An electrothermally controlled release gel based on dynamic nucleic acid quadruplexes and temperature-sensitive polymers

Abstract

The present application relates to a kind of electrothermal controlled-release gels based on dynamic nucleic acid quadruplex and temperature-sensitive polymer.The matrix of the electrothermal controlled-release gel is formed by the interpenetrating nucleic acid quadruplex network and temperature-sensitive polymer network, and the electrothermal controlled-release gel further includes conductive nanomaterial, which can produce electrothermal effect with the nucleic acid quadruplex network under the action of applied electric stimulus, and cause the volume change of the temperature-sensitive polymer network.The nucleic acid quadruplex network is obtained by rolling circle amplification of DNA chain with surface-modified thiol after temperature-sensitive polymer network, and the two are thus crosslinked and interpenetrated.The molecular level conformation regulation of the nucleic acid quadruplex and the macroscopic volume response of the temperature-sensitive polymer are efficiently coupled through the interpenetrating structure, which has the dual advantages of molecular scale release precision and macroscopic rapid response, and solves the problems that traditional nucleic acid materials are difficult to produce macroscopic effect and temperature-sensitive gel lacks fine molecular regulation ability.

Description

Technical Field

[0001] This invention relates to the field of biomedical technology, and in particular to an electrothermal controlled-release gel based on dynamic nucleic acid quadruplexes and thermosensitive polymers. Background Technology

[0002] High-precision, externally tunable molecular controlled-release systems hold significant value in precision drug delivery, smart biomaterials, bioelectronic devices, and soft medical systems. These applications require material systems that, while ensuring good biocompatibility, achieve rapid response, reversible regulation, and on-demand release. However, existing stimulus-responsive release materials still have significant shortcomings in response efficiency, control precision, and multifunctional synergy, making it difficult to meet the demands of complex application scenarios.

[0003] Currently, common controlled-release systems mainly rely on pH changes, enzyme triggering, light stimulation, or temperature stimulation to regulate release. Among these, pH or enzyme-responsive systems are highly dependent on the local biochemical environment, making it difficult to achieve precise and real-time control of stimulation conditions. While light-responsive systems have high spatial selectivity, their application in biological applications is limited by limited tissue penetration depth, potential phototoxicity, and the complexity of the equipment. Thermosensitive materials, especially hydrogel systems with phase transition properties, have been extensively studied due to their volume changes within a certain temperature range. However, traditional thermal stimulation usually relies on external overall heating, making it difficult to achieve precise local regulation, and the single macroscopic shrinkage mechanism of the gel is insufficient for precise molecular-scale release control.

[0004] Electrical stimulation is considered a highly promising exogenous stimulation method due to its non-invasive nature, easily controllable stimulation parameters, and rapid response. Existing electroresponsive release systems mostly rely on mechanisms such as redox reactions, electrochemical degradation, or ion migration to release substances. However, these mechanisms often suffer from irreversible release processes, slow response kinetics, or limited biocompatibility. Therefore, obtaining a material with a reversible release mechanism, rapid response kinetics, and good biocompatibility is a key technical problem urgently needing to be solved in the field of molecular controlled-release gels. Summary of the Invention

[0005] The purpose of this invention is to disclose an electrothermal controlled-release gel based on dynamic nucleic acid quadruplexes and thermosensitive polymers, in order to solve one or more technical problems existing in the existing methods and provide at least one beneficial option or create conditions.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The first aspect of this invention is to provide an electrothermal controlled-release gel. The matrix of the electrothermal controlled-release gel is composed of an interpenetrating nucleic acid quadruplex network and a thermosensitive polymer network. The electrothermal controlled-release gel also includes conductive nanomaterials. Under external electrical stimulation, the conductive nanomaterials synergistically generate an electrothermal effect with the nucleic acid quadruplex network, inducing a volume change in the thermosensitive polymer network. The nucleic acid quadruplex network is obtained by rolling circle amplification of thiol-modified DNA strands after the thermosensitive polymer network, thereby achieving cross-linking and interpenetration. The molecular-level conformational regulation of the nucleic acid quadruplex and the macroscopic volume response of the thermosensitive polymer are efficiently coupled through the interpenetrating structure, possessing both the advantages of molecular-scale release precision and macroscopic rapid response, solving the problems of traditional nucleic acid materials' difficulty in generating macroscopic effects and the lack of fine molecular regulation capabilities in thermosensitive gels. The conductive nanomaterials and the nucleic acid quadruplex network synergistically generate Joule heating, resulting in higher electrothermal conversion efficiency compared to single conductive materials or polymer systems. This achieves precise local heating under low voltage and avoids the non-specific release problems caused by traditional overall heating. After electrical stimulation stops, the electrothermal effect disappears, and the nucleic acid quadruplex network and thermosensitive polymer network can return to their initial state, enabling on-demand release of loaded drugs, reducing the risk of background leakage under non-stimulatory conditions, and making it suitable for scenarios with high control precision requirements, such as precision drug delivery.

