Silk fibroin/chitosan pH-sensitive controlled microneedles

Silk fibroin is a widely used biocompatible medical material with tunable mechanical, degradability and environmental non-toxicity. This paper prepared the silk fibroin/chitosan hydrogel microneedle with pH sensitivity by blending silk fibroin with chitosan to induce graft cross-linking. The cross-linked silk fibroin/chitosan microneedles network is expanded by hydrogen ions and water molecules, forming a more significant swelling. In vitro, the transdermal drug release showed that insulin loaded in microneedles exhibited pH-sensitive drug release behavior and was released faster under acidic conditions than under neutral conditions. By changing the pH of the solution, microneedles can achieve a stimulating response to the environment, thereby intelligently regulating the transdermal release of insulin.