Physical and bioactive properties of multi-layered PCL/silica composite scaffolds for bone tissue regeneration

The characteristic properties of nanosized silica, such as its high biocompatibility and hydrophilic property, have made it a potential component of materials for tissue engineering. However, the low processability and poor mechanical properties of silica have been obstacles to its use as a tissue regenerative material. In this study, composite scaffolds consisting of poly(ε-caprolactone) (PCL) and silica, fabricated by a melt-plotting/coating process, were assessed as a potential scaffold for bone tissue regeneration. The composite scaffolds were evaluated in terms not only of their physical properties (wetting/water absorption, surface roughness, and tensile properties), but also their biological properties (cell viability, ALP activity, and calcium deposition) by culturing pre-osteoblasts (MC3T3-E1) on various composites coated with various silica solutions (1.5, 3.7, 6.6wt%). Using a simple coating process, the composite scaffolds showed homogeneous surface roughness (R_a=8-11nm) and highly improved wetting/water absorption (~2.8-fold) without any mechanical loss compared with the pure PCL scaffold. The results of cell-seeding efficiency (~1.8-fold), cell viability (~5-fold at 7days) and proliferation, alkaline phosphatase (ALP) activity (~1.7-fold), and mineralisation (~1.5-fold) analyses showed that although only a small proportion of coating agent (silica) was used, the in vitro cellular activities were improved significantly.