A chiral Cu 2-x S-quantum dots, their preparation methods, and applications

Abstract

This invention relates to the field of nanomaterials technology and discloses a chiral Cu 2‑x S-quantum dots, their preparation methods, and applications: In an aqueous phase, a copper source and a complexing agent are mixed and reacted to obtain a copper complex solution. A sulfur source and a dextrorotatory penicillamine chiral ligand are added to the copper complex solution. The mixed reaction solution is heated to carry out nucleation and growth reactions. After centrifugation and drying of the precipitate, chiral Cu with high photothermal conversion efficiency is obtained. 2‑x S-quantum dots. This invention is the first to use dextrorotatory penicillamine, which has a significant steric hindrance effect, as a chiral ligand during the growth of quantum dots. Its unique molecular structure induces the formation of a specific surface coordination environment and chiral structure. This structure can significantly enhance the absorption of near-infrared light by quantum dots and promote the non-radiative relaxation conversion of light energy into heat energy, greatly improving photothermal conversion performance. This provides an efficient and feasible technical solution for the practical application of chiral quantum dots in the field of tumor photothermal therapy.

Description

Technical Field

[0001] This invention relates to the field of nanomaterials technology, and more particularly to a chiral Cu. 2-x S quantum dots, their preparation methods, and applications. Background Technology

[0002] In recent years, nanomaterials with photothermal conversion effects have shown great application potential in photothermal therapy, photoacoustic imaging, seawater desalination, and catalysis. Among these materials, cuprous sulfide nanocrystals, especially quantum dots, possess advantages such as strong localized surface plasmon resonance (LSPR) absorption in the near-infrared (NIR) region, good biocompatibility, and low preparation cost. In the biomedical field, quantum dots, through near-infrared light excitation, combined with the targeting recognition ability and excellent photothermal conversion performance of chiral quantum dots, can generate local high temperatures at tumor sites, thereby selectively inducing apoptosis of cancer cells. This further advances the exploration of biological applications. Furthermore, the chiral modification of chiral quantum dot Cu-based materials can further enhance the stability and targeting recognition ability of the materials, thereby enhancing the synergistic therapeutic effects in biological applications. These materials can also be used as antibacterial coatings in the antibacterial field, applying chiral Cu... 2-x When S quantum dots are embedded in medical dressings, they can effectively kill drug-resistant bacteria.

[0003] To further improve the performance of cuprous sulfide quantum dots, existing technologies typically employ surface ligand modification strategies. Introducing chiral molecules (such as cysteine) as ligands, through chiral induction, to induce chiral optical activity in the inorganic nanocrystals, has proven to be an effective way to improve their photothermal conversion efficiency. However, the improvement in photothermal conversion efficiency of cuprous sulfide quantum dots prepared using conventional chiral ligands remains limited, failing to meet the demands of more demanding applications. Furthermore, products obtained by some preparation methods exhibit poor stability and performance degradation after repeated light irradiation cycles, limiting their reliability and lifespan in practical applications. Therefore, developing a novel preparation method for chiral cuprous sulfide quantum dots that achieves higher photothermal conversion efficiency and better stability is a pressing technical problem in this field. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a chiral Cu with high photothermal conversion efficiency. 2-x S-quantum dots, their preparation methods, and applications solve the problems mentioned in the background section.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a chiral Cu 2-x The preparation method of S quantum dots includes the following steps: S1. In an aqueous phase, the copper source and complexing agent are mixed and reacted to obtain a copper complex solution; S2. Add a sulfur source and a dextrorotatory penicillamine chiral ligand to the copper complex solution to obtain a mixed reaction solution; the added raw materials make the molar ratio of copper source, dextrorotatory penicillamine and sulfur source in the reaction system (3.5-4.5):(2.0-3.0):1; S3. Heat the mixed reaction solution to carry out nucleation and growth reactions, yielding chiral Cu. 2-x Aqueous dispersions of S quantum dots; S4. Cool the obtained aqueous dispersion, centrifuge, discard the supernatant, wash the precipitate with deionized water and dry it to obtain chiral Cu with high photothermal conversion efficiency. 2-x S is a solid powder of quantum dots, where 0 < x ≤ 1.

[0006] Further, in step S1, the copper source and the complexing agent are stirred at room temperature and then pre-reacted under inert gas protection to obtain a copper complex solution.

[0007] Furthermore, in step S3, the heating temperature is 50°C to 70°C.

[0008] Furthermore, the heating time is 1.5 to 3 hours.

[0009] Furthermore, both steps S1 and S2 are performed under inert gas protection.

[0010] Preferably, the copper source is copper chloride dihydrate; the sulfur source is thiourea; and the complexing agent is trisodium citrate dihydrate.

[0011] This invention also discloses a chiral Cu obtained by the above preparation method. 2-x S-quantum dots.

