Green production of microalgae-based silver chloride nanoparticles with antimicrobial activity against pathogenic bacteria

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• 作者：Veronica da Silva Ferreira^a ; ^e ; Mateus Eugenio ConzFerreira^a ; ^e ; Luí ; s Maurí ; cio T.R. Lima^b ; Susana Frasé ; s^c ; ^d ; Wanderley de Souza^c ; ^d ; ^e ; Celso Sant&rsquo ; Anna^a ; ^c ; ^e ; ^{celso.santanna@gmail.com}
• 关键词：Microalgae ; Chlorella vulgaris ; Silver chloride nanoparticles ; Green synthesis ; Antimicrobial activity
• 刊名：Enzyme and Microbial Technology
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：97
• 期：Complete
• 页码：114-121
• 全文大小：2193 K
• 卷排序：97

文摘

Silver nanoparticles are powerful antimicrobial agents. Here, the synthesis of silver chloride nanoparticles (AgCl-NPs) was consistently evidenced from a commercially valuable microalgae species, Chlorella vulgaris. Incubation of C. vulgaris conditioned medium with AgNO3 resulted in a medium color change to yellow/brown (with UV–vis absorbance at 415 nm), indicative of silver nanoparticle formation. Energy-dispersive X-ray spectroscopy (EDS) of purified nanoparticles confirmed the presence of both silver and chlorine atoms, and X-ray diffraction (XRD) showed the typical pattern of cubic crystalline AgCl-NPs. Transmission electron microscopy (TEM) showed that most particles (65%) were spherical, with average diameter of 9.8 ± 5.7 nm. Fourier transform infrared spectroscopy (FTIR) of purified nanoparticle fractions suggested that proteins are the main molecular entities involved in AgCl-NP formation and stabilization. AgCl-NPs (from 10 μg/mL) decreased by 98% the growth of Gram-positive Staphylococcus aureus and Gram-negative Klebsiella pneumoniae bacterial pathogens, and had a dose-dependent effect on cell viability, which was measured by automated image-based high content screening (HCS). Ultrastructural analysis of treated bacteria by TEM revealed the abnormal arrangement of the chromosomal DNA. Our findings strongly indicated that the AgCl-NPs from C. vulgaris conditioned medium is a promising ‘green’ alternative for biomedical application as antimicrobials.