Drug Delivery and Tissue Engineering Division, School of Pharmacy, and School of Chemistry, University of Nottingham, Nottingham, NG7 2RD, United Kingdom and Critical Pharmaceuticals Limited, BioCity, Pennyfoot Street, Nottingham, NG1 1GF, United Kingdom.
Biomacromolecules. 2010 Nov 8;11(11):2854-65. doi: 10.1021/bm100522c. Epub 2010 Sep 27.
The aim of the present work is to investigate if conditions can be devised where PEGylation of chitosan would reduce its toxicity toward the nasal mucosa while maintaining its ability to open the cellular tight junctions and, consequently, produce an enhancement of macromolecular permeability. A series of mPEG-g-chitosan copolymers with varying levels of mPEG substitution, mPEG molecular weight, and chitosan molecular weight were synthesized by grafting carboxylic acid-terminated mPEGs (Mw 1.9 and 5.0 × 10(3) g mol(-1)) to chitosans (Mw 28.9 and 82.0 × 10(3) g mol(-1)) using a NHS/EDC coupling system. The synthesized mPEG-g-chitosans were fully characterized using a number of techniques, including FT-IR, (1)H NMR, and SEC-MALLS and their physicochemical properties were analyzed by TGA and DSC. Thereafter, the conjugates were tested for their cytotoxicity and tight junction modulating property in a relevant cell model, a mucus producing Calu-3 monolayer. mPEG-g-chitosan conjugates exhibited reduced toxicity toward cells, as compared to unmodified chitosan counterparts. Furthermore, the conjugates demonstrated a dramatic effect on cell monolayer transepithelial electrical resistance (TEER) and enhancement of permeability of model macromolecules. TEER and permeability-enhancing effects, as measurable indicators of tight junction modulation, were found to be pH-dependent and were notably more pronounced than those exhibited by unmodified chitosans. This work therefore demonstrates that conditions can be contrived where PEGylation improves the toxicity profile of chitosan, while preserving its effect on epithelial tight junctions in the nose.
本工作旨在研究是否可以设计条件，使壳聚糖的 PEG 化在保持其打开细胞紧密连接的能力的同时，降低其对鼻黏膜的毒性，从而提高大分子通透性。通过 NHS/EDC 偶联系统，将羧酸封端的 mPEG（Mw 1.9 和 5.0×103 g mol-1）接枝到分子量分别为 28.9 和 82.0×103 g mol-1 的壳聚糖上，合成了一系列不同取代度的 mPEG-g-壳聚糖共聚物、mPEG 分子量和壳聚糖分子量。采用傅里叶变换红外光谱（FT-IR）、（1）H NMR 和 SEC-MALLS 等多种技术对合成的 mPEG-g-壳聚糖进行了充分的表征，并通过 TGA 和 DSC 分析了其物理化学性质。然后，在相关的细胞模型（黏液产生的 Calu-3 单层）中测试了这些共聚物的细胞毒性和调节紧密连接的特性。与未修饰的壳聚糖相比，mPEG-g-壳聚糖缀合物表现出较低的细胞毒性。此外，该缀合物对细胞单层跨上皮电阻（TEER）和模型大分子通透性的增强具有显著影响。作为紧密连接调节的可测量指标，TEER 和通透性增强效应被发现是 pH 依赖性的，并且明显比未修饰的壳聚糖更显著。因此，这项工作表明，可以设计条件，使壳聚糖的 PEG 化改善其毒性特征，同时保持其对鼻腔上皮紧密连接的作用。