[0012] Furthermore, the chiral Cu 2-x S quantum dots include L-Cys-Cu 2-x S quantum dots and D-Cys-Cu 2-x S quantum dots, chiral Cu 2-x An aqueous dispersion of S quantum dots, at a concentration of 1 mg / mL, was subjected to a power density of 1.6 W / cm². 2 After irradiation with an 808nm laser for 480 seconds, under these conditions, L-Cys-Cu 2-x The highest temperature of S quantum dots is 41.1℃, and that of D-Cys-Cu is... 2-x The highest temperature of S quantum dots is 41.6℃.

[0013] This invention also discloses the chiral Cu obtained by the above preparation method. 2-x Application of S quantum dots in the preparation of drugs for treating tumors.

[0014] Furthermore, the drug is delivered into the body via intravenous injection, where quantum dots are passively enriched in the tumor area. Near-infrared lasers, which have a deep penetration depth into biological tissues, are used to irradiate the tumor site externally. The quantum dots enriched there efficiently convert light energy into heat energy, causing the local temperature of the tumor area to rise rapidly, thereby achieving precise thermal ablation of cancer cells.

[0015] The beneficial effects of this invention are: 1. This invention uses dextrorotatory penicillamine as a chiral ligand and utilizes the unique steric hindrance effect in its molecular structure to induce the formation of a specific surface coordination environment and chiral structure. This structure can more effectively promote the conversion of light energy absorbed by quantum dots into heat energy through non-radiative relaxation pathways, thereby significantly improving the photothermal conversion efficiency of the material and enabling it to achieve a higher temperature rise under the same conditions.

[0016] 2. Due to the chiral nature of Cu 2-x S quantum dots exhibit excellent photothermal stability. By introducing chiral ligands into the reaction system during the nucleation and growth stages of quantum dots, the integrated and stable combination of ligands and quantum dots is ensured. After undergoing multiple cycles of laser irradiation and cooling, the photothermal conversion performance of the resulting product shows no significant attenuation, exhibiting high stability and long service life.

[0017] 3. The preparation method of this invention is simple, mild, and reproducible. The entire preparation process is completed in an aqueous system, and all raw materials used are commercially available conventional chemical reagents. No harsh reaction conditions are required, reducing production costs and environmental pollution, and facilitating large-scale production. Quantum dots, excited by near-infrared light, combined with the targeted recognition function and excellent photothermal conversion properties of chiral quantum dots, can generate localized high temperatures at the tumor site, thereby selectively inducing apoptosis of cancer cells. Furthermore, the chiral modification of the chiral quantum dot Cu-based material can further enhance the material's stability and targeted recognition ability, thereby enhancing the synergistic therapeutic effect in biological applications. This type of material can also be used as an antibacterial coating in the antibacterial field, applying chiral Cu... 2-x When S quantum dots are embedded in medical dressings, they can effectively kill drug-resistant bacteria. Attached Figure Description

[0018] Figure 1 The chiral Cu of the present invention 2-x Flowchart of the preparation method of S quantum dots.

[0019] Figure 2 Chiral Cys-Cu 2-x S quantum dot XRD image.

[0020] Figure 3 Chiral D-Pen-Cu2-x XRD pattern of S quantum dots.

[0021] Figure 4 Chiral D-Pen-Cu 2-x TEM spectrum of S quantum dots.

[0022] Figure 5 In this context, 'a' represents chiral D-Pen-Cu. 2-x S is the CD spectrum of quantum dots, and b is the CD spectrum of D-Pen molecules.

[0023] Figure 6 Chiral Cys-Cu 2-x S quantum dot CD spectrum.

[0024] Figure 7 Chiral D-Pen-Cu with different output power densities 2-x The single-pass photothermal response curves of the S quantum dot are shown, where a is 1.0 W and b is 1.6 W.

[0025] Figure 8 For L-Cys-Cu with an output power density of 1.6 W 2-x S and D-Cys-Cu 2-x The single-shot photothermal response of S quantum dots.

[0026] Figure 9 D-Pen-Cu with different output power densities 2-x Cyclic photothermal response curves of S quantum dots, where a is 1.0 W and b is 1.6 W.

[0027] Figure 10 For L-Cys-Cu with an output power density of 1.6 W 2-x S and D-Cys-Cu 2-x Cyclic photothermal response of S quantum dots.

