cell. FIG.21 is a graph of intensity versus binding energy, illustrating the High-resolution XPS spectra of the Fe 2p regions of cubical bipyramid Co-IONPs. FIG.22 provides high-resolution XPS spectra of the Fe 3p (left) and O 1S (right) regions of cubical bipyramid Co-IONPs. FIG.23 is a graph of intensity versus binding energy, illustrating the High-resolution XPS spectra of the Co 2p regions of cubical bipyramid Co-IONPs. FIG.24 is a graph of temperature versus time, illustrating the heating profiles of octahedron (red) and cubical bipyramid (blue) Co-IONPs solutions (1 mg mL-1Fe) exposed to an AMF (^^= 26.8 kA m-1and f = 315 kHz). 245-112651-02 09 / 12 / 25 OSU-24-52 FIG.25 is a graph of magnetization versus magnetic field, illustrating a magnified view of M(H) isotherms in the low field regime for octahedron and cubical bipyramid Co-IONPs. FIG.26 provides M(H) isotherms of the octahedron and cubical bipyramid Co-IONPs (left), and initial magnetization curves (right) of the octahedron and cubical bipyramid Co-IONPs along with LAS fit (solid black lines in the high field region). FIG.27 is a graph of magnetization versus temperature, illustrating the FC-ZFC curves of octahedron and cubical bipyramid Co-IONPs. FIG.28 provides TEM images of spherical Co-IONPs (left), commercially available iron oxide nanoparticles (Ocean Nanotech) (middle), and previously reported hexagonal Co-IONPs (right). FIG.29 is a graph of temperature versus time, illustrating heating profiles of solutions (1 mg mL-1Fe) of cubical bipyramid Co-IONPs, synthesized spherical Co-IONPs, previously reported Co-doped hexagonal nanoparticles with a magnetite core and maghemite shell, and commercially available iron oxide nanoparticles (Ocean NanoTech) exposed to an AMF (^^= 26.8 kA m-1and f = 315 kHz). FIG.30 is a graph of SAR versus frequency, illustrating SAR values of cubical bipyramid Co- IONPs solution (1 mg mL-1) exposed to an AMF at different frequencies and comparable field strengths (H0). FIG.31 provides graphs of temperature versus time, illustrating heating profiles of cubical bipyramid Co-IONPs solution (1 mg mL-1Fe) exposed to an AMF at different frequencies (f) and comparable field strengths (H0) (left), and heating profiles of cubical bipyramid Co-IONPs solution (1 mg mL-1Fe) exposed to an AMF at different field strengths (H0) and a constant 315 kHz frequency (f) (right). FIG.32 is a graph of SAR versus magnetic field, illustrating SAR values of cubical bipyramid Co-IONPs solution (1 mg mL-1) exposed to an AMF at different field strengths and a constant 315 kHz frequency. FIG.33 provides XPS survey scan (top left), deconvoluted C1s (top right), and N1s regions (bottom) for non-modified Co-IONPs. FIG.34 provides XPS survey scan (top left), deconvoluted C1s (top right), and N1s regions (bottom) for LHRH-PEG-PCL encapsulated cubical bipyramid Co-IONPs. FIG.35 provides DLS profiles of freshly prepared non-targeted (PEG-Co-IONPs) and LHRH- targeted (LHRH-Co-IONPs) cubical bipyramid Co-IONPs (Day 0), with additional profiles for LHRH- Co-IONPs stored at 4°C for 15 days (Day 15) and 30 days (Day 30) (left), and Zeta potential values of PEG-Co-IONPs and LHRH-Co-IONPs at Day 0 (right). FIG.36 provides a TEM image of LHRH-Co-IONPs after staining the nanoparticles with 1% uranyl acetate (left), and a Cryo-TEM image of LHRH-Co-IONPs (right). 245-112651-02 09 / 12 / 25 OSU-24-52 FIG.37 provides representative digital photographs demonstrating the dispersion state of LHRH- Co-IONPs in various physiological media (top), and DLS size distribution profiles of LHRH-Co-IONPs after incubation in different biological environments (bottom). FIG.38 is a graph of temperature versus time, illustrating the heating profiles of hydrophobic Co- IONPs in tetrahydrofuran and LHRH-Co-IONPs encapsulated in PEG-PCL polymer and dispersed in 5% dextrose medium (Fe concentration =1.0 mg mL-1) under AMF (f = 418 kHz, H = 28.7 kA m-1). FIG.39 provides a graph of cell viability versus concentration illustrating the cell viability of ES- 2 cells treated with LHRH-Co-IONPs at concentrations ranging from 0.05 to 50 µg mL-1for 24 hours (left), and a graph illustrating cell viability of ES-2 cells following 24-hour incubation with LHRH-Co- IONPs or medium alone, and subsequent exposure to AMF (418 kHz, 28.7 kA m-1) for 15 minutes (right). FIG.40 is a graph of hemolysis versus concentration, illustrating the hemolytic activity assessment of LHRH-Co-IONPs tested at concentrations ranging from 0.05 to 50 µg mL-1, using PBS and 1% Triton X-100 as negative and positive controls, respectively, and with the insert showing representative photographs of supernatants collected from each sample following centrifugation, demonstrating the degree of hemolysis. FIG.41 provides graphs illustrating cellular uptake of Nile Red-labeled non-targeted and LHRH- targeted Co-IONPs in ES-2 ovarian cancer cells evaluated using flow cytometry after 24-hour incubation. Flow cytometry histogram illustrates the cellular internalization of non-targeted and LHRH-targeted nanoparticles (left), and on the right, quantitative analysis of mean fluorescence intensity, normalized to untreated control cells, demonstrates significantly enhanced uptake of LHRH-targeted nanoparticles. FIG.42 provides graphs illustrating the body weights (left) and serum levels of biomarkers (right) in mice after IV administration of 5% dextrose (control) and LHRH-targeted Co-IONPs at a dose of 4 mg kg-1Fe for three consecutive days. FIG.43 provides graphs illustrating the hematological parameters in mice after IV administration of 5% dextrose (control) and LHRH-targeted Co-IONPs at a dose of 4 mg kg-1Fe for three consecutive days. FIG.44 provides graphs illustrating the proteins (left) and electrolytes (right) in mice after IV administration of 5% dextrose (control) and LHRH-targeted Co-IONPs at a dose of 4 mg kg-1Fe for three consecutive days. FIG.45 provides NIR fluorescence images of mice with ES-2 ovarian cancer xenografts recorded 24 hours after IV injection with 5% dextrose (control), non-targeted, and LHRH-targeted (LHRH-Co- IONPs) cubical bipyramid-shaped Co-IONPs (top left); Quantitative analysis of corrected total fluorescence signals in resected tumors and major organs from different treatment groups (non-targeted 245-112651-02 09 / 12 / 25 OSU-24-52 Co-IONPs and LHRH-Co-IONPs), calculated using ImageJ (top right); and NIR fluorescence images of resected tumors (bottom left) and organs (bottom right). Fig.46 are T2-weighted MR images of subcutaneous tumor-bearing mice after IV injection with 5% dextrose (Control) (left), non-targeted Co-IONPs (middle), and LHRH-Co-IONPs (4 mg kg−1) (right), with cancer tumors represented by dashed circles. FIG.47 are representative NIR fluorescence images of mice with ES-2 subcutaneous xenografts acquired at multiple timepoints: before injection (day 0), and at 24 hours (day 1), 48 hours (day 2), and 14 days after administration of SiNc-loaded LHRH-Co-IONPs, with the bottom panel showing NIR fluorescence images of the tumor and resected organs collected 14 days post-injection. FIG.48 provides a schematic diagram illustrating the experimental design of systemically delivered magnetic hyperthermia mediated by LHRH-targeted Co-IONPs (top); intratumoral temperature profiles recorded in mice with ES-2 ovarian cancer grafts following IV injection of 5% dextrose (control), non-targeted, and LHRH-targeted (LHRH-Co-IONPs) nanoparticles at a dose of 4 mg kg-1Fe, and exposed to AMF (418 kHz, 28.7 kA m-1) 24 hours post-administration (bottom left); and changes in tumor volumes subjected to the following treatments from the experiment illustrated in FIG.48, with: Control - mice received IV injections of 5% dextrose; AMF - mice received IV injections of 5% dextrose and were exposed to AMF (418 kHz, 28.6 kA m-1) for 30 minutes; LHRH-Co-IONPs - mice received a single IV injection of LHRH-targeted nanoparticles at a dose of 4 mg kg-1Fe; LHRH-Co-IONPs + AMF - mice received a single IV injection of LHRH-targeted nanoparticles at a dose of 4 mg kg-1Fe and were exposed to AMF (418 kHz, 28.6 kA m-1) for 30 minutes, 24 hours post-administration (bottom right). FIG.49 provides representative images of mice bearing ES-2 ovarian cancer grafts, taken on day 14 post-treatment (top); representative images and weights of tumors resected on day 14 post-treatment (bottom left), and changes in body weights of mice following the aforementioned treatments (bottom right). FIG.50 are representative NIR fluorescence images of mice bearing ES-2 ovarian cancer xenografts, captured before (0 h), 24 h, and 48 h after IV injection of LHRH-targeted nanoparticles (LHRH-Co-IONPs) (left), and representative intratumoral temperature profiles of mice bearing ES-2 ovarian cancer xenografts, measured at 24 h and 48 h after IV injection of LHRH-Co-IONPs at a dose of 4 mg kg⁻¹ Fe and exposure to AMF (418 kHz, 28.7 kA m-1) (right), with the control mice receiving 5% dextrose injections followed by AMF exposure. 245-112651-02 09 / 12 / 25 OSU-24-52 DESCRIPTION OF THE SEQUENCES The nucleic and amino acid sequences listed in the accompanying sequence listing are shown using standard letter abbreviations for nucleotide bases, and single letter code for amino acids, as defined in 37 C.F.R.1.822. Only one strand of each nucleic acid sequence is shown, but the complementary strand is understood as included by any reference to the displayed strand. In the accompanying sequence listing: SEQ ID NOS.1-3 and 7 are exemplary LHRH targeting peptides. SEQ ID NO.4 is an exemplary vascular endothelial growth factor receptor 2 (KDR) targeting moiety. SEQ ID NO.5 is an exemplary α-3 integrin receptor targeting protein. SEQ ID NO.6 is an exemplary ROR1 targeting protein. DETAILED DESCRIPTION I. Terms and Definitions The following explanations of terms and methods are provided to better describe the present disclosure and to guide those of ordinary skill in the art in the practice of the present disclosure. The singular forms “a,” “an,” and “the” refer to one or more than one, unless the context clearly dictates otherwise. The term “or” refers to a single element of stated alternative elements or a combination of two or more elements, unless the context clearly indicates otherwise. As used herein, “comprises” means “includes.” Thus, “comprising A or B,” means “including A, B, or A and B,” without excluding additional elements. All references, including patents and patent applications cited herein, are incorporated by reference. Unless otherwise indicated, all numbers expressing quantities of components, molecular weights, percentages, temperatures, times, and so forth, as used in the specification or claims, are to be understood as being modified by the term “about.” Unless context indicated otherwise, “about” refers to plus or minus 5% of a reference value. For example, “about” 100 refers to 95 to 105. Accordingly, unless otherwise indicated, implicitly or explicitly, the numerical parameters set forth are approximations that may depend on the desired properties sought and / or limits of detection under standard test conditions / methods. When directly and explicitly distinguishing aspects from discussed prior art, the aspect numbers are not approximates unless the word “about” is recited. Unless explained otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or 245-112651-02 09 / 12 / 25 OSU-24-52 testing of the present disclosure, suitable methods and materials are described below. The materials, methods, and examples are illustrative only and not intended to be limiting. The terms “administer,” “administering,” “administration,” and the like, as used herein, refer to methods that may be used to enable delivery of compositions to the desired site of biological action. These methods include, but are not limited to, intraarticular (in the joints), intravenous (i.v.), intramuscular, intratumoral, intradermal, intraperitoneal, subcutaneous, orally, topically, intrathecally, inhalationally, transdermally, rectally, direct injection into a tumor, and the like. Administration techniques that can be employed with the agents and methods described herein are found in e.g., Goodman and Gilman, The Pharmacological Basis of Therapeutics, current ed.; Pergamon; and Remington's, Pharmaceutical Sciences (current edition), Mack Publishing Co., Easton, Pa. “Nanoparticle” refers to a particle having a size of from 1 to less than 1000nm, typically, from 1 to 500 nm or from 1 to 100 nm, unless otherwise specified herein. “Nucleic acid” refers to a polynucleotide molecule. The polynucleotide may be a naturally occurring polynucleotide or a synthetic polynucleotide. A nucleic acid may be a DNA, RNA or mixture of DNA and RNA nucleotides. Typically, the nucleic acid contains from 20 to 10,000 nucleotides or more, such as from 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, or 5000 nucleotides to 10,000 nucleotides. Exemplary nucleic acids include, but are not limited to, single stranded DNA, single stranded RNA, double stranded DNA, RNA-RNA hybrid, DNA-RNA hybrid, shortmer, antagomir, antisense, ribozyme, small interfering RNA (siRNA), asymmetrical interfering RNA (aiRNA), microRNA (miRNA), Dicer-substrate RNA (dsRNA), small hairpin RNA (shRNA), sgRNA / pegRNAs, transfer RNA (tRNA), messenger RNA (mRNA), or a combination thereof. “Peptide” refers to a compound comprising amino acid residues connected by peptide bonds. Typically a peptide compound has from 2 to about 50 amino acid residues. "Pharmaceutically acceptable excipient" and "pharmaceutically acceptable carrier" refer to a substance that aids the formulation and / or administration of an active agent to and / or absorption by a subject and can be included in the compositions of the present disclosure without causing a significant adverse toxicological effect on the subject. Non-limiting examples of pharmaceutically acceptable excipients include water, NaCl, normal saline solutions, lactated Ringer’s, normal sucrose, normal glucose, binders, fillers, disintegrants, lubricants, coatings, sweeteners, flavors, salt solutions (such as Ringer's solution), alcohols, oils, gelatins, carbohydrates such as lactose, amylose or starch, fatty acid esters, hydroxymethycellulose, polyvinyl pyrrolidine, and colors, and the like. Such preparations can be sterilized and, if desired, mixed with auxiliary agents such as lubricants, preservatives, stabilizers, wetting 245-112651-02 09 / 12 / 25 OSU-24-52 agents, emulsifiers, salts for influencing osmotic pressure, buffers, coloring, and / or aromatic substances and the like that do not deleteriously react with or interfere with the activity of the compounds provided herein. One of ordinary skill in the art will recognize that other pharmaceutical excipients are suitable for use with disclosed compounds. “Polypeptide” refers to a compound comprising amino acid residues connected by peptide bonds. When the amino acids are alpha-amino acids, either the L-optical isomer or the D-optical isomer can be used. In some aspects, a polypeptide has from about 50 amino acid residues to 2000 or more amino acid residues. “Protein” refers to a molecule or complex comprising one or more polypeptides having secondary, tertiary and / or quaternary structure. The secondary, tertiary and / or quaternary structure of a protein typically is stabilized using non-covalent bonds, such as ionic bonds, hydrogen bonds, hydrophobic interactions, and / or van der Walls interactions. Additionally, or alternatively, a protein may include disulfide bonds, such as between the thiol groups of cysteine residues. “Size” and “average size” as used herein with respect to nanoparticle size, refers to the mode average size of the nanoparticles, that is the size with the greatest number of nanoparticles in a sample, or the peak of a distribution curve. For example, in a size distribution histogram, the mode average is the size with the highest bar in the histogram. Unless otherwise specified, the nanoparticle size is measured as the longest distance between two opposite sides or vertices of the nanoparticle. “Small Molecule” refers to an organic molecule having a molecular weight of about 2000 Daltons or less. In some aspects, the term “small molecule” refers to a compound that is not a polypeptide, protein, or nucleic acid molecule. A small molecule may be a small molecule therapeutic and / or prophylactic, such as an antibiotic, anti-inflammatory, anticancer, antiviral, immunosuppressant, analgesic, antifungal, antiparasitic, anticonvulsants, antidepressant, anti-anxiety, anti-psychotic, and the like. “Subject” refers to mammals and other animals, particularly humans. Thus disclosed methods are applicable to both human therapy and veterinary applications. In some aspects, the subject is a human. II. Overview Nanoparticles with high heating efficiency are essential for several important reasons. First, they ensure the generation of sufficient intratumoral temperatures, which is vital for the effectiveness of the treatment. Second, high heating efficiency allows for the administration of lower doses of nanoparticles, thereby minimizing the risk of toxicity and side effects. Clinical trials have demonstrated that high doses of conventional iron oxide nanoparticles, often exceeding 30 mg per cm³ of tumor volume, are required to 245-112651-02 09 / 12 / 25 OSU-24-52 attain the desired therapeutic temperature. Third, nanoparticles with high heating efficiency and rapid heating rates can enable therapeutic temperatures to be reached more quickly within the tumor. This rapid attainment of therapeutic temperatures can reduce the duration of each hyperthermia session, enhancing patient comfort and compliance. Fourth, clinical evidence suggests that magnetic hyperthermia using conventional iron oxide nanoparticles is unable to eradicate cancer tumors after multiple sessions and primarily results in slowing tumor growth. Therefore, nanoparticles with high heating efficiency have the potential to significantly improve the therapeutic outcomes of magnetic hyperthermia, potentially achieving more robust tumor growth inhibition or even complete eradication with fewer treatment sessions. Conventional magnetic hyperthermia typically requires the direct intratumoral injection of currently available magnetic nanoparticles to achieve sufficient concentration and the necessary therapeutic temperatures within the tumor. This approach presents a significant challenge in treating tumors that are difficult to access or unsuitable for direct injections. The limitation stems from the moderate heating efficiency of currently used iron oxide nanoparticles, combined with the relatively low tumor accumulation of systemically administered nanoparticles at clinically relevant doses (< 10 mg per kg). Nanoparticles with exceptional heating efficiency have the potential to reach the required therapeutic temperatures even when they accumulate in lower concentrations at the tumor site after systemic administration. This approach can expand the application of magnetic hyperthermia to hard-to-reach tumors and metastases, making the treatment more versatile and widely used. Various strategies have been explored to enhance the heating efficiency of conventional spherical iron oxide nanoparticles for magnetic hyperthermia. These include doping with transition metals such as cobalt (Co) and