Cartilage engineering benefits from the fabrication of random fibrous constructs, mimicking the structures found in the extracellular matrix of natural tissue, to support the attachment and proliferation of cells. Here, a novel approach is demonstrated for the production of fibers with controlled dimensions in the micron regime from the naturally derived biopolymer chitosan. The process involves filling an array of microchannels recessed into a mold surface with a solution bearing chitosan, inducing a pH-dependent coagulation, and releasing the structures from the mold into a medium where they assume random orientation. The dimensions and shape of these channels in the master template were defined by a standard photolithographic process followed by anisotropic reactive ion etching of the underlying silicon wafer. Replica castings of this silicon wafer surface in elastomeric polydimethylsiloxane (PDMS) served as the mold for chitosan. The resulting scaffolds were produced with fiber cross-sectional widths of 22 ± 4 µm, 13 ± 3 µm, 4.7 ± 1.6 µm, 1.7 ± 0.6 µm, and 1.1 ± 0.4 µm and were found to consist of 97.8 ± 0.5% medium when hydrated. Study of the nanoscale morphology of the fibers revealed that the effects of liquid surface tension play a significant role in the preservation of this open form and that lyophilization of the product is the preferred long term storage method.
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