以幾丁聚醣製備多孔道週邊神經導管之生物適應性

Abstract

對於週邊神經的再生，通常會使用人造的神經導管作為輔助，以避免直接縫合受損的神經時，對神經所造成的張力。幾丁聚醣在目前所使用作為人造神經導管當中，是相當具有潛力的一種材料，因為其良好的性質，如生物適應性、生物可降解性、引起較少的組織反應等等，幾丁聚醣也經過FDA認證，使得臨床的應用更為可能。 在本研究中，我們發展了一個全新的方法製造神經導管，包含了加熱線絲與冷凍乾燥的過程，不但容易且具有再現性。幾丁聚醣導管的性質，如表面微結構、結晶度以及中和劑的選用也被研究。實驗結果顯示含有中心孔道的幾丁聚醣導管具有高孔隙度，且適合使用弱鹼作為中和劑，使用弱鹼作為中和劑，不但可以保持導管內的微結構不變化，也可以保持幾丁聚醣的結晶性。幾丁聚醣導管的降解測試也顯示其在神經修復的期間之內，仍足以維持結構上的支持。 本實驗更進一步測試幾丁聚醣的細胞活性，使用許旺氏細胞培養於幾丁聚醣薄膜上，結果雖然顯示細胞在幾丁聚醣薄膜上缺乏良好的細胞貼附性，但是可以透過表面改質的方式接上生物分子（本實驗使用昆布胺酸），以增進細胞的貼附性。但另一方面，將細胞培養於幾丁聚醣的孔道內，卻顯示了生長不佳的結果，推測的原因可能因為孔道內表面缺乏生物分子的修飾，也可能是因為孔道的形態不適合細胞生長。

For peripheral nerve regeneration, it often uses artificial nerve conduits to prevent the nerve from the tension applied during suturing the injured nerve directly. Chitosan is one of the most potential materials to be used for manufacture artificial nerve conduits due to its outstanding characteristics, such as biocompatibility, biodegradability, induce less tissue response and so on. Chitosan is also proved medicinal by FDA so as to make it possible to be used on clinic. In this study, we develop a brand new method, wire-heating and lyophilizing process, for manufacturing nerve conduit, and make it facile and reproducible. The characteristics of chitosan conduits, such as micro surface morphology, crystalline, and the choice of neutralizer are also evaluated. The experiment results show that the chitosan conduits with the hollow channels are highly porous, and are appropiate to use weak base as neutralizer. Using weak base as neutralizer can not only hold the micro-structure but also keep the crystalline of chitosan. The degradation rate test of chitosan conduits also shows that the conduits can provide with a longer lasting structure support during the period of nerve regeneration. Furthermore, we also evaluate the cell viability of chitosan. Schwann Cells were cultured on chitosan membrane, and further on conduits. It shows that chitosan membrane surface modified with biomolecules, one of which laminin was used in this study, can improve the poor condition of cell adhesion to chitosan membrane. However, it was also found that a poor result appeared in the culture of Schwann Cells in chitosan conduits. It is assumed that one reason could be the absence of biomolecular modification, and the other one could be the shape of the channel not being adapted to the cells.