Effects of Gamma Sterilization on the Physico-Mechanical and Thermal Properties of Gelatin-Based Novel Hydrogels

Hydrogels are attracting ample attention for tissue engineering application thanks to their water-loving attribute and closely mimicry to the natural extracellular matrix. However, effectively and efficiently sterilization of hydrogels without compromising their end-use beneficial attributes is a major challenge. The aim of this work is to study the resistance to gamma sterilization of newly developed gelatin-based hybrid hydrogels for tissue engineering. This study reported the investigation of 25 kGy gamma sterilization, a typical sterilization procedure for healthcare products, on the physico-mechanical and thermal properties of a three set of gelatin-based novel hydrogels, namely, gelatin-polyethylene glycol (G/PEG), gelatin-polyethylene glycol-hydroxyethyl cellulose (G/PEG/HEC) and gelatin-polyethylene glycol-chitosan (G/PEG/CH). FTIR and TGA were done to evaluate the chemical change and variation of thermal behavior, respectively, imposed by the gamma exposure, and the results showed that gamma sterilization did not modify the chemical composition and thermal degradation behavior of the hydrogels. The water uptake, mechanical properties (both in tension and compression) and stress relaxation experiments revealed that parent G/PEG and interpenetrating polymer network (IPN) G/PEG/CH were nearly negligibly sensitive to the gamma sterilization. However, semi-interpenetrating polymer network (semi-IPN) G/PEG/HEC appeared to be slightly vulnerable to the gamma exposure: a decrease in modulus and strength but simultaneous increase in water uptake, percentage dissipation energy and stress relaxation responses were observed.