A New Crosslinker for the Preparation of Silk Fibroin Hydrogels

Abstract

SummarySilk fibroin (SF) hydrogels has recently been explored as promising matrices for biomedical applications due to their excellent biodegradability, biocompatibility and hydrophilicity. Despite these, native SF hydrogels showed poor water resistance with typical uncontrollable gelation kinetics. To overcome these drawbacks, a new method of chemical crosslinking using O'O‐bis[2‐(N‐succinimidyl succinylamino) ethyl]polyethylene glycol (NHSP) as a homobifunctional protein crosslinker was employed. A crosslinking reaction, performed under physiological conditions, was completed within 24 hours, producing a hybrid interconnected porous architecture. This network formation contributed to the shortened gelation kinetics and was confirmed by the appearance of a new IR absorption peak of the ether linkage (1102–1104 cm−1). A new thermal degradation temperature found at 430 °C also reconfirmed the presence of such newly‐formed covalent network within the samples. In addition, NHSP could induce a silk phase transformation from the α‐helices into the β‐sheets, as convinced by the shifts of the amide absorption bands (Amide I, Amide II and Amide III), illustrating their strong intermolecular interactions. The new proposed method has thus, proven its potential use to render the silk‐based materials for controlled drug delivery applications.