[0007] In a further embodiment of the first aspect of the present invention, the electrothermal controlled-release gel further includes an ionic component for stabilizing the nucleic acid quadruplex network. The ionic component specifically binds to the nucleic acid quadruplex network, neutralizing its internal electrostatic repulsion and preventing spontaneous unfolding of the quadruplexes. This allows the electrothermal controlled-release gel to maintain its intact interpenetrating network structure during storage and under non-stimulated conditions, extending the product's shelf life. Furthermore, the ionic component can act as a charge carrier to enhance the internal conductivity of the electrothermal controlled-release gel, promoting the electrothermal coupling efficiency between the conductive nanomaterials and the nucleic acid quadruplex network. This results in faster and more uniform heating under electrical stimulation, thereby ensuring the synchronicity of nucleic acid conformational changes and polymer volume changes.

[0008] In a further embodiment of the first aspect of the present invention, the ionic component is selected from one or more of metal ions, polyvalent cations, monovalent ions, divalent ions, and organic cations; preferably, the ionic component is K. + The binding of the ionic components exhibits temperature-dependent reversible characteristics, and their binding and dissociation processes with the tetrachain can further refine the release kinetics (e.g., adjusting the release rate, delaying the release initiation time), thereby enhancing the flexibility of controlled release. K + The ionic radius of Na+ is highly matched with the core channel of the nucleic acid quadruplex, and its binding constant is much higher than that of Na+. + Li + Other ions can more stably maintain the tetrachain conformation, ensuring the consistency between gel structure and function.

[0009] In a further embodiment of the first aspect of the present invention, the conductive nanomaterial is selected from one or more of metal nanoparticles, metal nanostructures, carbon-based nanomaterials, or inorganic nanomaterials with electrothermal effects; the metal nanoparticles are selected from one or more of gold, silver, copper, and platinum nanoparticles; the metal nanostructures are selected from one or more of nanorods, nanowires, and nanoshells; and the carbon-based nanomaterials are selected from one or more of graphene, graphene oxide, and carbon nanotubes. All of the conductive nanomaterials can form stable composite systems with nucleic acid molecules and thermosensitive polymers without phase separation or side reactions, ensuring the integrity of the interpenetrating network structure and the stability of the electrothermal response.

[0010] In a further embodiment of the first aspect of the present invention, the conductive nanomaterial and the nucleic acid quadruplex network are connected via thiol bonds, amino-metal coordination, click chemistry, electrostatic adsorption, or covalent grafting. All the listed connection methods can form a strong interfacial bond, preventing detachment due to electrical stimulation or temperature changes, thus ensuring the continuity of the electrothermal synergistic effect; and without damaging the folding ability of the nucleic acid molecules or the electrothermal properties of the conductive nanomaterial, allowing the core functions of both to be fully preserved and synergistically utilized.

[0011] In a further embodiment of the first aspect of the present invention, the temperature-sensitive polymer network is formed by crosslinking polymerization of iso-polyacrylamide and a crosslinking agent; the crosslinking agent is N,N'-methylenebisacrylamide. The low critical temperature (LCST) of iso-polyacrylamide (NIPAM) is close to physiological temperature, matching the temperature response range of nucleic acid quadruplexes. It can rapidly undergo a volume phase transition under the mild thermal effect generated by electrical stimulation, thus improving the release response rate. The three-dimensional network formed by crosslinking NIPAM with the crosslinking agent N,N'-methylenebisacrylamide (MBAM) has good elasticity, formability, and reversible swelling / shrinkage, supporting the spatial structure of the nucleic acid quadruplex network and is not easily damaged during repeated electrothermal cycles. Both NIPAM and MBAM are biocompatible polymer materials with no obvious toxicity. The crosslinked polymer network is stable and not easily degraded to produce harmful products, making it suitable for biomedical applications.

