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Atomic Layer Deposition Surface Modified Porous Polymer for Tissue Engineering Applications

Xinhua Liang1, Aaron D. Lynn1, David M. King2, Stephanie J. Bryant1, and Alan W. Weimer3. (1) Chemical and Biological Engineering, University of Colorado, 1111 Engineering Drive, Campus Box 424, Boulder, CO 80309-0424, (2) Department of Chemical Engineering, University of Colorado, 1111 Engineering Dr., Campus Box 424, Boulder, CO 80309, (3) Department of Chemical and Biological Engineering, University of Colorado, 1111 Engineering Drive, Boulder, CO 80309-0424

The overall research goal is to develop novel porous polymer/ceramic composite materials for bone tissue engineering applications. Towards this goal, the main objective of this study is to demonstrate the feasibility of using atomic layer deposition (ALD) to coat the surface of porous polymers for bone scaffolds. As a proof of concept, highly porous poly(styrene-divinylbenzene) (PS-DVB) particles were employed and were successfully coated with alumina and titania films at the atomic level in a fluidized bed reactor using a low-temperature scalable particle ALD process. Alumina and titania films were deposited by the alternating reactions of trimethylaluminum (TMA) and H2O at 33 C, and titanium tetrachloride (TiCl4) and H2O2 (50 wt.% in H2O) at 100 C, respectively. Analytical characterization revealed that conformal alumina and titania films were grown on internal and external polymer particle surfaces. ALD provides a controllable method for reinforcing porous polymeric structures while modifying surface properties. The ALD layers can improve the bioactivity and cell adhesion of the polymer substrate. The bioactive behavior of the composites was assessed by the formation of bone-like apatite on the material surfaces. The improved cell adhesion was demonstrated by protein adsorption of the composites from fetal bovine serum (FBS) as well as NIH/3T3 cell attachment and spreading on particle surfaces.