Multifunctional composite radiofrequency ablation instrument and preparation method thereof

Abstract

The invention relates to the technical field of tumor treatment instruments, in particular to a multifunctional composite radiofrequency ablation instrument and a preparation method thereof. The multifunctional composite radiofrequency ablation instrument provided by the invention comprises a radiofrequency needle body, a sodium alginate-calcium ion cross-linked network attached to the radiofrequency needle body, mesoporous CaCO3 loaded on the sodium alginate-calcium ion cross-linked network, and a chemotherapeutic drug adsorbed by the mesoporous CaCO3, the composite material can further comprise tert-butyl nitrite grafted on the sodium alginate-calcium ion cross-linked network. Imaging monitoring, local ablation, drug / gas release and immune regulation are fused into one-time operation, multi-dimensional treatment breakthrough from local ablation to system immune activation is achieved through targeted delivery, multi-mechanism cooperation and immune microenvironment regulation, and the system is remarkably superior to the prior art in the aspects of curative effect accuracy, safety and long-acting relapse / metastasis resistance.

Description

Technical Field

[0001] This invention relates to the field of tumor treatment device technology, and in particular to a multifunctional composite radiofrequency ablation device and its preparation method. Background Technology

[0002] Radiofrequency ablation, as a major thermal ablation modality in interventional ultrasound therapy, has been widely used in clinical practice.

[0003] However, given the prevalence of tumors, radiofrequency ablation remains challenging when treating small or occult tumors. These tumors may be difficult to ablate effectively due to difficulties in imaging localization and the complexity of radiofrequency needle puncture. Furthermore, even with larger tumors, incomplete treatment can occur if the margins are not clearly defined during ablation, leaving tumor residue and increasing the risk of recurrence and metastasis.

[0004] To overcome these limitations, some studies have proposed using adjuvant therapies to eliminate residual tumors and inhibit metastasis and recurrence, such as chemotherapy combined with radiofrequency ablation, or immunotherapy combined with radiofrequency ablation. Currently, radiofrequency ablation combined with other treatments involves intravenous or intratumoral injection of relevant anti-tumor drugs, followed by radiofrequency ablation. This inevitably involves multiple invasive drug administrations, which easily increases the risk of needle tract metastasis, and the systemic diffusion of drugs reduces the amount of drug reaching the tumor, affecting the treatment effect. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a multifunctional composite radiofrequency ablation device and its preparation method. The multifunctional composite radiofrequency ablation device provided by this invention can reduce the risk of needle tract metastasis, significantly increase the local drug concentration in the tumor, and achieve controlled release in response to the tumor microenvironment.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a multifunctional composite radiofrequency ablation device, comprising a radiofrequency needle body, a sodium alginate-calcium ion crosslinking network attached to the radiofrequency needle body, mesoporous CaCO3 loaded on the sodium alginate-calcium ion crosslinking network, and chemotherapy drugs adsorbed by the mesoporous CaCO3.

[0008] Preferably, it also includes tert-butyl nitrite grafted onto the sodium alginate-calcium ion crosslinking network.

[0009] Preferably, the chemotherapy drugs include one or more of doxorubicin, paclitaxel, docetaxel, vincristine, trastuzumab, and imatinib.

[0010] This invention provides a method for preparing the multifunctional composite radiofrequency ablation device described above, comprising the following steps: (1) immersing the radiofrequency needle body in an aqueous solution of sodium alginate for modification to obtain a sodium alginate-modified radiofrequency needle; immersing the sodium alginate-modified radiofrequency needle in an aqueous solution of a first soluble calcium salt for Ca... 2+ Coordination and cross-linking form a sodium alginate-calcium ion cross-linking network, yielding RF-needle@Alg;

[0011] (2) The RF-needle@Alg is immersed in an aqueous solution containing a second soluble calcium salt and a chemotherapeutic drug. Then, the pH of the system is adjusted to 7-8 with a buffer solution. A carbonate solution is added to the resulting buffer system. The RF-needle@Alg forms mesoporous CaCO3 in situ to adsorb the chemotherapeutic drug, resulting in RF-needle@Alg / drug-CaCO3, which serves as the multifunctional composite radiofrequency ablation device.

[0012] Preferably, when the multifunctional composite radiofrequency ablation device further includes tert-butyl nitrite grafted onto the sodium alginate-calcium ion crosslinking network, step (2) is replaced with the following steps:

[0013] The RF-needle@Alg was activated with carboxylic acid, and NH2-PEG-SH was added to the carboxylic acid activated system to carry out a coupling reaction. NH2-PEG-SH was grafted onto RF-needle@Alg to obtain RF-needle@Alg-SH.

[0014] RF-needle@Alg-SH was impregnated in an aqueous solution containing a second soluble calcium salt and a chemotherapeutic drug. The pH of the system was then adjusted to 7-8 with a buffer solution. A carbonate solution was added to the resulting buffer system, and the RF-needle@Alg-SH formed mesoporous CaCO3 in situ to adsorb the chemotherapeutic drug, resulting in RF-needle@Alg-SH / drug-CaCO3.

[0015] The RF-needle@Alg-SH / drug-CaCO3 was impregnated in an organic solution of tert-butyl nitrite to undergo a grafting reaction, resulting in RF-needle@Alg-SNO / chemotherapeutic drug-CaCO3, which serves as the multifunctional composite radiofrequency ablation device.

[0016] Preferably, the carboxylic acid activation includes: immersing the RF-needle@Alg in a buffer solution containing NHS and EDC for activation; the buffer solution containing NHS and EDC has a pH of 6-7, wherein the concentration of NHS is 2-10 mg / mL and the concentration of EDC is 1-5 mg / mL; and the activation reaction takes 4-8 hours.

[0017] Preferably, the concentration of NH2-PEG-SH in the reaction system during the coupling reaction is 1-5 mg / mL; and the coupling reaction time is 7-9 h.

[0018] Preferably, the concentration of the second soluble calcium salt in the aqueous solution containing the second soluble calcium salt and the chemotherapeutic drug is 1-5 mol / L; the second soluble calcium salt includes CaCl2.

[0019] Preferably, before immersing the radio frequency needle body in an aqueous sodium alginate solution for modification, the radio frequency needle body is further subjected to sanding.

[0020] Preferably, the concentration of the sodium alginate aqueous solution is 5-20 mg / mL; the concentration of the first soluble calcium salt aqueous solution is 0.5-1.5 mol / L; and the first soluble calcium salt includes CaCl2.