[0012] A second aspect of the present invention is to provide a method for preparing the electrothermal controlled-release gel described in the first aspect of the present invention. The preparation method includes the following steps: (1) DNA strands are modified onto the surface of conductive nanomaterials to obtain nucleic acid-modified conductive nanomaterials; (2) Mix the thermosensitive polymer monomer, crosslinking agent, dNTP, DNA polymerase, buffer, DTT, DNA circular template with the nucleic acid modified conductive nanomaterial obtained in step (1), add initiator and promoter, react to form a gel, and incubate at room temperature to allow the rolling circle amplification reaction to proceed fully and form an electrothermal controlled release gel.

[0013] The preparation method simultaneously performs nucleic acid modification, thermosensitive polymer polymerization, and DNA rolling circle amplification of conductive nanomaterials in the same reaction system, ensuring uniform interpenetration between the nucleic acid network and the polymer network and avoiding structural inhomogeneity problems caused by stepwise preparation. Room temperature incubation completes gelation and rolling circle amplification, eliminating the need for extreme conditions such as high temperature and high pressure, reducing equipment costs and operational difficulty, and avoiding the damage to DNA polymerase activity and nanomaterial stability caused by high temperatures. The coordinated execution of each reaction step allows for precise control of the ratio and distribution of the nucleic acid network and polymer network, ensuring structural and performance consistency across different batches and meeting the requirements for large-scale preparation.

[0014] In a further embodiment of the second aspect of the present invention, the electrothermal controlled-release gel obtained in step (2) is heated to above the lower critical dissolution temperature, shrinks to release the internal liquid, and after the liquid is aspirated, deionized water is added at room temperature to restore it. This process is repeated several times to achieve purification. Through the cyclic treatment of "heating-shrinkage-restoration", unreacted monomers (such as NIPAM), residual reagents and other toxic impurities can be efficiently removed, further improving the biocompatibility of the gel and meeting the safety requirements for in vivo application. The purified gel has a denser and more uniform network structure, avoiding interference from impurities on the electrothermal response efficiency and making the release control more precise; at the same time, the purified gel has no excess impurities competing for binding sites, and the loaded material can be more stably adsorbed in the network, reducing non-specific leakage.

[0015] In a further embodiment of the second aspect of the present invention, the DNA polymerase in step (2) is Phi29 DNA polymerase or Bst DNA polymerase; the initiator is ammonium persulfate (APS) or azobisisobutyramidine hydrochloride; and the promoter is N,N,N',N'-tetramethylethylenediamine, triethanolamine or sodium bisulfite.

[0016] The second aspect of this invention lies in providing application directions for the electrothermal controlled-release gel described in the first aspect of this invention. These mainly include the ability to achieve targeted, timed, and quantitative drug release due to its precise controlled-release characteristics, reducing drug side effects, and making it particularly suitable for intelligent drug delivery scenarios such as cancer treatment and chronic disease management. Its excellent biocompatibility and electrothermal responsiveness make it suitable as a tissue engineering scaffold, biosensor substrate, etc., to regulate cell behavior or signal detection through electrical stimulation, thereby improving the intelligence level of biomaterials and meeting the application requirements of electrostimulation-responsive biomaterials. The volume change and electrothermal response of the gel can be converted into mechanical driving force, making it suitable as an electro-controlled software system for devices such as micro-soft robots and electro-controlled valves. Compared with traditional driving methods, it has advantages such as rapid response, precise regulation, and good biocompatibility. Attached Figure Description

[0017] Figure 1 This is a characterization of the gold nanoparticles before and after DNA functionalization in Example 2; Figure 2 This is a characterization of RCA amplification and gel formation in Example 2; Figure 3 This is a fluorescence confocal image of the RCA gel formation assay in Example 2; Figure 4 This is a graph showing the thermal response characteristics of the nucleic acid quadruplex of the RCA gel in Example 3; Figure 5 These are the electrical performance analysis diagrams of the PNIPAM hydrogel and RCA gel in Example 3; Figure 6 These are scanning electron microscope images of the PNIPAM hydrogel and RCA gel in Example 3 at different temperatures. Detailed Implementation

[0018] The following embodiments further illustrate the content of the present invention, but should not be construed as limiting the present invention. Any modifications and substitutions made to the methods, steps, or conditions of the present invention without departing from the spirit and essence of the present invention are within the scope of the present invention.

