- 9:50 AM

Advanced Nanobiomedical Application of the Phosphorylcholine-Polymer Surface Technology (Pcst)

Kazuhiko Ishihara, Department of Materials Engineering, Center for NanoBio Integration, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan

How to make an excellent biointerfaces between biological system and artificial materials is interesting and important issue in biomedical, bioengineering, and bioscience research fields. Particularly, recent progress in the biotechnology requires much more high performance on the biointerfaces. In this communication, I will present a special concept for preparing biointerfaces based on “PC surface technology (PCST)”, which are phospholipids and phospholipid polymers assembling technology. By using this PCST, the surface of the artificial materials converts to “artificial cell membrane” surface. That means, this technology is new and key bridge to connect biological field and materials engineering. Various materials have been used as materials for manufacturing biomedical devices. However, these materials do not have enough blood compatibility and biocompatibility; therefore, infusion of an anticoagulant is required during clinical treatments using these biomedical devices to avoid clot formation. A development of new biomaterials was proposed based upon the mimicking of a simple component present on the extracelluar surfaces of the lipid bilayer that forms the matrix of the plasma membranes of cells, namely, the phosphorylcholine (PC) group of phosphatidylcholine. PC group, an electrically neutral, zwitter ionic head group, which represents the dominant property of the phospholipid head groups present on the external surface of cells, is inert in coagulation assays. The clotting time of blood was extended on the phospholipid-treated surface compared with that on the non-treated substrate. From the results of these studies, it can be said that these polymerizable phospholipid derivatives are useful for making polymer biomaterials. It was proposed a new concept for making polymer biomaterials that have good stability, processability and applicability using a methacrylate monomer with a phosphorylcholine group, 2-methacryloyloxyethyl phosphorylcholine (MPC). It was developed finely the synthetic route and purification method of MPC and a sufficient amount of MPC with excellent purity could be obtained. Thus, it became possible to prepare the PC-polymer and their functionality was carefully evaluated. Also, many derivatives of the MPC and their polymers have been prepared in the world. The PC-polymers are useful not only for artificial organs but also medical devices due to their excellent properties, for example, excellent biocompatibility even in vivo and surface lubrication action. The PCST is one of the triggers for opening surface modifications of the substrate with phospholipid derivatives and these surfaces also demonstrated the usefulness of the improvement of protein adsorption and cell adhesion resistance. Therefore, the construction of the artificial cell membrane surface became a general concept to obtain not only blood-contacting medical devices, which can be safely and clinically applied for longer periods, but also devices or equipment for bioengineering and tissue engineering. It is convinced that the PC-polymers will become important materials in the not only biomedical and nano-scaled bioengineering and chemical engineering fields.