[0021] This invention provides a multifunctional composite radiofrequency ablation device, comprising a radiofrequency needle body, a sodium alginate-calcium ion crosslinking network attached to the needle body, mesoporous CaCO3 loaded on the sodium alginate-calcium ion crosslinking network, and chemotherapeutic drugs adsorbed by the mesoporous CaCO3. This invention loads chemotherapeutic drugs onto the radiofrequency needle, achieving simultaneous and targeted release during ablation, significantly increasing the local drug concentration in the tumor and avoiding the systemic diffusion problems associated with traditional intravenous / intratumoral injection. The integrated design reduces the need for multiple invasive procedures, eliminating the risk of needle tract metastasis caused by multiple punctures in traditional drug delivery. Furthermore, the radiofrequency ablation device of this invention is loaded with mesoporous CaCO3, which adsorbs the chemotherapeutic drugs. The slightly acidic environment of the tumor (pH 6.0-6.8) triggers the decomposition of CaCO3, releasing the chemotherapeutic drugs and CaCO3. 2+ Simultaneously, CO2 is generated, in which Ca... 2+ It can deposit and induce calcium death in tumor cells, and the released chemotherapy drugs can enhance chemotherapy, exhibiting multiple tumor cell killing mechanisms. Meanwhile, CO2 bubbles can enhance the contrast of ultrasound imaging, and the high-dose cavitation effect can enhance the efficiency of radiofrequency energy deposition, thereby improving the treatment effect. Since the loaded chemotherapy drugs are released through the tumor microenvironment response (pH triggers CaCO3 decomposition), it can achieve precise spatiotemporal control and reduce off-target toxicity.

[0022] In addition, CaCO3 has high biocompatibility, and its degradation products (CaCO3, Ca ... 2+ CO2 can participate in physiological metabolism.

[0023] Furthermore, the multifunctional composite radiofrequency ablation device provided by this invention also includes tert-butyl nitrite grafted onto the sodium alginate-calcium ion crosslinking network. The tert-butyl nitrite can respond to the radiofrequency thermal field and release NO. The released NO can regulate the tumor immune microenvironment and enhance the immunotherapy effect. Specifically, NO can regulate the immunosuppressive tumor microenvironment by activating macrophages to an anti-tumor state, increasing T cell infiltration, and reducing PD-L1 expression.

[0024] This invention integrates imaging monitoring, local ablation, drug / gas release, and immune modulation into a single operation. Through targeted delivery, multi-mechanism synergy, and immune microenvironment regulation, it achieves a multi-dimensional therapeutic breakthrough from local ablation to systemic immune activation. It is significantly superior to existing technologies in terms of efficacy precision, safety, and long-term anti-recurrence / metastasis effects. Attached Figure Description

[0025] Figure 1 The BET isotherm adsorption curve for calcium carbonate is shown.

[0026] Figure 2 This is a line graph showing the particle size variation of calcium carbonate over time under different pH conditions.

[0027] Figure 3 TEM images of calcium carbonate at different pH values ​​and at different times;

[0028] Figure 4 TEM images of calcium carbonate treated in different media (ethanol, water, DMEM culture medium, serum FBS) for 1 day and 2 days;

[0029] Figure 5 TEM (a) and SEM (b) of DOX@CaCO3, particle size distribution of DOX@CaCO3 and CaCO3 (c), and Zeta potential diagrams of DOX, CaCO3 and DOX@CaCO3 (d).

[0030] Figure 6 TEM and mapping images of DOX@CaCO3;

[0031] Figure 7 The graph shows the linear relationship between doxorubicin concentration and UV absorption peak.

[0032] Figure 8 Graphs showing drug release at different temperatures after 1-3 reuses of the RF-needle@Alg-SH / DOX-CaCO3 radiofrequency needle;

[0033] Figure 9 Figure 1 shows the drug release at different pH levels after 1-3 reuses of the RF-needle@Alg-SH / DOX-CaCO3 radiofrequency needle.

[0034] Figure 10 SEM and TEM images of the RF-needle@Alg-SH / DOX-CaCO3 radio frequency needle and the material peeled off from the RF needle are shown. Among them, ab are SEM images of the RF needle at different magnifications, c, e, and f are TEM images of the peeled material, and d is the SEM image of the peeled material.

[0035] Figure 11 TEM images of DOX@CaCO3 at different pH values;

[0036] Figure 12 This is an ultrasound image of calcium carbonate.

[0037] Figure 13 SEM morphology of calcium carbonate loaded with radiofrequency needles at different pH values ​​for 0-3 reuses;

[0038] Figure 14 SEM morphology of calcium carbonate loaded with radiofrequency needles for 0-3 reuses at different temperatures;

[0039] Figure 15 Graphs showing cell viability in different treatment groups;

[0040] Figure 16 Cell staining images for different treatment groups;

[0041] Figure 17 Graphs showing intracellular pH measurements in different treatment groups;

[0042] Figure 18 Intracellular Ca in different treatment groups 2+ Content detection chart. Detailed Implementation

[0043] This invention provides a multifunctional composite radiofrequency ablation device, comprising a radiofrequency needle body, a sodium alginate-calcium ion crosslinking network attached to the radiofrequency needle body, mesoporous CaCO3 loaded on the sodium alginate-calcium ion crosslinking network, and chemotherapy drugs adsorbed by the mesoporous CaCO3.

[0044] The multifunctional composite radiofrequency ablation device provided by this invention includes a radiofrequency needle body. This invention does not have special requirements for the radiofrequency needle body; any radiofrequency needle body well-known in the art can be used, such as medical-grade stainless steel or nickel-titanium alloy. The radiofrequency needle body serves to provide radiofrequency energy conduction and mechanical support.

[0045] The multifunctional composite radiofrequency ablation device provided by this invention includes a sodium alginate-calcium ion crosslinking network attached to the radiofrequency needle body. In this invention, the sodium alginate-calcium ion crosslinking network serves as a carrier for each component, loading each component onto the radiofrequency needle body. Simultaneously, sodium alginate also exhibits excellent biocompatibility.

[0046] The multifunctional composite radiofrequency ablation device provided by the present invention includes mesoporous CaCO3 loaded on the sodium alginate-calcium ion crosslinking network and chemotherapy drugs adsorbed by the mesoporous CaCO3.

[0047] In this invention, the chemotherapeutic drug can be selected according to actual needs, specifically one or more of doxorubicin, paclitaxel, docetaxel, vincristine, trastuzumab, and imatinib. This invention does not impose specific limitations on the loading amounts of the mesoporous CaCO3 and the chemotherapeutic drug; those skilled in the art can adjust the loading amounts by adjusting the preparation conditions to meet actual needs. In this invention, the average pore size of the mesoporous CaCO3 is preferably 2-5 nm, and in a specific embodiment, it is 4.4360 nm; the specific surface area of ​​the mesoporous CaCO3 is preferably 15-20 m² / g. 2 / g, which is 16.2860m in the specific embodiment. 2 / g.