[0028] Figure 11 The image shows a thermal image with an output power density of 1.6 W, where 'a' represents D-Cys-Cu diluted 5 times. 2-x Thermal imaging of S-FA quantum dots, b is L-Cys-Cu diluted 5 times. 2-x Thermal imaging of S-FA quantum dots, c is L-Cys-Cu diluted 10 times. 2-x Thermal imaging of S-FA quantum dots, where d represents D-Cys-Cu diluted 10-fold. 2-x Thermal imaging of S-FA quantum dots. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] In the text, L-Cys-Cu 2-x S quantum dots represent L-cysteine ​​copper sulfide quantum dots, D-Cys-Cu 2-x S represents dextrocysteine ​​copper sulfide quantum dots, D-Pen-Cu 2-x S quantum dots represent dextrorotatory penicillamine cuprous sulfide quantum dots, D-Pen molecule represents dextrorotatory penicillamine molecule, Cys-Cu 2-x S quantum dots represent cysteine ​​cuprous sulfide quantum dots, D-Cys-Cu 2- x S-FA quantum dots represent folic acid-coupled dextrocysteine ​​cuprous sulfide quantum dots, L-Cys-Cu 2-x S-FA quantum dots represent folic acid-coupled L-cysteine ​​cuprous sulfide quantum dots.

[0031] The chiral Cu with high photothermal conversion efficiency of the present invention 2-x S quantum dots consist of raw materials in the following molar ratio: Copper source: 3.5–4.5 parts; Dextrorotatory penicillamine chiral ligand: 2.0–3.0 parts; Sulfur source: 1 part; And complexing agents.

[0032] In the molecular structure of dextrorotatory penicillamine, there are two methyl groups on the β-carbon atom that connects the thiol group, which produces a significant steric hindrance effect. During the nucleation and growth of quantum dots, the thiol group of dextrorotatory penicillamine coordinates with the copper atoms on the surface of the quantum dots. Its steric hindrance structure can induce the formation of a specific surface coordination environment and defect state structure that is conducive to photothermal conversion.

[0033] The D-configuration chirality of dextrorotatory penicillamine is transferred and solidified into the lattice or surface structure of inorganic cuprous sulfide through coordination, enabling the entire quantum dot nanocrystal to exhibit overall chiral optical activity. The specific chiral structure and surface electronic states induced by dextrorotatory penicillamine can significantly enhance the absorption of near-infrared light by quantum dots and effectively promote the conversion of absorbed light energy into heat energy through non-radiative relaxation pathways, while suppressing energy loss through radiative pathways such as fluorescence. This results in a photothermal conversion efficiency significantly higher than that of products prepared using conventional chiral ligands.

[0034] Preferably, the copper source is copper chloride dihydrate; the sulfur source is thiourea; and the complexing agent is trisodium citrate dihydrate. The raw materials used are all conventional and readily available chemical reagents, with low cost, mild reaction conditions, and easy industrial production.

[0035] Preferably, the molar ratio of the raw materials is copper source: dextrorotatory penicillamine chiral ligand: sulfur source = 4:2.5:1. The modification of the chiral ligand and the growth of the quantum dots are balanced, which can obtain a product with higher photothermal conversion efficiency.

[0036] Preferably, the chiral Cu 2-x An aqueous dispersion of S quantum dots, at a concentration of 1 mg / mL, was subjected to a power density of 1.6 W / cm². 2 After irradiation with an 808nm laser for 480 seconds, the temperature rise reached over 42°C. The performance parameters directly demonstrate the high photothermal conversion efficiency of the quantum dots of this invention, providing performance assurance for their practicality in related application fields.

[0037] like Figure 1 As shown, the chiral Cu with high photothermal conversion efficiency of the present invention 2-x The preparation method of S quantum dots includes the following steps: S1. In an aqueous phase, the copper source and complexing agent are mixed and reacted to obtain a copper complex solution; S2. Add a sulfur source and a dextrorotatory penicillamine chiral ligand to the copper complex solution to obtain a mixed reaction solution; the added raw materials make the molar ratio of copper, dextrorotatory penicillamine and sulfur in the reaction system (3.5-4.5):(2.0-3.0):1; S3. Heat the mixed reaction solution to carry out nucleation and growth reactions, yielding chiral Cu. 2-x Aqueous dispersions of S quantum dots; S4. Cool the obtained aqueous dispersion, centrifuge, discard the supernatant, wash the precipitate with deionized water and dry it to obtain chiral Cu with high photothermal conversion efficiency. 2-x S is a solid powder of quantum dots, where 0 < x ≤ 1.

[0038] Through a stepwise reaction, precise control of the nucleation and growth process of quantum dots was achieved. First, the copper source reacts with the complexing agent to form a stable copper complex, avoiding the instantaneous and uncontrollable precipitation of cuprous sulfide caused by excessively high copper ion concentration when the sulfur source is added directly. Through the complexation effect, the concentration of free copper ions in the system is effectively controlled, thereby achieving the regulation of the subsequent reaction rate.

[0039] By simultaneously injecting the sulfur source and the dextrorotatory penicillamine chiral ligand into the precursor solution, the chiral ligand is ensured to participate in the reaction from the initial stage of quantum dot nucleation, rather than being surface modified after the quantum dots are formed.

