Development of nanocomposite collagen/ HA/β-TCP scaffolds with tailored gradient porosity and permeability using...

The production of the biomimetic scaffolds with well-designed porosity parameters is a critical and challenging factor in biomaterials processing. The porosity parameters (i.e., pore size, pore shape, and distribution pattern) impact scaffold permeability, proteins/cells infiltration, and angiogenesis. This study introduced a new approach for the production of gradient porous nanocomposite scaffolds with controllable porosity and permeability using basic biomaterials of collagen and nanobiphasic calcium phosphate (nBCP) powder consisting of nano HA/β-TCP. A modified freeze-drying method (i.e., variables; collagen/nBCP ratio and quenching rates) was integrated for the first time with the chemical foaming method with the use of vitamin E as a potential surfactant and porogen. Vitamin E successfully increased the range of pore size, pore interconnection, and scaffold permeability. Further control of collagen/nBCP ratios and quenching rates allowed modulation of the pore morphology, total porosity, and the surface roughness of the scaffold. Scaffolds produced using vitamin E with collagen/nBCP ratio of 92/8% at -80°C quenching rate displayed a multimodal heterogeneous pore network with a wide range of pore sizes of mostly round/oval and polygonal pore morphology. Furthermore, these scaffolds revealed a more consistent gradient porous network with peripheral large pores-that gradually become smaller toward scaffold central-that produced a significantly higher permeability and better support of initial cellular performances. Accordingly, considering the various potentials of vitamin E, this study would provide promising insight into the production of smart and customized scaffolds for regenerative and therapeutic applications.