6 - Gas foaming technologies for 3D scaffold engineering

The effect of scaffold pore size and interconnectivity as well as porosity are undoubtedly crucial factors for most tissue engineering applications. This premise is the basis of worldwide efforts that have been spent to develop increasingly sophisticate fabrication techniques to control the scaffold microarchitecture and build efficient synthetic analogues of extracellular matrix. Among the plethora of techniques developed for this purpose, gas-in-liquid foam templating has emerged as one that conjugates simplicity of the technology involved, use of inert gases as the templating phase (thus avoiding the use of potentially toxic organic solvents), employment of a large variety of biocompatible and often bioactive biopolymers, and obtainment of highly porous and interconnected scaffolds. Experience gained in cell culturing pointed out the main limits of gas-foamed scaffolds, that is the polydispersed nature of both pores and interconnects dimension that cause an uneven distribution of seeded cells within the enclosed 3D space. The awareness of such a limit and increasing demands of more reliable in vitro cellular models stimulated researchers to exploit the potentials offered by microfluidics in the generation of monodisperse gas-in-liquid foam templates. Foam templating through microfluidics gives the opportunity to finely tune the porous texture of the scaffolds, i.e., the dimension of pores and interconnect, eventually independently one from the other, thus responding to the morphological requirements posed by a particular cell type. © 2018 Elsevier Ltd. All rights reserved.