The Effects of Varying Ratios of PEGDA:PDMS on the Mechanical Properties of Hydrogels with Differring PEGDA Concentrations for Bone Tissue Engineering

The mechanical properties of hydrogels play a crucial role in determining their suitability as scaffolds for cell growth. Properties such as biocompatibility, porosity, and mechanical properties dictate the success of a candidate scaffold material. The effects on the mechanical properties of varying ratios of Poly (ethylene glycol) diacrylate (PEGDA) to polydimethylsiloxane (PDMS) have been reported; however, the effects of differing PEGDA:PDMS ratios in varying amounts of water have not been studied. In this work, the effects of varying ratios of PEGDA:PDMS (90:10, 85:15, 80:20) on the mechanical properties of PEGDA concentrations (20%, 40%, 60%, 80%, 100%) were investigated and compared with the embedment of SiO₂ nanoparticles (NPs). PEGDA, PDMS, water, and photoinitiator were mixed and cured under a 365 nm UV light for 10-30 minutes (increasing by 5 minutes with increasing PEGDA concentrations). Compressive testing was performed on all samples using a QT/50 Universal Testing Machine at a 5mm/min rate until breaking. Results indicate that introducing silicon and increasing oxygen strengthens PEGDA hydrogels significantly, regardless of concentration. The comparison of SiO₂ embedded samples to varying PEGDA:PDMS samples reflects the tunability that makes PEGDA hydrogels ideal candidates for tissue engineering.