Study On Preparation And Properties Of Different Functionalized Plasma Polymeric Films

Biomedical metal materials have been widely used in coronary stents and vena cava filter which are implantable device due to there chemical durability and excellent mechanical properties. However, the key problem is how to improve the biocompatibility when the metal materials are long time implantation. Consequently, surface modification should be used to improved biocompatibility of the metal materials. Plasma polymerization technique is used in surface modification of biomaterial, and it is used to get functionalized surfaces on metal biomaterials surfaces for better biocompatibility.In this paper,316L stainless steel (316L SS) is chosen as the metal material in our research., and the polyethylene glycol (PEG), allyl alcohol, allylamine and acrylic acid vapor were employed as precursors for fabricating functionalized surfaces containing hydroxyl (-OH), amino group (-NH2) and carboxyl (-COOH) by pulsed plasma polymerization technique respectively. The blood compatibility and cellular compatibility of pulsed plasma polymerized films were investigated.The Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) results show that plasma polymerized films were successfully fabricated on the SS surfaces. It was indicated that these films had been retained some precursor structure after the plasma polymerization and got functionalized surface successfully. After surface plasma polymerization, the SS surface had better hydrophilicity. The plasma polymeried films deposited at the optimizing process had excellent dynamical stability.The result of in vitro adhesion behavior of endothelial cells (EC) on the surface showed that all functionalized surfaces could accelerate the EC adhesion and spreading, especially the amino-functionalized surface exhibited best cell viability. However, the PP-PEG could inhibited the EC adhesion and spreading on the surface because there were ethylene oxide (EO) units in the PP-PEG film and EO units has the hrdrogel property which could prohibit the protein adhesion. The platelet adhesion test indicated that the PP-PEG had good anticoagulation property.Functionalized surfaces of amino groups showed the best cell compatibility in the EC adhesion and spreading test. Furthermore the bipolar films by sequential layer by layer deposition of PPAam (pulsed plasma polymeric allylamine) and PPAac (pulsed plasma polymeric acrylic acid) for protonated functionality surfaces were prepared. The result of XPS and surface energy test showed that the protonated bipolar films had more polar. Compared to the PPAam in EC adhesion and proliferation, the bipolar films had more EC viability.