Preparation, characterization and evaluation of a biopolymeric gold nanocomposite with antimicrobial activity

Abstract

The present study describes the antimicrobial activity of C-AuNp-Amp (chitosan-capped gold nanoparticles coupled with ampicillin). C-AuNp-Amp was synthesized using the wet precipitation method and characterized using FTIR (Fourier-transform IR) spectroscopy and AFM (atomic force microscopy) techniques. The optimal level of ampicillin concentration that couples with the C-AuNp nanocomposite was determined by using UV-visible spectroscopy. The agar-well diffusion method was used to evaluate the antimicrobial activity, and the broth dilution assay was used to determine the MIC (minimum inhibitory concentration). The size of the ellipsoidal C-AuNp-Amp particles was found to be in the range of 50-100 nm. The FTIR spectrum confirms the bonding between amino groups of chitosan and carboxylic groups of ampicillin. The maximum coupling of ampicillin with C-AuNp was found to be 4.07 mg/10 ml. These results revealed the antimicrobial efficacy of C-AuNp-Amp and a 2-fold increase in activity was achieved when compared with that of free ampicillin. By reducing the antibiotic dosage to 50%, the side effects produced by antibiotics can be minimized.

Recent Nanotechnology Approaches for Prevention and Treatment of Biofilm-Associated Infections on Medical Devices

“…Nevertheless, gold NPs bound to antibiotics [180], active compounds, or biomolecules [181] show considerable bactericidal and biofilm inhibitory activities against a variety of pathogens, including multidrug resistant strains [182]. Since gold NPs are nontoxic to cells, they have been conjugated with targeting molecules to achieve specific antibiofilm activities (Table 1) [183].…”

Nano-antibiotics: Nanotechnology in Fighting Against Infectious Diseases

“…33,45 The antimicrobial activity of gold seems to be attributed to the strong electrostatic attractions to the negatively charged bilayer of the cell membrane, 14,15 further supported by the observation that cationic particles were found to be moderately toxic while anionic particles were not. 46 Au NPs conjugated with antimicrobial agents and antibodies have been explored to obtain selective antimicrobial effects.…”

“…In a recent study, chitosan-capped Au NPs coupled with ampicillin exhibited a doubling in the increase in antimicrobial activity, compared with that of free ampicillin. 14 Chitosan's antimicrobial mechanisms have been explained by various mechanisms. One is the binding to the negatively charged bacterial surface to cause clumping, increasing the permeability of the microbial wall, which eventually leads to a leakage of intracellular components.…”

“…30 Silver nanoparticles (Ag NPs) have proven to be the most effective against bacteria, viruses, and other eukaryotic microorganisms amongst the many different types of metallic and metal oxide NPs. 14,[32][33][34] Ag NPs work by attacking the respiratory chain and cell division that finally lead to cell death, while simultaneously releasing Ag ions that enhance antibacterial activity. 11 The antimicrobial properties of Ag NPs is inversely dependent on size 12,13 and shape 10 of the particle.…”

Size-dependent antimicrobial properties of sugar-encapsulated gold nanoparticles synthesized by a green method

“…All tubes were incubated at 37°C, and the growth of bacteria was monitored by measuring the optical density (OD) at 600 nm for 12 h. OD 600 is an acronym indicating the optical density of a sample measured at a wavelength of 600 nm. Optical density at 600 nm is a common method used in molecular biology to quantify the bacteria by determining the absorbance at 600 nm [39,40]. …”