Siotey Akash, Jain Purnima, Singhania Unnati, Pathan Ejaj K, Sonawane Swapnil L
Department of Chemistry, Netaji Subhas University of Technology, Dwarka, New Delhi 110078, India.
Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Lavale, Pune, Maharashtra 412115, India.
ACS Appl Bio Mater. 2025 Jul 21;8(7):6368-6378. doi: 10.1021/acsabm.5c00839. Epub 2025 Jun 7.
Functional biomaterials with responsive properties are in high demand due to their potential application as antimicrobial agents. In this study, we have developed a photochromic chitosan-Azo-Schiff base using condensation reactions of chitosan with three derivatives of azobenzene. The biopolymers thus produced were characterized by Fourier-transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, and X-ray diffraction. The results showed that the materials had good thermal stability, an amorphous nature, and belt-like morphology. The optical properties of the Schiff bases as a function of the azobenzene moieties present in chitosan were examined by absorption spectroscopy. The photoresponsive behavior of the Schiff bases was studied under UV illumination. Of the three Schiff bases, ChS-Azo-P showed π-π* and n-π* features with no reversible changes, while peak broadening with absorbance enhancement was observed in ChS-Azo-O (87% at λ = 404 nm) and ChS-azo-S (93.2% at λ = 364 nm). The antimicrobial activities of the Schiff bases were evaluated against human pathogenic fungi, ATCC10231 (MIC 4-64 μg/mL), NCYC388 (MIC 16-128 μg/mL), ATCC34664 (MIC 4-16 μg/mL) as well as Gram-positive bacteria, ATCC29213 (MIC 0.5-4 μg/mL) and Gram-negative bacteria, ATCC10799 (MIC 1-8 μg/mL), ATCC700603 (MIC 2-16 μg/mL), and ATCC19606 (MIC 2-8 μg/mL). Chitosan-Azo-Schiff bases inhibited the growth of the human pathogens (fungal and bacterial) at concentrations lower than those of clinically used antifungal and antibacterial drugs. Interestingly, none of the ChS-Azo-Schiff bases showed significant hemolytic activity (<5%) and were found to be hemocompatible. The finding opens an avenue for developing biodegradable polymers comprising azo-dye-based photoresponsive materials for biointerface applications.
具有响应特性的功能性生物材料因其作为抗菌剂的潜在应用而备受需求。在本研究中，我们通过壳聚糖与三种偶氮苯衍生物的缩合反应，开发了一种光致变色壳聚糖 - 偶氮 - 席夫碱。通过傅里叶变换红外光谱、热重分析、差示扫描量热法、扫描电子显微镜和X射线衍射对由此产生的生物聚合物进行了表征。结果表明，这些材料具有良好的热稳定性、无定形性质和带状形态。通过吸收光谱研究了席夫碱的光学性质与壳聚糖中存在的偶氮苯部分的关系。在紫外光照射下研究了席夫碱的光响应行为。在三种席夫碱中，ChS - Azo - P显示出π - π和n - π特征且无可逆变化，而在ChS - Azo - O（在λ = 404 nm处为87%）和ChS - azo - S（在λ = 364 nm处为93.2%）中观察到峰展宽且吸光度增强。评估了席夫碱对人类致病真菌ATCC10231（MIC 4 - 64 μg/mL）、NCYC388（MIC 16 - 128 μg/mL）、ATCC34664（MIC 4 - 16 μg/mL）以及革兰氏阳性菌ATCC29213（MIC 0.5 - 4 μg/mL）和革兰氏阴性菌ATCC10799（MIC 1 - 8 μg/mL）、ATCC700603（MIC 2 - 16 μg/mL）和ATCC19606（MIC 2 - 8 μg/mL）的抗菌活性。壳聚糖 - 偶氮 - 席夫碱在低于临床使用的抗真菌和抗菌药物浓度下抑制了人类病原体（真菌和细菌）的生长。有趣的是，没有一种ChS - Azo - 席夫碱显示出显著的溶血活性（<5%），并且被发现具有血液相容性。这一发现为开发包含基于偶氮染料的光响应材料的可生物降解聚合物用于生物界面应用开辟了一条途径。