manganese; optimizing nanoparticle morphology into shapes like hexagons, cubes, and clovers; fine-tuning particle size; developing core-shell structures; and forming clusters of multiple magnetic nanoparticles. Setting a benchmark for heating efficiency among magnetic nanoparticles, Lee et al. developed iron oxide nanoparticles with a Co-doped core and Mn-doped shell that exhibited a specific absorption rate (SAR) of 2,280 W g-1when exposed to AMF at 500 kHz and 37.3 kA m-1. In subsequent work, Jang et al. reported magnesium-doped γ-Fe2O3 superparamagnetic nanoparticles that demonstrated a heating performance approximately three times higher than the above-mentioned core-shell nanoparticles. When administered through intratumoral injections, both the core-shell and magnesium- doped γ-Fe2O3nanoparticles exhibited significant anticancer effects. In addition to demonstrating the enhanced therapeutic efficacy of advanced nanoparticles for magnetic hyperthermia through intratumoral injection, several studies have also established their feasibility for systemically administered magnetic hyperthermia. For example, Demessie et al. reported Co-doped core-shell iron oxide nanoparticles with 245-112651-02 09 / 12 / 25 OSU-24-52 ultrahigh heating capacity. They demonstrated that, following systemic administration at a dose of 4 mg kg-1, these nanoparticles, attached with a targeting LHRH peptide, efficiently accumulate in ovarian cancer xenografts and elevate the temperature up to 50°C under AMF (420 kHz, 26.9 kA m-1). In another study, Liu et al. developed Co-doped iron oxide nanoparticles with a clover shape that exhibit enhanced heat induction efficiency. Their animal studies revealed that these gallic acid-coated nanoparticles, after intravenous injection at a relatively high dose of 25 mg kg-1, preferentially bound to blood vessels of gliomas and increased the intratumoral temperature to 48.4°C upon exposure to AMF (371 kHz, 27 kA m-1). However, current reports indicate that systemically delivered magnetic hyperthermia, utilizing recently developed magnetic nanoparticles with enhanced heating efficiency, fails to reduce tumor size or halt tumor growth. Instead, it predominantly leads to a deceleration of tumor progression. Therefore, the development of novel nanoparticles with superior heating efficiency compared to those currently reported is essential to significantly improve the therapeutic outcome of systemically delivered magnetic hyperthermia. To address this challenge, the inventors developed cobalt-doped iron oxide nanoparticles (Co- IONPs) with a cubical bipyramid shape. These nanoparticles exhibit one of the highest reported heating efficiencies, surpassing the ultrahigh heating capacity of core-shell Co-IONPs previously described by Demessie et al. By experimentally comparing their heating performance under identical conditions (315 kHz, 26.8 kA m-1), the disclosed results revealed that the newly developed cubical bipyramid nanoparticles possess a specific absorption rate (SAR) of 14,686 ± 396 W g-1Fe, considerably higher than the 7,490 ± 306 W g-1Fe displayed by the previously reported core-shell nanoparticles. Furthermore, animal studies showed that the disclosed nanoparticles, administered intravenously (IV) at a low and clinically relevant dose of 4 mg kg-1, effectively halted the growth of ovarian cancer tumors after a single 30-minute session of magnetic hyperthermia. III. Nanoparticles Disclosed herein are aspects of a nanoparticle suitable for magnetic hyperthermia applications. In some aspects, the nanoparticle is a cubical bipyramid cobalt iron oxide nanoparticle (Co-IONP). That is, at least 50%, such as at least 60%, at least 70%, at least 80% at least 90%, at least 95%, at least 97%, at least 99%, or substantially all of the nanoparticles have a cubical bipyramid morphology. In some aspects, the nanoparticle comprises, consists essentially of, or consists of, cobalt, iron, and oxygen. In some aspects, there are no additional elements in the nanoparticle. The nanoparticle may have from 2 atom% to 10 atom% cobalt, such as from 3 atom% to 9 atom%, from 4 atom% to 8 atom%, or from 5 atom% to 7 atom%. The nanoparticle may have from 25 atom% to 55 atom% iron, such as from 30 245-112651-02 09 / 12 / 25 OSU-24-52 atom% to 50 atom%, or from 35 atom% to 45 atom%. And nanoparticle also has sufficient oxygen to make the total amount of cobalt, iron and oxygen equal 100 atom%. In certain aspects, a nanoparticle has from 35 atom% to 75 atom% oxygen, such as from 40 atom% to 70 atom%, from 45 atom% to 65 atom%, or from 50 atom% to 60 atom%. In certain aspects, the nanoparticle comprises, consists essentially of, or consists of 5 atom% to 7 atom% cobalt, from 35 atom% to 45 atom% iron, and from 50 atom% to 60 atom% oxygen. And in certain other aspects, the nanoparticle comprises, consists essentially of, or consists of about 6 atom% cobalt, about 40 atom% iron, and about 54 atom% oxygen. In other aspects, the cubical bipyramid nanoparticles have a molecular formula according to Formula I: CoxFe3-xO4 Formula I With respect to Formula I, x is from 0.1 to 0.8, such as from 0.2 to 0.6, or from 0.3 to 0.5. In certain aspects, x is about 0.4. The nanoparticles may have a size of from 15 nm to 25 nm, from 15 nm to 20 nm, from 16 nm to 19 nm or from 17 nm to 18 nm. The size of the nanoparticles is an average size measured as the longest distance between two opposite sides or vertices, for example, from a TEM image. In some aspects, the nanoparticle has a specific absorption rate (SAR) of from 10,000 W g-1Fe to 20,000 W g-1Fe or more, such as from 10,000 W g-1Fe to 17,000 W g-1Fe, from 12,000 W g-1Fe to 16,000 W g-1Fe, or from 14,000 W g-1Fe to 15,000 W g-1Fe, as measured at ^^= 26.82 kA m-1and f = 315 kHz. IV. Compositions Also disclosed herein are aspects of a composition comprising the disclosed nanoparticles. The composition may further comprise a polymer and / or a targeting moiety, such as a peptide. A. Polymer The polymer may be any polymer suitable to encapsulate the Co-IONP into a polymer, such as by forming a polymer nanoparticle around the nanoparticle. Additionally, or alternatively, the polymer might be selected to facilitate improving the water solubility of the nanoparticle and / or to facilitate conjugating a targeting moiety. The polymer may be a block copolymer. At least one monomer of the copolymer may be selected to enhance or improve the water solubility of the polymer nanoparticle, and / or at least one monomer of the copolymer may be selected to provide an environment in the polymer nanoparticle 245-112651-02 09 / 12 / 25 OSU-24-52 suitable for encapsulating inorganic nanoparticles, such as the disclosed Co-IONP. The copolymer may be selected such that it forms a polymer nanoparticle comprising a core suitable to encapsulate Co-IONP. In some aspects, the copolymer is selected such that it forms a polymer nanoparticle comprising a hydrophobic core and a hydrophilic outer surface. In some aspects, the copolymer comprises a polyethylene glycol (PEG) moiety. The copolymer may also comprise one or more additional monomers. The additional monomer(s) may be selected to provide an environment suitable to encapsulate the photosensitive compound. Suitable additional monomers include, but are not limited to, polyesters, polyacids and polylactones. In certain aspects, the copolymer is polyethylene glycol-block-polycaprolactone (PEG-b-PCL), methoxy polyethylene glycol-block-polycaprolactone (mPEG-b-PCL), polyethylene glycol-block- polyvalerolactone (PEG-b-PVL), polyethylene glycol-block-polylactic acid (PEG-b-PLA) or polyethylene glycol-block-poly(lactic acid-co-glycolic acid) (PEG-b-PLGA). In certain aspects, the polymer is mPEG- b-PCL. In particular aspects, the mPEG-b-PCL comprises an mPEG moiety of from 2,000 Da to 8,000 Da, such as from 3,000 Da to 7,000 Da, or from 4,000 Da to 6,000 Da, and a PCL moiety of from 7,000 Da to 13,000 Da, such as from 8,000 Da to 12,000 Da, or from 9,000 Da to 11,000 Da. In one aspects, the mPEG-b-PCL polymer comprises an mPEG moiety of 5,000 Da and a PCL moiety of 10,000 Da. In other aspects, the PEG-b-PVL comprises a PEG moiety of from 1,000 Da to 7,000Da, such as from 2,000 Da to 5,000 Da, and a PVL moiety of from 8,000 Da to 25,000Da or more, such as from 10,000Da to 20,000Da. In certain disclosed aspects, the polymer is The polymer may be selected to have a molecular weight suitable to form a polymer nanoparticle and encapsulate the Co-IONP. In some aspects, the polymer has a molecular weight of from about 10,000 Da to 20,000 Da, such as from 13,000 Da to 17,000 Da. As used herein, the “molecular weight” is a weight averaged molecular weight determined by proton NMR and size exclusion chromatography. In certain aspects, the copolymer had an average molecular weight that is from 13,500 Da to 16,500 Da, such as about 15,000 Da. 245-112651-02 09 / 12 / 25 OSU-24-52 B. Targeting moiety In some aspects, the composition comprises a targeting moiety. The targeting moiety is any moiety that can target or direct the composition to a particular site of action, thereby promoting accumulation at that site, and / or reducing systemic distribution. Suitable targeting moieties include, but are not limited to, peptides, proteins, small molecules (for example, folic acid), nucleic acid sequences or antibodies. In some aspects, the targeting moiety is covalently attached to the polymer nanoparticle. However, in alternative aspects, the composition does not comprise a targeting moiety. In some aspects, the targeting moiety is covalently attached to the polymer nanoparticle. In certain aspects, the targeting moiety is attached to a PEG moiety on the polymer. There are numerous methods to attach the targeting moiety to the polymer nanoparticle, as a person of ordinary skill in the art will understand. Additional information concerning coupling techniques is provided by Greg T. Hermanson in Bioconjugate Techniques; Academic Press, 1996, which is incorporated herein by reference. The percentage of targeting moiety attached to the polymer nanoparticle may be any amount suitable to facilitate targeting the polymer nanoparticle to a desired organ or tumor. In some aspects, the amount of targeting moiety attached to the polymer nanoparticle is from greater than zero to 50% or more, weight / weight (weight of polymer labeled with targeting moiety / weight of non-labeled polymer), such as from 1% to 50%, from 1% to 25%, from 5% to 15%. That is, from greater than zero to 50% of the polymer present in the polymer nanoparticle is labeled with the targeting moiety. In particular aspects, the amount of targeting moiety used was 1%, 5%, 10%, 25% or 50% w / w targeting moiety-polymer / non- labeled polymer, and in certain aspects, about 10% w / w targeting moiety-polymer / non-labeled polymer is used. 1) Cancer In some aspects, the targeting moiety is a peptide that preferentially targets the composition to cancer cells. In some aspects, the peptide is targeted to a receptor that is overexpressed in cancer cells, is not detectably expressed in non-cancer cells, is mutated in cancer cells, or any combination thereof. In some aspects, the cancer targeting moiety is an EGFR (Epidermal growth factor receptor), Integrin αvβ6, Neuropilin-1, PD-L1, a HER2 receptor, or a combination thereof. In some aspects, the cancer is ovarian cancer. In such aspects, the peptide may be a luteinizing- hormone-releasing hormone (LHRH). Exemplary LHRH peptides suitable for use in any disclosed aspects include, but are not limited to, Gln-His-Trp-Ser-Tyr-DLys(DCys)-Leu-Arg-Pro-NH2(SEQ ID NO.1); Glp-His-Trp-Ser-Tyr-D-Lys-Leu-Arg-Pro-Gly-NH2(SEQ ID NO.2); and Glp-His-Trp-Ser-His- Asp-Trp-Lys-Pro-Gly-NH2(SEQ ID NO.3). 245-112651-02 09 / 12 / 25 OSU-24-52 Other targeting moieties suitable for targeting ovarian cancer include, but are not limited to, α-3 integrin receptor (for example, cyclic peptide cDGWGPNc, SEQ ID NO.5), ROR1(Receptor tyrosine kinase–like orphan receptor1) (for example VATNGKEVVSSTGVLFVKFGP, SEQ ID NO.6), HE4(Human epididymis protein 4), 5-Protein signature (OVA1), or a combination thereof. 2) Endometriosis In some other aspects, the targeting moiety is a peptide that preferentially targets the composition to endometrium. In such aspects, the composition may be useful for treating endometriosis. Targeting moieties suitable for targeting the composition to the endometrium include, but are not limited to, CD44, EphB4, CXCL13, CTLA4, CD10, vascular endothelial growth factor receptor 2 (KDR) targeting moiety (such as ATWLPPR, SEQ ID NO.4), or a combination thereof. V. Heat generation Exposure of the disclosed nanoparticles to a magnetic field, such as an alternating magnetic field (AMF) leads to heat generation, possibly through Brownian relaxation. The movement of these nanoparticles in a suspension generates frictional loss with the environment if the viscosity of the environment allows free rotation. Magnetic nanoparticles with a high SAR are highly attractive for magnetic hyperthermia application as higher intra-tumoral temperatures can be achieved with a lower nanoparticle concentration in a short period of time. Heating capacity of magnetic nanoparticles is measured in terms of specific absorption rate (SAR), which describes the power generated by magnetic nanoparticles (MNPs) per unit mass. SAR = Power / m = C (△T / △ t) (1 / m) Where C is the specific heat capacity, m is the mass concentration of magnetic nanoparticles, and delta T / t is the temperature increase over time. Bulk materials have several magnetic domains, with each of these domains having their own orientation. In smaller magnetic nanoparticles with mean particle diameter greater than 30 nm, there is only a single domain (mono domain), but larger nanoparticles up to 100 nm can have several magnetic domains. For mono domain nanoparticles, heat generation occurs mainly through Brownian relaxation. The movement of these nanoparticles in a suspension generates frictional loss with the environment. However, this is only if the viscosity of the environment allows free rotation. In the case of restrained physical rotation, the most prevalent heat generation is primarily through Neel relaxation, which is the rotation of the magnetic moments inside the magnetic nanoparticle. 245-112651-02 09 / 12 / 25 OSU-24-52 The disclosed cubical bipyramid cobalt doped iron oxide nanoparticles have an SAR that is higher than SAR values reported in the literature for iron oxide nanoparticles and other cobalt-doped iron oxide nanoparticles that have different morphologies. VI. Synthesis A. Nanoparticle formation In some aspects, cubical bipyramid Co-IONPs are synthesized from seed nanoparticles. In some aspects, the seed nanoparticles are octagonal nanoparticles. To form the seed nanoparticles, a cobalt compound and an iron compound are mixed in a solvent system and heated to a temperature suitable to facilitate nanoparticle formation under a flow of an inert gas. The cobalt compound can be any cobalt compound suitable to be a cobalt source for nanoparticle formation, such as, but not limited to, cobalt(II) chloride (CoCl2), cobalt(II) chloride hexahydrate (CoCl26H2O), cobalt(II) sulphate (CoSO4), cobalt(II) sulphate heptahydrate (CoSO47H2O), cobalt(II) nitrate hexahydrate (Co(NO3)26H2O), cobalt(II) carbonate (CoCO3), or a combination thereof. In certain aspects, cobalt(II) chloride hexahydrate was used as the cobalt source. The iron compound can be any iron compound suitable to be an iron source for nanoparticle formation, such as, but not limited to, (Zero-valent) Fe(CO)5, iron(III) acetylacetonate (Fe(acac)3), iron(II) sulfate (ferrous sulfate, FeSO₄), iron(II) chloride (FeCl₂, ferrous chloride), iron(III) nitrate (Fe(NO₃)₃, ferric nitrate), iron(III) sulfate (Fe(SO₄)₃, ferric sulfate), iron(III) chloride (FeCl₃, ferric chloride), or a combination thereof. In certain aspects, iron(III) acetylacetonate was used as the iron source. The solvent system can be any solvent system suitable to facilitate the octagonal nanoparticle formation reaction. In some aspects, the solvent system is a mixture of one or more solvents and one or more surface capping agents. Suitable solvents include, but are not limited to, trioctylamine, docosane, n- octylether, benzyl ether, or a combination thereof. In certain aspects, the solvents in the solvent system comprises, consists essentially of, or consists of, n-octylether and benzyl ether. In some aspects, the n- octylether and benzyl ether are present in about equal volumes. Suitable surface capping agents include, but are not limited to, oleic acid, oleylamine, 1,2- hexadecandiol, or a combination thereof. In certain aspects, the surface capping agents comprise, consist essentially of, or consist of, oleic acid, oleylamine, and 1,2-hexadecanediol. In some aspects, each of the one or more surface capping agents is used in a molar ratio of from 1.1:1 surface capping agent: iron compound to 1.7:1 surface capping agent: iron compound, such as from 1.2:1 surface capping agent: iron compound to 1.6:1 surface capping agent: iron compound. 245-112651-02 09 / 12 / 25 OSU-24-52 The reaction may proceed under a flow of an inert gas, such as nitrogen or argon. In certain aspects, nitrogen is used. The flow rate of the inert gas is from greater than zero to 100 mL / min or more, such as from 0.25 mL / min to 50 mL / min, from 0.5 mL / min to 25 mL / min, from 0.5 mL / min to 10 mL / min, from 0.5 mL / min to 5 mL / min, from 0.5 mL / min to 2.5 mL / min, or about 1 mL / min. The reaction is heated to a temperature suitable to facilitate nanoparticle formation. The temperature may be from 250 °C to 350 °C, such as from 270 °C to 325 °C, from 275 °C to 310 °C or from 280 °C to 290 °C. And the reaction may be heated for from 30 minutes to 90 minutes, such as from 45 minutes to 75 minutes. In some aspects, the reaction is heated to one or more intermediate temperatures before reaching the final reaction temperature, such as one intermediate temperature, or two intermediate temperatures. In some aspects, the reaction is heated to a first intermediate temperature of from 80 °C to 150 °C, such as from 90 °C to 130 °C or from 100 °C to 120 °C, for a first intermediate time period of from 15 minutes to 1 hour or more, such as from 20 minutes to 45 minutes. The reaction then is heated to a second intermediate temperature of from 180 °C to 240 °C, such as from 190 °C to 230 °C, or from 200 °C to 220 °C, for a second intermediate time period of from 90 minutes to 3 hours, such as from 105 minutes to 2 ½ hours, or from 110 minutes to 2 ¼ hours, before being heated to the final reaction temperature for the disclosed time period. After heating, the reaction is allowed to cool to room temperature and the seed nanoparticles are isolated. In a second step, the seed nanoparticles are optionally suspended in an inert solvent, such as hexanes, to facilitate transfer to a reaction vessel. The same reagents as described in the seed nanoparticle synthesis, and in the same concentrations, are added and the reaction is heated under a flow of an inert gas, such as nitrogen gas. In some aspects, cobalt(II) chloride hexahydrate was used as the cobalt source, iron(III) acetylacetonate was used as the iron source, the surface capping agents comprise, consist essentially of, or consist of, oleic acid, oleylamine, and 1,2-hexadecanediol, and the solvents in the solvent system comprises, consists essentially of, or consists of, n-octylether and benzyl ether. The flow rate of the inert gas is from greater than zero to 25 mL / min or more, such as from 0.1 mL / min to 12.5 mL / min, from 0.1 mL / min to 5 mL / min, from 0.1 mL / min to 2.5 mL / min, from 0.1 mL / min to 1 mL / min, or from 0.2 mL / min to 0.5 mL / min. The reaction is heated to a temperature of from 180 °C to 240 °C, such as from 190 °C to 230 °C, or from 200 °C to 220 °C. The reaction may be heated at a ramp rate of from 5 °C / min to 25 °C / min or more, such as from 10 °C / min to 20 °C / min, or from 12 °C / min to 16 °C / min. And the reaction is heated for a time period of from 30 minutes to 90 minutes, such as from 45 minutes to 75 minutes. 