Proteomic analysis of antimicrobial effects of pegylated silver coated carbon nanotubes in Salmonella enterica serovar Typhimurium

Seong B Park,Jean M Feugang,Shree R Singh,Atul A Chaudhari,Scott T Willard,Christy S Steadman,Shreekumar R Pillai,Peter L Ryan

doi:10.1186/s12951-018-0355-0

Seong B Park, Jean M Feugang + Show 6 more

Open Access

https://doi.org/10.1186/s12951-018-0355-0

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Abstract

BackgroundSynthesis of silver nano-compounds with enhanced antimicrobial effects is of great interest for the development of new antibacterial agents. Previous studies have reported the antibacterial properties of pegylated silver-coated carbon nanotubes (pSWCNT-Ag) showing less toxicity in human cell lines. However, the mechanism underlining the pSWCNT-Ag as a bactericidal agent remained unfolded. Here we assessed the pSWCNT-Ag effects against foodborne pathogenic bacteria growth and proteome profile changes.ResultsMeasurements of bioluminescent imaging, optical density, and bacteria colony forming units revealed dose-dependent and stronger bactericidal activity of pSWCNT-Ag than their non-pegylated counterparts (SWCNT-Ag). In ovo administration of pSWCNT-Ag or phosphate-buffered saline resulted in comparable chicken embryo development and growth. The proteomic analysis, using two-dimensional electrophoresis combined with matrix assisted laser desorption/ionization time of flight/time of flight mass spectrometry, was performed on control and surviving Salmonella enterica serovar Typhimurium to pSWCNT-Ag. A total of 15 proteins (ten up-regulated and five down-regulated) differentially expressed proteins were identified. Functional analyses showed significant reduction of proteins associated with biofilm formation, nutrient and energy metabolism, quorum sensing and maintenance of cell structure and cell motility in surviving S. Typhimurium. In contrast, proteins associated with oxygen stress, DNA protection, starvation, membrane rebuilding, and alternative nutrient formation were induced as the compensatory reaction.ConclusionsThis study provides further evidence of the antibacterial effects of pSWCNT-Ag nanocomposites and knowledge of their mechanism of action through various protein changes. The findings may lead to the development of more effective and safe antimicrobial agents.

Highlights

Synthesis of silver nano-compounds with enhanced antimicrobial effects is of great interest for the development of new antibacterial agents
The successful pegylation is observed through the detection of specific peaks (18.9° and 23.3°) in the pSWCNT-Ag alone, indicating the presence of the PLPEG 5000-amine
E. coli in culture media containing 25 μg/ml pSWCNT-Ag had a delayed exponential initiation of 18 h, while the presence of 31.25 μg/ml provided 36 h delayed

Summary

Introduction

Synthesis of silver nano-compounds with enhanced antimicrobial effects is of great interest for the development of new antibacterial agents. Numerous studies have demonstrated the antimicrobial effects of nano-sized metals (i.e., silver, silica, and gold), metal oxides (silver oxide, titanium oxide, and copper oxide), and carbon-based compounds (i.e., fullerene, graphene oxide and single-walled carbon nanotubes or SWCNTs) against Gram-negative and -positive bacteria [12,13,14]. These nanoparticles are easy to synthesize and possess large surface area-to-volume ratio and high versatility that favor their uses for antimicrobial growth without affecting human eukaryote cells [11, 15]. Among the currently tested nanoparticles, silver and SWCNT have exhibited high potentials for the treatment of multidrug resistance in various bacteria, including foodborne strains [16,17,18]

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