The effect of the concentration of crosslinkers on the mechanical properties of PEGDA hydrogels

Abstract

Polyacrylamide (PAAm) hydrogel sheets with varying concentrations of poly(ethylene glycol) diacrylate (PEGDA) as the crosslinker were successfully synthesized via photopolymerization using Irgacure 2959 (I2959) as the photoinitiator. The aim was to study the effects of the crosslinker on the mechanical properties of hydrogels intended for biomedical applications. Fabricated hydrogel sheets were characterized using a tensile test, a swelling test, and a rheology test. The increase in PEGDA concentration resulted in a significant increase in the crosslinking density and Young’s modulus, while causing a significant decrease in the equilibrium water content (EWC). Moreover, from the rheology test results, the increasing concentration of PEGDA in the hydrogel causes the storage modulus (G’) to increase while causing the loss modulus (G”) to decrease.

In addition, Silk Fibroin (SF) was added to the PAAm-PEGDA hydrogels at varying concentrations to analyze their adhesive properties. The adhesive hydrogels are useful for dermatological applications such as wound dressing. The increase in SF concentration resulted in increase in adhesion, while causing the Young’s modulus and strength to decrease.

Since the hydrogels were intended for biomedical applications, their biocompatibility was also examined. Results from the biocompatibility test shows that the addition of SF introduces cell adhesion sites on PAAm-PEGDA hydrogel.