The Preparation And Performance Study Of The Modified Silk Fibroin Microspheres For Transcatheter Arterial Chemoembolization

Transcatheter Arterial Chemoembolization（TACE）is one of the most important methods for the treatment of liver cancer,the development of the ideal embolic microspheres is a key step in TACE.At present,the embolic microspheres in the market are expensive and imported,their physical and chemical properties are not perfect,and still can not meet the expectations of people.Preparation of microspheres which have the the advantages of good sphericity,good biocompatibility and biodegradability,suitable and uniform particle size,the amount of drug loaded can meet the dosage required for treatment,and has the double action of embolism and slow release is the key problem to be solved urgently.Based on the physical and chemical properties of ideal embolic microspheres,the modified silk fibroin（SF）microspheres for TACE were prepared.SF was modified by sodium alginate（SA）by emulsifying cross-linking method to prepare embolic microspheres,and the optimum preparation process was selected by single factor experiment and orthogonal experiment.The microspheres were characterized by inverted optical microscope,scanning electron microscopy,infrared spectroscopy and laser particle size analyzer.The swelling ratio,in vitro degradability,pH sensitivity and temperature sensitivity were tested.According to the National Biomaterials Safety Standard,the cytocompatibility of the microspheres was evaluated by L929 and HUVEC.At the same time,the blood compatibility was evaluated.Rabbit ears of New Zealand white rabbits were used as animal models to embolize the middle ear artery of New Zealand rabbits.The embolization effect and degradability of the microspheres in the blood vessel were studied by macroscopical observation and histopathological observation.The drug-carrying microspheres of the adriamycin hydrochloride are prepared,and the drug-carrying amount,the encapsulation rate and the in-vitro release curve of the drug-loaded microspheres are determined.The experimental results show that the particle size and swelling degree of the microspheres have been improved significantly after the modification of SF by SA.The optimum proportion of materials was selected as follows:SA:SF=6:4,SA:Ca²⁺=8:2,1ml glutaraldehyde,the pH value of SF-CaCl₂ solution is 3.5,the percentage of Span-80 in aqueous phase is 4%.The results of inverted optical microscope and scanning electron microscope showed that the surface of the microspheres was smooth and the spheroidization was good;Ir spectra show that SF and SA interact with each other by strong hydrogen bonding and electrostatic interaction;The average particle size of the microspheres was141.839μm and the average particle size was uniform;The results of the property investigation show that the maximum swelling ratio of the microspheres was 474.29%,which was sensitive to pH and temperature,and had good biodegradability.The cytotoxicity grade of the microsphere is below 2,which has good cell compatibility and blood compatibility in accordance with the national standard for the safety of biomaterials.Arterial embolization in rabbit ear showed that microspheres could effectively block arterial blood flow and cause vascular endothelial cell proliferation and necrosis of tissues around the distal end of rabbit ear,and 21 days after injection,the microspheres have not been degraded yet.The drug loading and entrapment efficiency of adriamycin hydrochloride microspheres were（54.25±2.56）%and（10.64±0.83）%,respectively.The microspheres were rapidly released within 30 hours,the release rate is 71%,and then slowly release the drug to a balance.The release of the drug is in accordance with the law of diffusion.The drug can be released before the microsphere degradation,and has a good drug release effect.According to the above complaint,this microspheres have good sphericity,uniform particle size,the particle size and swelling degree meet the requirements of embolic microspheres.Microspheres have certain pH sensitivity and temperature sensitivity,and have good biodegradability,and the embolization effect of middle ear artery in rabbits was also obvious.After drug loading,the drug loading and entrapment efficiency of the microspheres were high,and microspheres have proper drug release effect.This study provides a new idea for the preparation of new embolic microspheres and has a broad prospect in the application of TACE.