Brush-on fabrication of suspended PLLA-PEO-PLLA triblock copolymer fibers

Parallel fibers can be rapidly created by manually brushing solvated polymer solutions over arrays of micro-fabricated pillars. Recently, this technique has been utilized to produce suspended arrays of micron and sub-micron scale fibers consisting of a new triblock copolymer composed of a hydrophilic mid-block of polyethylene oxide (PEO) surrounded by two hydrophobic end groups of poly-L-lactic acid (PLLA). A solution of this polymer in chloroform has been used to fabricate fibers with diameters ranging from 125 nm to >50 μm. Annealing these fibers in water induces the formation of ultrastructural nanoscale pores that can be selectively oriented through variation of the surface treatment. Because the PLLA-PEO-PLLA triblock copolymer is both biocompatible and biodegradable, these arrays of fibers are excellent candidates for biomimetic extracellular matrix (ECM) structures. Additionally, the porous ultrastructure of the fibers may provide a platform for the in situ delivery of growth factors to stimulate endothelial cell proliferation, migration, and lumen formation.