Elmehbad Noura Y, Mohamed Nadia A, Abd El-Ghany Nahed A, Abdel-Aziz Marwa M
Department of Chemistry, Faculty of Science and Arts, Najran University, Najran, Saudi Arabia.
Department of Chemistry, College of Science, Qassim University, Buraidah 51452, Saudi Arabia; Department of Chemistry, Faculty of Science, Cairo University, Giza 12613, Egypt.
Int J Biol Macromol. 2023 Aug 15;246:125582. doi: 10.1016/j.ijbiomac.2023.125582. Epub 2023 Jun 27.
Two novel chemically cross-linked chitosan hydrogels were successfully prepared via insertion of oxalyl dihydrazide moieties between chitosan Schiff's base chains (OCsSB) and between chitosan chains (OCs). For more modification, two different concentrations of ZnO nanoparticles (ZnONPs) were loaded into OCs to obtain OCs/ZnONPs-1 % and OCs/ZnONPs-3 % composites. The prepared samples were recognized using elemental analyses, FTIR, XRD, SEM, EDS and TEM. Their inhibitory action against microbes and biofilms were classified as: OCs/ZnONPs-3 % > OCs/ZnONPs-1 % > OCs > OCsSB > chitosan. OCs has inhibition activity similar to Vancomycin of minimum inhibitory concentration (MIC) value of 3.9 μg/mL against P. aeruginosa. OCs exhibited minimum biofilm inhibitory concentration (MBIC) values (from 31.25 to 62.5 μg/mL) less than that of OCsSB (from 62.5 to 250 μg/mL) which lower than that of chitosan (from 500 to 1000 μg/mL) against S. epidermidis, P. aeruginosa and C. albicans. OCs/ZnNPs-3 % showed MIC value (that caused 100 % inhibition of Clostridioides difficile, C. difficile) of 0.48 μg/mL much lower than Vancomycin (1.95 μg/mL). Both OCs and OCs/ZnONPs-3 % composite were safe on normal human cells. Thus, inclusion of oxalyl dihydrazide and ZnONPs into chitosan greatly reinforced its antimicrobial activity. This is a good strategy to accomplish adequate systems for competing traditional antibiotics.
通过在壳聚糖席夫碱链之间（OCsSB）以及壳聚糖链之间（OCs）插入草酰二肼部分，成功制备了两种新型化学交联壳聚糖水凝胶。为了进行更多修饰，将两种不同浓度的氧化锌纳米颗粒（ZnONPs）负载到OCs中，以获得OCs/ZnONPs-1%和OCs/ZnONPs-3%复合材料。使用元素分析、傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）、扫描电子显微镜（SEM）、能谱分析（EDS）和透射电子显微镜（TEM）对制备的样品进行表征。它们对微生物和生物膜的抑制作用分类如下：OCs/ZnONPs-3%＞OCs/ZnONPs-1%＞OCs＞OCsSB＞壳聚糖。OCs对铜绿假单胞菌具有与万古霉素相似的抑制活性，最低抑菌浓度（MIC）值为3.9μg/mL。对于表皮葡萄球菌、铜绿假单胞菌和白色念珠菌，OCs表现出的最低生物膜抑制浓度（MBIC）值（31.25至62.5μg/mL）低于OCsSB（62.5至250μg/mL），而OCsSB又低于壳聚糖（500至1000μg/mL）。OCs/ZnNPs-3%对艰难梭菌的MIC值（导致艰难梭菌100%抑制）为0.48μg/mL，远低于万古霉素（1.95μg/mL）。OCs和OCs/ZnONPs-3%复合材料对正常人体细胞均安全。因此，将草酰二肼和ZnONPs引入壳聚糖大大增强了其抗菌活性。这是构建足以与传统抗生素竞争的合适体系的良好策略。