245-112651-02 09 / 12 / 25 OSU-24-52 After heating, the reaction is allowed to cool to room temperature and the cubical bipyramid nanoparticles are isolated. B. Composition Aspects of a method for preparing a composition comprising the disclosed nanoparticles, and a polymer and / or a targeting moiety also is disclosed herein. In some aspects, the method comprises forming a suspension comprising the cobalt iron oxide nanoparticles in a suitable solvent, such as tetrahydrofuran (THF). A solution comprising the desired polymer in a suitable solvent, such as THF, also is prepared. The nanoparticle suspension and the polymer solution then are combined to facilitate forming polymer nanoparticles encapsulating at least some of the Co-IONP. In some aspects, the nanoparticle suspension is added to the polymer solution. Dextrose solution in water may be added and the organic solvent is evaporated. Any non-encapsulated, hydrophobic Co-IONPs and non-soluble polymer molecules are separated from the polymer nanoparticles loaded with Co-IONP, such as by centrifuging, filtering, and / or using a magnetic field. The size of final nanoparticles was determined using Dynamic Light Scattering (DLS) spectra and Cryo-TEM. In aspects comprising a targeting moiety, the targeting moiety may be conjugated to the polymer. In some aspects, the targeting moiety is attached to the polymer before the polymer nanoparticle is formed. In certain aspects, the polymer comprises a PEG moiety and the targeting moiety is conjugated to a PEG moiety in the polymer. In some aspects, the polymer, such as a PEG-containing polymer, is treated with a carbodiimide reagent, such as N,N′-dicyclohexylcarbodiimide (DCC), and N-hydroxysuccinimide (NHS) in a suitable solvent, such as an aprotic solvent, for example, acetonitrile. VII. Applications and dosage The disclosed nanoparticles and compositions thereof are useful to treat diseases and conditions where hyperthermia treatment is useful. In some aspects, the disclosed nanoparticles or compositions thereof, are useful to treat cancer, for example, solid tumor cancers, such as, but are not limited to, ovarian cancer, breast cancer, prostate cancer, pancreatic cancer, head and neck cancer, liver cancer and skin melanomas. In certain aspects, the cancer is ovarian cancer. In other aspects, the disease or condition is non-cancerous, such as non-cancerous lesions. In some aspects, the disease or condition is endometriosis. In any aspects, the nanoparticle, or a composition thereof, is administered to a subject in need thereof in an amount sufficient to treat the disease or condition. The subject may be a human or animal subject, such as a mammal. In some aspects, the subject is a human. In any aspects, the nanoparticle, or a 245-112651-02 09 / 12 / 25 OSU-24-52 composition thereof, is administered in an amount sufficient to administer from 1 mg or less to 100 mgs or more iron to the subject, such as from 1 mg to 50 mgs iron, from 1 mg to 25 mgs iron or from 1 mg to 10 mgs iron. After administration, the subject is exposed to a magnetic field, such as an alternating magnetic field. In some aspects, the magnetic field is applied by an MRI machine. The magnetic field may have a field strength of from 1 kA / m or less to 100 kA / m or more. And / or the magnetic field may have a frequency of from 50 kHz or less to 900 kHz or more. The magnetic field may be applied at any time period after the nanoparticle, or a composition thereof, is administered sufficient to provide a beneficial effect to the subject. In some aspects, the magnetic field is applied from substantially immediately after the nanoparticle, or a composition thereof, is administered to the subject, to 7 days or more after administration, such as from 1 minute after administration to 5 days after administration. The nanoparticle, or a composition thereof, may be administered to the subject by any suitable route. In some aspects, the nanoparticle, or a composition thereof, is administered by injection. In any aspects, administration may be systemic, or the administration may be a local administration, such as injecting directly into a tumor and / or tissue that is to be treated. The nanoparticle, or a composition thereof, may be administered as a pharmaceutical composition comprising the nanoparticle, or a composition thereof, and a pharmaceutically acceptable excipient. The pharmaceutically acceptable excipient may be any excipient suitable to formulate the nanoparticle, or a composition thereof, for administration by a desired route. In some aspects, the pharmaceutical composition is formulated for administration by injection. In some aspects, the pharmaceutically acceptable excipient is water, a PBS buffer, 5% dextrose solution or saline solution. VIII. Examples Materials: Iron (III) acetylacetonate and benzyl ether (99%) were obtained from Acros Organics (Thermo Fisher Scientific, Fair Lawn, NJ, USA). Oleic acid (90%) was sourced from Alfa Aesar (Ward Hill, MA, USA). Cis-1-amino-9-octadecene (oleylamine), cobalt (II) chloride hexahydrate, dimethyl sulfoxide (DMSO, >99.9%), tetrahydrofuran (THF), and n-hexane (95%) were purchased from Sigma Aldrich (EMD Millipore, Burlington, MA, USA).1,2-hexadecanediol (>98%) and n-octyl ether (>96%) were procured from TCI Co. Ltd. (Portland, OR, USA). Methoxy-poly (ethylene glycol)-5k-b-poly(ε- caprolactone)-10k (m-PEG-5k-b-PCL-10k) and maleimide-poly(ethylene glycol)-5k-b-(ε-caprolactone)- 10k (MAL-PEG-5k-b-PCL-10k) (>90%) were sourced from Advanced Polymer Materials Inc. (Montreal, QC, Canada). LHRH peptide (QHWSYK(C)LR (SEQ ID NO.7) (purity >90.0%) was obtained from 245-112651-02 09 / 12 / 25 OSU-24-52 Pepmic Co. Ltd. (Suzhou, China). Dextrose (5%) was acquired from Baxter Healthcare (Deerfield, IL, USA). SiNc (silicon 2,3-naphthalocyanine bis(trihexylsilyloxide)) was synthesized by Alfa Chemistry (Ronkonkoma, NY, USA). Other common chemicals, solvents, cell culture, and animal work supplies were purchased from MilliporeSigma, VWR, and Fisher Scientific. Example 1 Two-Step Seed and Growth Synthesis of Co-IONPs Step 1: Synthesis of Octahedron Co-IONPs (Seed): Iron (III) acetylacetonate (Fe(acac)₃; 1.77 g, 5.0 mmol), cobalt (II) chloride hexahydrate (CoCl₂.6H₂O; 0.39 g, 1.63 mmol), and 1,2-hexadecanediol (2.0 g, 7.7 mmol) were added into a 250 mL three-neck round-bottom flask, followed by n-octyl ether (10 mL), benzyl ether (10 mL), oleic acid (1.79 g, 6.3 mmol) and oleylamine (1.63 g, 6.1 mmol). Next, the reaction mixture was placed under a nitrogen flow while being magnetically stirred at 350 rpm. The reaction temperature was controlled using a Glas-Col heating mantle with a J-KEM Scientific temperature controller. The reaction mixture was heated to 110 °C at 14 °C per minute and maintained for 30 minutes under a 1.0 mL min-1nitrogen flow. The temperature was then raised to 210 °C at the same rate and held for 2 hours under the same nitrogen flow. Finally, the temperature was increased to 285 °C at the same rate and maintained for 1 hour under a reduced nitrogen flow of 0.25 mL min-1. After 1 hour of heating at 285 °C, the reaction mixture was allowed to cool down to room temperature and transferred to a 50 mL tube. The portion of the mixture was isolated and characterized by using TEM, XRD, EDX and EELS to identify the nanoparticle’s shape, size, and composition. Step 2: Synthesis of Cubical Bipyramid-shaped Co-IONPs (Growth): The octahedron Co-IONPs synthesized in the previous step were used as seeds to grow nanoparticles with a cubical bipyramid structure in the second synthesis phase.10 mL of the mixture from step 1 was centrifuged at 7800 rpm for 10 min with 30 mL of anhydrous ethanol (1:3 ratio). The supernatant was discarded, and the Co-IONPs (seed, about 80 mg) were resuspended in n-hexane (5 mL). This nanoparticle dispersion was transferred to a 250 mL three-neck round-bottom flask containing reagents at the same concentrations as used during seed synthesis (step 1). At a nitrogen flow rate of 0.25 mL min-1, the reaction mixture was heated directly to 285 °C at a rate of 14 °C min-1. After 1 hour of heating at 285 °C, the reaction mixture was allowed to cool down to room temperature and transferred to a 50 mL tube. 245-112651-02 09 / 12 / 25 OSU-24-52 Example 2 Characterization of Cubical Bipyramidal Co-IONPs: Ethanol-washed nanoparticles (5 µL) were drop- casted onto carbon-coated copper TEM grids (carbon formvar 400 Mesh copper grids, Ted Pella 01822- F). Low-magnification TEM images were collected using a Tecnai iCorr 120 keV TEM instrument equipped with a Gatan K3 camera (FEI, Hillsboro, OR, USA). SAED patterns and EDX analyses were obtained with a Talos F200X (FEI, Hillsboro, OR, USA). HRTEM and HAADF-STEM images were acquired using an aberration-corrected STEM (Titan 80-300, FEI, Hillsboro, OR, USA). EELS and elemental composition analyses were performed using a Tecnai G2 Spirit TEM-STEM (Titan 80-300 TEM unit with EDX and EELS, FEI, Hillsboro, OR, USA). HRTEM image analysis, FFT pattern and SAED pattern indexing were performed using Hyperspy (Python), DigitalMicrograph (Gatan Microscopy Suite, Pleasanton, CA, USA), and ImageJ software. For XPS and XRD analyses, THF-resuspended nanoparticles were drop-cast to form a thick layer on piranha-cleaned Si wafers. XPS data were acquired using a Nexsa G2 Surface Analysis System (Thermo Fisher Scientific, Waltham, MA, USA) and analyzed using Avantage software for peak deconvolution, peak marking, and calculating atomic percentages using the area under the curve. XRD analysis was conducted using an X-ray diffractometer (Rigaku, Tokyo, Japan) in Bragg-Brentano geometry equipped with a monochromator, scanning from 0° to 120° using Cu Kα radiation. The different XRD peaks were identified using the JCPDS database and relevant literature. Example 3 Magnetization Measurements: The magnetization curves of the prepared nanoparticles were recorded using their powder form, which had been washed three times to ensure the removal of excess surface capping agents. A vibrating sample magnetometer (VSM, P25-Quantum Design, San Diego, CA, USA) was used to record the magnetization curves M(H) with the maximum applied field of 70 kOe having 0.1 Tesla spacing and a 10-second stabilization time at room temperature (300 K). The temperature dependent magnetic behavior of the nanoparticles was recorded using ZFC and FC protocol with the maximum applied field of 50 Oe. Example 4 Magnetic Hyperthermia Efficiency: The magnetic hyperthermia efficiency of the prepared nanoparticles was analyzed using a Magnetic Hyperthermia System (MSI Automation, Wichita, KS, USA). A 1 mL glass vial containing magnetic nanoparticles (1 mg mL-1Fe) dispersed in THF was placed under insulation at the center of the water-cooled coil. Real-time temperature was monitored using an optical thermometer (NOMAD-Touch, Neoptix, Quebec, Canada) attached to a Neoptix T1 fiber optic probe. 245-112651-02 09 / 12 / 25 OSU-24-52 The field generated by the Magnetic Hyperthermia System with respect to different power and frequency coils was measured using a 2D HF magnetic field probe (AMF Life System, Auburn Hills, MI, USA) connected with a mixed-signal oscilloscope (Series 2, Tektronix, Beaverton, OR, USA). The field strength was calculated according to the formula provided in the manual. The SAR values of the nanoparticles were calculated using the following equations, ^^^ = ^ ∆^^^^^^. ^^^^^^^ ^ ∆^ ^^^ ^^^^ where C is the specific heat ◦C), ^^is the mass of the nanoparticles (g), ^!"#$. ^ %&"^mass (g) and∆^∆^is measured from the initial slope method from the temperature vs. time curve (C / s). Example 5 Conjugation of LHRH Peptide with Maleimide-PEG-PCL: A previously established protocol for conjugating LHRH peptide with Maleimide-PEG-PCL polymer was used, achieving a conjugation efficiency of 99.86%, as validated by a quantitative thiol conjugation assay. (Demessie, et al. Small Methods 2022, 6, 2200916.) In brief, maleimide, PEG-PCL (30 mg, 2 μmol) in acetonitrile and LHRH (3.36 mg, 2.5 μmol) in DMSO were mixed overnight using an Eppendorf MixMate at 1700 rpm. The mixture was then freeze-dried using a lyophilized (FreeZone 6 Plus, Labconco) to obtain the dried LHRH-PEG-PCL conjugate. Example 6 Preparation of SiNc loaded LHRH-Co-IONPs: SiNc-loaded LHRH-targeted Co-IONPs were prepared using a solvent evaporation method. First, 10 µL of SiNc solution (10 mg mL-1in THF) was mixed with 10 mg of LHRH-PEG-PCL conjugate and 50 mg of methoxy-terminated PEG-PCL (mPEG-PCL) in THF. The synthesized Co-IONPs were then added to the LHRH-PEG-PCL / mPEG-PCL mixture in THF at a concentration of 2 mg mL-1Fe, followed by the addition of 2 mL of 5% dextrose solution to enable phase transfer to the aqueous phase. The mixture was stirred continuously at room temperature and left in a fume hood for complete THF evaporation (approximately 24 hours). The resulting nanoparticles were purified by centrifugation at 3000g for 15 minutes to remove any unencapsulated SiNc and were filtered through a 0.2 μm syringe filter to remove any nanoparticle aggregates. The successful incorporation of SiNc was confirmed using the Pearl Impulse imaging system (Li-COR, Lincoln, Nebraska, USA) at the 780 nm fluorescence channel, and the loading efficiency was determined spectrophotometrically. 245-112651-02 09 / 12 / 25 OSU-24-52 Example 7 Assessment of In Vivo Toxicity: The in vivo toxicity of the synthesized LHRH-targeted Co-IONPs was evaluated using female Swiss Webster mice, which were divided into two groups (n=5): control group (5% dextrose solution) and treatment group (LHRH-targeted Co-IONPs) administered intravenously at a dose of 4 mg kg-1for three consecutive days, with continuous monitoring of body weights. At the end of the 4 weeks, blood samples were collected from all mice to analyze serum biomarkers by IDEXX Laboratories (Portland, OR, US). Example 8 In Vivo Biodistribution Studies: The subcutaneous cancer grafts of the human ovarian cancer model were developed in female nude mice by injecting 2 million ES-2 cells (ATCC, Manassas, VA, USA) suspended in PBS (50 μL) and mixed with Matrigel (50 μL). Mouse body weight and tumor volume were monitored from day 0 to evaluate nanoparticle toxicity and tumor growth, followed by treatments with both LHRH-targeted (n=3) and non-targeted nanoparticles (n=3). For the biodistribution studies, the nanoparticles were co-encapsulated with the NIR fluorescence dye SiNc (780 nm emission) at a 50 μg mL-1concentration. Fluorescence signals were recorded using the Pearl Impulse imaging system (Li- COR, Lincoln, Nebraska, USA), and the fluorescence intensity of different organs was quantified using ImageJ. The corrected total fluorescence (CTF) in each organ was calculated using the following formula: Corrected total fluorescence (CTF) = [Integrated Density − (Area of Selected Organ × Mean Fluorescence Signal of Background)] To minimize and exclude autofluorescence in the biodistribution studies, several control measures were implemented: pre-imaging baseline measurements were taken for each mouse before nanoparticle administration to establish background autofluorescence levels; control groups received either SiNc- unloaded nanoparticles or 5% dextrose solution to determine tissue-specific background signals; during image acquisition, specific filter sets were used that were optimized for SiNc (excitation: 775 nm, emission: 810 nm) to minimize interference from autofluorescent compounds; image processing included background subtraction using the control animal data, and the fluorescence intensity scale was normalized across all images using these controls; and quantitative analysis was performed by subtracting the average autofluorescence signal (from control animals) from the experimental group measurements. Example 9 In Vivo, Heating Efficiency of Co-IONPs: The intra-tumoral heating efficiency of the synthesized Co- IONPs was assessed in three different groups (n=4): Control (5% dextrose), non-targeted Co-IONPs, and 245-112651-02 09 / 12 / 25 OSU-24-52 LHRH-Co-IONPs, each administered intravenously at a dose of 4 mg kg-1.24- hours post intravenous administration, nude mice under isoflurane anesthesia were subjected to AMF (418 kHz, 28.7 kA m-1). A Neoptix T1 fiber optic probe was inserted into the tumor core, and temperature changes were recorded using an optical thermometer (NOMAD-Touch, Neoptix, Quebec, Canada). Example 10 Magnetic Hyperthermia Treatment: The anti-cancer effect of magnetic hyperthermia (418 kHz, 28.7 kA m-1) mediated by LHRH-targeted Co-IONPs was evaluated in mice (n=3) and compared to control groups, including 5% dextrose, AMF alone, nanoparticles alone without AMF, and LHRH-Co-IONPs + AMF. After 24 hours post intravenous administration of nanoparticles or 5% dextrose, the mice in corresponding groups underwent AMF treatment for 30 minutes. Body weight and tumor volume measurements were recorded for up to 14 days post-treatment, followed by evaluating the mice's tumor weight ex vivo. During AMF treatment, the field strength inside the coil at the tumor site was determined by using a 2D HF magnetic field probe. Statistical Analysis: Experimental data were examined using descriptive statistics and a two-tailed unpaired t-test. Results were provided as mean values ± standard deviation (SD) from three to five independent measurements. A one-way ANOVA was used to compare groups. Significant differences were defined as p-values < 0.05. Example 11 Synthesis of Co-IONPs excluding 1,2-hexadecanediol during the growth phase (Growth Experiment-1) and including a 2-hour slow nucleation step during the growth phase (Growth Experiment-2) Growth Experiment-1: The octahedron Co-IONPs synthesized in the 1ststep of the synthesis (refer experimental section, Step 1: Synthesis of Octahedron Co-IONPs (Seed)) were used as seeds to grow nanoparticles in the second synthesis phase. Briefly, 10 mL of the mixture from step 1 was centrifuged at 7800 rpm for 10 min with 30 mL of anhydrous ethanol (1:3 ratio). The supernatant was discarded, and the Co-IONPs (octahedron seed, ~ 80 mg) were resuspended in n-hexane (5 mL). This nanoparticle dispersion was transferred to a 250 mL round-bottom flask containing iron (III) acetylacetonate (Fe(acac)₃; 1.77 g, 5.0 mmol), cobalt (II) chloride hexahydrate (CoCl₂.6H₂O; 0.39 g, 1.63 mmol), n-octyl ether (10 mL), benzyl ether (10 mL), oleic acid (1.79 g, 6.3 mmol) and oleylamine (1.63 g, 6.1 mmol). At a nitrogen flow rate of 0.25 mL min-1, the reaction mixture was heated directly to 285°C at a rate of 14°C min-1. After 1 hour of 245-112651-02 09 / 12 / 25 OSU-24-52 heating at 285°C, the reaction mixture was allowed to cool down to room temperature and transferred to a 50 mL tube. Growth Experiment-2: The same amount of octahedron Co-IONPs were used as seeds (as described in the above growth experiment-1) to grow nanoparticles in the second synthesis phase. The octahedron nanoparticles dispersion in n-hexane was transferred to a 250 mL round-bottom flask containing reagents iron (III) acetylacetonate (Fe(acac)₃; 1.77 g, 5.0 mmol), cobalt (II) chloride hexahydrate (CoCl₂.6H₂O; 0.39 g, 1.63 mmol), 1,2-hexadecanediol (2.0 g, 7.7 mmol), n-octyl ether (10 mL), benzyl ether (10 mL), oleic acid (1.79 g, 6.3 mmol) and oleylamine (1.63 g, 6.1 mmol). The reaction mixture was heated to 110°C at 14°C per minute and maintained for 30 minutes under a 1.0 mL min-1nitrogen flow. The temperature was then raised to 210°C at the same rate and held for 2 hours under the same nitrogen flow. Finally, the temperature was increased to 285°C at the same rate and maintained for 1 hour under a reduced nitrogen flow of 0.25 mL min-1. After 1 hour of heating at 285°C, the reaction mixture was allowed to cool down to room temperature and transferred to a 50 mL tube. Example 12 Magnetic anisotropy calculations The cubic magnetocrystalline anisotropy constant or effective anisotropy ('()*+(, J⁄ m / ) of thesynthesized nanoparticles was calculated using the law of approach to saturation (LAS) method in the high field region. The LAS is valid at H >> HCwhere the magnetization saturates at higher applied fields (H). According to the LAS, the magnetization (M) depends on the applied fields can be represented as follows,1 = 1231 − b8 ^79 + ;^ (1)anisotropy constant, µ^ is constant 8 / 105 is correlatedwith the cubic anisotropy of randomly oriented polycrystalline materials, ; is the susceptibility under the high fields, and the forced magnetization term ;H is zero at room temperature (300 K). Hence, saturation magnetization (12) and b are the fitting parameters in Eqn.1 and for best fit the term ;H was also considered. The LAS fitting was done with Origin-2019b software using Eqn.1 by plotting the first 245-112651-02 09 / 12 / 25 OSU-24-52 quadrant magnetization vs applied field (FIG.22 right). It is evident from FIG.32 that the theoretical equation fits well with the experimental data (R2= 1), yielding the 12, b and zero k value. The surface anisotropy of the octahedron and cubical bipyramid nanoparticles was calculated using Eqn.3 to understand the effects of surface anisotropy on magnetic hyperthermia performance. 