Development of poly(l-lactic acid) hollow fiber membranes for artificial vasculature in tissue engineering scaffolds

In tissue engineering constructs, vascularization within in vitro cultured tissue is one of the major problems, as proliferating cells act themselves as a barrier for mass transfer. Issues related especially to nutrient and oxygen delivery to the cells limit tissue construct development to smaller than clinically relevant dimensions, which in-turn limits the ability for in vivo integration. In this work, we develop highly permeable biodegradable poly (l-lactic acid) (PLLA) hollow fibers (HF) which when integrated with tissue engineered scaffolds in vitro can improve nutrient supply to the cells. In fact, we study various fiber spinning parameters to develop the optimum fiber structure. By using 1,4 dioxane as solvent and ethanol as non-solvent at very low temperature (−6 °C), we develop fibers with thin dense top-layer and spongy sub-layer. Porogens like poly-vinylpyrrolidone (PVP) and poly (ethylene-glycol) (PEG) are added to the dope solution. Subsequent treatment with sodium hypochlorite produces open fiber surface and increased pore interconnectivity. The produced fibers have good mechanical properties. The transport of bovine serum albumin (BSA) and of cell culture medium supplement with 10% fetal bovine serum (FBS) through the produced PLLA fiber is high (permeance 1963 L/(m2 h bar)) with low protein retention. In vitro static and dynamic cell culturing for 3 and 7 days using mouse pre-myoblast (C2C12) cells suggests that the fabricated PLLA hollow fibers are suitable for delivery of nutrients to the cells in a tissue engineering scaffold.