Laboratory of Optics and Photonics, Institute of Physics, Federal University of Mato Grosso do Sul, Ave. Costa e Silva s/n, Campo Grande 79070-900, MS, Brazil.
Department of Biosystems Engineering, "Luiz de Queiroz" College of Agriculture, University of São Paulo, Ave. Pádua Dias 11, Piracicaba 13418-900, SP, Brazil.
Int J Mol Sci. 2022 Oct 19;23(20):12519. doi: 10.3390/ijms232012519.
Multidrug-resistant bacteria represent a global health and economic burden that urgently calls for new technologies to combat bacterial antimicrobial resistance. Here, we developed novel nanocomposites (NCPs) based on chitosan that display different degrees of acetylation (DAs), and conjugated polymer cyano-substituted poly(-phenylene vinylene) (CNPPV) as an alternative approach to inactivate Gram-negative () and Gram-positive () bacteria. Chitosan's structure was confirmed through FT-Raman spectroscopy. Bactericidal and photobactericidal activities of NCPs were tested under dark and blue-light irradiation conditions, respectively. Hydrodynamic size and aqueous stability were determined by DLS, zeta potential (ZP) and time-domain NMR. TEM micrographs of NCPs were obtained, and their capacity of generating reactive oxygen species (ROS) under blue illumination was also characterized. Meaningful variations on ZP and relaxation time T confirmed successful physical attachment of chitosan/CNPPV. All NCPs exhibited a similar and shrunken spherical shape according to TEM. A lower DA is responsible for driving higher bactericidal performance alongside the synergistic effect from CNPPV, lower nanosized distribution profile and higher positive charged surface. ROS production was proportionally found in NCPs with and without CNPPV by decreasing the DA, leading to a remarkable photobactericidal effect under blue-light irradiation. Overall, our findings indicate that chitosan/CNPPV NCPs may constitute a valuable asset for the development of innovative strategies for inactivation and/or photoinactivation of bacteria.
多药耐药菌是全球健康和经济的负担，迫切需要新技术来对抗细菌对抗生素的耐药性。在这里，我们开发了基于壳聚糖的新型纳米复合材料（NCPs），其具有不同程度的乙酰化（DAs），并将共轭聚合物氰基取代聚（对苯撑乙烯）（CNPPV）作为一种替代方法来灭活革兰氏阴性（）和革兰氏阳性（）细菌。壳聚糖的结构通过 FT-Raman 光谱得到确认。在黑暗和蓝光照射条件下分别测试了 NCPs 的杀菌和光杀菌活性。通过 DLS、zeta 电位（ZP）和时域 NMR 测定了 NCPs 的水动力粒径和水稳定性。获得了 NCPs 的 TEM 显微照片，并对其在蓝光照射下产生活性氧物种（ROS）的能力进行了表征。ZP 和弛豫时间 T 的有意义变化证实了壳聚糖/CNPPV 的成功物理附着。所有 NCPs 根据 TEM 显示出相似的收缩球形形状。较低的 DA 负责驱动更高的杀菌性能，同时还有 CNPPV 的协同作用、较低的纳米分布谱和更高的正电荷表面。通过降低 DA，可以在具有和不具有 CNPPV 的 NCPs 中产生比例的 ROS 产生，从而在蓝光照射下产生显著的光杀菌效果。总的来说，我们的研究结果表明，壳聚糖/CNPPV NCPs 可能成为开发创新策略以灭活和/或光灭活细菌的有价值的资产。