[0048] In this invention, CaCO3 can respond to the acidic environment of the tumor, and upon being triggered, it decomposes to release chemotherapeutic drugs and Ca. 2+ Simultaneously, CO2 is generated, in which Ca... 2+ The device can deposit and induce calcium death in tumor cells, releasing chemotherapeutic drugs that enhance chemotherapy, exhibiting multiple cell-killing mechanisms. Meanwhile, CO2 bubbles enhance ultrasound imaging contrast, and the high-dose cavitation effect improves radiofrequency energy deposition efficiency, thus enhancing therapeutic efficacy. The chemotherapeutic drugs are released through a tumor microenvironment response (pH-triggered CaCO3 decomposition). Therefore, this multifunctional composite radiofrequency ablation device enables precise spatiotemporal control and reduces off-target toxicity.

[0049] Furthermore, the multifunctional composite radiofrequency ablation device provided by the present invention also includes tert-butyl nitrite grafted onto the sodium alginate-calcium ion crosslinking network; more preferably, the tert-butyl nitrite is grafted onto the sodium alginate-calcium ion crosslinking network via NH2-PEG-SH.

[0050] In this invention, the tert-butyl nitrite can respond to a radiofrequency thermal field and release NO. The released NO can regulate the tumor immune microenvironment and enhance the immunotherapy effect. Specifically, NO can regulate the immunosuppressive tumor microenvironment by activating macrophages to an anti-tumor state, increasing T cell infiltration, and reducing PD-L1 expression.

[0051] This invention provides a method for preparing the multifunctional composite radiofrequency ablation device described above, comprising the following steps: (1) immersing the radiofrequency needle body in an aqueous solution of sodium alginate for modification to obtain a sodium alginate-modified radiofrequency needle; immersing the sodium alginate-modified radiofrequency needle in an aqueous solution of a first soluble calcium salt for Ca... 2+ Coordination and cross-linking form a sodium alginate-calcium ion cross-linking network, yielding RF-needle@Alg;

[0052] (2) The RF-needle@Alg is immersed in an aqueous solution containing a second soluble calcium salt and a chemotherapeutic drug. Then, the pH of the system is adjusted to 7-8 with a buffer solution. A carbonate solution is added to the resulting buffer system. The RF-needle@Alg forms mesoporous CaCO3 in situ to adsorb the chemotherapeutic drug, resulting in RF-needle@Alg / drug-CaCO3, which serves as the multifunctional composite radiofrequency ablation device.

[0053] Unless otherwise specified, all raw materials used in this invention are commercially available products well known in the art.

[0054] In this invention, the radio frequency needle body is immersed in an aqueous solution of sodium alginate for modification, thereby obtaining a sodium alginate-modified radio frequency needle.

[0055] Prior to the modification, the radiofrequency needle body is preferably first sanded. In this invention, the sanding is preferably performed sequentially with 200-grit and 1000-grit sandpaper, each time for 2-5 times. This invention first uses 200-grit sandpaper for coarse sanding to quickly remove the oxide layer, contaminants, and processing residues from the surface of the radiofrequency needle body, exposing the unoxidized metal substrate; then, 1000-grit sandpaper is used for fine sanding to refine the surface roughness, reduce scratch depth, and further clean the surface. By sanding, this invention imparts an appropriate rough surface to the radiofrequency needle body, which can promote cell adhesion and subsequent sodium alginate modification.

[0056] In this invention, the concentration of the sodium alginate aqueous solution is preferably 5-20 mg / mL, and in specific embodiments it can be 5, 10, 15, or 20 mg / mL. In this invention, the immersion time is preferably 30-60 min, and in specific embodiments it can be 30, 40, 50, or 60 min. This invention physically attaches sodium alginate to the radiofrequency needle body by immersing it in a sodium alginate aqueous solution. After the immersion is completed, the radiofrequency needle body is removed, washed with water, and a sodium alginate-modified radiofrequency needle is obtained.

[0057] After obtaining the sodium alginate-modified radiofrequency needle, the present invention immerses the sodium alginate-modified radiofrequency needle in an aqueous solution of a first soluble calcium salt for Ca2+ treatment. 2+Coordination and cross-linking are performed to form a sodium alginate-calcium ion cross-linked network, yielding RF-needle@Alg.

[0058] In this invention, the first soluble calcium salt preferably includes CaCl2; the concentration of the aqueous solution of the first soluble calcium salt is preferably 0.5-1.5 mol / L, and in specific embodiments it can be 0.5, 1, or 1.5 mol / L. In this invention, the soaking time in the aqueous solution of the first soluble calcium salt is preferably 2-4 hours, and in specific embodiments it can be 2, 3, or 4 hours. This invention achieves CaCl2 absorption by soaking in the aqueous solution of the first soluble calcium salt. 2+ The adsorption of sodium alginate promotes cross-linking, forming a sodium alginate-calcium ion cross-linked network. After impregnation, the radio frequency needle body is removed and washed with water to obtain RF-needle@Alg. In this invention, RF-needle@Alg refers to a radio frequency needle body with an attached sodium alginate-calcium ion cross-linked network.

[0059] After obtaining RF-needle@Alg, the present invention impregnates the RF-needle@Alg in an aqueous solution containing a second soluble calcium salt and a chemotherapeutic drug, and then adjusts the pH of the system to 7-8 with a buffer solution to obtain a buffer system.

[0060] In this invention, the concentration of the second soluble calcium salt in the aqueous solution containing the second soluble calcium salt and the chemotherapeutic drug is preferably 1-5 mol / L, and in specific embodiments it can be 1, 2, 3, 4, or 5 mol / L. In this invention, the second soluble calcium salt preferably includes CaCl2. This invention does not specifically limit the content of the chemotherapeutic drug in the aqueous solution containing the second soluble calcium salt and the chemotherapeutic drug; it is determined according to actual needs. Specifically, the total mass of the chemotherapeutic drug can be 5-30 mg, such as 5, 10, 15, 20, 25, or 30 mg.

[0061] In this invention, the immersion time of the RF-needle@Alg-SH in an aqueous solution containing a second soluble calcium salt and a chemotherapeutic drug is preferably 10-14 hours, and in specific embodiments it can be 10, 11, 12, 13 or 14 hours.

[0062] In this invention, the buffer solution is preferably a Tris-HCl buffer solution; the concentration of the Tris-HCl buffer solution is preferably 1×10⁻⁶. -3 M, with a pH value preferably 8. In this invention, a buffer solution is used to adjust the pH of the system to 7-8; in specific embodiments, this can be 7, 7.3, 7.5, 7.8, or 8. Adjusting the pH of the reaction system to 7-8 in this invention facilitates the subsequent reaction of Na₂CO₃ with CaCl₂ to produce CaCO₃.

