The Relationship Between Chemical Modification Of Amino Acid Side-chains Of Silk Fibroin And Its Degradation Rate

Silk fibroin as a natural animal protein has good biocompatibility and a wide rangeof raw materials is obtained easily. In addition, it has good mechanical properties, andcan be biodegraded without toxicity degradation products. As a result, it has greatapplication potential in the field of biomedical materials. As the biomedical material,one of the most important requirements is the degradation rate and regeneration ratemust be matching. In this paper, the chemical modification of Antheraea pernyi silkfibroin was studied in order to change the side chain of Antheraea pernyi silk fibroin bymeans of a variety of tests. The chemical modification of Antheraea pernyi silk fibroinwas prepared, and then it is used in vitro experiments. We explored the effect of sidechain structure of Antheraea pernyi fibroin protein on its degradation rate.Firstly, the methylglyoxal(MG) modification of Antheraea pernyi silk fibroinsolution was prepared, and then solution was made into three-dimensional porous silkfibroin scaffolds by freeze-drying method. The zeta potentials and isoelectric point ofAntheraea pernyi silk fibroin were tested. The results showed that the negative chargeof Antheraea pernyi silk fibroin was increased and the isoelectric point was reduced.The MG-modified Antheraea pernyi silk fibroin porous materials were tested by FTIR,1H-NMR and amino acid analysis. The results suggested that the amino acid side-chainsof Antheraea pernyi silk fibroin were changed as a result of the reaction betweenarginine and methylglyoxal.Secondly, the acylation modification of Antheraea pernyi silk fibroin solution wasprepared, and then the solution was made into three-dimensional porous silk fibroinscaffolds. The zeta potentials and isoelectric point of the solution were tested. The resultsuggested that the negative charge of Antheraea pernyi silk fibroin was increased andthe isoelectric point was reduced. At the same time, the acylation degree of acylationmodification of Antheraea pernyi silk fibroin solution was evaluated by the color reaction of ninhydrin with amino acid. When the quality of succinic anhydrideaccounting for the quality of Antheraea pernyi silk fibroin was4%, the acylation degreeof acylation modification was higher. The result of FTIR showed that the phenolic groupof tyrosine and the amino group of lysine reacted with succinic anhydride.Additionally, the chemical modification of Antheraea pernyi silk fibroin porousmaterials were degraded in vitro with collagenase IA. The results showed that therandom coil structure content of MG-modified Antheraea pernyi silk fibroin materialwas the most. The results showed that the degradation rate of porous scaffolds orderedas MG-modified Antheraea pernyi silk fibroin> acylation modification of Antheraeapernyi silk fibroin> Antheraea pernyi silk fibroin. To some extent, the different sidechain molecular structure will have an influence on the degradation rate of Antheraeapernyi silk fibroin.