Sangsanoh Pakakrong, Supaphol Pitt
Technological Center for Electrospun Fibers and the Petroleum and Petrochemical College, Chulalongkorn University, Soi Chula 12, Phyathai Road, Pathumwan, Bangkok 10300, Thailand.
Biomacromolecules. 2006 Oct;7(10):2710-4. doi: 10.1021/bm060286l.
Further utilization of chitosan nanofibrous membranes that are electrospun from chitosan solutions in trifluoroacetic acid (TFA) with or without dichloromethane (DCM) as the modifying cosolvent is limited by the loss of the fibrous structure as soon as the membranes are in contact with neutral or weak basic aqueous solutions due to complete dissolution of the membranes. Dissolution occurs as a result of the high solubility in these aqueous media of -NH(3)(+)CF(3)COO(-) salt residues that are formed when chitosan is dissolved in TFA. Traditional neutralization with a NaOH aqueous solution only maintained partial fibrous structure. Much improvement in the neutralization method was achieved with the saturated Na(2)CO(3) aqueous solution with an excess amount of Na(2)CO(3)(s) in the solution. We showed that electrospun chitosan nanofibrous membranes, after neutralization in the Na(2)CO(3) aqueous solution, could maintain its fibrous structure even after continuous submersion in phosphate buffer saline (pH = 7.4) or distilled water for 12 weeks.
由壳聚糖在三氟乙酸（TFA）中、有或没有二氯甲烷（DCM）作为改性助溶剂的情况下电纺而成的壳聚糖纳米纤维膜，一旦与中性或弱碱性水溶液接触，由于膜的完全溶解，纤维结构的丧失限制了其进一步利用。溶解是由于壳聚糖溶解在TFA中时形成的 -NH(3)(+)CF(3)COO(-) 盐残基在这些水性介质中的高溶解度所致。用NaOH水溶液进行传统中和只能维持部分纤维结构。在溶液中加入过量Na(2)CO(3)(s)的饱和Na(2)CO(3)水溶液，中和方法有了很大改进。我们表明，电纺壳聚糖纳米纤维膜在Na(2)CO(3)水溶液中中和后，即使在磷酸盐缓冲盐水（pH = 7.4）或蒸馏水中连续浸泡12周后仍能保持其纤维结构。
