Rapid prototyping of three-dimensional nanocomposite hydrogel constructs: effect of silica nanofiller on swelling and solute release behaviors of the nanocomposite hydrogels.

Three-dimensional (3D) patterning and engineering of biomaterials and biointerfaces have helped bioengineers harness the full potential of cell immobilization for different biomedical applications. However, the bioengineering of an efficient cell immobilized tool, having application in cell biology and tissue engineering, often comes into realization only when a cell friendly immobilization technique is combined with a compatible 3D patterning scheme. We have previously demonstrated the successful blue light induced photopolymerization of poly (ethyleneglycol) diacrylate (PEGDA) based hydrogels for the entrapment of Saccharomyces cerevisiae and NIH 3T3 fibroblast cells. In the present work we have modified rheology of the prepolymer solution by mixing fumed silica nanofiller in different concentrations. Here we demonstrate the rapid prototyping of cell immobilized nanocomposite hydrogels, where S. cerevisiae loaded nanofilled prepolymer solution was directly written in layer-by-layer fashion using solid free form fabrication also known as rapid prototyping technique and was cross-linked into 3D cell loaded construct via blue light induced polymerization. The swelling trend was found to be a function of silica nanofiller concentration and transitioned from decreasing to increasing type at 10% w/v nanofiller concentration. Dynamic swelling profile predicted that the swelling agent transported with in the gels via super case II type transport mechanism irrespective of the crosslink density. In contrast, the mode of transportation of the loaded solute was found to be fickian and nonfickian type respectively for loosely and tightly crosslinked gels. Spatial heterogeneity in the crosslinked network was resulted upon blue light curing, subsequently the 3D growth of the immobilized cells was observed to be a function of crosslink density. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 3237–3249, 2015.