'Z[TUU = 'V)WX + 6 \ (3)' ) is the bulk magnetic anisotropy of length of the nanoparticle (m).Theoretically, the term b8 H7 in Eqn. 1 represents contributions of magnetocrystalline, stress, and shapeanisotropies of the In this context, '()*+(is considered as 'TUUfor '2calculation. The average edge length of the after growth was found to be 14.5 nm and 17.5 nm, respectively. Example 13 XPS analysis of cubical bipyramid-shaped Co-IONPs encapsulated in LHRH-conjugated PEG-PCL polymer A comprehensive XPS investigation was conducted to validate the effective encapsulation of the cubical bipyramid Co-IONPs by PEG-PCL polymer conjugated with LHRH peptide, focusing on the C1s and N1s regions. In these studies, as-prepared Co-IONPs (FIG.33) were used as controls to compare differences before and after encapsulation with LHRH-PEG-PCL polymer (FIG.34). FIGS.33 top left and 34 top left show the survey scans of as-prepared Co-IONPs and Co-IONPs encapsulated by LHRH- PEG-PCL polymer, respectively. After deconvolution, the C1s region of the LHRH-Co-IONPs displayed distinct peaks with binding energies of 283.5 eV, 284.2 eV, 284.9 eV, 286.2 eV, 288.9 eV, and 292.2 eV (FIG.34 top right). These peaks indicate the presence of carbon in different environments. The peak at 283.5 eV is typically assigned to carbon interacting with electro-positive elements, in this case, carbons binding to iron or cobalt. It could represent oleic acid or any organic molecule bound to Fe or Co on the nanoparticle surface. In the deconvoluted C1s region of the as-prepared Co-IONPs (FIG.33 top right), a very low- intensity peak at 283.5 eV is observed, indicating the presence of oleic acid interacting with Fe or Co as respective oleates. However, in the LHRH-PEG-PCL encapsulated Co-IONPs (FIG.34 top right), the intensity of the 283.5 eV peak increases, which is attributed to the organic carbon (with metallic Fe or Co) from the LHRH-PEG-PCL polymer, in addition to the Fe-oleate or Co-oleate complex. The peaks at 284.2 eV and 284.9 eV, observed in both the as-prepared Co-IONPs (FIG.33 top right) and LHRH-Co- IONPs (FIG.34 top right), represent the C-C and C-H bonds of the oleate coating of the as-prepared Co- 245-112651-02 09 / 12 / 25 OSU-24-52 MNPs or the encapsulating LHRH-PEG-PCL polymer. These bonds are predominant in both PEG and PCL segments, as well as in the adventitious or organic carbon on the surface of these nanoparticles. The peaks at 286.2 eV and 288.9 eV correspond to C-O bonds and C=O bonds, respectively. Furthermore, a peak at 292.2 eV was observed in the case of LHRH-Co-IONPs (FIG.34 top right), which was not evident in the bare Co-IONPs (FIG.33 top right). The XPS signal at 292.2 eV is assigned to carbon atoms with delocalized π electrons in aromatic compounds, indicating the presence of a π to π* satellite peak. This peak suggests the existence of conjugated π systems, which can be attributed to aromatic amino acids such as tryptophan (Trp) in the LHRH peptide sequence. In addition to the C1s region, the N1s region of as-prepared Co-IONPs (FIG.33 bottom) and LHRH-Co-IONPs (FIG.34 bottom) were investigated. This analysis is important for establishing the presence of the LHRH peptide on the nanoparticles' surface and providing insight into nitrogen- containing functional groups. After deconvoluting the N1s region of the as-prepared Co-IONPs (FIG.34 bottom), peaks were observed between 398.6 and 399 eV. Similar peaks were also noted in the LHRH- Co-IONPs (FIG.34 bottom). This region primarily represents amine nitrogen, which can be attributed to the use of oleylamine during synthesis. In addition to the amine region, two additional peaks were observed at 397.5 eV and 400 eV in the case of LHRH-Co-IONPs (FIG.34 bottom). Based on the literature, the peak at 397.5 eV is typically attributed to aromatic amines, which are contributed by the LHRH peptide, which contains histidine (His) and tryptophan (Trp) in its sequence. The peak at 400 eV is assigned to peptide bonds, further validating the presence of the LHRH peptide on the surface of the nanoparticles. Example 14 In Vitro studies Cell culture: ES-2 cells (ATCC, Manassas, VA, USA) were cultured in Dulbecco’s Modified Eagle Medium (DMEM) supplemented with 10% v / v fetal bovine serum (FBS) and 1% v / v antibiotic (Pen- Strep). Assessment of In Vitro Toxicity: To evaluate the cellular toxicity of LHRH-Co-IONPs, ES-2 cells were seeded at a density of 1 × 10⁴ cells per well in a 96-well culture plate. After a 24-hour incubation period, the cells were treated with varying concentrations of LHRH-Co-IONPs and incubated for an additional 24 hours at 37 °C in a CO₂ incubator. Following the treatment period, the culture medium containing nanoparticles was removed, and the cells were washed with phosphate-buffered saline (PBS). Cell viability was then assessed using the Calcein AM assay according to the manufacturer's protocol. 245-112651-02 09 / 12 / 25 OSU-24-52 In Vitro Magnetic Hyperthermia Generated by LHRH-Co-IONPs: To evaluate the in vitro hyperthermia effect, ES-2 cells were seeded at a density of 1 × 10⁵ cells per well in 35 mm cell culture plates and incubated for 24 hours at 37 °C in a CO₂ incubator. After the initial incubation, the cells were treated with LHRH-Co-IONPs at a concentration of 10 µg mL-1and incubated for an additional 24 hours under the same conditions. Following the treatment period, the cells were washed with phosphate-buffered saline (PBS), and the cell culture plate lid was sealed with parafilm. The plate was placed inside the induction coil, and the temperature around the coil was maintained at 37 °C using a circulating chiller. The cells were then exposed to an alternating magnetic field (AMF) at a frequency of 418 kHz and a field strength of 28.7 kA m-1for 15 minutes. After AMF exposure, fresh cell culture media was added to the plate, and the cells were incubated for an additional 12 hours at 37 °C in a CO₂ incubator. Two control groups were established: (1) cells exposed to AMF without LHRH-Co-IONPs, and (2) untreated cells (without nanoparticles or AMF exposure). Cell viability for all experimental and control groups was assessed using the Calcein AM assay according to the manufacturer's protocol. Cellular Internalization of non-targeted and LHRH-targeted nanoparticles: During the encapsulation process, Nile Red dye (50 µg mL-1) with Co-IONPs were co-loaded into the PEG-PCL carrier for both LHRH-targeted and non-targeted nanoparticles to evaluate their cellular internalization. ES-2 ovarian cancer cells were seeded at 150,000 cells per well in 6-well plates and incubated with the nanoparticles for 24 hours. After incubation, cells were collected and washed three times with PBS to remove any unbound nanoparticles before flow cytometry analysis. Using a 488 nm laser for excitation and a 585 / 40 nm bandpass filter to capture the Nile Red emission signal, the fluorescence intensity of treated cells was quantified and compared to untreated control cells to determine the differences in cellular uptake between non-targeted and LHRH-targeted Co-IONPs. Hemolysis Assay: Fresh mouse blood was collected via cardiac puncture into EDTA-coated tubes to prevent clotting. The tubes were gently inverted 8–10 times to mix with the anticoagulant, then kept on ice and processed within 2 hours of collection to maintain cell integrity. To isolate RBCs, whole blood was transferred to 15 mL centrifuge tubes and diluted with an equal volume of cold PBS. The tubes were centrifuged at 1500 × g for 10 minutes at 4°C. Plasma and buffy coat were carefully aspirated and discarded to leave the RBC pellet intact. The RBCs were resuspended in cold PBS (4°C), inverted gently to mix, and centrifuged again at 1500 × g for 10 minutes at 4°C. This wash step was repeated twice more, for a total of three washes, to ensure purity. Following the final wash, PBS was removed as thoroughly as 245-112651-02 09 / 12 / 25 OSU-24-52 possible without disturbing the RBC pellet. A 4% v / v RBC suspension is prepared by diluting RBCs in PBS; for a total volume of 10 mL, 200 μL of packed RBCs were added to 9.8 mL of cold PBS and mixed gently by inverting the tube multiple times. Microcentrifuge tubes were labeled according to each concentration of LHRH-Co-IONPs, as well as for controls. For each tube, 300 μL of the 4% RBC suspension was combined with 300 μL of the LHRH-Co-IONP solution at varying concentrations (0.05 µg mL-1to 50 µg mL-1). The final concentration of RBCs in each sample was maintained at 2% v / v after mixing equal volumes of the nanoparticle colloidal solution and the RBC suspension. Control samples included a negative control (300 μL RBC suspension + 300 μL PBS) and a positive control (300 μL RBC suspension + 300 μL of 1% Triton X-100). The tubes were gently flicked to mix the contents, then incubated at 37°C with gentle shaking for 2 hours. Following incubation, samples were centrifuged at 1500 × g for 10 minutes at 4°C. From each tube, 100 μL of the supernatant was carefully collected without disturbing the pellet and transferred to a 96-well plate, maintaining the sample layout. Absorbance of the supernatant was measured at 540 nm using a multiplate reader, and percentage hemolysis is calculated for each sample as following: ^^^_`abcb d%f = B ^g^h`^ ^ib − j^kglcm^ ^_nlo_` ^ib− × 100 Example 15 T2*-weighted MR Imaging and Signal Measurement: Magnetic resonance imaging was performed as postmortem imaging 24 hours after the intravenous injection of the targeted and non-targeted Co-IONPs and 1 hour after euthanasia on a Bruker 11.75 Tesla (T) / 500 MHz horizontal magnet with Bruker Advanced Neo software (Ettlingen, Germany). The imaging parameters were as follows: T2*-weighted imaging; repetition time (TR), 400 ms; matrix size, 384 × 384; slice thickness, 0.5 mm; flip angle, 40 degrees; field of view, 3.5 cm × 3.5 cm; echo time (TE), 4.5 ms. The signal intensity of subcutaneous tumors in mice on MR images was measured using DICOM viewer software (MicroDicom ver.2024.3, MicroDicom Ltd., Sofia, Bulgaria), based on the consensus of two radiologists. Furthermore, in this process, the radiologists were blinded to the nanoparticles administered to the mice. Results and Discussion concerning Examples 1-15 A. Synthesis and Characterization of Cubical Bipyramid-Shaped Magnetic Nanoparticles A two-step seed-and-growth thermal decomposition method was developed to synthesize Co- IONPs with a cubical bipyramid morphology. In the initial step, octahedron Co-IONPs were prepared to 245-112651-02 09 / 12 / 25 OSU-24-52 serve as seeds for the subsequent growth of cubical bipyramid-shaped nanoparticles (FIG.1). This advanced thermal decomposition approach was devised by refining a previously reported synthetic method for hexagonal core-shell nanoparticles. An inert atmosphere was used at a low temperature (110 °C), followed by nucleation and a subsequent thermal digestion step, to enable controlled and directional nanoparticle growth. In the thermal decomposition method for synthesizing Co-IONPs, cobalt (Co) and iron (Fe) precursors are dissolved and decomposed upon heating, leading to the formation of nuclei that subsequently grow into magnetic nanoparticles. Typically, oleic acid forms strong coordinate bonds with Fe3+or Fe2+ions, preventing nanoparticle agglomeration during nucleation and promoting uniform growth on all facets of iron oxide nanocrystals. Consequently, this process typically yields iron oxide nanoparticles with spherical morphology and increased size. In contrast, oleylamine promotes the anisotropic growth of iron oxide nanocrystals. When adsorbed on the nanoparticle surface, it selectively alters the surface energy of specific facets, favoring directional growth along particular crystallographic planes. These capping agents thus enable precise control over nanoparticle morphology and size distribution. In the disclosed method, an equal ratio of oleic acid and oleylamine was used, combined with 1,2-hexadecanediol, to modulate the surface energy of Co-doped iron oxide nanocrystal facets, resulting in nanoparticles with the desired morphology and size. Initially, the reaction mixture containing metal precursors (iron acetylacetonate and cobalt chloride hexahydrate), surface capping agents (oleic acid, oleylamine, and 1,2-hexadecandiol), and solvents (n-octyl ether and benzyl ether), was heated at 110 °C for 30 minutes under a nitrogen flow of 1 mL min-1to eliminate aqueous and volatile organic impurities. This step ensured a clean environment for nucleation and maintained uniformity in crystal size and shape. During the next nucleation step, thermal decomposition of Co and Fe precursors in the presence of surface capping agents (oleic acid, oleylamine, and 1,2-hexadecanediol) initiated the formation of small nuclei. Facet-selective aggregation of these nuclei and their subsequent transformation into primary seed particles were achieved by maintaining the reaction mixture at 210 °C for 2 hours, promoting continuous nucleation. This step is important for modulating the morphology of iron oxide nanocrystals from spherical to octahedral, as the slower, continuous nucleation process (lasting 2 hours) provides an extended temporal window for nuclei consumption and directional growth. The facet-controlled primary seed particles, formed during nucleation, then undergo growth based on the chemical potential of the {100}, {110}, and {111} crystallographic planes, with {100} having the highest potential, followed by {110}, and then {111}. In face-centered cubic crystalline nanostructures, the {100} planes are the least densely packed and most reactive, while the {111} planes are the most densely packed and least reactive. 245-112651-02 09 / 12 / 25 OSU-24-52 The selective adsorption of 1,2-hexadecanediol, owing to its binding affinity for {111} planes, creates a barrier for ion deposition on these planes while promoting growth on {100} and {110} planes. Consequently, the {111} planes exhibit slower growth rates, maintaining their flat surfaces and retaining their facets. This differential growth leads to the formation of nanoparticles with an octahedral morphology (FIG.1). The final thermal digestion step, important for controlling nanoparticle size, was conducted at 285 °C for 1 hour with a reduced nitrogen flow of 0.25 mL min-1. Under these conditions, the oxidation of benzyl ether to benzaldehyde contributed to increasing the average size of the nanoparticles. Qiao et al. demonstrated that benzaldehyde, produced by the oxidation of benzyl ether during high-temperature synthesis, plays a critical role in forming monodisperse nanoparticles with sizes ranging from 4 nm to 55 nm. In the disclosed synthesis protocol, reducing the nitrogen flow from 1.0 mL min-1to 0.25 mL min-1facilitated the oxidation of benzyl ether to benzaldehyde. However, this introduced a stability challenge due to the significant difference in boiling points between benzaldehyde (179 °C) and benzyl ether (298 °C), potentially destabilizing the reaction mixture at 285 °C. To mitigate this issue, n-octyl ether was introduced, which is a high-boiling-point solvent (287 °C), in equal proportion to benzyl ether. This solvent combination effectively stabilized the reaction mixture, preventing premature boiling and ensuring consistent synthesis conditions. Transmission electron microscopy (TEM) studies revealed that the synthesized nanoparticles exhibit a uniform distribution and an average edge length of 14.5 ± 2.5 nm (FIGS.2-5). To validate the octahedron shape of the synthesized nanoparticles, their various 2D orientations observed in TEM images were analyzed (FIGS.2-5). FIG.6 provides high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images of octahedron Co-IONPs observed under different orientations with their corresponding high-resolution TEM (HRTEM) images and Fast Fourier Transform (FFT) patterns. With reference to FIG.6, the top row illustrates multi-modal characterization of the hexagonal projection of octahedron Co-IONPs. From top left to top right the images are: a HAADF-STEM micrograph; a HRTEM image displaying lattice fringes with 2.5 Å spacing, corresponding to the (311) planes; a FFT pattern demonstrating crystallographic symmetry; and a 3D model of the hexagonal projection along the ^111^ zone axis. The bottom row illustrates the analogous analysis of the rhombohedral projection of octahedron Co-IONPs. From bottom left to bottom right the images are: a HAADF-STEM micrograph; a HRTEM image revealing lattice fringes with 4.9 Å spacing, attributed to the (111) planes; the corresponding FFT pattern; and a 3D model of the rhombohedral projection along the ^110^ zone axis. According to the literature, octahedron-shaped magnetic nanoparticles typically exhibit different orientations along the hexagonal