[0040] Under controlled heating conditions, the copper complex slowly releases copper ions, which react with a sulfur source to form Cu. 2-x The S-crystal nucleus, along with the dextrorotatory penicillamine ligand, coordinates with the nucleus surface in real time and accompanies the entire crystal growth process, enabling the chiral information to be effectively induced and solidified into the structure of the entire nanocrystal, ultimately forming a specific chiral structure with efficient photothermal conversion performance.

[0041] By precisely controlling the reactant release rate and the timing of ligand intervention, the unique structural advantages of dextrorotatory penicillamine were maximized, thus enabling the stable and reproducible preparation of chiral Cu with high photothermal conversion efficiency. 2-x S-quantum dots.

[0042] Preferably, in step S1, after stirring the copper source and the complexing agent at room temperature, a pre-reaction is carried out under the protection of an inert gas to obtain the copper complex solution. The pre-reaction step ensures that the copper ions and the complexing agent are fully coordinated to form a uniform and stable precursor solution, which lays the foundation for the uniform nucleation of quantum dots in the subsequent process.

[0043] Preferably, in step S3, the heating temperature is 50°C to 70°C, and the heating time is 1.5 hours to 3 hours. This range of process parameters is suitable for obtaining Cu with uniform size and good crystallinity. 2-x The optimized conditions for S quantum dots can effectively balance the crystal growth rate and the surface modification efficiency of chiral ligands.

[0044] Preferably, in step S2, the added raw materials make the molar ratio of copper, dextro-penicillamine and sulfur in the reaction system (3.5-4.5):(2.0-3.0):1. The defined molar ratio of reactants ensures adequate coverage of chiral ligands, thereby maximizing their regulatory effect on the photothermal properties of quantum dots.

[0045] Preferably, steps S1 and S2 are both performed under inert gas protection. Inert gas protection prevents the oxidation of cuprous ions in the system, ensuring the phase purity of the product and thus obtaining high-quality Cu. 2-x A crucial safeguard for S-quantum dots.

[0046] This invention provides chiral Cu with high photothermal conversion efficiency. 2-x The preparation method of S quantum dots, the main raw materials and reagents used in the following examples and comparative examples, and their sources and specifications are as follows. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products: Copper chloride dihydrate, with the molecular formula CuCl2·2H2O and CAS number 10125-13-0, is used in this invention as a copper source to provide copper ions.

[0047] Trisodium citrate dihydrate, with the molecular formula C6H5Na3O7·2H2O and CAS number 6132-04-3, is used as a complexing agent in this invention to form a stable precursor complex with copper ions.

[0048] Thiourea, with the molecular formula CH4N2S and CAS number 62-56-6, is used in this invention as a sulfur source to react with copper ions to generate cuprous sulfide.

[0049] Dextrorotatory penicillamine, with the molecular formula C5H 11 NO2S, chemically named (2R)-2-amino-3-methyl-3-mercaptobutyric acid (CAS number 52-67-5), is used as a chiral ligand in this invention to modify the surface of quantum dots to regulate their photothermal conversion properties.

[0050] Dextrocysteine, with the molecular formula C3H7NO2S and chemical name (R)-2-amino-3-mercaptopropionic acid, CAS number 52-89-1, is used as a comparative chiral ligand in the comparative examples of this invention.

[0051] L-cysteine, with the molecular formula C3H7NO2S and chemical name (S)-2-amino-3-mercaptopropionic acid, CAS number 52-90-4, is used as a comparative chiral ligand in the comparative examples of this invention.

[0052] Deionized water, with the molecular formula H2O and CAS number 7732-18-5, is used as the solvent for all reactions in this invention.

[0053] Example 1 This embodiment provides chiral Cu with high photothermal conversion efficiency. 2-x The preparation method of S quantum dots includes the following steps: Step 1: Add 0.0277g of copper chloride dihydrate and 0.0528g of trisodium citrate dihydrate to a two-necked flask equipped with a magnetic stir bar, and add 19mL of deionized water to the flask; stir the mixture in the flask magnetically for 10 minutes at room temperature; then evacuate the flask and introduce nitrogen gas, and continue stirring the reaction for 30 minutes under nitrogen protection to obtain a copper complex solution.

[0054] Step 2: While the aforementioned steps are being performed, prepare a 0.2 mol / L thiourea solution and a 0.1 mol / L dextrorotatory penicillamine solution, respectively. After the reaction in Step 1 is completed, under nitrogen protection, inject 200 μL of thiourea solution and 1 mL of dextrorotatory penicillamine solution into the flask using a syringe. After injection, evacuate the flask again and introduce nitrogen gas.

[0055] Step 3: The mixed reaction solution obtained in Step 2 is stirred continuously at room temperature for 5 minutes; then, the flask is placed in a water bath at 60°C and the reaction is continuously heated and stirred for 2 hours. After the reaction is completed, D-Pen-Cu is obtained. 2-x Aqueous dispersions of S quantum dots.

