Evaluation of “Vitamin E” as an active surfactant for production of novel bone scaffolds with controlled porosity and hydrophilicity
Porosity is one of the most critical aspects during fabrication of porous scaffold for bone tissue engineering. Porosity parameters can modify the scaffold hydrophilicity and permeability that in turn regulate the protein adsorption, cellular attachment and infiltration, and vascularization of the scaffold. Various methods have been investigated for control of porosity parameters; however, the field still suffers from major controversies and challenges; i.e., inability to customize the porosity and hydrophilicity at different levels. Therefore, considering the biomimetic strategies in replicating the natural tissue, this study explored a new integrated approach for control of porosity within nanocomposite collagen/nano-biphasic calcium phosphate (collagen/nBCP) scaffold. For this purpose, the ability of “TPGS (vitamin E) as a potent biocompatible porogen was explored during a modified freeze-drying procedure. Several processing variables were studied in parallel in controlling the porosity parameters including; different quenching rates (-18 ℃, -80 ℃, and -196 ℃), collagen/nBCP ratios (92/8% and 85/15%), and TPGS ratios (5% and 15%). The physicochemical characteristics of the scaffold were studied using different techniques with a particular focus on porosimetry analysis. The results showed that careful control of TPGS and quenching rate could increase the range of pore size and actively modify the pore shape, while collagen/nBCP ratio mostly affected total porosity and roughness. The collagen/nBCP ratio of 92/8% with TPGS treated at the quenching rate of -80 ℃ showed more favorable and consistent physicochemical behaviors, i.e., higher porosity and hydrophilicity. This method allowed production of scaffold displaying multimodal heterogeneous pore distribution with an increase in the range of pore size of mostly round/oval pore morphology (similar to natural bone) and a high hydrophilicity that supported a better cellular performance. Considering the various medical benefits of TPGS, its careful application as surfactant-porogen tailored with its therapeutic potentials could provide a promising insight for production of customized scaffold for various tissue engineering applications. Further in vitro and in vivo studies are required to fully explore the potential of this integrated approach.