[0111] and rhombohedral

[0110] 245-112651-02 09 / 12 / 25 OSU-24-52 directions. Among these directions, octahedron nanoparticles preferentially align along the hexagonal ^111^ zone axis, enclosed under eight low energy {111} facets. This orientation results in a hexagonal projection of octahedron-shaped nanoparticles under electron microscopy. In a cubic crystal system, the diffraction spots in the FFT pattern display hexagonal symmetry when viewed along the

[0111] direction, a rectangular or rhombohedral pattern along the

[0110] direction, and a square or cubic arrangement along the

[0100] direction. FIGS.4 and 5 depict octahedral nanoparticles, marked with circles, which present hexagonal projections in the bright-field TEM and HAADF-STEM images. HRTEM images revealed that the synthesized nanoparticles, when viewed along this orientation, exhibit an interplanar distance of 2.5 Å, corresponding to the (311) lattice plane of the cubic spinel structure (FIG.6 top row middle image). This lattice spacing, when observed in this projection, results in a hexagonal arrangement of atomic columns. Finally, analysis of the FFT pattern confirms a hexagonal symmetry in the observed diffraction spots, characteristic of the

[0111] projection and the hexagonal appearance of octahedral Co-IONPs (FIG.6 top row right image). Similar results for octahedron-shaped iron oxide nanoparticles have been documented in previous studies. In FIGS.3 and 5, octahedron nanoparticles, denoted by a circle, highlight their rhombohedral projection under electron microscopy. Along this orientation, the synthesized nanoparticles exhibit an interplanar spacing of 4.9 Å, corresponding to the (111) lattice plane (FIG.6 bottom row middle image). Analysis of the FFT pattern reveals a projection along the

[0110] crystallographic direction, resulting in the observed rhombohedral appearance of the octahedral nanoparticles (FIG.6 bottom row right image). The HRTEM image and corresponding FFT pattern clearly demonstrate the

[0110] projection of these nanoparticles enclosed under {111} facets (FIG.6 bottom row). The 3D illustration of the octahedron structure along the hexagonal ^111^ zone axis, and the rhombohedral ^110^ zone axis enclosed under {111} facets are shown in FIG.6 in shapes on the far right side of the top and bottom rows. The elemental composition of the synthesized magnetic nanoparticles was analyzed using energy dispersive X-ray analysis (EDX) spectroscopy (FIGS.7A-7C) and corroborated with electron energy loss spectroscopy (EELS). The EELS data reveal that the octahedron seeds consist of oxygen (50.50%), iron (43.21%), and cobalt (6.29%) (FIG.9) with a molecular formula of Co₀.₃₈Fe₂.₆₂O₄. Finally, x-ray diffraction (XRD) (FIG.9) and selected area electron diffraction (SAED) analysis (FIG.10 and Table 1) of octahedron-shaped Co-IONPs revealed crystallographic planes that correspond to the JCPDS data for cobalt-doped iron oxide nanoparticles (JCPDS files 88-2152 and 22-1086). The identified planes include (111), (220), (311), as well as (400), (422), (511), (440), (620), (622), (444), (642), (731), (800), (660), (662), and (840) (FIG.9 and Table 1). These findings confirm the formation of 245-112651-02 09 / 12 / 25 OSU-24-52 a complex spinel structure characteristic of cobalt ferrite, suggesting that cobalt doping likely preserves the inverse spinel structure typical of magnetite. Table 1. d-spacing and hkl values of different planes deduced from SAED patterns of the octahedron (seed) and cubical bipyramids (growth) Co-IONPs. S.No. Seed Growth d-spacing (Ao) hkl values d-spacing (Ao) hkl values In t he next step, Co-IONPs with a cubical bipyramid morphology were synthesized via a seed- mediated growth method. This process employed the octahedral Co-IONPs as seeds. The synthesis involved adding identical amounts and ratios of precursors (iron acetylacetonate and cobalt chloride hexahydrate) and surface capping agents (oleic acid, oleylamine, and 1,2-hexadecanediol), as in the initial step, to the octahedron Co-IONP seeds. The reaction mixture was heated to 285 °C and maintained at that temperature for 1 hour under a nitrogen flow of 0.25 mL min-1to promote nanoparticle growth, bypassing the 2-hour nucleation phase at 210 °C used in the seed preparation procedure. This approach ensured that the newly thermally decomposed Co and Fe precursors preferentially deposited on the existing octahedron Co-IONPs. Bright-field TEM images (FIG.11) and corresponding HAADF-STEM images (FIG.12) reveal that the synthesized cubical bipyramidal Co-IONPs exhibit a uniform size distribution with an average edge length of 17.5 ± 2.8 nm. Morphological validation of the synthesized Co-IONPs was further conducted through a comprehensive analysis of various projections observed in HAADF-STEM (FIG.13C) and HRTEM (FIG.13D) images, along with their corresponding FFT patterns (FIG.13E). These experimental data 245-112651-02 09 / 12 / 25 OSU-24-52 were compared with 3D illustrated projections of the cubical bipyramidal structure along different crystallographic orientations (FIG.13F). Structurally, a cubical bipyramid is a polyhedron formed by attaching two square pyramids to opposite faces of a central cube (FIG.13A). This configuration results in a geometry with four square faces and eight equilateral triangular faces. Depending on their orientation, a cubical bipyramid displays three distinct two-dimensional (2D) projections: (i) a square or cubic projection when viewed along the

[0100] direction (top view, FIG.13B, top), (ii) a hexagonal projection when viewed from the side (FIG. 13B, middle) and (iii) a hexagonal projection with a different aspect ratio when viewed from a diagonal angle (FIG.13B, bottom). The synthesized nanoparticles were investigated from various orientations using HRTEM images and FFT patterns to identify their interplanar spacing, lattice planes, crystallographic directions, and the above-discussed 2D projections (FIGS.13C-13F). Previous studies have reported that interplanar distances of 3.0 Å and 4.9 Å in iron oxide nanoparticles correspond to the (220) and (111) lattice planes, respectively. These planes are associated with nanostructures oriented along the

[0100] and

[0110] zone axis, enclosed by {100} and {111} facets. HRTEM analysis of our nanoparticles (FIG.13D, top) revealed a lattice spacing of 3.0 Å, consistent with the (220) lattice plane. The FFT pattern confirmed the

[0100] zone axis (FIG.13E, top), validating the cubic projection of the nanoparticles as represented in their 2D (FIG.13B, top) and 3D structure (FIG.13F, top). HAADF-STEM and HRTEM images (FIGS.13C, top and 13D, top) clearly show grain boundaries linking equilateral triangular faces, forming pyramid-like structures atop the nanoparticles when viewed along the

[0100] direction. Two additional projections of the cubical bipyramids were also examined: hexagonal from the side view (FIG.13B, middle) and hexagonal from the diagonal view (FIG.13B, bottom). HAADF-STEM images highlight the hexagonal appearance of the nanoparticles from both the diagonal view (FIG.13C, middle) and the side view (FIG.13C, bottom). FIG.13C, middle to FIG.13F, bottom represent the 2D projections of the cubical bipyramid Co-IONPs compared to their corresponding HAADF-STEM and HRTEM images, along with the FFT patterns viewed from the side (hexagon, FIGS.13C-13F, middle) and diagonal (hexagon, FIGS.13C-13F, bottom). Analysis of the HRTEM images (FIGS.13D, middle and 13D, bottom) revealed lattice fringes with a spacing of 4.9 Å, corresponding to the (111) lattice plane. The FFT patterns (FIGS.13E, middle and 13E, bottom) indicated that the nanoparticles exhibit

[0110] zone axis along these two orientations. FIG.14 presents a high-resolution HAADF-STEM image of a cubical bipyramid from the side view indicated in FIG.13C, middle and clearly reveals the {111} and {220} crystallographic planes. These observations confirm that all four facets of the central cubic part of these nanoparticles are bounded by four low-energy {111} facets. 245-112651-02 09 / 12 / 25 OSU-24-52 The results discussed herein, along with the literature analysis, suggested a potential mechanism for the transition of octahedron seeds into cubical bipyramid-shaped nanoparticles during the seed- mediated growth method. HRTEM images and corresponding FFT patterns revealed that the nanoparticles with a cubical bipyramid morphology are primarily enclosed by {111} planes when observed from the

[0110] projection and by {100} planes when observed from the

[0100] projection (FIGS. 13C-13F). The {111} planes are present in the center part of the cubical bipyramid nanostructure (FIG.1 and FIG.13C, middle, to FIG.13F, bottom), while the {100} planes are situated on the top part, forming pyramid-like projections (FIG.1 and FIGS.13C-13F, top). To synthesize such nanoparticles enclosed by the high and low index facets {111} and {100}, the ions need to attach to the {110} facets of the octahedron seeds to direct the growth along ^110^ direction during the growth step (FIG.1). Swihart et al. (Qiao, et al., ACS Nano 2017, 11, 6370) elucidated the mechanism by which octahedron-shaped iron oxide nanoparticles, when dominated by growth in the ^110^ direction, change their morphology to tetradecahedron with reduced {110} and {111} facets. In the disclosed synthesis method, it was hypothesized that a similar mechanism promotes growth in the ^110^ direction of the octahedron seeds. However, in the present case, the newly developed cubical bipyramids were observed to retain the {111} facets, along with {100} facets. Without being bound to a particular theory, it is believed that the inclusion of 1,2-hexadecanediol in the present synthesis maintains a similar largest activation barrier for the deposition of new ions or nuclei. This may be due to 1,2-hexadecanediol's high affinity towards {111} facets, which slows down growth in the ^111^ direction, allowing the {111} planes to retain their facets again. Additionally, HRTEM analysis revealed that these nanoparticles are enclosed by {100} planes towards the top part, likely due to reduced growth towards ^100^ direction (FIGS.13C-13F, top). It was hypothesized that the growth in ^110^ direction dominated due to the influx of new ions from the rapid decomposition of organo-metallic precursors. The restricted growth on {111} planes is due to the stronger binding of 1,2-hexadecanediol at these sites. This process results in nanoparticles that are primarily enclosed by {111} and {100} facets, ultimately forming a cubical bipyramid morphology with distinct sharp edges and flat surfaces (FIGS.13A-13F). To validate the proposed mechanism for cubical bipyramidal nanoparticle formation, two control growth experiments were conducted (Example 11 and FIG.15). In the first experiment, nanoparticles were synthesized using octahedron seeds but excluding 1,2-hexadecanediol during the growth phase. This resulted in the transformation of octahedron seeds into spherical nanoparticles with an increased average diameter of 18 ± 4.0 nm (FIG.15, left). This observation suggested that 1,2-hexadecanediol plays an important role in preserving the {111} facets of the nanoparticles, possibly due to its higher binding affinity for these crystallographic planes. For the second control experiment, the two-step seed-and- 245-112651-02 09 / 12 / 25 OSU-24-52 growth thermal decomposition method was followed but included a 2-hour slow nucleation step during the growth phase. This modification led to the formation of nanoparticles with a truncated octahedral morphology and blunt edges (FIG.15, right). These control experiments yield two key insights. First, the presence of 1,2-hexadecanediol is essential for maintaining the {111} facets during nanoparticle growth, possibly due to its preferential adsorption on these surfaces. Second, the rapid decomposition of the synthesis precursor is crucial for increasing the influx of new ions, which is necessary for initiating growth along the ^110^ direction. The extended nucleation step during the growth phase in the second control experiment likely reduced the ion concentration, leading to slower growth and truncation of the octahedral morphology. The prepared cubical bipyramid-shaped nanoparticles were characterized using a range of advanced techniques to elucidate their structure, composition, and properties. The XRD and SAED analysis revealed multiple peaks at the (101), (111), (220), (302), (311), (400), (422), (511), (440), (622), (444), (642), (731), (800), (660), (662), and (840) planes (FIGS.17 and 9 and Table 1), which are consistent with the JCPDS data for cobalt-doped iron oxide nanoparticles (JCPDS file 22-1086; 88-2152). Notably, the presence of new (101) and (302) planes observed during XRD analysis (FIG.9) corresponding to maghemite (γ-Fe2O3, JCPDS file 80-2186) suggests the existence of an additional maghemite phase alongside the magnetite phase in the final nanoparticle structure (FIG.9 and Table 1). The maghemite phase formation could be attributable to the surface oxidation of the prepared magnetite nanoparticles under the specific experimental conditions of the developed thermal decomposition method, including a high temperature of 285 °C and a low nitrogen flow of 0.25 mL min-1. The inventors’ previous studies revealed that Co-doped magnetite nanoparticles undergo surface oxidation to maghemite when exposed to high temperatures and residual oxygen, which was not entirely eliminated from the reaction by nitrogen supplied at a low flow rate. These experimental conditions resulted in the formation of nanoparticles with a magnetite core and a maghemite shell. HRTEM analysis of the synthesized cubical bipyramid-shaped nanoparticles revealed surface roughness (FIG.18), suggesting surface oxidation due to the incorporation of additional oxygen atoms into the crystal lattice, which likely leads to the formation of vacancies at the nanoparticle surface (FIG. 19). This roughness and surface oxidation particularly appeared when the nanoparticles were oriented towards the

