In this work, it was developed three-dimensional (3D) porous hydrogel sponges produced by the freeze-dried process using chitosan polymer functionalized by 11-mercaptoundecanoic acid (MUA). These chitosan-based sponges were used as cationic adsorbents for the removal of anionic methyl orange (MO) dye, simulating a model organic pollutant in aqueous medium. Moreover, these porous 3D constructs were also evaluated as 'antibiotic-free' antibacterial materials against gram-negative and gram-positive bacteria, Pseudomonas aeruginosa and Staphylococcus aureus, respectively, which were used as model pathogens possibly found in contaminated hospital discharges. These 3D hydrogels were comprehensively characterized through morphological methods such as scanning electron microscopy and X-ray micro-computed tomography techniques, combined with FTIR, Raman, and UV-visible spectroscopy analyses. Additionally, the surface area, the degree of swelling, and the adsorption profiles and kinetics of these scaffolds were systematically investigated. The chemically thiolated chitosan (CHI-MUA) hydrogels were successfully produced with a supramolecular polymeric network based on hydrogen bonds, disulfide bonds, and hydrophobic interactions that resulted in higher stability in aqueous medium than hydrogels of pristine chitosan. CHI-MUA exhibited sponge-like three-dimensional structures, with highly interconnected and hierarchical pore size distribution with high porosity and surface area. These architectural aspects of the 3D sponges favoured the high adsorption capacity for MO dye (∼388 mg.g-1) in water with removal efficiency greater than 90% for MO solutions (from 20 mg.L-1-1200 mg.L-1). The adsorption data followed a pseudo-second-order kinetic model and adsorption isotherm analysis and spectroscopy studies suggested a multilayer behaviour with coexistence of adsorbent-adsorbate and adsorbate-adsorbate interactions. Additionally, the in vitro evaluation of toxicity (MTT and LIVE-DEAD® assays) of 3D-sponges revealed a non-toxic response and preliminary suitability for bio-related applications. Importantly, the 3D-sponges composed of chitosan-thiolated derivative proved high antibacterial activity, specificity against P. aeruginosa (model hazardous pathogen), equivalent to conventional antibiotic drugs, while no lethality against S. aureus (reference commensal bacteria) was observed.

中文翻译：

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用于潜在环境污染修复的化学功能化壳聚糖 3D 海绵：用于阴离子染料吸附和“无抗生素”抗菌活性的生物吸附剂

在这项工作中，使用由 11-巯基十一烷酸 (MUA) 功能化的壳聚糖聚合物，通过冷冻干燥工艺开发了三维 (3D) 多孔水凝胶海绵。这些基于壳聚糖的海绵用作阳离子吸附剂，用于去除阴离子甲基橙 (MO) 染料，模拟水性介质中的模型有机污染物。此外，这些多孔 3D 结构还被评估为“不含抗生素”的抗菌材料，分别针对革兰氏阴性和革兰氏阳性细菌、铜绿假单胞菌和金黄色葡萄球菌，它们被用作可能在受污染的医院出院中发现的模型病原体。这些 3D 水凝胶通过扫描电子显微镜和 X 射线显微计算机断层扫描技术等形态学方法，结合 FTIR，进行了综合表征，拉曼光谱和紫外可见光谱分析。此外，系统地研究了这些支架的表面积、溶胀程度以及吸附曲线和动力学。化学硫醇化壳聚糖 (CHI-MUA) 水凝胶通过基于氢键、二硫键和疏水相互作用的超分子聚合物网络成功制备，在水性介质中比原始壳聚糖水凝胶具有更高的稳定性。CHI-MUA表现出海绵状的三维结构，具有高度互连和分级的孔径分布，具有高孔隙率和表面积。3D 海绵的这些结构方面有利于 MO 染料（~388 mg.g-1）在水中的高吸附能力，MO 溶液（从 20 mg.L-1-1200 mg.L-）的去除效率大于 90% 1）。吸附数据遵循准二级动力学模型，吸附等温线分析和光谱研究表明吸附剂-吸附质和吸附质-吸附质相互作用共存的多层行为。此外，3D 海绵的体外毒性评估（MTT 和 LIVE-DEAD® 分析）揭示了无毒反应和生物相关应用的初步适用性。重要的是，由壳聚糖硫醇衍生物组成的 3D 海绵证明具有高抗菌活性，对铜绿假单胞菌（模型有害病原体）具有特异性，相当于常规抗生素药物，而对金黄色葡萄球菌（参考共生菌）没有观察到致死性。