For peripheral nerve injury, most tissue regeneration processes are carried out with the use of autografts. However, for lesions no larger than 1 centimeter,
[1] it is possible to replace them by using nerve guide conduits (NGC).
[2]Much of the regeneration process occurs on the surface of the NGC,
[1] therefore, our work is focused on improving the performance of NGCs thanks to the modification of the surface using the layer-by-layer technique. A successful surface modification can be achieved by generating coatings with natural polymers present in the extracellular matrix, which would allow to increase cell adhesion in NGC and even incorporate proteins such as nerve growth factor (NGF) to improve cell proliferation. In our previous works,
[3,4] we modified different surfaces with coatings of six bilayers of heparin and collagen (HEP/COL) and we were able to determine that the chemical structure of collagen and heparin is present in multilayers on flat silicon plates. We also use our coatings in the presence or absence of the NGF and we found that real-time monitoring cell behavior showed an initial adhesion region, a proliferation phase, and a cell confluence stage and that Layer-by-layer coatings increase cell adhesion and proliferation up to 2.5 times compared to the tissue culture plastic control. Finally, we demonstrated that, where the layer-by-layer coatings were used, hSCs showed an enhanced initial cell adhesion response and their cell morphology was normal. In this research, we evaluated cell migration and protein expression of human Schwann cells that were seeded on HEP/COL. We found an improved expression mainly of BDNF which is known to promote the time and duration of the myelination processes in hSCs. On the other hand, cell migration yielded the best results in the conditions with HEP/COL without NGF, although it is known that NGF increases cell adherence and inhibits migration. The surface modification of a commercial NGC also showed favorable results for cell performance, increasing cell viability by 200% compared to uncoated NGCs. In conclusion, HEP/COL coatings seem to be a potential tool for enhancing the functions of NGCs.
References:
[1] J. Choi, J.H. Kim, J.W. Jang, H.J. Kim, S.H. Choi, S.W. Kwon, Decellularized sciatic nerve matrix as a biodegradable conduit for peripheral nerve regeneration, Neural Regen. Res. 13 (2018) 1796–1803. https://doi.org/10.4103/1673-5374.237126.
[2] R. Ayala-caminero, L. Pinzón-herrera, C.A. Rivera Martinez, J. Almodovar, Polymeric scaffolds for three-dimensional culture of nerve cells: a model of peripheral nerve regeneration, MRS Commun. 7 (2017) 391–415. https://doi.org/10.1557/mrc.2017.90.
[3] D.A. Castilla-Casadiego, L. Pinzon-Herrera, M. Perez-Perez, B.A. Quiñones-Colón, D. Suleiman, J. Almodovar, Simultaneous characterization of physical, chemical, and thermal properties of polymeric multilayers using infrared spectroscopic ellipsometry, Colloids Surfaces A. 553 (2018) 155–168. https://doi.org/10.1016/j.colsurfa.2018.05.052.
[4] L. Pinzon-Herrera, J. Mendez-Vega, A. Mulero-Russe, D.A. Castilla-Casadiego, J. Almodovar, Real-time monitoring of human Schwann cells on heparin-collagen coatings reveals enhanced adhesion and growth factor response, J. Mater. Chem. B. 8 (2020) 8809–8819. https://doi.org/10.1039/d0tb01454k.