[0019] Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0020] Example 1: Preparation of Electrothermal Controlled-Release Gel Thiol-modified DNA strands were designed and synthesized and then modified onto gold nanoparticles using specific methods (including but not limited to salt aging, freeze-thaw, and microwave modification). The DNA modified on the gold nanoparticles served as primers to match the synthesized circular template strand for subsequent rolling circle amplification. Subsequently, 15 mg of NIPAM, 10 μL of 1 mg / mL MBAM, 20 μL of dNTPs, 0.3 μL of 250 U Phi29 DNA polymerase, 2 μL of the matching buffer, 1 μL of 100 mmol / L DTT, 5 μL of 10 μmol / L DNA circular template, and 100 μL of DNA-modified gold nanoparticles were added. Then, 3 μL of 10 mg / mL APS solution and 0.5 μL of TEMED were added. After gel formation, the mixture was incubated at room temperature for 12 h until the RCA reaction within the gel was fully completed. Based on the thermal responsiveness of PNIPAM (it shrinks its network structure and releases its contained liquid when the temperature exceeds its own LCST), the prepared electrothermal controlled-release gel (hereinafter referred to as RCA gel) was heated to above LCST (40℃) to completely release its contained liquid and aspirate the produced liquid. Then, 100 μL of deionized water was added at room temperature to restore the shrunken hydrogel. This process was repeated 2-3 times to remove unreacted NIPAM and reduce the cytotoxicity of the hydrogel.

[0021] The hydrogel that released the liquid was then placed in a drug-containing solution at room temperature to obtain a drug-loaded RCA gel, which allows for drug release when an electric current is applied.

[0022] Example 2, Compositional Analysis of RCA Gel The RCA gel obtained in Example 1 was placed under an electrochemical workstation to verify its electrothermal performance.

[0023] (1) Verify that DNA was successfully modified onto gold nanoparticles.

[0024] To verify the successful DNA modification onto gold nanoparticles, the experiment was conducted using ultraviolet spectroscopy, nanoparticle size and zeta potential meter, and field emission scanning electron microscopy.

[0025] The test results are as follows Figure 1 As shown, Figure 1 The image at point a is a scanning electron microscope (SEM) image of bare gold nanoparticles, showing a uniform spherical morphology; Figure 1 The image at point b is a SEM image of DNA-functionalized gold nanoparticles, showing a diffuse halo around the particles. SEM characterization reveals a distinct halo around the modified DNA surface, and particle size analysis shows significant size expansion of the gold nanoparticles, confirming successful surface modification. Figure 1The particle size distribution of gold nanoparticles before and after DNA functionalization is shown at point c. Figure 1 The UV-Vis absorption spectra at point d are those of bare gold nanoparticles and DNA-functionalized gold nanoparticles. Under UV spectroscopy, a significant shift in the peak position of the gold nanoparticles is observed, indicating that DNA modification was successfully applied to them.

[0026] (2) Verify rolling circle amplification inside the RCA gel.

[0027] To verify that the designed and synthesized DNA strands could be successfully amplified inside the gel, the DNA strands were characterized by polyacrylamide gel electrophoresis and fluorescence confocal microscopy.

[0028] The results are as follows Figure 2 As shown, Figure 2 The result at point a is the 1% agarose gel electrophoresis result, which shows that the molecular weight of the RCA product is much higher than 5000 bp, proving that the amplification effect is good. Figure 2 The image at point b is a fluorescence confocal image obtained from the RCA gel formation assay.

[0029] (3) RCA gel formation determination.

[0030] Samples with and without phi29 DNA polymerase were compared. After staining for 10 minutes, the gels were stained with 1× GelRed staining agent and observed under a fluorescence confocal microscope. The gels were then observed under a fluorescence confocal microscope (excitation light 488). It was observed that the RCA gel with phi29 polymerase exhibited significant fluorescence (e.g., ...). Figure 3 As shown in the figure, the above results indicate that the designed and synthesized DNA sequence can successfully undergo RCA reaction inside the gel.