[0100] projection, which represents the top pyramid-like projections enclosed under the (220) lattice plane (FIGS.18 right and 19). The predominant formation of maghemite on the {100} planes is attributed to their low-index nature and high reactivity, enabling them to readily interact with available oxygen during synthesis. Inverse FFT analysis of the HRTEM images distinctly reveals vacancies and lattice mismatches between the inner core and the outer surface, indicating the coexistence of two distinct 245-112651-02 09 / 12 / 25 OSU-24-52 phases within the nanoparticles (FIG.19). FIG.20 illustrates the unit cell of cobalt ferrites and depict the formation of vacancies (O-occupied sites). These vacancies occur due to the permeation of oxygen atoms into the crystal lattice of magnetite, resulting in the formation of the maghemite phase on the outer surface of the nanoparticle. The EDX and EELS analyses further revealed that the atomic percentages of Co, Fe, and O in the cubical bipyramid-shaped nanoparticles are 6.06%, 39.79%, and 54.15%, respectively (FIG.16). Based on the EELS data, their molecular formula is determined to be Co₀.₄₀Fe₂.₆₀O₄. The ~4% increase in the oxygen atomic percentage (54.15%) of the cubical bipyramid-shaped nanoparticles compared to the seeds (50.5%) is likely due to the co-existence of magnetite and maghemite phases of iron oxide nanoparticles. To further validate the presence of different valence states of Fe, O, and Co species, a comprehensive X-ray Photoelectron Spectroscopy (XPS) analysis of the Fe 2p, Fe 3p, O 1s, and Co 2p regions of the synthesized nanoparticles was conducted. Peak fitting was performed using the National Institute of Standards and Technology XPS Database (SRD 20, version 5.0) for accurate identification of Fe, O, and Co species. The analysis of the Fe 2p region revealed a complex spectrum with prominent peaks at binding energies of 706.5, 708.4, 711.3, 714.8, 719.8, 723.0, and 728.4 eV (FIG.21), indicating the presence of multiple iron oxidation states and their distribution within the nanoparticles. Specifically, the peaks at 706.5 eV, 708.4 eV, and 711.3 eV in the Fe 2p3 / 2 region indicate the coexistence of Fe²⁺ and Fe³⁺ ions, suggesting mixed oxidation states. According to the literature, magnetite, which has a mixed oxidation state of Fe²⁺ and Fe³⁺, accounts for the lower binding energy peaks (706.5 and 708.4 eV), while the predominantly Fe³⁺ maghemite phase is responsible for the higher binding energy peaks (711.3 eV) and satellite features. This dual presence suggested a sophisticated oxide structure in the disclosed nanoparticles, comprising two different phases of iron oxide, such as magnetite (Fe₃O₄) and maghemite (γ-Fe₂O₃). Additionally, the peaks at 719.8 eV and 723 eV in the Fe 2p1 / 2 region reinforced the predominance of Fe³⁺ ions. These findings, along with the satellite features at 714.8 eV and 728.4 eV in the Fe 2p3 / 2 and Fe 2p1 / 2 regions, respectively, suggested significant electronic interactions within the lattice. The satellite features are commonly associated with Fe³⁺ in a high-spin state and are characteristic of complex electronic environments, such as those found in cobalt-doped iron oxide nanoparticles. Furthermore, by integrating the total areas under the curves at 706.5 eV and 708.5 eV (representing the Fe²⁺ and Fe³⁺ oxidation states of magnetite) and the area under the curve at 711.3 eV (representing Fe³⁺ oxidation state of maghemite phase), it was determined that the disclosed nanoparticles primarily consisted of the magnetite phase, with the maghemite phase having a lower distribution within the nanostructure. 245-112651-02 09 / 12 / 25 OSU-24-52 The mixed oxidation states were further confirmed by analyzing the Fe 3p XPS region (FIG.22 left). Peaks at 52.9 eV and 54.8 eV corresponded to the Fe 3p3 / 2 region, indicating the presence of Fe²⁺ and Fe³⁺ ions, respectively. Additionally, peaks at 58.4 eV and 60.8 eV in the Fe 3p1 / 2 region demonstrated electronic interactions and covalency within the iron-cobalt oxide matrix. The presence of lattice oxygen (Fe-O) further reflected the coexistence of magnetite and maghemite phases within the nanoparticles (FIG.22 right). Finally, the analysis of the Co 2p XPS region revealed insights into the Co oxidation state, coordination, and structural role in the nanoparticles (FIG.23). Peaks at 780.5 eV, 784 eV (Co 2p3 / 2), 787.7 eV (satellite), 795.6 eV (Co 2p1 / 2), and additional satellites at 801.9 eV, 803.3 eV, and 805 eV indicated Co integration into the iron oxide matrix. The Co 2p3 / 2 peaks at 780.5 eV and 784 eV represented Co²⁺ ions, suggesting a diverse cobalt environment occupying both octahedral and tetrahedral positions. The Co 2p1 / 2 peak at 795.6 eV further confirmed cobalt's divalent state, with satellite features at 801.9 eV, 803.3 eV, and 805 eV. This analysis indicated that cobalt predominantly exists as Co²⁺ ions, which in cobalt ferrites prefer octahedral sites, suggesting these nanoparticles possess an inverse spinel structure. In the analysis, the presence of the maghemite phase was specifically observed in the cubical bipyramidal Co-IONPs, despite similar synthesis conditions being used for both octahedron and cubical bipyramidal Co-IONPs. This difference may arise due to the inclusion of a 3-step synthesis process for octahedral Co-IONPs and maintaining a nitrogen flow rate of 1.0 mL min-1during steps 1 and 2. This higher nitrogen flow effectively removes moisture and volatile components from the reaction mixture, ensuring a clean synthesis environment. The smooth and well-defined surfaces of the octahedrons are confirmed by electron microscopy images (FIGS.2-5). Under these controlled conditions, maghemite formation in the octahedrons is negligible, as supported by the XRD pattern (FIG.9) and the planes calculated from their SAED pattern. In contrast, for cubical bipyramids, octahedrons were used as seeds, and the nitrogen flow rate was reduced to 0.25 mL min-1from the beginning of the reaction as the temperature increased from room temperature to 285 °C, skipping the degassing step at 110 °C. This lower nitrogen flow likely increases the oxidation of the benzyl ether solvent during synthesis, contributing to the formation of additional maghemite phases. The presence of maghemite is corroborated by crystallographic data and TEM images (FIG.18), which show slight surface roughness at the edges of the nanoparticles. 245-112651-02 09 / 12 / 25 OSU-24-52 B. Magnetic Properties and Heating Efficiency of Octahedron and Cubical Bipyramid Co- IONPs The heating efficiency of the developed Co-IONPs, with both octahedron and cubical bipyramid morphologies, was evaluated by comparing their induction heating profiles under identical conditions (FIG.24). Solutions of the same Fe concentration (1 mg mL-1) were exposed to an AMF at 315 kHz and 26.8 kA m-1. The concentration of 1 mg mL-1Fe has been widely adopted as a standard condition for SAR measurements in previous reports. The results demonstrated that cubical bipyramid-shaped Co-IONPs exhibit a very high SAR of 14,686 ± 396 W g-1Fe with a heating rate of 3.73 °C s-1. This value is 2.5 times greater than that of the octahedron seeds, which display a SAR of 5,866 ± 507 W g-1Fe with a heating rate of 1.49 °C s-1(Table 2). Table 2. Heating and magnetic properties of octahedron and cubical bipyramid nanoparticles SAR qrstuvwwurNanoparticle ) Octahedron Cubical bipyramid To elucidate the superior heating efficiency of cubical bipyramid-shaped Co-IONPs compared to their octahedron counterparts, a comprehensive analysis and comparison of their magnetic properties were conducted. Magnified M(H) plots at low field regime (FIG.25) illustrate the M(H) isotherm of the tested nanoparticles, measured under a maximum applied magnetic field of ±7 kOe at 300 K. The presence of open hysteresis loops (FIG.25), with nonzero remnant magnetization (1^) and coercivity (^^), confirms the ferromagnetic nature of both nanoparticle types. Moreover, the results indicate that the cubical bipyramid-shaped Co-IONPs exhibit a significantly higher saturation magnetization (12= 89.5 emu g-1) (FIG.26) and coercivity (^^= 393 Oe) compared to the octahedron nanoparticles (12= 53.5 emu g-1, ^^= 285 Oe, FIG.26 and Table 2). The higher 12value for cubical bipyramid-shaped Co- IONPs could be attributed to an increase in particle volume as observed from TEM images (FIGS.2-4 and 12). Consequently, the superior heating efficiency of cubical bipyramid-shaped Co-IONPs can be explained by their enhanced 12and ^^, which results in improved energy dissipation under AMF. Furthermore, both the effective magnetic anisotropy ('TUU) and surface anisotropy ('2) constants were calculated for the octahedron and cubical bipyramid Co-IONPs to evaluate their contributions to the heating efficiency of both nanoparticles (Example 12). The 'TUUvalues for octahedron and cubical 245-112651-02 09 / 12 / 25 OSU-24-52 bipyramid Co-IONPs were determined to be 3.5 x 10⁵ J m-³ and 5.1 x 10⁵ J m-³, respectively (Table 2). The increase in 'TUUfor cubical bipyramid nanoparticles is attributed to the increased particle volume, coercivity (^^), and surface contribution. This transition from octahedron to cubical bipyramid morphology significantly influences the net magnetic anisotropy, thereby enhancing the heating efficiency of the cubical bipyramid Co-IONPs. In contrast, the similar KS values for the octahedron (38.23 x 10⁻⁴ J m-2) and cubical bipyramid (40.54 x 10⁻⁴ J m-2) nanoparticles (Table 2) suggest that surface anisotropy does not significantly contribute to the superior heating efficiency of the cubical bipyramid nanoparticles. Finally, the temperature dependence of the magnetic behavior of both nanoparticles was analyzed using zero-field cooled (ZFC) and field-cooled (FC) techniques, with an applied magnetic field of 50 Oe and temperatures ranging from 5 K to 400 K (FIG.27). The ZFC and FC curves for both octahedron and cubical bipyramid nanoparticles did not converge even up to 400 K, and no peak points were observed in ZFC curves (FIG.27). This suggests that the nanoparticles remain in a blocked state at room temperature, where the magnetic anisotropy energy (^^) dominates over the thermal energy (;VT). Notably, the transition point between 300 K and 350 K, observed on the ZFC curve of the octahedron Co-IONPs, is absent after nanoparticle growth, indicating an increase in particle volume and magnetic anisotropy in the cubical bipyramid Co-IONPs, consistent with the 'TUUconstant analysis (FIG.27, black arrow). Furthermore, a pronounced transition point between 50 K and 100 K on the ZFC curve of the cubical bipyramid Co-IONPs suggests the presence of a soft maghemite (γ-Fe2O3) phase within the nanoparticle structure, corroborating the HRTEM, XRD, and XPS results (FIGS.9, 13A-13F, 21, and 23). The coexistence of both hard magnetite and soft maghemite phases within a single nanostructure positively impacts the net magnetic anisotropy of the system via exchange coupling, thereby significantly improving the heating efficiency of the cubical bipyramid nanoparticles. To illustrate the superior heating efficiency of the developed Co-IONPs, characterized by their cubical bipyramid morphology (17.5 nm ± 2.8 nm), a comparative analysis was conducted against several magnetic nanoparticles of comparable sizes. These included spherical Co-IONPs (18 nm ± 4.0 nm, FIG. 28 left), commercially available spherical iron oxide nanoparticles (19.5 nm ± 3.6 nm, FIG.28, middle), and the inventors’ previously reported Co-doped hexagonal nanoparticles with a magnetite core and maghemite shell (21.6 nm ± 4.2 nm) exhibiting ultrahigh heating efficiency (FIG.28, right). Upon exposure to an AMF at 315 kHz and 26.8 kA m-1, the disclosed nanoparticles exhibited a SAR of 14,686 ± 396 W g-1Fe, significantly surpassing the SAR values of commercially available spherical iron oxide nanoparticles (1,200 ± 53 W g-1Fe) and spherical Co-IONPs (1,725 ± 263 W g-1Fe) by factors of 11.9 and 8.3, respectively (FIG.29, Table 3). Remarkably, the cubical bipyramid-shaped Co-IONPs (SAR = 245-112651-02 09 / 12 / 25 OSU-24-52 14,686 ± 396 W g-1Fe) achieve 1.9 times higher heating performance under identical experimental conditions compared to Co-doped hexagonal nanoparticles with a magnetite core and maghemite shell (SAR = 7,490 ± 306 W g-1Fe), previously reported for their ultrahigh heating efficiency (FIG.29, Table 3). The enhanced heating efficiency of the cubical bipyramid-shaped Co-IONPs can be attributed to their higher saturation magnetization (12= 89.5 emu g-1) and coercivity (^^= 393 Oe) compared to the Co- doped hexagonal nanoparticles with a similar core-shell structure (12= 76.0 emu g-1, ^^= 345 Oe). The cubical bipyramid-shaped Co-IONPs feature significantly thicker shells of 3.1 nm (FIG.18, left), which may contribute to their enhanced heating efficiency. Table 3: The Calculated SAR values of various nanoparticles at ^^= 26.82 kA m-1and f = 315 kHz. The values are presented as mean ± SD (n = 4). Nanoparticles Size (nm) Morphology SAR (W / g Fe) Cubical bipyramid Co-IONPs 17.5 Cubical bipyramids 14686 ± 396 Spherical Co-IONPs 18 Spherical 1725 ± 263 Hexagonal Co-IONPs 21.6 Hexagonal 7490 ± 306 Commercial IONPs 19.5 Spherical 1200 ± 53 Finally, the heating efficiency of the disclosed cubical bipyramid-shaped Co-IONPs was evaluated under AMF with varying frequencies (f) and magnetic field strengths (H0). Exposing the nanoparticles to AMF with varying frequencies but similar magnetic field strengths (f = 235 kHz & ^^= 27.0 kA m-1, f = 315 kHz & ^^= 26.8 kA m-1, and f = 418 kHz & ^^= 24.7 kA m-1) resulted in distinct SAR values: 11,825 ± 1,401 W g-1Fe at 235 kHz, 14,686 ± 396 W g-1Fe at 315 kHz, and 12,777 ± 807 W g-1Fe at 418 kHz (FIGS.30-31 and Table 4). Table 4. Calculated SAR values of cubical bipyramid-shaped Co-IONPs at different frequencies and comparable field strengths. The values are presented as mean ± SD (n = 4). Frequency Magnetic field SAR (W / g Fe) (kHz) strength (kA / m) 235 27.05 11,825 ± 1401 315 26.82 14,686 ± 396 418 24.67 12,777 ± 807 While these results demonstrate some frequency dependence, with optimal heating efficiency observed at 315 kHz, the variation in SAR values is relatively modest compared to the effects of changing field strength (FIG.32). Unlike superparamagnetic nanoparticles, ferromagnetic nanoparticles, such as cubical 245-112651-02 09 / 12 / 25 OSU-24-52 bipyramids, exhibit high magnetic anisotropy and a strong magnetic moment. As a result, their magnetization reversal is primarily determined by the field amplitude with a secondary dependence on frequency, which drives hysteresis loss toward an enhanced SAR. For the cubical bipyramidnanoparticles, the measurement time (^^ = 18 L^ L^2^^ = 6.77 × 10 s to 3.8 × 10 s) is too short toachieve effective magnetization reversal making relaxational loss less significant compared to hysteresis losses. in high anisotropic cubical bipyramid nanoparticles due to the dominance of the anisotropy energy barrier (^ ) over thermal energy.^Furthermore, analysis indicates that the maximum magnetization reversal occurs at a field frequency of 315 kHz, suggesting that this frequency may be optimal for achieving a high SAR in cubical bipyramid nanoparticles, especially when increasing the field strength. In the subsequent step, the impact of different magnetic field strengths was assessed on the heating performance of the disclosed nanoparticles by subjecting them to AMF at the optimal frequency -1of 315 kHz while varying the field strength from 3.0 to 26.8 kA m (FIGS.31 right, 32 and Table 5). Table 5. Calculated SAR values of cubical bipyramid-shaped nanoparticles at different field strengths (3.05 kA / m to 26.82 kA / m) and fixed frequency (315 kHz). Magnetic field SAR (W / g Fe) (kA / m) 3.05 1 6.84 461 13.92 2,362 19.73 4,882 26.82 14,686 The results revealed a non-linear rise in the SAR values with increasing magnetic field strength (FIG.32), demonstrating that the heating efficiency of the disclosed nanoparticles was more strongly influenced by the intensity of the applied field than by frequency variations. To further analyze the effect of field b amplitude on SAR, a power law, SAR ≈ AH , derived from linear response theory, was applied which is0 valid for H ˂˂ H (large anisotropic particles or extremely small applied fields). Here, A and b are free0 C parameters, and the fitting was performed using Origin 2019b software (FIG.32). From the fitting, the value of b was found to be 3.26, which deviates from the linear response theory limit (b = 2). This higher value of b suggests that when H ≈ H , the area of the hysteresis loop increases rapidly in a nonlinear0 C manner as H0increases, approaching the magnetic anisotropy. Based on this study, it was concluded that 245-112651-02 09 / 12 / 25 OSU-24-52 while the disclosed cubical bipyramids show some frequency dependence, their heating efficiency is predominantly determined by field strength (H0). C. Preparation and Characterization of LHRH-Targeted Cubical Bipyramid Co-IONPs To evaluate the in vivo efficiency of the developed cubical bipyramid-shaped Co-IONPs for systemically delivered magnetic hyperthermia, their surface was modified with luteinizing hormone- releasing hormone (LHRH) peptide, targeting the overexpressed LHRH receptors in various cancers, including ovarian carcinoma. The major goal in this study was to assess the therapeutic performance of these nanoparticles after IV administration in mice bearing ES-2 ovarian clear cell carcinoma xenografts and to compare the findings with previously published results for LHRH-targeted core-shell Co-IONPs with ultrahigh heating capacity, tested in the same animal model under comparable dosing (4 mg kg-1) and AMF parameters (420 kHz, 26.9 kA m-1vs.418 kHz, 28.6 kA m-1). Following established protocols, maleimide-terminated