Polysaccharide-capped silver Nanoparticles inhibit biofilm formation and eliminate multi-drug-resistant bacteria by disrupting bacterial cytoskeleton with reduced cytotoxicity towards mammalian cells

Abstract

Development of effective anti-microbial therapeutics has been hindered by the emergence of bacterial strains with multi-drug resistance and biofilm formation capabilities. In this article, we report an efficient green synthesis of silver nanoparticle (AgNP) by in situ reduction and capping with a semi-synthetic polysaccharide-based biopolymer (carboxymethyl tamarind polysaccharide). The CMT-capped AgNPs were characterized by UV, DLS, FE-SEM, EDX and HR-TEM. These AgNPs have average particle size of ~20–40 nm, and show long time stability, indicated by their unchanged SPR and Zeta-potential values. These AgNPs inhibit growth and biofilm formation of both Gram positive (B. subtilis) and Gram negative (E. coli and Salmonella typhimurium) bacterial strains even at concentrations much lower than the minimum inhibitory concentration (MIC) breakpoints of antibiotics, but show reduced or no cytotoxicity against mammalian cells. These AgNPs alter expression and positioning of bacterial cytoskeletal proteins FtsZ and FtsA. CMT-capped AgNPs can effectively block growth of several clinical isolates and MDR strains representing different genera and resistant towards multiple antibiotics belonging to different classes. We propose that the CMT-capped AgNPs can have potential bio-medical application against multi-drug-resistant microbes with minimal cytotoxicity towards mammalian cells.

Interaction between a Broad-spectrum Antibiotic and Silver Nanoparticles in a Human Gut Ecosystem

“…Although there are reports of mammalian cell cytotoxicity [8][9][10], these effects are likely relatively minimal at the concentrations used for antimicrobial activity [11]. Biofilms, which provide a refuge for Gram positive and negative bacteria, appear to be also inhibited by AgNPs [11]. Taken together, these observations have helped foster the use of AgNPs for medical and personal health applications.…”

“…However, multiple studies have highlighted the critical role of nano-size dependent effects compared to ionic silver, with an emphasis on the unique properties of AgNPs [5][6][7]. Although there are reports of mammalian cell cytotoxicity [8][9][10], these effects are likely relatively minimal at the concentrations used for antimicrobial activity [11]. Biofilms, which provide a refuge for Gram positive and negative bacteria, appear to be also inhibited by AgNPs [11].…”

Uso de antimicrobiano nanoparticulado para o tratamento da mastite subclínica de ovelhas de corte no período seco

“…Diversas pesquisas foram realizadas nos últimos anos avaliando vetores de liberação de fármacos em sítios específicos quanto a eficiência e citotoxicidade (Bilensoy et al 2008, Toti et al 2011, Sanyasi et al 2016. Sistemas nanoparticulados têm sido propostos para a internalização de agentes antimicrobianos no ambiente intracelular, contribuindo assim para aumentar o índice terapêutico de antimicrobianos nos locais das infecções (Lecároz et al 2006).…”

Silver Nanoparticles Impact Biofilm Communities and Mussel Settlement

“…Due to their efficacious antimicrobial actions against bacteria, diatoms and viruses1234, silver nanoparticles (AgNPs) have been applied in the food sector5, medical devices6, textile finishings7 and water treatment systems8. While the impact of nanoparticles (NPs) on aquatic microbes has been investigated9, few studies101112 have been conducted in the marine environment to examine the impact of AgNPs on natural biofilms that play key roles in biogeochemical cycling processes and larval and spore recruitment1314.…”