[0031] Example 3, Performance Verification of RCA Gel (1) In order to verify that the designed and synthesized DNA sequence can successfully form a nucleic acid quadruplex, measurements were performed in this embodiment using a circular dichroism spectrometer and a fluorescence spectrophotometer.

[0032] Figure 4 At position a, the nucleic acid quadruplex and K + A schematic diagram of the combination.

[0033] CD results are as follows Figure 4 As shown at point b, add K. + After entry, the CD spectrum amplitude increased / the relative peak intensity changed, indicating that the ionic conditions changed the equilibrium state. This suggests that the nucleic acid quadruplex was successfully formed rather than being explained by a single non-specific aggregation.

[0034] At different DNA concentrations, while keeping the ThT and K ion concentrations constant (5 mg / L ThT, 50 µmol / L KCl), the fluorescence intensity of ThT under 425 nm excitation light was measured. The results showed... Figure 4 As shown at point c, the fluorescence intensity of ThT exhibits a clear DNA concentration dependence, meaning that the fluorescence intensity increases with increasing DNA concentration. This further indicates that the RCA chain in K... + Driven by this process, it can successfully fold into a nucleic acid quadruplex.

[0035] The thermal response behavior of PNIPAM thermosensitive hydrogel and RCA gel in the range of 25–40 °C was investigated through controlled heating experiments at a precise heating rate of 0.5 °C / min. The RCA gel experienced rapid mass loss (70.56%) in the range of 27–30 °C, corresponding to a lower critical solution temperature (LCST) of approximately 27.8 °C (e.g., ...). Figure 4 (As shown at point f). LCST at approximately 36°C with PNIPAM thermosensitive hydrogel (e.g., ... Figure 4 Compared to (as shown at point e), the LCST of the RCA gel decreased by approximately 8°C, and the weight loss was also significantly reduced. This is likely due to the structural changes in the aqueous microenvironment caused by the nucleic acid quadruplex network.

[0036] (2) Investigate the differences in electrical behavior between RCA gel and PNIPAM hydrogel through electrical experiments.

[0037] IT curve as follows Figure 5 As shown at point a, the initial increase followed by a decrease in current in the RCA hydrogel originates from the directional rearrangement of the DNA quadruplex under an electric field and the initial enhanced conductivity caused by the migration of endogenous ions. After approximately 25 seconds, electrode polarization and electrothermal activity cause network contraction, leading to a decrease in current. The PNIPAM hydrogel, lacking rearrangeable charged structures, exhibits a typical monotonic decreasing behavior.

[0038] At 5 V voltage and different K + The IT curve of RCA gel measured at the specified concentration is shown below. Figure 5 As shown at point b, at 5 V voltage and different K + The IT curve of PNIPAM hydrogel measured at the specified concentration is as follows: Figure 5As shown at point c, both PNIPAM hydrogel and RCA gel exhibit a significant K ion concentration dependence, meaning that conductivity increases with higher K ion concentration. The IT curve of PNIPAM hydrogel shows a rapid rise followed by a rapid fall, primarily due to the rapid migration of ions under the electric field, forming a significant ion depletion layer near the electrode. Since the PNIPAM network lacks fixed charges and cannot temporarily store or regulate ions, its internal ions are rapidly evacuated, causing a sharp increase in equivalent resistance and a rapid decay of current. In contrast, in RCA gel, the fixed negative charge of the phosphate backbone can enrich and temporarily store K ions. + This significantly delayed the ion depletion behavior under the influence of the electric field. Furthermore, some K... + Specifically captured by the nucleic acid quadruplex network, allowing free K + The concentration was further reduced, thereby weakening the initial ion migration rate. This dual mechanism enabled the RCA gel to operate at low Kc concentrations. + Under these conditions, it exhibits a high and stable current plateau. However, the number of capture sites in the nucleic acid quadruplex network is limited, and the high K... + Under these conditions, the fixed charge effect is strongly shielded, thus a large number of free K atoms remain. + It participates in migration and forms a depletion region near the electrode. With continuous application of the electric field, the RCA gel at high K... + At this concentration, it eventually enters a steady state dominated by migration depletion, therefore its final current converges to 40 mmol / LK. + The range of conditions that are similar.