[0063] After obtaining the buffer system, the present invention adds a carbonate solution to the obtained buffer system, and the RF-needle@Alg forms mesoporous CaCO3 in situ to adsorb the chemotherapeutic drug, thus obtaining RF-needle@Alg / drug-CaCO3.

[0064] In this invention, the carbonate solution preferably includes a Na₂CO₃ solution; the concentration of the carbonate solution is preferably 1-5 mol / L, and in specific embodiments it can be 1, 2, 3, 4, or 5 mol / L; the molar ratio of the carbonate in the carbonate solution to the second soluble calcium salt in the aqueous solution containing the second soluble calcium salt and the chemotherapeutic drug is preferably 1:1. This invention preferably adds the carbonate solution dropwise to the buffer system. After the addition is complete, this invention preferably sonicates the resulting reaction system for 1-5 minutes. In this invention, the sonication power is preferably 10W. This invention promotes the full reaction between the second soluble calcium salt and the carbonate through sonication. After stopping the sonication, this invention observes the reaction system; when the color of the reaction system becomes turbid, the radiofrequency needle body is removed, washed with water, and RF-needle@Alg / drug-CaCO₃ is obtained.

[0065] In this invention, the RF-needle@Alg / drug-CaCO3 includes a radiofrequency needle body, a sodium alginate-calcium ion crosslinking network attached to the radiofrequency needle body, mesoporous CaCO3 loaded on the sodium alginate-calcium ion crosslinking network, and a chemotherapy drug adsorbed by the mesoporous CaCO3.

[0066] In this invention, the RF-needle@Alg / drug-CaCO3 can be used directly as a multifunctional composite radiofrequency ablation device, or it can be grafted with tert-butyl nitrite on the basis of RF-needle@Alg / drug-CaCO3 to serve as a multifunctional composite radiofrequency ablation device.

[0067] When grafting tert-butyl nitrite, step (2) above is replaced with the following steps:

[0068] The RF-needle@Alg was activated with carboxylic acid, and NH2-PEG-SH was added to the carboxylic acid activated system to carry out a coupling reaction. NH2-PEG-SH was grafted onto RF-needle@Alg to obtain RF-needle@Alg-SH.

[0069] RF-needle@Alg-SH was impregnated in an aqueous solution containing a second soluble calcium salt and a chemotherapeutic drug. The pH of the system was then adjusted to 7-8 with a buffer solution. A carbonate solution was added to the resulting buffer system, and the RF-needle@Alg-SH formed mesoporous CaCO3 in situ to adsorb the chemotherapeutic drug, resulting in RF-needle@Alg-SH / drug-CaCO3.

[0070] The RF-needle@Alg-SH / drug-CaCO3 was impregnated in an organic solution of tert-butyl nitrite to undergo a grafting reaction, resulting in RF-needle@Alg-SNO / chemotherapeutic drug-CaCO3, which serves as the multifunctional composite radiofrequency ablation device.

[0071] In this invention, the RF-needle@Alg is activated with carboxylic acid, and NH2-PEG-SH is added to the activated carboxylic acid system to carry out a coupling reaction. NH2-PEG-SH is grafted onto RF-needle@Alg to obtain RF-needle@Alg-SH.

[0072] In this invention, the carboxylic acid activation preferably includes: immersing the RF-needle@Alg in a buffer solution containing NHS (N-hydroxysuccinimide) and EDC (1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride) for activation.

[0073] In this invention, the pH value of the buffer solution containing NHS and EDC is preferably 6-7, and in specific embodiments it can be 6, 6.2, 6.5, 6.8 or 7; wherein, the concentration of NHS is preferably 2-10 mg / mL, and in specific embodiments it can be 2, 5, 7 or 10 mg / mL; the concentration of EDC is preferably 1-5 mg / mL, and in specific embodiments it can be 1, 2, 3, 4 or 5 mg / mL. This invention does not have special requirements for the type of buffer solution, as long as it meets the above pH requirements, it can be MES buffer solution, HEPES (4-(2-hydroxyethyl)-1-piperazine ethanesulfonic acid) buffer solution or phosphate buffer solution.

[0074] In this invention, the activation reaction time is preferably 4-8 hours, and in specific embodiments it can be 4, 5, 6, 7 or 8 hours.

[0075] In this invention, NHS and EDC are used in combination to activate the carboxyl groups on the sodium alginate-calcium ion crosslinking network (the sodium alginate molecular chain contains a large number of carboxyl groups -COO). - Activated carboxylic acids can react with primary amines (-NH2) or other nitrogen-containing nucleophiles to form stable amide bonds.

[0076] After the carboxylic acid is activated, NH2-PEG-SH is added to the activated carboxylic acid system to carry out a coupling reaction. NH2-PEG-SH is grafted onto RF-needle@Alg to obtain RF-needle@Alg-SH.

[0077] In this invention, the amount of NH2-PEG-SH added preferably satisfies the requirement that the concentration of NH2-PEG-SH in the coupling reaction system is 1-5 mg / mL, and in specific embodiments, it can be 1, 2, 3, 4, or 5 mg / mL. In the embodiments of this invention, the NH2-PEG-SH is a commercially available product with a molecular weight of 2000, manufactured by Ponsure, catalog number: ps2-sn-2k. In this invention, the coupling reaction time is preferably 7-9 hours, and in specific embodiments, it can be 7, 8, or 9 hours. This invention grafts NH2-PEG-SH onto RF-needle@Alg via a coupling reaction. After completing the coupling reaction, this invention preferably washes twice with the aforementioned buffer solution to obtain RF-needle@Alg-SH.

[0078] In this invention, the RF-needle@Alg-SH includes a radio frequency needle body and a sodium alginate-calcium ion crosslinking network attached to the radio frequency needle body; the sodium alginate-calcium ion crosslinking network is grafted with NH2-PEG-SH.

[0079] After obtaining RF-needle@Alg-SH, the present invention impregnates the RF-needle@Alg-SH in an aqueous solution containing a second soluble calcium salt and a chemotherapeutic drug, then adjusts the pH of the system to 7-8 with a buffer solution, adds a carbonate solution to the resulting buffer system, and the RF-needle@Alg-SH forms mesoporous CaCO3 in situ to adsorb the chemotherapeutic drug, thus obtaining RF-needle@Alg-SH / drug-CaCO3.

[0080] In this invention, the preparation conditions of RF-needle@Alg-SH / drug-CaCO3 are the same as those of RF-needle@Alg / drug-CaCO3, except that RF-needle@Alg is replaced with RF-needle@Alg-SH.