poly(ethylene glycol)-block-poly(ε- caprolactone) (PEG-PCL) was conjugated to the thiol group of the D-cysteine residue in the LHRH decapeptide. The cubical bipyramid-shaped Co-IONPs were then coated with the synthesized LHRH- PEG-PCL using a solvent evaporation approach. For comparison, non-targeted nanoparticles coated with methoxy-terminated PEG-PCL were also prepared. The selection of PEG-PCL polymeric nanoparticles as a delivery platform for the disclosed Co- IONPs was motivated by several key advantages. Previous studies have confirmed the minimal toxicity profile and efficient body clearance of PEG-PCL polymer. PEG-PCL-based nanocarriers have also demonstrated exceptional capabilities in preclinical research, particularly in delivering hydrophobic agents while preventing their premature release during systemic circulation, ultimately facilitating their accumulation in tumor tissues after systemic administration. A significant advantage of PEG-PCL formulations lies in their straightforward preparation process, yielding nanoparticles with consistent size distributions and stability during storage. These characteristics, combined with reproducible manufacturing potential, align well with the requirements for clinical translation. Moreover, the versatility of PEG-PCL chemistry allows for easy incorporation of various functional groups, facilitating the attachment of targeting molecules to enhance therapeutic specificity. These combined features make our PEG-PCL-based formulation advantageous compared to alternative nanocarrier systems for magnetic hyperthermia applications. Comprehensive XPS analysis of the LHRH-coated Co-IONPs (LHRH-Co-IONPs) confirmed the presence of PEG-PCL polymer and LHRH peptide on the surface of the nanoparticles (Example 13 and FIGS.33 and 34). Dynamic Light Scattering (DLS) results further revealed that the non-targeted Co- 245-112651-02 09 / 12 / 25 OSU-24-52 IONPs have an average hydrodynamic size of 35.5 ± 5.7 nm and a polydispersity index (PDI) of 0.16 ± 0.02 (FIG.35 left). In contrast, LHRH-Co-IONPs exhibited a slightly larger average size of 48.8 ± 4.6 nm and a PDI of 0.29 ± 0.04, likely due to the conjugation of the LHRH peptide to the nanoparticle. The morphology of LHRH-PEG-PCL-coated Co-IONPs was further investigated using two complementary techniques: conventional TEM with 1% uranyl acetate negative staining and cryo-TEM imaging (FIG. 36). Both methods revealed well-dispersed nanoparticles without significant aggregation. The polymer coating was visible as a distinct shell surrounding the Co-IONP cores in both imaging methods, confirming successful functionalization. Zeta potential measurements indicated a transition from a near-neutral surface charge in non- targeted Co-IONPs (-2.71 ± 0.23 mV) to a positive charge (+12.5 ± 0.61 mV) in LHRH-functionalized nanoparticles (FIG.35 right). These results align well with our previous report, which demonstrated that LHRH peptides impart a slightly positive charge to PEG-PCL-coated nanoparticles. The LHRH-Co-IONPs were monitored for one month at 4 °C and no significant changes in average size, PDI, or zeta potential were identified, confirming their stability under these conditions (FIG. 35 and Table 6). Table 6: DLS size and Zeta potential values of LHRH-Co-IONPs at Day 0 and Day 30 Days Average DLS Size Polydispersity Zeta Potential (nm) Index (PDI) (mV) 0 48.8 ± 4.6 0.29 ± 0.04 +12.5 ± 0.61 30 43.8 ± 0.01 0.24 ± 0.01 +11.9 ± 0.87 Further investigation of colloidal stability in biologically relevant media (phosphate-buffered saline (PBS), serum, plasma, and normal saline) revealed no observable aggregation or precipitation, as evidenced by digital photographic documentation (FIG.37 top). DLS measurements corroborated these observations, showing negligible variations in particle size distribution before and after exposure to these biological media (FIG.37 bottom). For the DLS measurements the LHRH-Co-IONPs were initially dispersed in 5% dextrose solution and subsequently mixed in a 1:1 volume ratio with physiological buffers (PBS and normal saline) or biological fluids (serum and plasma). All samples were incubated under continuous agitation for 2 hours at 37 °C. The consistently low PDI values (ranging from 0.25 to 0.29) across all conditions indicated preservation of monodisperse populations (Table 7). These results comprehensively demonstrate the exceptional stability of LHRH-Co-IONPs under physiologically relevant conditions, establishing their suitability for biological applications. 245-112651-02 09 / 12 / 25 OSU-24-52 Table 7: DLS size and PDI values of LHRH-Co-IONPs in various biological media Media DLS Size Polydispersity (nm) Index (PDI) 5 % Dextrose 34.74 0.29 PBS 35.83 0.27 Serum 30.70 0.27 Plasma 38.51 0.27 Normal Saline 41.81 0.25 After encapsulation step, the heating performance of LHRH-Co-IONPs was examined under AMF (418 kHz, 28.7 kA m-1). While the results showed that PEG-PCL coating initially decreases the heating rate, with non-coated Co-IONPs in THF reaching a maximum temperature of 67 °C within 13 seconds compared to LHRH-Co-IONPs requiring 100 seconds, the functionalized nanoparticles ultimately achieved a significantly higher maximum temperature of 100°C in aqueous solution (FIG.38). This difference in heating kinetics may be attributed to surface modification and solvent viscosity variations (THF: 0.48 cP vs. water: 0.89 cP at 25°C). Notably, previous studies have shown that PEG-PCL-based nanocarriers disintegrate in the intracellular environment of cancer cells, leading to the release of hydrophobic cargos, suggesting that the effect of PEG-PCL coating on heating rate of the disclosed nanoparticles would be minimized following tumor accumulation. D. In Vitro Evaluation of LHRH-Targeted Cubical Bipyramid-Shaped Co-IONPs The biosafety of LHRH-Co-IONPs at a cellular level was assessed through cytotoxicity and hemolysis studies at concentrations ranging from 0.05 to 50 µg mL-1(Example 14). This concentration range was selected to encompass the estimated blood concentration (about 40 µg mL-1) of LHRH-Co- IONPs achieved in the in vivo studies, where mice received intravenous injection of 100 µg nanoparticles per animal (4 mg Fe kg-1, based on an average mouse blood volume of 2.5 mL). The results demonstrated that LHRH-Co-IONPs exhibited no significant toxicity or hemolytic activity across all tested concentrations (FIGS.39 and 40). The targeting efficiency of the disclosed LHRH-Co-IONPs was investigated using ES-2 ovarian cancer cells as a model system (Example 14). Flow cytometric analysis demonstrated that LHRH peptide conjugation enhanced cellular internalization, evidenced by a 1.5-fold increase in mean fluorescence intensity compared to non-targeted Co-IONPs (FIG.41). To evaluate the therapeutic efficacy of LHRH-Co-IONPs-based magnetic hyperthermia, ES-2 cells were incubated with LHRH-Co-IONPs at a non-toxic concentration (10 µg mL⁻¹) and exposed to 245-112651-02 09 / 12 / 25 OSU-24-52 AMF (418 kHz, 28.7 kA m-1) for 15 minutes. This treatment resulted in a substantial reduction in cell viability to approximately 35%. Notably, control experiments confirmed that AMF exposure alone had no detectable effect on cell viability, demonstrating that the observed cytotoxicity was specifically attributable to the hyperthermia effect generated by LHRH-Co-IONPs under AMF conditions (FIG.39 right). These findings collectively demonstrate the potential of LHRH-Co-IONPs as an effective platform for targeted magnetic hyperthermia therapy. E. Evaluation of Safety, Biodistribution, Intratumoral Heating Efficiency, and Therapeutic Performance of LHRH-Targeted Cubical Bipyramid-Shaped Co-IONPs As magnetic hyperthermia following systemic administration of iron oxide-based nanoparticles has not been evaluated in clinical trials, clinically safe systemic doses remain undefined. Using FDA- approved ferumoxytol (17-31 nm magnetic iron oxide nanoparticles) for iron deficiency anemia as a reference point, which has a recommended IV dosage of 510 mg Fe (8.5 mg kg-1for a 60 kg patient), an IV dose of 4 mg kg-1Fe for LHRH-Co-IONPs was selected, approximately half of the FDA-approved ferumoxytol dosage. To evaluate the safety profile of the developed LHRH-targeted Co-IONPs, three IV injections of the nanoparticles (4 mg kg-1Fe each) were administered to mice, spaced one day apart, and compared the outcomes to a control group treated with 5% dextrose. Changes in body weight were monitored throughout the study, and blood samples were collected following euthanasia on day 28 post-injection. The extensive blood analysis encompassed a broad spectrum of physiological biomarkers, including alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), blood urea nitrogen (BUN), creatinine (Cr), creatine kinase (CK), red blood cell count (RBC), white blood cell count (WBC), electrolytes, different types of white blood cells, and plasma proteins. The findings revealed no significant differences in the measured biomarkers between the LHRH-Co-IONPs-treated and control groups, indicating that all parameters remained within normal physiological ranges and were comparable between the two groups (FIGS.42 right and 43-44). Additionally, both groups exhibited similar increases in body weight throughout the study, further confirming the biocompatibility and safety of the LHRH-Co-IONPs (FIG.42 left). These results provide strong evidence for the long-term safety of LHRH-Co-IONPs, demonstrating that they are non-toxic, well-tolerated, and safe for systemic administration, with no detectable adverse effects on critical physiological biomarkers and body weight in treated mice. To further investigate the biodistribution and tumor accumulation of LHRH-targeted and non- targeted nanoparticles, They were labeled with the near-infrared (NIR) fluorophore silicon naphthalocyanine (SiNc) and administered a single IV injection to mice bearing ES-2 ovarian cancer 245-112651-02 09 / 12 / 25 OSU-24-52 xenografts. After 24 hours post-administration, fluorescence imaging revealed distinct differences in the biodistribution profiles between the targeted and non-targeted nanoparticles (FIG.45). LHRH-Co-IONPs exhibited pronounced accumulation in the tumor region (FIG.45 top left), as evidenced by higher fluorescence intensity while showing lower signals in the liver (FIG.45 top right and bottom left and right). In contrast, the non-targeted Co-IONPs displayed significant fluorescence in the liver, moderate signals in the tumor, and lower intensity across other major organs (FIG.45 top right and bottom left and right). Semi-quantitative fluorescence analysis using ImageJ corroborated these observations, revealing that the fluorescence intensity in the tumors treated with LHRH-Co-IONPs was 2.3 times higher compared to those treated with non-targeted nanoparticles (FIG.45 top right). Additionally, the fluorescence signal in the liver decreased by 1.4 times in the case of the LHRH-targeted nanoparticles. These findings are consistent with the inventors’ previous report, which demonstrated that LHRH peptides enhance the tumor accumulation of PEG-PCL-coated nanoparticles by more than two-fold. Exploiting the MRI contrast agent properties of Co-doped iron oxide nanoparticles, tumor localization of both non-targeted and LHRH-targeted Co-IONPs was confirmed through T2-weighted signal loss relative to the control (FIG.46), with LHRH-Co-IONPs showing enhanced signal reduction compared to non-targeted nanoparticles. The clearance of SiNc-loaded LHRH-Co-IONPs was evaluated in nude mice bearing ES-2 subcutaneous xenografts by monitoring SiNc fluorescence signals from day 0 to day 14 post- administration. The fluorescence intensity gradually decreased starting at 24 hours post-administration, with no detectable signals in either organs or tumors by day 14 (FIG.47), indicating complete clearance from the body within 14 days. The efficiency of the developed LHRH-Co-IONPs in elevating intratumoral temperature under AMF (418 kHz, 28.6 kA m-1) was evaluated in mice with ovarian cancer xenografts. Temperature changes within the tumor were recorded using a fiber optic probe 24 hours post a single IV injection at a dose of 4 mg kg-1Fe. The obtained temperature profiles demonstrated that LHRH-targeted Co-IONPs achieved an average intratumoral temperature of 50.1°C, reaching 43 °C within 9 minutes (FIG.48 bottom left). In contrast, non-targeted nanoparticles raised the average intratumoral temperature to 46 °C, surpassing the 43 °C threshold within 15 minutes. The increased intratumoral temperatures achieved with the targeted nanoparticles not only validate their enhanced accumulation but also underscore their potential for more effective tumor treatment during hyperthermia therapy. To the best of the inventors’ knowledge, this study is the first to demonstrate that systemically administered nanoparticles at a low dose of 4 mg kg-1Fe can achieve intratumoral temperatures exceeding 50°C while exhibiting a relatively 245-112651-02 09 / 12 / 25 OSU-24-52 high heating rate, reaching 43 °C within 9 minutes. Notably, the developed cubical bipyramid-shaped Co- IONPs show superior in vivo heating efficiency compared to previously reported LHRH-targeted core- shell hexagonal Co-IONPs known for their ultrahigh heating capacity. Demessie et al. reported that 24 hours post-IV injection at a dose of 4 mg kg-1Fe in the identical animal model, these nanoparticles elevated the intratumoral temperature to 48 °C, achieving 43 °C within 16 minutes under comparable AMF parameters (420 kHz, 26.9 kA m-1). Finally, the therapeutic efficacy of systemically delivered magnetic hyperthermia mediated by the developed LHRH-targeted cubical bipyramid-shaped Co-IONPs was evaluated in mice bearing ES-2 ovarian cancer xenografts. Animals were intravenously injected with LHRH-Co-IONPs at a dose of 4 mg kg-1and exposed to AMF for 30 minutes, 24 hours post-administration (FIG.48 top). The selection of the 24-hour timepoint represents an optimal balance between three critical factors: efficient tumor accumulation of LHRH-Co-IONPs, sufficient clearance from major organs, and maximum achievable intratumoral temperature. Temporal biodistribution studies demonstrated peak tumor accumulation of nanoparticles at 24 hours, followed by a significant signal reduction at 48 hours (FIG.50 left). Notably, the maximum intratumoral temperature achieved at 48 hours was only 42 °C, further indicating reduced nanoparticle accumulation in the tumor at this later timepoint (FIG.50 right). In addition, at 24 hours post-administration, efficient clearance of nanoparticles from major organs was observed (FIG.45 top left and bottom left), which is important for minimizing potential side effects of magnetic hyperthermia. The therapeutic efficacy study demonstrated that the average tumor volume before and after treatment was 80 mm³ and 79 mm³, respectively (FIG.48 bottom right, blue curve), indicating that a single session of magnetic hyperthermia halted tumor growth. Furthermore, the average volume of treated tumors was about ten times smaller compared to untreated controls (FIGS.48 bottom right and 49 top), and the average mass of the resected tumors after magnetic hyperthermia was 7.3 times lower than controls (FIG.49 bottom left). The results also indicated that the tumor mass in mice treated with either nanoparticles or AMF alone did not significantly differ from that of the control group, suggesting that neither AMF exposure nor nanoparticle administration independently confers anticancer efficacy. Finally, the lack of apparent toxicity from LHRH-Co-IONPs-mediated hyperthermia was demonstrated by similar body weight values in all experimental groups (FIG. 49 bottom right). These results demonstrate that that the newly developed LHRH-targeted cubical bipyramid- shaped Co-IONPs exhibit markedly enhanced anticancer efficacy compared to the previously documented LHRH-targeted core-shell hexagonal Co-IONPs. The latter only managed to decelerate tumor growth and achieve a 3.4-fold reduction in tumor mass relative to controls under comparable experimental conditions. 245-112651-02 09 / 12 / 25 OSU-24-52 F. Conclusions A two-step seed-and-growth thermal decomposition method was been developed to synthesize Co-doped iron oxide nanoparticles with a unique cubical bipyramid morphology. The disclosed nanoparticles exhibited exceptional induction heating performance, with a SAR of 14,686 ± 396 W g⁻¹ Fe under AMF conditions. The developed LHRH-targeted cubical bipyramid nanoparticles demonstrated biocompatibility and efficient tumor accumulation in vivo. Most notably, when administered systemically at a clinically relevant low dose of 4 mg kg⁻¹ Fe, these nanoparticles achieved intratumoral temperatures exceeding 50°C with a rapid heating rate, reaching the therapeutic threshold of 43°C within just 9 minutes. This high heating efficiency translated to significant therapeutic outcomes, effectively halting tumor growth after a single 30-minute session of magnetic hyperthermia. The development of highly efficient cubical bipyramidal nanoparticles addresses critical limitations in current approaches, offering the potential to broaden the applicability of magnetic hyperthermia for treating a wider range of cancer types, particularly deep-seated tumors and metastatic diseases, where the nanoparticles' ability to accumulate in cancer tissues following systemic administration could be highly advantageous. In view of the many possible aspects to which the principles of the disclosed technology may be applied, it should be recognized that the illustrated aspects are only preferred examples of the disclosure and should not be taken as limiting the scope of the disclosure. Rather, the scope of the disclosure is defined by the following claims. We therefore claim as the disclosure all that comes within the scope and spirit of these claims.