[0056] Step four: Cool the aqueous dispersion obtained in step three to room temperature, centrifuge, discard the supernatant, wash the precipitate 2 to 3 times with deionized water, and then dry it to obtain chiral D-Pen-Cu. 2-x Solid powder of S quantum dots.

[0057] Example 2 This embodiment provides chiral Cu with high photothermal conversion efficiency. 2-x The preparation method of S quantum dots includes the following steps: Steps one, two, and four of the method are exactly the same as in Example 1.

[0058] Step 3: The mixed reaction solution obtained in Step 2 is stirred continuously at room temperature for 5 minutes; then, the flask is placed in a water bath at 50°C and the reaction is continuously heated and stirred for 2 hours. After the reaction is completed, D-Pen-Cu is obtained. 2-x Aqueous dispersions of S quantum dots.

[0059] Example 3 This embodiment provides chiral Cu with high photothermal conversion efficiency. 2-x The preparation method of S quantum dots includes the following steps: Steps one, two, and four of the method are exactly the same as in Example 1.

[0060] Step 3: The mixed reaction solution obtained in Step 2 is stirred continuously at room temperature for 5 minutes; then, the flask is placed in a water bath at 70°C and the reaction is continuously heated and stirred for 2 hours. After the reaction is completed, D-Pen-Cu is obtained. 2-x Aqueous dispersions of S quantum dots.

[0061] Example 4 This embodiment provides chiral Cu with high photothermal conversion efficiency. 2-x The preparation method of S quantum dots includes the following steps: Steps one, three, and four of the method are exactly the same as in Example 1.

[0062] Step 2: While the aforementioned steps are being performed, prepare a 0.2 mol / L thiourea solution and a 0.08 mol / L dextrorotatory penicillamine solution, respectively. After the reaction in Step 1 is completed, under nitrogen protection, inject 200 μL of thiourea solution and 1 mL of dextrorotatory penicillamine solution into the flask using a syringe. After injection, evacuate the flask again and introduce nitrogen gas.

[0063] Comparative Example 1 The difference from Example 1 is that the chiral ligand dextromethorphanamine used in step two is replaced with an equimolar amount of dextrocysteine.

[0064] Comparative Example 2 The difference from Example 1 is that the chiral ligand dextromethorphanamine used in step two is replaced with an equimolar amount of levocysteine.

[0065] Comparative Example 3 The difference compared to Example 1 is that no chiral ligand solution is added in step two.

[0066] Comparative Example 4 The difference from Example 1 is that the chiral ligand dextro-penicillamine used in step two is replaced with its enantiomer levo-penicillamine.

[0067] Test Example 1: Structural Confirmation This test case aims to confirm that the material prepared by the method of this invention is chiral Cu. 2-x S quantum dots were developed and verified.

[0068] Through data processing, the L / D-Cys-Cu was further investigated. 2-x The crystal structure of S quantum dots, such as Figure 2 As shown, both synthesized quantum dots contained Cu₂S (JCPDS, 12-0227, 02-1294) and CuS (JCPDS, 65-3556). Peaks consistent with those of cuprous sulfide and copper sulfide further indicate the presence of Cu. 2-x Formation of S quantum dots.

[0069] Figure 3 It is a chiral D-Pen-Cu 2-x XRD images of S quantum dots. Further investigation of D-Pen-Cu was conducted through data processing. 2- x The crystal structure of S quantum dots revealed the presence of CuS (JCPDS, 06-0464) and Cu₂S (JCPDS, 46-1195, 53-0522). Peaks consistent with those of cuprous sulfide and copper sulfide further indicate the presence of Cu. 2-x Formation of S quantum dots.

[0070] Test Example 2: Regarding morphology Figure 4 Chiral D-Pen-Cu was shown 2-xTEM image of S quantum dots. Monodisperse quantum dots with uniform size and an average diameter of 3.5 nm can be clearly seen, and clear crystal planes with a lattice spacing of 0.36 nm can be observed.

[0071] Test Example 3: On Chirality This test case aims to confirm the chiral Cu prepared by the method of the present invention. 2-x Whether the S quantum dots have successfully acquired chiral optical activity, and whether this chirality originates from the D-penicillamine ligand used.

[0072] Experimental steps: First, the D-Pen-Cu prepared in Example 1 was... 2-x S quantum dot solid powder and raw material D-penicillamine solid powder were prepared and diluted with deionized water to a concentration suitable for spectral testing. A quartz cuvette with an optical path length of 1 cm was used, with deionized water as a blank background reference. A circular dichroism spectrometer was used, with the scanning wavelength range set to 300-900 nm, the scanning speed to 100 nm / min, and the data point resolution to 1 nm. The two sample solutions were scanned by circular dichroism (CD) at room temperature, and their signal intensity was recorded.

