Fabrication Of Porous Silk Fibroin Particles And Their Application As Doxorubicin Drug Carriers

Silk fibroin has been widely used in the field of biomedical materials because of its wide range of sources,biodegradability and good biocompatibility,especially in drug carriers.Silk has been favored by more and more researchers.At present,there are many methods to prepare drug carriers,but it is still challenging to prepare a highly efficient,controllable release and targeted drug carrier.In this paper,silk fibroin was used as raw material,doxorubicin was used as an anticancer drug model,and the porous silk fibroin particles were obtained by salting out method,and doxorubicin is added into the particle formation process,so that the drug can be wrapped in the particles.The folate receptor on cancer cell surface was over expressed.Amino groups were modified into the particle surface,then folic acid was grafted,folic acid groups can make the particles combine with folate receptor,giving the drug loaded particles target cancer cells.After the particles were modified,the surface will contain large amounts of amino groups which can combine with doxorubicin through chemical bonds on particle surface.Thus,two times of drug loading particles were prepared.The release behavior of drug was simulated under different pH conditions in vitro.The biocompatibility of silk fibroin particles and cytotoxicity of drug loaded silk fibroin particles were evaluated by CCK8 method.The tumor cell targeting of drug loaded particles was studied by confocal laser scanning microscopy and flow cytometry.Specific research contents and results are as follows:1.Preparation of drug loaded fibroin particles and characterization of their basic structures and propertiesSilk fibroin particles were prepared by salting out method in phosphate solution,and the microscale and nanoscale porous fibroin particles could be prepared by changing the reaction parameters.In the formation process of particles,doxorubicin was encapsulated inside the particles by electrostatic action,then doxorubicin and the targeted groups of folic acid were added on the surface of the particles by chemical grafting.The results showed that doxorubicin was successfully loaded onto the particle and the folate group was successfully grafted onto the surface of the particles.2.Evaluation of bading and releasing properties ofsilk fibroin particles on doxorubicin The loading condition of doxorubicin was determined by changing the dosage ratio.The result showed that the drug loading rate of doxorubicin was 30.71 mg/mg.Drug release behavior of the drug loaded silk fibroin particles was studied by using different pH solutions of PBS to simulate the microenvironment of different organelles in vivo which provided the basis for controlled release of drugs.3.Cytotoxicity and targeting evaluation of folic acid grafted silk fibroin particlesWhen silk fibroin particles were co cultured with Hela cells,the cell proliferation was almost unaffected,indicating that the biocompatibility of the carrier materials was good.Doxorubicin can inhibit the proliferation and growth of cancer cells.When co-culture of drug loaded silk fibroin particles with Hela cells,we can find that the cell viability decreased with the increase of the drug loading of fibroin particles,the effect of drug loaded particles with target groups on cell viability was higher than that without graft target groups.Laser confocal microscopy and flow cytometry were used to study the process of phagocytosis of drug carriers by Hela cells.The results showed that the tumor targeting drug carriers were more concentrated around the cells.