Molecularly engineered p(HEMA)-based hydrogels for implant biochip biocompatibility

The strategy of phospholipid-based biomimicry has been used to molecularly engineer poly(2-hydroxyethyl methacrylate) [p(HEMA)]-based hydrogels for improved in vitro and potential in vivo biocompatibility. Two methacrylate-based monomers, poly(ethylene glycol) (200) monomethacrylate (PEGMA) and 2-methacryloyloxyethyl phosphorylcholine (MPC), were incorporated at varying mole fractions of 0.0–0.5 mol% PEGMA and 0–10 mol% MPC respectively, into 3 mol% tetraethyleneglycol diacrylate (TEGDA) cross-linked p(HEMA) networks. Upon hydration of these engineered hydrogels, a reduction in receding contact angle from 22±1.2° for p(HEMA) to 8±2.7° for p(HEMA) containing 0.5:10 mol% PEGMA:MPC was observed, reflecting the significant increase in surface hydrophilicity with increasing PEGMA and MPC content upon prolonged hydration. Hydrogels containing MPC showed a temporal increase in hydrophilicity following continuous immersion in DI water over 5 days. Hydrogels containing 0.5 mol% PEGMA and MPC in the range of 5–10 mol% displayed reduced protein adsorption when incubated with the common extracellular matrix proteins; fibronectin, collagen or laminin, producing up to 64% less protein adsorption compared to p(HEMA). Compositional optima for cell viability and proliferation established from two-factor Central Composite design analysis of human muscle fibroblasts cultured on these hydrogels suggest that those containing PEGMA between 0.3 and 0.5 mol% and MPC levels around 5–10 mol% exhibit desirable characteristics for implant material coatings—high viability (>80%) with low proliferation (<40%), confirming a lack of cytotoxicity.