[0081] In this invention, the RF-needle@Alg-SH / drug-CaCO3 includes a radiofrequency needle body, a sodium alginate-calcium ion crosslinking network attached to the radiofrequency needle body, mesoporous CaCO3 loaded on the sodium alginate-calcium ion crosslinking network, and a chemotherapy drug adsorbed by the mesoporous CaCO3; the sodium alginate-calcium ion crosslinking network is grafted with NH2-PEG-SH.

[0082] After obtaining RF-needle@Alg-SH / drug-CaCO3, the present invention impregnates the RF-needle@Alg-SH / drug-CaCO3 in an organic solution of tert-butyl nitrite to carry out a grafting reaction, thereby obtaining RF-needle@Alg-SNO / chemotherapeutic drug-CaCO3, which serves as a multifunctional composite radiofrequency ablation device.

[0083] In this invention, the organic solution of tert-butyl nitrite comprises tert-butyl nitrite and an organic solvent; the organic solvent preferably comprises a methanol-toluene mixture; the volume ratio of methanol to toluene in the methanol-toluene mixture is preferably 1:1. Preferably, the RF-needle@Alg-SH / drug-CaCO3 is first impregnated in the organic solvent before tert-butyl nitrite is added.

[0084] In this invention, the volume ratio of the organic solvent to tert-butyl nitrite is preferably (3-5):1, and in specific embodiments it can be 3:1, 4:1 or 5:1.

[0085] The present invention does not have special requirements on the amount of organic solution of tert-butyl nitrite, as long as it is sufficient to submerge the modified part of the radiofrequency needle tip (i.e., RF-needle@Alg-SH / drug-CaCO3).

[0086] In this invention, the grafting reaction is preferably carried out under light-protected stirring conditions; the grafting reaction time is preferably 12-24 hours, and in specific embodiments it can be 12, 16, 20 or 24 hours.

[0087] In the grafting reaction process of the present invention, the nitrosyl group (-ONO) of tert-butyl nitrite reacts with the thiol group of NH2-PEG-SH and is grafted onto RF-needle@Alg-SH / drug-CaCO3.

[0088] After the grafting reaction is completed, the present invention preferably removes the radiofrequency needle body and washes it with water to obtain RF-needle@Alg-SNO / chemotherapeutic drug-CaCO3.

[0089] In this invention, the RF-needle@Alg-SNO / chemotherapeutic drug-CaCO3 includes a radiofrequency needle body, a sodium alginate-calcium ion crosslinking network attached to the radiofrequency needle body, mesoporous CaCO3 loaded on the sodium alginate-calcium ion crosslinking network, and a chemotherapeutic drug adsorbed by the mesoporous CaCO3, and also includes tert-butyl nitrite grafted onto the sodium alginate-calcium ion crosslinking network.

[0090] When RF-needle@Alg-SNO / chemotherapeutic drug-CaCO3 is used as a multifunctional composite radiofrequency ablation device, tert-butyl nitrite releases NO under the action of radiofrequency heat, which plays a role in regulating the tumor immune microenvironment.

[0091] The following detailed description of the multifunctional composite radiofrequency ablation device and its preparation method provided by the present invention, with reference to the embodiments, should not be construed as limiting the scope of protection of the present invention.

[0092] Example 1

[0093] The radio frequency (RF) needle was sanded twice each with 200-mesh and 1000-mesh sandpaper, then immersed in a 5 mg / mL sodium alginate aqueous solution for 30 minutes. After washing twice with water, a sodium alginate-modified RF needle was obtained. This needle was then immersed in a 1 mol / L CaCl2 solution for 3 hours to achieve Ca... 2+ The adsorption and cross-linking of sodium alginate were performed, followed by washing twice with water to obtain RF-needle@Alg. The prepared RF-needle@Alg was then immersed in a MES buffer solution (pH = 6.2) with an NHS concentration of 5 mg / mL and an EDC concentration of 2 mg / mL, and reacted for 4 h. Subsequently, NH2-PEG-SH was added to achieve a NH2-PEG-SH concentration of 2 mg / mL, and the coupling reaction continued for 8 h. The mixture was then washed twice with the MES buffer solution to obtain RF-needle@Alg-SH. RF-needle@Alg-SH was then immersed in an aqueous solution containing CaCl2 (1 M concentration) and 30 mg doxorubicin for 12 h, followed by slow addition of 1 × 10⁻⁶ mg / mL of the solution. -3 The pH of M was adjusted to 7.8 using a Tris-HCl buffer solution (pH = 8.0), and then 1 mol / L Na2CO3 was added dropwise to the solution. The mixture was sonicated for 1 min at a power of 10 W until the color became turbid. The solution was washed twice with water to obtain RF-needle@Alg-SH / DOX-CaCO3.

[0094] Example 2

[0095] RF-needle@Alg-SH / DOX-CaCO3 was prepared following the steps in Example 1;

[0096] The prepared RF-needle@Alg-SH / DOX-CaCO3 was further impregnated in 6 mL of methanol / toluene mixed solution (volume ratio 1:1), followed by the addition of 2 mL of tert-butyl nitrite. The mixture was stirred in the dark for 24 h, and then washed three times with water to obtain RF-needle@Alg-SNO / DOX-CaCO3.

[0097] Example 3

[0098] The radio frequency (RF) needle was sanded twice each with 200-mesh and 1000-mesh sandpaper, then immersed in a 5 mg / mL sodium alginate aqueous solution for 30 minutes. After washing twice with water, a sodium alginate-modified RF needle was obtained. This needle was then immersed in a 1 mol / L CaCl2 solution for 3 hours to achieve Ca... 2+ The adsorption and cross-linking of sodium alginate were performed, followed by washing twice with water to obtain RF-needle@Alg. RF-needle@Alg was immersed in an aqueous solution containing CaCl2 (1 mol / L) and 30 mg doxorubicin for 12 h, followed by slow addition of 1 × 10⁻⁶ mg of sodium alginate. -3 The pH of M was adjusted to 7.8 using a Tris-HCl buffer solution (pH = 8.0). Then, 1 mol / L Na2CO3 was added dropwise to the solution, and the mixture was sonicated for 1 min at a power of 10 W until the color became turbid. The solution was washed twice with water to obtain RF-needle@Alg / DOX-CaCO3.

[0099] Comparative Example 1

[0100] The only difference from Example 1 is that doxorubicin (DOX) was not added, resulting in RF-needle@Alg-SH / CaCO3.

