Ghosh Sreejita, Das Ujjal, Dutta Bandita, Ray Rina Rani
Microbiology Research Laboratory, Department of Biotechnology, Maulana Abul Kalam Azad University of Technology, West Bengal, India.
UGC-DAE CSR, Kolkata Centre, LB-8, Sector III, Salt Lake, Kolkata, 700106, West Bengal, India.
Microb Pathog. 2025 Aug;205:107710. doi: 10.1016/j.micpath.2025.107710. Epub 2025 May 16.
The aim of this study was to compare the antimicrobial, anti-biofilm and anti-quorum sensing activities against Pseudomonas aeruginosa of biogenic silver nanoconjugates synthesized from two indigenous weeds, Tinospora cordifolia and Leonurus sibiricus followed by determination of the superiority of the nanoconjugate type in clearing away the antibiotic-resistant biofilm network.
Microdilution techniques were used to determine the minimum inhibitory concentration (MIC), MTT assay was used for determination of minimum biofilm eradication concentration (MBEC) followed by crystal violet assay for determining reduction of biofilms, time kill assay, flow cytometric measurements and confocal laser scanning microscopy for assessing the cell viability, scanning electron micrographs to show the disruption of biofilm network, Fourier Transformed Infrared spectroscopy to analyse the changes in the functional groups of biofilm matrix components and denaturation of quorum sensing compounds. The HaCaT cell line was used for cytotoxicity testing.
Silver nanoconjugates from L.sibiricus (LS-AgNP) and T.cordifolia (TC-AgNP) showed MICs of 0.001 μM and 10 μM against P.aeruginosa ATCC 15442, respectively. Both the green silver nanoconjugates showed considerable reduction in the viable number of cells, in biofilm network disruption, modification of the functional groups of biofilm matrix components and destruction of QS pathway but no cytotoxicity.
TC-AgNPs were more effective than LS-AgNPs in clearing the biofilm cells of P.aeruginosa, although LS-AgNPs were found to be more stable with a very low zeta potential. Hence, TC-AgNPs may be utilized in the near future as a promising alternative to available antibiotics thereby overcoming the ever-increasing problem of antibiotic resistance.
本研究旨在比较由两种本土杂草——心叶青牛胆和益母草合成的生物源银纳米缀合物对铜绿假单胞菌的抗菌、抗生物膜和群体感应抑制活性，随后确定纳米缀合物类型在清除抗生素抗性生物膜网络方面的优势。
采用微量稀释技术测定最低抑菌浓度（MIC），采用MTT法测定最低生物膜清除浓度（MBEC），随后采用结晶紫法测定生物膜减少情况，采用时间杀菌试验、流式细胞术测量和共聚焦激光扫描显微镜评估细胞活力，采用扫描电子显微镜显示生物膜网络的破坏情况，采用傅里叶变换红外光谱分析生物膜基质成分官能团的变化以及群体感应化合物的变性。使用HaCaT细胞系进行细胞毒性测试。
来自益母草（LS-AgNP）和心叶青牛胆（TC-AgNP）的银纳米缀合物对铜绿假单胞菌ATCC 15442的MIC分别为0.001 μM和10 μM。两种绿色银纳米缀合物均显示出活细胞数量显著减少、生物膜网络破坏、生物膜基质成分官能团改变以及群体感应途径破坏，但无细胞毒性。
尽管发现LS-AgNPs具有非常低的zeta电位且更稳定，但TC-AgNPs在清除铜绿假单胞菌生物膜细胞方面比LS-AgNPs更有效。因此，TC-AgNPs在不久的将来可能作为现有抗生素的一种有前景的替代品被利用，从而克服日益严重的抗生素耐药性问题。
