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Biomimetic coatings for implants
|Tomasz Ciach , Beata Butruk|
Warsaw University of Technology, Faculty of Chemical and Process Engineering (WUT), Warynskiego, Warsaw 00645, Poland
Ageing societies demands "spare parts" but the number donors is always too small. Technology of artificial organs for humans is developing very quickly but the still unsolved problem is an interface between artificial lifeless structure and living organism. Especially implants having a constant contact with human blood, like heart or vascular prosthesis, are a source of constant problems. Contact activation of blood platelet causes clot formation at the implant surface or somewhere in our circulatory system. Clot formed at the implant surface can block the blood flow and function of the prosthesis; clot formed in the circulatory system can block small vessels in lungs or brain, what can be fatal for a patient. We propose to solve this problem by the biomimetic approach, formation of coatings that mimics natural inner surface of human vascular system at three different levels of mimicry. To check this approach three types of coatings for medical polyurethanes have been synthesized. First is a poly vinyl pyrrolidone based hydrogel coating, which mimics extracellular matrix and exhibit a very low surface energy. This prevents small protein adsorption and activation of complement immunological system. Second type of the coatings is mimicking outer layer of cellular membrane. Coating is made of dipalmitoyl phosphatidylcholine, which molecules are organized like in the cellular membrane. Third type of the coatings is a macromolecular nanostructure constructed step by step at the polymer surface. This structure is able to present certain sequence of aminoacids. The aim of this structure is to attract and anchor a certain type of human cells – endothelial cells, which monolayer naturally covers all tissues which have contact with blood. Once anchored cells start to divide and form a monolayer of self healing properties. Endothelium is able to actively prevent platelet activation by presenting proper surface ligands and releasing substances able to prevent cascade activation and even to deactivate platelet and dissolve small clot pieces. First two types of coatings were tested with human blood in static and dynamic conditions, and the third one was tested with human umbilical cord endothelial cells. All the coatings are very promising candidates for various types for blood contacting medical devices.
Presentation: Polish Research Projects at Nano and Advanced Materials Workshop and Fair, by Tomasz Ciach
See On-line Journal of Nano and Advanced Materials Workshop and Fair
Submitted: 2013-06-30 09:02 Revised: 2013-07-01 07:49