[0101] Comparative Example 2

[0102] Dissolve 1.1098 g of calcium chloride powder in 10 mL of ultrapure water to obtain a 1 mol / L calcium chloride solution; slowly add 1.059 g of sodium carbonate to the calcium chloride solution while stirring, and a milky white precipitate will form to obtain a calcium carbonate solution.

[0103] The RF-needle@Alg from Example 1 was immersed in a calcium carbonate solution and stirred for 24 hours to adsorb calcium carbonate, thus obtaining RF-needle@Alg / CaCO3.

[0104] Structural and performance characterization

[0105] The preparation process of calcium carbonate used in the following test is as follows: 1.1098g of calcium chloride powder was added to 10mL of ultrapure water and dissolved to obtain a 1mol / L calcium chloride solution; 1.059g of sodium carbonate was slowly added to the calcium chloride solution while stirring, and a milky white precipitate was formed, which is calcium carbonate. After separation, calcium carbonate was obtained.

[0106] The preparation process of DOX@CaCO3 is as follows: 10 mg of the calcium carbonate prepared above was added to 5 mL of a DOX aqueous solution with a concentration of 600 μg / mL. The mixture was continuously stirred at room temperature in the dark for 72 h. After centrifugation at 10000 g for 10 min, it was washed with deionized water. Subsequently, the precipitate was freeze-dried to obtain DOX@CaCO3.

[0107] Calcium carbonate was subjected to a BET test, and the results were as follows: Figure 1 As shown. By Figure 1 It can be seen that the specific surface area of ​​calcium carbonate is 16.2860 m². 2 / g, with an average pore size of 4.4360nm.

[0108] Calcium carbonate was suspended in 3 mL of PBS solution with pH values ​​of 5.0, 6.5, and 7.4, respectively, and placed in dialysis bags with a molecular weight cutoff of 3500 kDa, sealing both ends with dialysis clamps. The dialysis bags containing calcium carbonate were completely immersed in 10 mL of PBS solution of the same pH value and incubated in a shaker at 150 rpm and 37°C under light-protected conditions. At specific time intervals, 1 mL of dialysis solution was taken from the system, and the particle size was measured; the solution was then returned to the original solution. 1 mL of sample was taken using a pipette and injected into a plastic cuvette. The particle size analyzer parameters were set (refractive index: 1.0 and sample solution: anhydrous ethanol), and the test was run 3–5 times (average value was taken) to obtain the particle size distribution of calcium carbonate. Calcium carbonate samples at different pH values ​​were collected at 0, 30, 60, 90, 120, and 150 min to determine the particle size distribution. The results are shown below. Figure 2 As shown. By Figure 2 It can be seen that the particle size of calcium carbonate decreases continuously over time, and the lower the pH, the smaller the particle size, indicating that calcium carbonate is acid sensitive.

[0109] 5 mg of calcium carbonate was weighed and placed in PBS buffer solutions at pH 5.0, 6.5, and 7.4, respectively. Samples were removed at 2 min, 30 min, 2 h, and 4 h, and their morphology was observed using transmission electron microscopy. The results are as follows: Figure 3 As shown. By Figure 3 It is known that an acidic environment can accelerate the degradation of calcium carbonate.

[0110] The morphological changes of calcium carbonate were observed after 1 day and 2 days in different media (ethanol, water, DMEM culture medium, and serum FBS). The results are as follows: Figure 4 As shown. By Figure 4 It can be seen that calcium carbonate can be well preserved in ethanol and serum, easily crystallizes in water, and is slightly lost in culture medium.

[0111] Scanning electron microscopy and transmission electron microscopy were performed on DOX@CaCO3, and the results are as follows: Figure 5 As shown in a and b. From Figure 5 As shown in a and b, the drug-loaded calcium carbonate remains approximately spherical. Particle size analysis of CaCO3 and DOX@CaCO3 was performed, and the results are shown below. Figure 5 c in the middle, by Figure 5 As shown in Figure c, the particle size of CaCO3 increases after drug loading. Zeta potential measurements were performed on DOX, CaCO3, and DOX@CaCO3; the results are shown below. Figure 5 d. By Figure 5 As shown in Figure d, the potential of DOX@CaCO3 after drug loading changed significantly compared to DOX and CaCO3, reaching -15.01mV, indicating successful drug loading.

[0112] Figure 6 The TEM and mapping images of DOX@CaCO3 show that carbon, oxygen, and calcium are evenly distributed, proving that DOX@CaCO3 was successfully synthesized.

[0113] 5 mg of DOX@CaCO3 was weighed and placed in PBS buffer at pH 5.0, 6.5, and 7.4, respectively. Samples were removed at 2 min, 30 min, 2 h, and 4 h, and their morphology was observed using transmission electron microscopy. The results are shown in the figure. Figure 11 .Depend on Figure 11 It is known that an acidic environment can accelerate the degradation of DOX@CaCO3.

[0114] 5 mg of calcium carbonate was weighed and placed in PBS buffer solutions at pH 5.0, 6.5, and 7.4, respectively. Carbon dioxide production was detected using ultrasonic grayscale imaging. The results are shown in [Figure number missing]. Figure 12 The circled area represents the carbon dioxide bubbles produced. Figure 12 It is known that an acidic environment can cause calcium carbonate to produce more carbon dioxide gas.

[0115] The RF-needle@Alg-SH / DOX-CaCO3 radiofrequency needle was characterized by SEM, and the results are shown in the figure. Figure 10 In sections a and b, the loaded material was peeled off from the radiofrequency needle using a blade, and observed by SEM. The results are shown in [Figure number missing]. Figure 10 In section d, the exfoliated material was observed using transmission electron microscopy at different magnifications. The results are shown in [Figure d]. Figure 10 c, e, and f. From Figure 10 It can be seen that the morphology of calcium carbonate loaded on the needle is basically the same as that of pure calcium carbonate, proving that this loading method does not affect its morphology and function.

[0116] Figure 7 The graph shows the linear relationship between doxorubicin concentration and ultraviolet absorption peak, which can be used to quantitatively calculate the doxorubicin concentration.