[0039] Based on this, further investigation was conducted on 40 mmol / LK + The electrothermal properties of RCA gel at different concentrations are as follows: Figure 5 As shown at point d, it can be observed that the temperature rise rate of the RCA gel increases significantly with increasing voltage, exhibiting a strong voltage dependence. Simultaneously, it can be detected that under constant voltage, the heating rate of the RCA gel is relatively constant (e.g., ...). Figure 5 (As shown at point e), this makes it possible to control the on-demand release of RCA gel by voltage intensity, i.e., energizing time.

[0040] (3) The structural changes of RCA gel were characterized by scanning electron microscopy.

[0041] The obtained PNIPAM hydrogel and RCA gel were freeze-dried and then characterized by scanning electron microscopy.

[0042] The result is shown in the figure below. Figure 6As shown, compared to PNIPAM hydrogel, RCA gel has a smaller pore size in its gel network, which becomes denser when heated. This explains why RCA gel exhibits less water loss after heating. The denser network structure also makes RCA gel more temperature-sensitive, resulting in a lower LCST.

[0043] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. An electrothermal controlled-release gel, characterized in that, The matrix of the electrothermal controlled-release gel is composed of an interpenetrating nucleic acid quadruplex network and a thermosensitive polymer network. The electrothermal controlled-release gel also includes conductive nanomaterials. Under external electrical stimulation, the conductive nanomaterials can synergistically generate an electrothermal effect with the nucleic acid quadruplex network, causing a volume change in the thermosensitive polymer network.

2. The electrothermal controlled-release gel according to claim 1, characterized in that, It also includes ionic components for stabilizing the nucleic acid quadruplex network.

3. The electrothermal controlled-release gel according to claim 2, characterized in that, The ionic component is selected from one or more of metal ions, polyvalent cations, monovalent ions, divalent ions, and organic cations; preferably, the ionic component is K. + .

4. The electrothermal controlled-release gel according to claim 1, characterized in that, The conductive nanomaterial is selected from one or more of metal nanoparticles, metal nanostructures, carbon-based nanomaterials, or inorganic nanomaterials with electrothermal effects; the metal nanoparticles are selected from one or more of gold, silver, copper, and platinum nanoparticles; the metal nanostructures are selected from one or more of nanorods, nanowires, and nanoshells; and the carbon-based nanomaterials are selected from one or more of graphene, graphene oxide, and carbon nanotubes.

5. The electrothermal controlled-release gel according to claim 4, characterized in that, The conductive nanomaterial and the nucleic acid quadruplex network are connected by thiol bonds, amino-metal coordination, click chemistry, electrostatic adsorption, or covalent grafting.

6. The electrothermal controlled-release gel according to claim 1, characterized in that, The temperature-sensitive polymer network is formed by crosslinking and polymerization of iso-polyacrylamide and a crosslinking agent; the crosslinking agent is N,N'-methylenebisacrylamide.

7. A method for preparing the electrothermal controlled-release gel according to any one of claims 1 to 6, characterized in that, Including the following steps: (1) DNA strands are modified onto the surface of conductive nanomaterials to obtain nucleic acid-modified conductive nanomaterials; (2) Mix the thermosensitive polymer monomer, crosslinking agent, dNTP, DNA polymerase, buffer, DTT, DNA circular template with the nucleic acid modified conductive nanomaterial obtained in step (1), add initiator and promoter, react to form a gel, and incubate at room temperature to allow the rolling circle amplification reaction to proceed fully and form an electrothermal controlled release gel.

8. The preparation method according to claim 7, characterized in that, The electrothermal controlled-release gel obtained in step (2) is heated to above the lower critical dissolution temperature, shrinks and releases the internal liquid. After the liquid is aspirated, deionized water is added at room temperature to restore it. This process is repeated several times to achieve purification.

9. The preparation method according to claim 7, characterized in that, The DNA polymerase in step (2) is Phi29 DNA polymerase or Bst DNA polymerase; the initiator is ammonium persulfate or azobisisobutyramidine hydrochloride; and the promoter is N,N,N',N'-tetramethylethylenediamine, triethanolamine or sodium bisulfite.

10. The use of the electrothermal controlled-release gel according to any one of claims 1 to 6 in intelligent drug delivery, electrostimulation-responsive biomaterials, or electro-controlled software systems.

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