Department of Chemistry, Morgan State University, Baltimore, Maryland 21251, USA.
J Phys Chem B. 2012 Feb 9;116(5):1579-85. doi: 10.1021/jp210043w. Epub 2012 Jan 24.
A new method for covalently cross-linking chitosan is developed by chemically oxidizing catechol to o-quinone which subsequently reacts with and cross-links chitosan through Michael addition and Schiff base formation. The cross-linked chitosan film shows a pH-responsive, switchlike behavior toward the negatively charged redox probe, Fe(CN)(6)(3-/4-), and withstands harsh acidic conditions. The negative Fe(CN)(6)(3-/4-) is found to be trapped and enriched in the catechol-cross-linked chitosan film under acidic conditions and released into solution by either increasing pH or applying a negative voltage. Chitosan films made with different techniques, i.e., solvent evaporation (simple deposition), electrodeposition, and covalent cross-linking, are examined using cyclic voltammetry and electrochemical impedance spectroscopy (EIS), and the results demonstrate that fabrication methods greatly affect the properties of the chitosan films.
开发了一种将壳聚糖共价交联的新方法，通过化学氧化邻苯二酚生成邻醌，随后通过迈克尔加成和席夫碱形成反应与壳聚糖交联。交联壳聚糖薄膜对带负电荷的氧化还原探针 Fe(CN)(6)(3-/4-)表现出 pH 响应的开关行为，并能耐受苛刻的酸性条件。在酸性条件下，带负电的 Fe(CN)(6)(3-/4-)被捕获并富集在邻苯二酚交联壳聚糖薄膜中，通过增加 pH 值或施加负电压将其释放到溶液中。使用循环伏安法和电化学阻抗谱 (EIS) 对通过不同技术（即溶剂蒸发（简单沉积）、电沉积和共价交联）制备的壳聚糖薄膜进行了检查，结果表明，制备方法极大地影响了壳聚糖薄膜的性能。