[0117] Figure 8 and Figure 9 The demonstration showed that the RF-needle@Alg-SH / DOX-CaCO3 radiofrequency needle could be reused 1-3 times for drug release. The reuse process is as follows:

[0118] The used radiofrequency needles were thoroughly cleaned and dried. They were then sanded twice with 200-grit and 1000-grit sandpaper, respectively. Afterward, they were immersed in a 5 mg / mL sodium alginate aqueous solution for 30 minutes, followed by two washes with water to obtain sodium alginate-modified radiofrequency needles. These needles were then immersed in a 1 M CaCl2 solution for 3 hours to achieve Ca... 2+ The adsorption and cross-linking of sodium alginate were performed, followed by washing twice with water to obtain RF-needle@Alg. The prepared RF-needle@Alg was then immersed in a MES buffer solution (pH = 6.2) with an NHS concentration of 5 mg / mL and an EDC concentration of 2 mg / mL, and reacted for 4 h. Subsequently, NH2-PEG-SH was added to achieve a NH2-PEG-SH concentration of 2 mg / mL, and the coupling reaction continued for 8 h. The mixture was then washed twice with the MES buffer solution to obtain RF-needle@Alg-SH. RF-needle@Alg-SH was then immersed in an aqueous solution containing CaCl2 (1 M concentration) and 30 mg doxorubicin for 12 h, followed by slow addition of 1 × 10⁻⁶ mg / mL of the solution. -3 Adjust the pH of the M Tris-HCl buffer solution (pH=8.0) to 7.8, then add 1M Na2CO3 dropwise to the solution, sonicate for 1 min at a power of 10W until the color becomes turbid, wash twice with water to obtain RF-needle@Alg-SH / DOX-CaCO3.

[0119] Reusable microwave ablation needles loaded with drug (1-3 times) were wrapped with dialysis membranes, clamped at both ends, and placed in PBS buffers at different pH values ​​and temperatures. Specifically, PBS buffers with pH values ​​of 5.0, 6.5, and 7.4 (37℃) and PBS buffers with temperatures of 25℃, 37℃, and 45℃ (pH 7.4) were used. 1 mL of the dialysis solution was taken at specific time points for UV-Vis analysis. The results are shown in [Figure 1]. Figure 8 and Figure 9 .Depend on Figure 8 and Figure 9 It can be seen that with the increase of reuse, the final amount of drug released decreases slightly, and the drug release is stable. Note: 37℃ is within the normal human body temperature range, and 37℃ is generally selected for research. The pH value of 7.4 corresponds to the normal physiological environment pH range of the human body.

[0120] SEM morphology of calcium carbonate loaded with radiofrequency needles at different pH values ​​after 0-3 reuses: Figure 13 As shown, the SEM morphology of calcium carbonate loaded with an RF needle after 0-3 repeated uses is as follows: (The RF needle is heated, and the temperature is monitored using an infrared camera until it reaches a specific temperature.) Figure 14 As shown. By Figure 13 and Figure 14 It can be seen that increasing temperature and acidity does not affect the morphology of calcium carbonate.

[0121] The above reusability test results show that the radiofrequency needle of the present invention can be reused to prepare multifunctional composite radiofrequency ablation devices, while existing radiofrequency needles are often not reusable. The present invention greatly reduces the cost of radiofrequency ablation devices.

[0122] Cell killing ability test: Six groups were used: control (untreated cells), G1 (RF-needle), G2 (RF-needle@Alg), G3 (RF-needle@Alg / CaCO3), G4 (RF-needle@Alg-SH / DOX-CaCO3), and G5 (RF-needle@Alg-SNO / DOX-CaCO3). 4T1 cells were cultured overnight at 37℃ in a 5% CO2 incubator to allow adhesion. Then, the cells were treated with the above-mentioned treatments at 5W for 1 min. Cells were cultured for another 6 h. 10 μL of LCK-8 reagent was added to each well. The 96-well plate was returned to the incubator and incubated for 1–4 hours. After incubation, the absorbance (OD value) of each well was measured at 450 nm using a microplate reader to obtain cell viability. The test results are as follows: Figure 15 As shown, the cell survival rate was 100% in the Control group, 72.09% in the G1 group, 69.06% in the G2 group, 53.08% in the G3 group, 42.27% in the G4 group, and 36.29% in the G5 group. The cell-killing ability of the G5 group was stronger than the other groups, followed by the G4 group. RF-needle can kill tumor cells through high temperature; the increased calcium carbonate can cause calcium overload, leading to calcium death of tumor cells; the increased DOX is a chemotherapy drug that can kill tumor cells; and the -SNO group (-SNO is an abbreviation for the covalent bond structure -S-NO formed by the reaction of thiol (-SH) and tert-butyl nitrite) can also cause tumor death. Therefore, G5 represents a combination of four treatment modalities and has the strongest killing power compared to the other groups.

[0123] Cell staining experiment: 4T1 cells were seeded into culture plates and, after adhesion, were divided into 6 groups: control (untreated cells), G1 (RF-needle), G2 (RF-needle@Alg), G3 (RF-needle@Alg / CaCO3), G4 (RF-needle@Alg-SH / DOX-CaCO3), and G5 (RF-needle@Alg-SNO / DOX-CaCO3). After irradiation at 5W for 1min, the cells were cultured for 12h. Then, the following steps were performed: 1. Remove the old culture medium and wash gently once with PBS. 2. Dilute Calcein-AM and PI to working concentrations with PBS (or serum-free medium) according to the kit instructions. 3. Add an appropriate amount of Calcein-AM / PI staining solution to each well / tube of cells. Gently mix and incubate at 37°C for 20–30 minutes, protected from light. 4. After staining, wash once slowly with PBS to remove excess dye. 5. Microscopic observation: Live cells: green fluorescence; Dead cells: red fluorescence. Results are shown below. Figure 16 .Depend on Figure 16 It can be seen that the G5 group had the highest number of dead cells, indicating that the G5 group had the strongest killing effect on cells, followed by the G4 group.

[0124] Intracellular pH detection: 4T1 cells were seeded into culture plates and, after adhesion, were processed into 5 groups: G1 (RF-needle), G2 (RF-needle@Alg), G3 (RF-needle@Alg / CaCO3), G4 (RF-needle@Alg-SH / DOX-CaCO3), and G5 (RF-needle@Alg-SNO / DOX-CaCO3). After irradiation at 5W for 1 min, the cells were cultured for 12 h. BCECF-AM: An intracellular pH fluorescent probe that can be cleaved by intracellular esterases and emits green fluorescence (pH sensitive). The lower the pH of the cell microenvironment (the more acidic), the stronger the green fluorescence. DAPI: A nuclear dye that binds to DNA and emits blue fluorescence, commonly used for nuclear staining. The specific experimental procedure is as follows: 1. After processing, the culture medium was removed, and the cells were gently washed once with PBS. 2. Prepare BCECF-AM stock solution (1 mM) with DMSO according to the instructions, then dilute to the working concentration (5 μM) with serum-free medium or PBS. 3. Add an appropriate amount of BCECF-AM working solution to the cells (e.g., 100–200 μL per well). 4. Incubate at 37°C for 20–30 minutes, protected from light. 5. Wash 2–3 times with PBS to remove probes that have not entered the cells. 6. Dilute DAPI to the working concentration (1 μg / mL) with PBS, add DAPI staining solution, and incubate at room temperature in the dark for 5–10 minutes. 7. Wash 1–2 times with PBS to remove excess DAPI. 8. Observe using a fluorescence microscope. Results are shown in the table below. Figure 17 .Depend on Figure 17 It can be seen that the G5 group had the highest pH, and the acidic tumor microenvironment was alleviated to the greatest extent after treatment. This is because the G5 group had the most dead tumor cells, and the tumor cells had vigorous lactic acid metabolism, resulting in an acidic pH. After treatment, the number of tumor cells decreased, and less acidic substances were secreted, hence the higher pH compared to other groups.