[0073] To understand chiral D-Pen-Cu 2-x The chiral activity of S quantum dots was measured using CD measurements. Figure 5 a shows D-Pen-Cu 2-x CD spectrum of S quantum dots Figure 5 b shows the CD spectrum of the D-penicillamine chiral ligand. The figure shows that the original penicillamine chiral ligand has a CD signal at 224 nm, while the quantum dots derived from the penicillamine ligand have a CD signal at 207 nm, altering the position of the CD spectrum. The addition of the penicillamine chiral ligand endows the sample with chirality.

[0074] Figure 6 Test data showed that L-Cys / D-Cys-Cu 2-x The CD spectrum of CdSe or CdS quantum dots shows a near-perfect mirror image in the spectral range of 400 to 900 nm. Unlike the CD spectrum of ordinary CdSe or CdS quantum dots, chiral Cu... 2-x S quantum dots exhibit strong CD mirror signals not only in the visible region but also in the near-infrared region. The dual signal with two peaks at 650 nm and 800 nm is generated by ligand-induced hybridization and localized surface plasmon resonance (LSPR). To quantitatively assess the chiral activity of chiral quantum dots, their anisotropy factor (g-factor) was calculated, which is the ratio of the difference in absorbance between left-handed and right-handed circularly polarized light to the total absorbance. According to the formula:

[0075] This represents the asymmetry factor, used to indicate the degree of asymmetry in the system's response to left- and right-circularly polarized light. A larger value indicates a stronger chiral optical response. This indicates the absorption intensity of left-handed circularly polarized light; This indicates the absorption intensity of right-handed circularly polarized light; This represents the absorption difference, which reflects the difference in the system's ability to absorb left and right circularly polarized light; Indicates the total absorbed intensity; This refers to the intensity of the circular dichroism signal, measured in millidegrees. 32980 is a unit conversion factor; Abs is absorbance, which is the absorbance value at the corresponding wavelength in the UV-Vis absorption spectrum. The L-Cys-Cu is calculated from this. 2-x S quantum dots and D-Cys-Cu 2-x The g-factor of S quantum dots is 0.6 × 10⁻⁶. -4 and 1.72×10 -4 .

[0076] The appearance of circular dichroism signals in the product confirms that the chiral ligand D-penicillamine has been successfully induced and transferred to the inorganic cuprous sulfide quantum dots through the method of the present invention, enabling the entire nanocrystal to exhibit overall chiral optical activity. The successful construction of this chiral structure is the structural basis for the high photothermal conversion efficiency of the quantum dots subsequently prepared by this method.

[0077] Test Example 3: Photothermal Performance This test example aims to quantitatively compare the photothermal conversion performance of quantum dot samples prepared by the embodiments of the present invention and different comparative examples.

[0078] Experimental steps: The quantum dot solid powders prepared in Examples 1 to 4 and Comparative Examples 1 to 4 were each prepared into an aqueous dispersion with a concentration of 1 mg / mL using deionized water. 2 mL of each sample dispersion was placed in a standard quartz cuvette. The cuvette was placed on a sample holder, and the position of the 808 nm semiconductor laser was adjusted so that its beam completely covered the sample solution in the cuvette. The output power density of the laser was set to 1.6 W / cm². 2 Use a non-contact infrared thermometer and focus its temperature measurement on the area in the center of the sample liquid that is irradiated by the laser.

[0079] At the start of the test, the laser and temperature recorder were turned on simultaneously. The infrared thermometer recorded the center temperature of the sample liquid every second. The laser was turned off after irradiation for 480 seconds, and the temperature was recorded until the sample liquid cooled to room temperature naturally. The above test process was repeated for each sample.

[0080] Experimental data such as Figure 7 As shown.

[0081] It can be visually observed that when D-Pen-Cu is irradiated with 808 nm near-infrared lasers of different power densities, the effect is different. 2-x S quantum dots exhibit instantaneous response and rapid heating, and the highest achievable temperature increases with increasing output power density. It can be seen that at an output power density of 1.0 W, D-Pen-Cu exhibits rapid heating after 480 s of excitation. 2-x The highest temperature achievable by S quantum dots is 37.6 °C; the output power density is 1.6 W, and after 480 s of excitation, D-Pen-Cu 2-x The highest temperature achievable with S quantum dots is 43.2℃. Meanwhile, D-Pen-Cu... 2-x The highest temperature that S quantum dots can reach after irradiation for 480 s with an 808 nm near-infrared laser output power of 1.6 W is 41.6 ℃.

[0082] Figure 8 For L-Cys-Cu with an output power density of 1.6 W 2-x S and D-Cys-Cu 2-x The single-shot photothermal response of L-Cys-Cu quantum dots can be visually observed when irradiated with an 808 nm near-infrared laser at a power density of 1.6 W. 2-x S quantum dots and D-Cys-Cu 2-x S quantum dots exhibit instantaneous response and rapid heating, and the highest temperature that can be reached increases with the increase of output power density.

