Biomimetic Ploy(Lactic Acid) Nanofibrous Scaffolds For Tissue Engineering: Preparation And Effects On Cells

Tissue engineering aims to develop biologically functional living substitutes fortraumatized and diseased tissues. Scaffolds play a pivotal role in providingthree-dimensional templates and synthetic extracellular matrix (ECM) environments fortissue regeneration. It is often beneficial for the scaffolds to mimic certain advantageouscharacteristics of the natural ECM. Oriented tissue bundles, such as nerve and tendon, havebundled tubular ECM structures comprised with longitudinally aligned type I nanofibers.In this study, molds composed of glass tube, needles and spacers were assembled tofabricate channeled scaffolds. By utilizing the molds, a method combining injectionmolding and thermally induced phase separation techniques was developed to create single-and multiple-channeled nanofibrous poly(l-lactic acid)(PLLA) scaffolds. The overall shape,the number and spatial arrangement of channels, the channel wall matrix architecture, theporosity and mechanical properties of the scaffolds were all tunable.To control the nanofiber orientation, a gel stretching method was introduced into thethermally induced phase separation techniques to produce aligned nanofibrous scaffolds.The nanofiber alignment was achieved by the slippage of the polymer-rich phases withinphase-separated PLLA/tetrahydrofuran gels. The degree of nanofiber alignment, theporosity and mechanical properties of the scaffolds could be manipulated by the gelstretching ratio.The porous nanofibrous channel wall provided an excellent microenvironment for proteinadsorption and the attachment of PC12neuronal cells and tendon fibroblast cells, while thealigned nanofiber exhibited the capability for contact guidance, showing that the scaffoldsmimicking the key structural features of natural ECM have potential for neural and tendontissue regeneration.