Surface modification of biomaterials using He glow-discharge plasma and NH3 treatment for augmenting biocompatibility

Helium glow-discharge plasma followed by exposure to ammonia gas was used to enhance biocompatibility of biomaterials. Biocompatibility of polyurethane film was evaluated using endothelial cell growth and contact angle measurements. Human coronary artery endothelial cell (HCAE) growth was studied on (1) untreated, (2) helium plasma-treated and (3) helium plasma-treated polyurethane films followed by exposure to ammonia gas respectively. The untreated polyurethane surface was hydrophobic with a contact angle of 90° and had poor cell growth (cell concentration ≈ 333/cm²). The atmospheric pressure helium plasma treatment of the polyurethane film for four minutes increased the hydrophilicity of the surface (contact angle, θ = 79°) resulting in enhanced HCAE cell growth on the film (cell concentration ≈ 15,208/cm²). Further, a polyurethane film was plasma-treated for four minutes followed by one minute exposure to ammonia gas. Although, there was a significant drop in contact angle (θ = 52°), there was no appreciable increase in the cell growth (cell concentration ≈ 16,719/cm²).