POLYMER/POROUS SILICON (pSi) COMPOSITE MATERIALS FOR TISSUE ENGINEERING:POLYMER DEGRADATION STUDIES IN VITRO

This study focuses on composites of porous silicon (pSi) with the biocompatible polymer polycaprolactone (PCL). In particular, the degradation behavior of the composites as a function of their morphology and the effect of pSi on polymer degradation has been evaluated. Two base polymer platforms were used: 1) non-woven polymer fibers ~10 μm in diameter prepared by an electrospinning method and 2) solid films based on fibers fused at a temperature of 65-80 o C. Two types of pSi were selected to prepare the composites; oxidized pSi (ox-pSi) with particle size of ~30 μm and as-prepared hydride-terminated pSi (AP-pSi) with a particle size of ~200 μm. PSi particles were physically embedded into a given PCL structure resulting in two categories of samples: pSi/PCL fibers and pSi/PCL films.  All samples were incubated at 37 o C in three types of solutions: cell culture medium, phosphate-buffered saline (PBS), and distilled water. Composite evolution after 5 weeks degradation was examined by determining weight loss, polymer crystallinity by differential scanning calorimetry (DSC), and surface morphology/composition  (SEM/EDX).