Design, fabrication and characterization of a double-network alginate-pHEMA hydrogel coating for PDMS-based biomedical implants

Traditional silicone biomedical implants, such as urinary catheters, often suffer from high surface friction, high stiffness, and a lack of hydrophilicity, which can cause discomfort or discomfort. To tackle these challenges, we developed a double-network alginate-pHEMA hydrogel “cushion” coating for polydimethylsiloxane (PDMS) biomedical implants. The double-network hydrogel presented here consists of two distinct networks made of alginate and pHEMA, respectively. The alginate network is covalently bonded to PDMS substrates as scaffolding, and the denser pHEMA network fills the free space within the alginate network. In this proof of concept study, the double-network hydrogel achieved a compressive fracture stress of 502.04±14.41 kPa, which is 5.8-fold stronger than the alginate hydrogel, while its elasticity is still comparable to soft tissues. The proposed double-network hydrogel has a negligible amount of swelling in biological fluids and exhibits no cytotoxicity, which are desirable qualities for biomedical and coating applications. Both chemical modification using APTES and micropillar anchors have been used to improve the coating stability. We found that the adhesion strength of the hydrogel coating on micropillar PDMS substrates is 55% stronger than on bare PDMS substrates when both substrates are grafted with APTES. In comparison to native PDMS and K-Y Jelly-lubricated PDMS, the double-network alginate-pHEMA hydrogel-coated PDMS demonstrated significantly less friction and superior hydrophilicity.Applied Science, Faculty ofMechanical Engineering, Department ofGraduat