Biocompatible interface films deposited within porous polymers by Atomic Layer Deposition (ALD)

Ultrathin ceramic films were deposited throughout highly porous poly(styrene-divinylbenzene) (PS-DVB) particles using a low-temperature atomic layer deposition (ALD) process. Alumina and titania films were deposited by alternating reactions of trimethylaluminum and H2O at 33 degrees C and of titanium tetrachloride and H2O2 (50 wt % in H2O) at 100 degrees C, respectively. Analytical characterization revealed that conformal alumina and titania films were grown on internal and external polymer surfaces. The improved bioactivity of the polymer substrates was revealed on the basis of the formation of hydroxyapatite (HA) in simulated body fluid. The accelerated formation of HA on the ALD-modified polymer surface was caused by the negatively charged surface provided by the ultrathin ceramic interface. The potential for ALD films to support cell attachment was demonstrated.