Coating stability and blood compatibility of stainless steel surface modified with phospholipid polymer

To improve the blood compatibility of the surface of stainless steel, which is used as a base material of stent for cardiovascular treatment, the surface was coated with a 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer. 4-Methacryloyloxyethyl trimellitate anhydride (4-META)/methyl methacrylate (MMA) polymer was precoated on the stainless steel plate as a binder to obtain the long term stability of the MPC polymer. The surface of modified stainless steel was analyzed with XPS. The amount of the polymer eluted from the surfaces was evaluated by soaking samples in water for 14 days at 37°C. All of MPC polymer directly coated on stainless plate was eluted after 14 days soaking. On the other hand, the elution of the MPC polymer was significantly reduced by precoating of 4-META/MMA polymer on stainless plate. This surface effectively reduced protein adsorption and platelet adhesion. MPC polymer coated with 4-META/MMA polymer on stainless steel will be a useful technique as surface modification of the stent.