A comparative study of the antibacterial mechanisms of silver ion and silver nanoparticles by Fourier transform infrared spectroscopy

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• 作者：Haoyi Li ; Yachao Gao ; Chunxiao Li ; Gang Ma ; ^{gangma@hbu.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Yanli Shang ; ^{ylshang@hbu.cn" class="auth_mail" title="E-mail the corresponding author} ; Ying Sun
• 关键词：Antibacterial ; FTIR spectroscopy ; Silver ; Silver ion ; Silver nanoparticles ; Escherichia coli.
• 刊名：Vibrational Spectroscopy
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：85
• 期：Complete
• 页码：112-121
• 全文大小：1631 K

文摘

In this study, we performed the first comparative study of the antibacterial mechanisms of silver ion (Ag⁺) and silver nanoparticles (AgNPs) on Escherichia coli (E. coli) using Fourier transform infrared (FTIR) spectroscopy. Through a thorough analysis of the FTIR spectra of E. coli after silver treatment in the spectral regions corresponding to thiol group, protein, lipopolysaccharide (LPS), and DNA, we were able to reveal a multifaceted antibacterial mechanism of silver at the molecular level for both Ag⁺ and AgNPs. Features of such mechanism include: (1) silver complexes with thiol group; (2) silver induces protein misfolding; (3) silver causes loss of LPS from bacterial membrane; (4) silver changes the overall conformation of DNA. Despite the similarities between Ag⁺ and AgNPs with respect to their antibacterial mechanisms, we further revealed that Ag⁺ and AgNPs display quite different kinetics for silver-thiol complexation and loss of LPS, with Ag⁺ displaying fast kinetics and AgNPs displaying slow kinetics. At last, we proposed a hypothesis to interpret the observed different behaviors between Ag⁺ and AgNPs when interacting with E. coli.