[0083] Under the same testing conditions, D-Pen-Cu prepared in Example 1 2-x The highest temperature and temperature rise achievable by S quantum dots are higher than those of all comparative products.

[0084] Specifically, the product of Example 1 (temperature rise of 43.3°C) showed a significantly higher temperature rise compared to Comparative Example 1 (temperature rise of 41.5°C) which used the D-cysteine ​​ligand in the prior art. Furthermore, the comparison results between Example 1 (D-penicillamine) and Comparative Example 4 (L-penicillamine), as well as the comparison results between Comparative Example 1 (D-cysteine) and Comparative Example 2 (L-cysteine), all confirmed that the D-configuration chiral ligand is superior to its corresponding L-configuration in improving photothermal performance. Comparative Example 3 (without chiral ligand) showed the lowest temperature rise effect, demonstrating that chiral ligand modification is a necessary structural basis for achieving efficient photothermal conversion.

[0085] The test results confirm that the preparation method provided by the present invention, which uses dextrorotatory penicillamine as a chiral ligand, can obtain cuprous sulfide quantum dots with higher photothermal conversion efficiency than those prepared using conventional ligands such as cysteine ​​or under ligand-free conditions.

[0086] Test Example 4: This test case aims to evaluate the ability of quantum dots prepared by the method of the present invention to retain their photothermal conversion performance after being subjected to multiple laser irradiation and cooling cycles.

[0087] Experimental steps: The product of Example 1, which exhibited the best photothermal performance in Test Example 3, and the product of Comparative Example 1, which served as the main comparison, were selected for testing. The instruments and equipment used in the tests, sample concentration, and laser power density (1.6 W / cm²) were as follows: 2 The temperature recording method is the same as that in Test Example 3.

[0088] For each test sample, a complete photothermal conversion test was performed, which involved irradiating the sample with an 808nm laser for 480 seconds and recording the highest temperature that could be reached. The laser was then turned off, and the sample was allowed to cool naturally to the initial room temperature. This process was counted as the first cycle. After the sample had completely cooled down, the aforementioned irradiation and cooling steps were repeated for a total of four cycles. The highest temperature that could be reached in each cycle was recorded and compared.

[0089] Experimental data: such as Figure 9 As shown.

[0090] After 4 radiation / cooling cycles, the trend of the curve remained unchanged in each cycle for D-Pen-Cu. 2-x The maximum temperature that S quantum dots can reach remains almost unchanged, which clearly demonstrates their excellent photostability.

[0091] Figure 10 For L-Cys-Cu with an output power density of 1.6 W 2-x S and D-Cys-Cu 2-x Cyclic photothermal response of S quantum dots.

[0092] After 4 radiation / cooling cycles, the trend of the curve remained unchanged in each cycle for L-Cys-Cu. 2-x S quantum dots and D-Cys-Cu 2-x The maximum temperature that S quantum dots can reach remains almost unchanged, clearly demonstrating their excellent photostability. Furthermore, we found that during cycling, D-Cys-Cu... 2-x The highest temperature of S quantum dots is consistently higher than that of L-Cys-Cu. 2-x This is consistent with our conclusion regarding S quantum dots. Example 1 shows the preparation of D-Pen-Cu. 2-xThe S quantum dot sample did not show a significant decrease in its maximum temperature after four cycles of laser irradiation and natural cooling. The peak temperature of each cycle remained around 68℃. The sample in Comparative Example 1 also showed a certain degree of stability, but its peak temperature showed a slight decreasing trend during the cycle.

[0093] The results confirm that the quantum dots obtained by the preparation method provided in this invention possess excellent photothermal stability. This stability ensures that the material can continuously provide efficient and reliable photothermal conversion output in applications requiring repeated illumination, which is an important foundation for its practical application.

[0094] The products prepared by this invention are mainly used in the biomedical field, specifically photothermal therapy: quantum dots can be delivered into the body via intravenous injection or other methods. Due to the enhanced permeability and retention effect (EPR effect) of tumor tissue, quantum dots can be passively enriched in the tumor area. At this time, near-infrared lasers (such as 808nm lasers) with a deep penetration depth into biological tissue are used to irradiate the tumor site externally. The quantum dots enriched there will efficiently convert light energy into heat energy, causing the local temperature of the tumor area to rise rapidly to above 42°C, thereby achieving precise thermal ablation of cancer cells with minimal damage to surrounding normal tissues. The high photothermal conversion efficiency of the quantum dots in this invention means that an effective treatment temperature can be achieved with lower laser power density and shorter irradiation time, reducing the risk of side effects.

