Introduction: One of the greatest challenges in peripheral nerve tissue engineering is to align regenerating nerves with their targets. Fibrous scaffolds, typically containing collagen, can be engineered to direct the growth of neurites in an oriented fashion. The production of collagen in its fibrous form is a challenging task that suffers from low throughput production and poor cell infiltration due to small pore sizes of collagen-based scaffolds. The Frampton lab has previously demonstrated that contact drawing is an easily scalable technique for production of aligned collagen fiber substrates under ambient conditions without the need for specialized equipment or hazardous solvents (1). Materials and Methods: A contact drawing technique was used to produce high-collagen-content polyethylene oxide (PEO)-collagen fibers that can be anchored to an elastomeric support for the alignment of cells. Raman spectroscopy and Fourier-transform infrared spectroscopy (FTIR) were utilized to examine the composition of the fibers and the mechanical properties of individual fibers were investigated by tensile testing. Both primary dorsal root ganglion (DRG) and immortalized PC12 cells were seeded onto collagen fiber substrates, and their morphologies, alignment with respect to the collagen fibers, and length of neurites were measured over time. Results, Conclusions, and Discussions: FTIR and Raman spectroscopy confirmed the presence of collagen and absence of PEO in the fibers after rehydration. Tensile testing revealed that the resulting fibers had mechanical properties that were tunable within the range reported for various soft tissues. Cell viability was comparable between cells cultured on tissue culture plastic and cells cultured on collagen fibers by both live/dead and MTT assays. Neuronal cells cultured on collagen fiber substrates readily aligned along the fibers and maintained their alignment during multiple days of culture.
We were able to produce PEO-collagen fibers using water as a solvent by way of a highly efficient and cost effective contact drawing method. The collagen fibers exhibited appropriate mechanical properties and supported attachment and alignment of PC12 and DRG cells when anchored on an elastomeric support. This versatile method will enable production of custom scaffolds that enhance neural cell attachment and aid in neurite guidance.
1.Verma SK, Yaghoobi H, Slaine P, Baldwin SJ, Rainey JK, Kreplak L, Frampton JP. Multi-pin contact drawing enables production of anisotropic collagen fiber substrates for alignment of fibroblasts and monocytes. Colloids Surf B Biointerfaces. 2022 Jul;215:112525. doi: 10.1016/j.colsurfb.2022.112525. Epub 2022 Apr 28. PMID: 35500531.