[0125] Intracellular Ca 2+ Content detection: 4T1 cells were seeded into culture plates and, after adhesion, were processed into 5 groups: G1 (RF-needle), G2 (RF-needle@Alg), G3 (RF-needle@Alg / CaCO3), G4 (RF-needle@Alg-SH / DOX-CaCO3), and G5 (RF-needle@Alg-SNO / DOX-CaCO3). After irradiation at 5W for 1 min, the cells were cultured for 12 h. Fluo-4 AM: an intracellular calcium ion fluorescent probe, cleaved by intracellular esterases, enters the cell and reacts with Ca2+. + Combined with green fluorescence, it is often used to detect the concentration of intracellular free calcium ions; the stronger the fluorescence accumulation, the greater the calcium ion accumulation. DAPI: a nuclear dye that binds to DNA and emits blue fluorescence, labeling the cell nucleus. The experimental procedure is as follows: 1. After treatment, remove the culture medium and gently wash once with PBS. 2. Prepare Fluo-4 AM stock solution (1 mM) with DMSO, and dilute to the working concentration (5 μM) with serum-free medium or HBSS. 3. Add Fluo-4 AM working solution to the cells (e.g., 100–200 μL per well). Incubate at 37°C for 30–45 minutes in the dark. 4. Wash 2–3 times with PBS to remove dye that has not entered the cells. 5. Incubate again at 37°C for 10–20 minutes to help the probe completely deesterify. 6. Dilute DAPI to the working concentration (1 μg / mL) with PBS, add DAPI staining solution, incubate at room temperature in the dark for 5–10 minutes, and wash 1–2 times with PBS to remove excess DAPI. 7. Observe using a fluorescence microscope. The results are shown in [Figure number missing]. Figure 18 .Depend on Figure 18 It is known that groups G4 and G5 have the highest calcium ion content. Increased calcium ion content can cause calcium overload leading to cell death, and their tumor-killing ability is expected to be the strongest.

[0126] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A multifunctional composite radiofrequency ablation device, characterized in that, It includes a radiofrequency needle body, a sodium alginate-calcium ion crosslinking network attached to the radiofrequency needle body, mesoporous CaCO3 loaded on the sodium alginate-calcium ion crosslinking network, and chemotherapy drugs adsorbed by the mesoporous CaCO3.

2. The multifunctional composite radiofrequency ablation device according to claim 1, characterized in that, It also includes tert-butyl nitrite grafted onto the sodium alginate-calcium ion crosslinking network.

3. The multifunctional composite radiofrequency ablation device according to claim 1 or 2, characterized in that, The chemotherapy drugs include one or more of doxorubicin, paclitaxel, docetaxel, vincristine, trastuzumab, and imatinib.

4. A method for preparing the multifunctional composite radiofrequency ablation device according to any one of claims 1-3, comprising the following steps: (1) The radio frequency needle body was immersed in an aqueous solution of sodium alginate for modification to obtain a radio frequency needle modified with sodium alginate; The sodium alginate-modified radiofrequency needle was immersed in an aqueous solution of a first soluble calcium salt for Ca2+ processing. 2+ Coordination and cross-linking form a sodium alginate-calcium ion cross-linking network, yielding RF-needle@Alg; (2) The RF-needle@Alg is immersed in an aqueous solution containing a second soluble calcium salt and a chemotherapeutic drug. Then, the pH of the system is adjusted to 7-8 with a buffer solution. A carbonate solution is added to the resulting buffer system. The RF-needle@Alg forms mesoporous CaCO3 in situ to adsorb the chemotherapeutic drug, resulting in RF-needle@Alg / drug-CaCO3, which serves as the multifunctional composite radiofrequency ablation device.

5. The preparation method according to claim 4, characterized in that, When the multifunctional composite radiofrequency ablation device further includes tert-butyl nitrite grafted onto the sodium alginate-calcium ion crosslinking network, step (2) is replaced with the following steps: The RF-needle@Alg was activated with carboxylic acid, and NH2-PEG-SH was added to the carboxylic acid activated system to carry out a coupling reaction. NH2-PEG-SH was grafted onto RF-needle@Alg to obtain RF-needle@Alg-SH. RF-needle@Alg-SH was impregnated in an aqueous solution containing a second soluble calcium salt and a chemotherapeutic drug. The pH of the system was then adjusted to 7-8 with a buffer solution. A carbonate solution was added to the resulting buffer system, and the RF-needle@Alg-SH formed mesoporous CaCO3 in situ to adsorb the chemotherapeutic drug, resulting in RF-needle@Alg-SH / drug-CaCO3. The RF-needle@Alg-SH / drug-CaCO3 was impregnated in an organic solution of tert-butyl nitrite to undergo a grafting reaction, resulting in RF-needle@Alg-SNO / chemotherapeutic drug-CaCO3, which serves as the multifunctional composite radiofrequency ablation device.

6. The preparation method according to claim 5, characterized in that, The carboxylic acid activation includes: immersing the RF-needle@Alg in a buffer solution containing NHS and EDC for activation; the buffer solution containing NHS and EDC has a pH of 6-7, wherein the concentration of NHS is 2-10 mg / mL and the concentration of EDC is 1-5 mg / mL; the activation reaction takes 4-8 hours.

7. The preparation method according to claim 5, characterized in that, The concentration of NH2-PEG-SH in the reaction system during the coupling reaction is 1-5 mg / mL; the coupling reaction time is 7-9 h.

8. The preparation method according to claim 4 or 5, characterized in that, The concentration of the second soluble calcium salt in the aqueous solution containing the second soluble calcium salt and the chemotherapeutic drug is 1-5 mol / L; the second soluble calcium salt includes CaCl2.

9. The preparation method according to claim 4, characterized in that, Before immersing the radio frequency needle body in an aqueous sodium alginate solution for modification, the radio frequency needle body is further subjected to sanding.

10. The preparation method according to claim 4, characterized in that, The concentration of the sodium alginate aqueous solution is 5-20 mg / mL; the concentration of the first soluble calcium salt aqueous solution is 0.5-1.5 mol / L; the first soluble calcium salt includes CaCl2.

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