[0095] The thermal image was taken after the synthesized chiral quantum dot solution was injected into mice and irradiated with an 808 nm laser at a power density of 1.6 W. Figure 11 a is D-Cys-Cu diluted 5 times. 2-x Thermal imaging of S-FA quantum dots; Figure 11 b is L-Cys-Cu diluted 5 times. 2-x Thermal imaging of S-FA quantum dots; Figure 11 c is L-Cys-Cu diluted 10 times. 2-x Thermal imaging of S-FA quantum dots; Figure 11 d is D-Cys-Cu diluted 10 times. 2-x Thermal imaging of S-FA quantum dots.

[0096] During the same irradiation time of approximately 4 minutes, D-Cys-Cu diluted 5 times... 2-x The temperature at the site of S-FA quantum dot melanoma can reach 30.1℃; L-Cys-Cu diluted 5 times... 2-x The temperature at the site of S-FA quantum dot melanoma can reach 26.8℃; L-Cys-Cu diluted 10 times... 2-xThe temperature at the site of S-FA quantum dot melanoma can reach 27.4℃; D-Cys-Cu diluted 10 times... 2- x The temperature at the melanoma site of S-FA quantum dots can reach 25.4℃. Comparative analysis shows that for L-Cys-Cu... 2-x For S-FA quantum dots, a 10-fold dilution resulted in relatively high temperatures achievable at melanoma sites in mice; while for D-Cys-Cu... 2-x For S-FA quantum dots, a 5-fold dilution resulted in relatively high temperatures achievable at melanoma sites in mice. Considering the heating effects of the four samples, the 5-fold dilution of D-Cys-Cu showed the best heating effect. 2-x S-FA quantum dots. The size of melanomas in mice was observed after laser irradiation, and slight changes in melanoma size were found.

[0097] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A chiral Cu 2-x The method for preparing S quantum dots is characterized by: Includes the following steps: S1. In an aqueous phase, the copper source and complexing agent are mixed and reacted to obtain a copper complex solution; S2. Add a sulfur source and a dextrorotatory penicillamine chiral ligand to the copper complex solution to obtain a mixed reaction solution; the added raw materials make the molar ratio of copper source, dextrorotatory penicillamine and sulfur source in the reaction system (3.5-4.5):(2.0-3.0):1; S3. Heat the mixed reaction solution to carry out nucleation and growth reactions, yielding chiral Cu. 2-x Aqueous dispersions of S quantum dots; S4. Cool the obtained aqueous dispersion, centrifuge, discard the supernatant, wash the precipitate with deionized water and dry it to obtain chiral Cu with high photothermal conversion efficiency. 2-x S is a solid powder of quantum dots, where 0 < x ≤ 1.

2. The chiral Cu according to claim 1 2-x The method for preparing S quantum dots is characterized by: In step S1, the copper source and the complexing agent are stirred at room temperature and then pre-reacted under inert gas protection to obtain a copper complex solution.

3. The chiral Cu according to claim 1 2-x The method for preparing S quantum dots is characterized by: In step S3, the heating temperature is 50°C to 70°C.

4. The chiral Cu according to claim 3 2-x The method for preparing S quantum dots is characterized by: The heating time is 1.5 to 3 hours.

5. The chiral Cu according to claim 1 2-x The method for preparing S quantum dots is characterized by: Both steps S1 and S2 are performed under inert gas protection.

6. The chiral Cu according to claim 1 2-x The method for preparing S quantum dots is characterized by: The copper source is copper chloride dihydrate; the sulfur source is thiourea; and the complexing agent is trisodium citrate dihydrate.

7. Chiral Cu prepared by any one of the preparation methods described in claims 1-6 2-x S-quantum dots.

8. The chiral Cu according to claim 7 2-x S-quantum dots, characterized in that, The chiral Cu 2-x S quantum dots include L-Cys-Cu 2-x S quantum dots and D-Cys-Cu 2-x S quantum dots, chiral Cu 2-x An aqueous dispersion of S quantum dots, at a concentration of 1 mg / mL, was subjected to a power density of 1.6 W / cm². 2 After irradiation with an 808nm laser for 480 seconds, under these conditions, L-Cys-Cu 2-x The highest temperature of S quantum dots is 41.1℃, and that of D-Cys-Cu is... 2-x The highest temperature of S quantum dots is 41.6℃.

9. Chiral Cu prepared by any one of the preparation methods described in claims 1-6 2-x S quantum dots or chiral Cu as described in claim 7 or 8 2-x Application of S quantum dots in the preparation of drugs for treating tumors.

10. The chiral Cu according to claim 9 2-x The application of S quantum dots in the preparation of anti-tumor drugs is characterized by, The drug is prepared for delivery into the body via intravenous injection, where quantum dots are passively enriched in the tumor region, and the tumor site is irradiated externally using a near-infrared laser with a deep penetration depth into biological tissue.

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