Preparation Of Flower-like Carbon And Fe₃O₄ Composites Nanocarrier And Study On The Properties Of Microwave Controlled Release Drugs

In recent years,various drug delivery systems have been constructed to improve the therapeutic effect of cancer in order to solve the toxic side effects of anticancer drugs on healthy tissue cells in the traditional chemotherapy process.The design of the targeted drug delivery system is mainly based on the consideration of two factors,one is the carrier’s high-efficiency loading of the drugs,and the other is the timing,fixed-point and quantitative release.Therefore,the choice of carrier material and the design of the vector structure are decisive for efficient targeted delivery of targeted delivery systems.Among the candidate materials,nanocarbon materials stand out,the preparation technology is mature,and a variety of pore structures can be prepared by the soft or hard template method,which is beneficial to the high-efficiency loading of the medicine.Carbon materials are used as conductive loss-type materials.And the design of the pore structure has a significant influence on its microwave absorption performance,which is beneficial to realize the microwave control response of the carrier.In addition,carbon materials have good application prospects in biomedicine compared with other metal oxide carriers,which are light in weight,easy to degrade and have good biocompatibility.Based on the above analysis,the flower-like mesoporous carbon spheres were constructed as the base material.A series of carbon-based composite nanoparticles were designed and prepared as drug carriers according to their structure,composition and surface properties.Their mesoporous properties,magnetic properties and microwave thermal conversion properties were analyzed and compared,meanwhile the loading and microwave controlled release properties of these materials for doxorubicin（DOX）were also investigated.The main research contents and results are as follows:1.Designing the structure of carbon nanoparticles for efficient drug loading and microwave absorption.The flower-like mesoporous carbon spheres was obtained by controlled synthesis firstly.Flower-like mesoporous carbon microspheres were prepared by using the TEOS as a structural support,CTAC as a surfactant,and urea modified phenolic resin（UPR）as a carbon precursor.And the mechanism of its synthesis was explored.The study found that with the increase of urea dosage the particle diameter increased from 208 nm to 617 nm,and the surface morphology changed from meshing,folding,and flowering to flower-like clusters.With the increase of ammonia dosage,the diameter of flower-like carbon spheres increased from 200 nm to 350 nm,the specific surface area decreased from 730 m²/g to 439 m²/g,and the flower-like mesoporous pore size increased from 18.4 nm to 28.9 nm.With the increase of the carbonization temperature,the degree of graphitization of the flower-like carbon sphere increases,but the surface of the flower-like carbon sphere will melt and collapse when the temperature is too high.Therefore,the optimal conditions for synthesizing hollow mesoporous flower carbon spheres are obtained.In addition,it was found that the flower carbon spheres heated up to 60°C from the initial 27°C after 140 s with 200W of microwave irradiation,indicating that the flower carbon spheres exhibits excellent microwave absorption thermal conversion properties.2.Designing composition and modify the surface of carbon-based nanocarriers to improve carrier drug delivery and drug release properties.The flower-like carbon spheres as the base material,and then in-situ deposition of small Fe₃O₄ nanoparticles by thermal decomposition of ferric nitrate to obtain the Fe₃O₄/HMCNFs composite nanoparticles.Finally,the surface properties of Fe₃O₄/HMCNFs were modified by SiO₂ to obtain Fe₃O₄/HMCNFs-SiO₂ composite nanoparticle drug carrier.The study found that the monodisperse flower-like Fe₃O₄/HMCNFs-SiO₂ nanoparticles have a large BET specific surface area（292 m²/g）,a uniform pore size（5.6 nm）,good magnetic separation（Saturation magnetization is 8.91 emu/g）and high microwave response performance:the temperature of the system is raised from 27°C to 60°C after 120 s.At the same time,Fe₃O₄/HMCNFs-SiO₂composite nanocarriers also have higher drug loading rate（70.2 wt%,175.5 mg/g）and expected drug release behavior:it maintains a very low drug release rate of only 1.5 wt%at pH 7.4,and then increases to 25.2 wt%after microwave stimulation at pH 5.0.3.Optimization composition and modify the surface of carbon-based nanocarriers to improve carrier drug delivery and drug release properties.The flower carbon sphere is used as a base material,the small particle size Fe₃O₄ is prepared by hydrothermal method as a magnetic targeting agent,and the ZnO nanoparticle is used as a sealing agent,after the surface modification of the carboxyl group and the amino group Fe₃O₄/HMCNFs-ZnO composite nanoparticles were prepared by amidation.The introduction of ZnO nanoparticle further enhances the microwave absorption performance while achieving the function of pH gating,and obtains a drug carrier with double response of pH and microwave.The study found that after surface modification,the drug loading and drug release performance of the carrier was improved.It was found that when m_Carrier:m _DOX=2:1 is the optimal ratio,the drug loading rate is as high as 83.1 wt%.During the drug release experiment,the pH change had a significant effect on the drug release rate,with drug release rates of 8.2 wt%,19.0 wt%,and 56.3 wt%at pH 7.4,5.0,and 3.0,respectively;Moreover,microwave radiation also has a significant effect on drug release.The drug release rate increased from 8.1 wt%to 39.9 wt%after microwave stimulation.In this paper,a series of carbon-based nanocarriers with a flower-like mesoporous structure were prepared by changing the structure,composition and surface properties of the material.The flower-like Fe₃O₄/HMCNFs-ZnO composite nanoparticle carrier showed the best performance of drug-loaded,targeted and controlled release drugs.Moreover,the carrier also achieves microwave and pH dual controlled release,which lays an experimental foundation for further promoting the clinical application of targeted controlled release drugs.