School of Chemistry and Molecular Biosciences, The University of Queensland, Cooper Road, Brisbane, Queensland 4072, Australia.
Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Corner of College and Cooper Road, Brisbane, Queensland 4072, Australia.
Int J Biol Macromol. 2022 Nov 30;221:204-211. doi: 10.1016/j.ijbiomac.2022.08.179. Epub 2022 Sep 1.
PEGylation is a common method use to modify the physiochemical properties and increase the solubility of chitosan (CHI). Knowledge of optimal reaction conditions for PEGylation of CHI underpins its ongoing use in nanomedicine. This study synthesised methoxy polyethyleneglycol grafted CHI (mPEG-CHI) using carbodiimide-mediated coupling. The effect of reagent concentrations and pH on the degree of substitution (DS) and the PEGylation yield (conversion of free PEG to conjugated PEG) was evaluated through detailed chemical characterisation. Within the parameter space investigated, optimised reaction conditions (NH: COOH:NHS:EDC of 3.5:1:1:10, pH = 5) resulted in a DS of 24 % and a PEGylation yield of 84 %. An EDC-derived adduct formed at pH ≥ 5.5 and at a 15-fold excess of EDC relative to COOH. The adduct was evaluated to be a guanidine derivative formed by the reaction of the amine group of CHI directly with EDC. DS ≥ 12 % imparted water solubility to CHI at physiological pH and mPEG-CHI (0.2-1.0 mg/mL) was not cytotoxic against the breast cancer cell lines MCF-7 and MDA-MB-231, indicating its suitability for medical applications.
聚乙二醇化是一种常用的方法，用于修饰壳聚糖（CHI）的物理化学性质并提高其溶解度。了解 CHI 的聚乙二醇化的最佳反应条件是其在纳米医学中持续应用的基础。本研究使用碳二亚胺介导的偶联合成了甲氧基聚乙二醇接枝壳聚糖（mPEG-CHI）。通过详细的化学表征评估了试剂浓度和 pH 值对取代度（DS）和聚乙二醇化产率（游离 PEG 转化为共轭 PEG）的影响。在所研究的参数空间内，优化的反应条件（NH：COOH：NHS：EDC 为 3.5:1:1:10，pH=5）导致 DS 为 24%，聚乙二醇化产率为 84%。在 pH≥5.5 和 EDC 相对于 COOH 的 15 倍过量的情况下形成 EDC 衍生的加合物。该加合物被评估为 CHI 的胺基与 EDC 直接反应形成的胍衍生物。DS≥12%在生理 pH 值下赋予 CHI 水溶性，并且 mPEG-CHI（0.2-1.0mg/mL）对乳腺癌细胞系 MCF-7 和 MDA-MB-231 无细胞毒性，表明其适用于医学应用。