Claims

1. 245-112651-02 09 / 12 / 25 OSU-24-52 We claim:

1. A cobalt-doped iron oxide nanoparticle having a cubical bipyramid shape.

2. The nanoparticle of claim 1, wherein the nanoparticle comprises from 2 atom% to 10 atom% cobalt, from 25 atom% to 55 atom% iron, and from 35 atom% to 75 atom% oxygen, such that the total amount of cobalt, iron and oxygen is 100 atom%.

3. The nanoparticle of claim 2, wherein the nanoparticle comprises from 5 atom% to 7 atom% cobalt, from 35 atom% to 45 atom% iron, and from 50 atom% to 60 atom% oxygen, such that the total amount of cobalt, iron and oxygen is 100 atom%.

4. The nanoparticle of any one of claims 1-3, wherein the nanoparticle has a molecular formula according to formula I CoxFe3-xO4 Formula I wherein x is from 0.1 to 0.

8.

5. The nanoparticle of claim 4, wherein x is from 0.3 to 0.

5.

6. The nanoparticle of any one of claims 1-5, wherein the nanoparticle has a size of from 15 nm to 25 nm.

7. The nanoparticle of any one of claims 1-6, wherein the nanoparticle has a specific absorption rate (SAR) of from 10,000 W g-1Fe to 20,000 W g-1Fe as measured at ^^= 26.82 kA m-1and f = 315 kHz.

8. The nanoparticle of claim 7, wherein the SAR is from 14,000 W g-1Fe to 15,000 W g-1Fe.

9. The nanoparticle of any one of claims 1-8, comprising from 5 atom% to 7 atom% cobalt, from 35 atom% to 45 atom% iron, and from 50 atom% to 60 atom% oxygen, such that the total amount of cobalt, iron and oxygen is 100 atom%; and245-112651-02 09 / 12 / 25 OSU-24-52 wherein the nanoparticle has a size of from 17 nm to 18 nm and a specific absorption rate (SAR) of from 14,000 W g-1Fe to 15,000 W g-1Fe.

10. A method for making the cubic bipyramid cobalt-doped iron oxide nanoparticle of any one of claims 1-9, the method comprising: providing an octagonal cobalt-doped iron oxide nanoparticle; combining the octagonal cobalt-doped iron oxide nanoparticle with a first cobalt compound, a first iron compound, and a first surface capping agent in a first solvent system to form a first mixture; heating the first mixture to a first temperature for a first time period; and isolating the cubic bipyramid cobalt-doped iron oxide nanoparticle.

11. The method of claim 10, wherein the first temperature is from 180 °C to 240 °C.

12. The method of claim 11, wherein the first temperature is from 200 °C to 220 °C.

13. The method of any one of claims 10-12, wherein the first time period is from 30 minutes to 90 minutes.

14. The method of claim 13, wherein the first time period is from 45 minutes to 75 minutes.

15. The method of any one of claims 10-14, wherein heating the first mixture to the first temperature comprises heating the first mixture at ramp rate of from 5 °C / min to 25 °C / min.

16. The method of claim 15, wherein the ramp rate is from 12 °C / min to 16 °C / min.

17. The method of any one of claims 10-16, wherein the combining and the heating is performed under a flow of an inert gas.

18. The method of claim 17, wherein the inert gas is nitrogen.

19. The method of any one of claims 17-18, wherein the flow of the inert gas has a flow rate of from greater than zero to 25 mL / min.245-112651-02 09 / 12 / 25 OSU-24-52 20. The method of claim 19, wherein the flow rate is from 0.2 mL / min to 0.5 mL / min.

21. The method of any one of claims 10-20, wherein the first cobalt compound is cobalt(II) chloride (CoCl2), cobalt(II) chloride hexahydrate (CoCl26H2O), cobalt(II) sulphate (CoSO4), cobalt(II) sulphate heptahydrate (CoSO47H2O), cobalt(II) nitrate hexahydrate (Co(NO3)26H2O), cobalt(II) carbonate (CoCO3), or a combination thereof.

22. The method of claim 21, wherein the first cobalt compound is cobalt(II) chloride hexahydrate.

23. The method of any one of claims 10-22, wherein the first iron compound is (Zero-valent) Fe(CO)5, iron(III) acetylacetonate (Fe(acac)3), iron(II) sulfate (ferrous sulfate, FeSO₄), iron(II) chloride (FeCl₂, ferrous chloride), iron(III) nitrate (Fe(NO₃)₃, ferric nitrate), iron(III) sulfate (Fe(SO₄)₃, ferric sulfate), iron(III) chloride (FeCl₃, ferric chloride), or a combination thereof.

24. The method of claim 23, wherein the first iron compound is iron(III) acetylacetonate.

25. The method of any one of claims 10-24, wherein the first surface capping agent comprises oleic acid, oleylamine, 1,2-hexadecandiol, or a combination thereof.

26. The method of claim 25, wherein the first surface caping agent comprises oleic acid, oleylamine, and 1,2-hexadecandiol.

27. The method of any one of claims 10-26, wherein the first solvent system comprises trioctylamine, docosane, n-octylether, benzyl ether, or a combination thereof.

28. The method of claim 27, wherein the first solvent system comprises n-octylether and benzyl ether.

29. The method of any one of claims 10-28, comprising: combining the octagonal cobalt-doped iron oxide nanoparticle with cobalt(II) chloride hexahydrate, iron(III) acetylacetonate, oleic acid, oleylamine, 1,2-hexadecandiol, n-octylether and benzyl ether to form the first mixture;245-112651-02 09 / 12 / 25 OSU-24-52 heating the first mixture at a ramp rate of from 12 °C / min to 16 °C / min to a temperature of from 200 °C to 220 °C for from 45 minutes to 75 minutes under a flow of nitrogen gas at a flow rate of from 0.2 mL / min to 0.5 mL / min; and isolating the cubic bipyramid cobalt-doped iron oxide nanoparticle.

30. The method of any one of claims 10-29, where in providing the octagonal cobalt-doped iron oxide nanoparticle comprises: mixing a second cobalt compound and a second iron compound with a second surface capping agent in a second solvent system to form a second mixture; heating the second mixture to a second temperature for a second time period to form; and isolating the octagonal cobalt-doped iron oxide nanoparticle.

31. The method of claim 30, wherein the second temperature is from 250 °C to 350 °C.

32. The method of claim 30 or claim 31, wherein the second time period is from 30 minutes to 90 minutes.

33. The method of any one of claims 30-32, wherein prior to heating the second mixture to a second temperature, the method comprises heating the second mixture to a first intermediate temperature of from 80 °C to 150 °C for a first intermediate time period of from 15 minutes to 1 hour.

34. The method of claim 33, wherein the method further comprises heating the second mixture to a second intermediate temperature of from 180 °C to 240 °C for a second intermediate time period of from 90 minutes to 3 hours.

35. The method of any one of claims 33-34, wherein: the first intermediate temperature is from 100 °C to 120 °C; the first intermediate time period is from 20 minutes to 45 minutes; the second intermediate temperature is from 200 °C to 220 °C; the second intermediate time period is from 110 minutes to 2 ¼ hours; or a combination thereof.245-112651-02 09 / 12 / 25 OSU-24-52 36. The method of any one of claims 30-35, wherein: the second temperature is from 280 °C to 290 °C; the second time period is from 45 minutes to 75 minutes; or a combination thereof.

37. The method of any one of claims 30-36, wherein the second cobalt compound is cobalt(II) chloride (CoCl2), cobalt(II) chloride hexahydrate (CoCl26H2O), cobalt(II) sulphate (CoSO4), cobalt(II) sulphate heptahydrate (CoSO47H2O), cobalt(II) nitrate hexahydrate (Co(NO3)26H2O), cobalt(II) carbonate (CoCO3), or a combination thereof.

38. The method of claim 37, wherein the second cobalt compound is cobalt(II) chloride hexahydrate.

39. The method of any one of claims 30-38, wherein the second iron compound is (Zero- valent) Fe(CO)5, iron(III) acetylacetonate (Fe(acac)3), iron(II) sulfate (ferrous sulfate, FeSO₄), iron(II) chloride (FeCl₂, ferrous chloride), iron(III) nitrate (Fe(NO₃)₃, ferric nitrate), iron(III) sulfate (Fe(SO₄)₃, ferric sulfate), iron(III) chloride (FeCl₃, ferric chloride), or a combination thereof.

40. The method of claim 39, wherein the second iron compound is iron(III) acetylacetonate.

41. The method of any one of claims 30-40, wherein the second surface capping agent comprises oleic acid, oleylamine, 1,2-hexadecandiol, or a combination thereof.

42. The method of claim 41, wherein the second surface caping agent comprises oleic acid, oleylamine, and 1,2-hexadecandiol.

43. The method of any one of claims 30-42, wherein the second solvent system comprises trioctylamine, docosane, n-octylether, benzyl ether, or a combination thereof.

44. The method of claim 43, wherein the second solvent system comprises n-octylether and benzyl ether.245-112651-02 09 / 12 / 25 OSU-24-52 45. The method of any one of claims 30-44, comprising: mixing cobalt(II) chloride hexahydrate and iron(III) acetylacetonate with oleic acid, oleylamine, and 1,2-hexadecandiol in a combination of n-octylether and benzyl ether under a flow of nitrogen gas to form a second mixture; heating the second mixture to a temperature from 100 °C to 120 °C for from 20 minutes to 45 minutes; heating the second mixture to a temperature of from 200 °C to 220 °C for from 110 minutes to 2 ¼ hours; heating the second mixture to a temperature of from 280 °C to 290 °C for from 45 minutes to 75 minutes; and isolating the octagonal cobalt-doped iron oxide nanoparticle.

46. A composition comprising a nanoparticle according to any one of claims 1-10, and a polymer.

47. The composition of claim 46, wherein the nanoparticle is encapsulated in the polymer.

48. The composition of claim 45 or claim 46, wherein the polymer is selected from polyethylene glycol-block-polycaprolactone (PEG-b-PCL), methoxy polyethylene glycol-block- polycaprolactone (mPEG-b-PCL), polyethylene glycol-block-polyvalerolactone (PEG-b-PVL), polyethylene glycol-block-polylactic acid (PEG-b-PLA) or polyethylene glycol-block-poly(lactic acid-co- glycolic acid) (PEG-b-PLGA).

49. The composition of any one of claims 46-48, wherein the polymer comprises a PEG moiety.

50. The composition of claim 49, wherein the polymer is a PEG-PCL polymer.

51. The composition of any one of claims 46-50, wherein the polymer has a molecular weight of from about 10,000 Da to 20,000 Da.

52. The composition of any one of claims 46-51, wherein the polymer has a molecular weight of from about from 13,000 Da to 17,000 Da.245-112651-02 09 / 12 / 25 OSU-24-52 53. The composition of claim 52, wherein the polymer has a molecular weight of from about 15,000 Da.

54. The composition of any one of claims 46-53, wherein the composition further comprises a targeting moiety conjugated to the polymer.

55. The composition of claim 54, wherein the targeting moiety is selected from a peptide, protein, small molecule, nucleic acid sequence, antibody, or a combination thereof.

56. The composition of claim 54 or claim 55, wherein the targeting moiety is an EGFR (Epidermal growth factor receptor), Integrin αvβ6, Neuropilin-1, PD-L1, a HER2 receptor, or a combination thereof.

57. The composition of any one of claims 54-56, wherein the targeting moiety is a targeting moiety for ovarian cancer.

58. The composition of any one of claims 54-57, wherein the targeting moiety is a LHRH peptide, α-3 integrin receptor, ROR1(Receptor tyrosine kinase–like orphan receptor1), HE4(Human epididymis protein 4), 5-Protein signature (OVA1), or a combination thereof.

59. A method, comprising: forming a solution or suspension comprising a nanoparticle of any one of claims 1-10 and a first organic solvent; forming a mixture comprising the solution or suspension and a polymer in a second organic solvent; and isolating a composition comprising the nanoparticle and the polymer.

60. The method of claim 59, wherein the composition is a composition according to any one of claims 46-58.245-112651-02 09 / 12 / 25 OSU-24-52 61. The method of claim 59 or claim 60, wherein the polymer comprises a targeting moiety.

62. The method of claim 61, wherein the composition is a composition according to any one of claims 54-58.

63. The method of any one of claims 59-62, wherein the first and second organic solvents are the same solvent.

64. A method, comprising administering the nanoparticle of any one of claims 1-10, or the composition of any one of claims 46-58, to a subject in need thereof.

65. The method of claim 64, wherein the method is a method of treating cancer.

66. The method of claim 65, wherein the cancer is ovarian cancer.

67. The method of claim 64, wherein the method is a method of treating non-cancerous lesions.

68. The method of claim 64, wherein the method is a method of treating endometriosis or ectopic pregnancy.

69. The method of any one of claims 64-68, wherein the method is a method hyperthermia treatment method.

70. The method of any one of claims 64-69, wherein administering comprises injecting the nanoparticle or the composition.

71. The method of claim 70, wherein the nanoparticle or the composition is injected systemically.

72. The method of claim 70, wherein the nanoparticle or the composition is injected locally.245-112651-02 09 / 12 / 25 OSU-24-52 73. The method of any one of claims 64-72, wherein the method further comprises applying an alternating magnetic field to the nanoparticle or composition.

74. The method of claim 73, wherein the alternating magnetic field has: a field strength of from 1 kA / m to 100 kA / m; a frequency of from 50 kHz to 900 kHz; or a combination thereof.

75. The method of any one of claims 64-74, wherein the nanoparticle or composition is administered in an amount sufficient to provide from 1 mg to 100 mgs of iron per kg weight of the subject.

76. The method of claim 75, wherein the amount administered is sufficient to provide from 1 mg to 50 mgs of iron per kg weight of the subject.

77. The method of claim 76, wherein the amount administered is sufficient to provide from 1 mg to 10 mgs of iron per kg weight of the subject.

78. A use of the nanoparticle of any one of claims 1-10, or the composition of any one of claims 46-58, in the manufacture of a medicament for administration to a subject in need thereof.

79. The use of claim 78, where the medicament is a medicament for treatment of cancer, non- cancerous lesions, endometriosis or ectopic pregnancy.

80. The use of claim 79, wherein the cancer is ovarian cancer.

81. The use of any one of claims 78-80, wherein the medicament is a medicament for hyperthermia treatment.

82. A nanoparticle of any one of claims 1-10, or a composition of any one of claims 46-58, for use in a method of administration to a subject in need thereof.245-112651-02 09 / 12 / 25 OSU-24-52 83. The nanoparticle or composition for use of claim 82, where the subject has cancer, non- cancerous lesions, endometriosis or ectopic pregnancy.

84. The nanoparticle or composition for use of claim 83, wherein the cancer is ovarian cancer.

85. The nanoparticle or composition for use of any one of claims 82-84, wherein the use is for hyperthermia treatment.

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