Silver nanoparticles immobilized on TRIS functionalized glass serve as an efficient antimicrobial surface against opportunistic pathogenic bacteria

---

Sharda Bharti, Soumyo Mukherji and Suparna Mukherji

IIT Bombay, India

: J Nanomater Mol Nanotechnol

Abstract

---

Increasing water pollution and limited access to safe water creates an immediate need to develop alternative antimicrobial agents. Silver nanoparticles (AgNPs) in their immobilized form can serve as a promising antimicrobial surface for pointof- use water disinfection. The present study focused on development of a unique nanoantimicrobial consisting of AgNPs immobilized on glass substrate with minimal silver leaching. AgNPs were synthesized via chemical reduction method using AgNO3 as metal precursor, NaBH4 as reducing agent and trisodium citrate as stabilizing agent. The nanocomposite was prepared by immobilizing AgNPs on N1-(3-trimethoxysilylpropyl) diethylenetriamine i.e., TRIS-functionalized glass substrate and characterized prior to use. A surface resonance peak at 398 nm in UV-Vis spectra indicated small sized AgNPs. FEG-TEM confirmed the spherical shape and small size of AgNPs with average size of 7.8± 2.9 nm. XRD spectra exhibited lattice plane of (111), (200), (220) and (311), i.e., fcc crystal structure favorable for enhanced reactivity. SEM imaging demonstrated a highly dense and homogenous coating of AgNPs on the surface. The characteristic peak in EDS spectra at 3 KeV confirmed the immobilization of silver with >30% silver loading. Atomic force microscopy further corroborated AgNP deposition by unveiling an increase in roughness of surface by 5.35 nm. Batch disinfection studies were conducted by immersing the AgNP immobilized substrate (1cm2) in 100 ml artificially contaminated water containing 103 CFU/ml of bacteria against four waterborne opportunistic pathogens, i.e., Escherichia coli (MTCC 443), Burkholderia cepacia (MTCC 5332), Pseudomonas aeruginosa and Acinetobacter baumanii. For both log and stationary phase cultures of these pathogenic strains >99% bactericidal effect was observed in <40 min and complete disinfection was achieved within 60 min. Complete killing was further confirmed using CLSM imaging. Only red fluorescence in treated water stained with Baclight kit, confirmed the absence of viable but non-culturable bacterial cells.

Biography

---

Email: shardabharti05@gmail.com