Enhancing the antimicrobial activity of natural extraction using the synthetic ultrasmall metal nanoparticles

Abstract

The use of Catechin as an antibacterial agent is becoming ever-more common, whereas unstable and easy oxidation, have limited its application. A simple and low-energy-consuming approach to synthesize highly stable and dispersive Catechin-Cu nanoparticles(NPs) has been developed, in which the stability and dispersivity of the NPs are varied greatly with the pH value and temperature of the reaction. The results demonstrate that the optimal reaction conditions are pH 11 at room temperature. As-synthesized NPs display excellent antimicrobial activity, the survival rates of bacterial cells exposed to the NPs were evaluated using live/dead Bacterial Viability Kit. The results showed that NPs at the concentration of 10 ppm and 20 ppm provided rapid and effective killing of up to 90% and 85% of S. aureus and E. coli within 3 h, respectively. After treatment with 20 ppm and 40 ppm NPs, the bacteria are killed completely. Furthermore, on the basis of assessing the antibacterial effects by SEM, TEM, and AFM, it was found the cell membrane damage of the bacteria caused by direct contact of the bacteria with the NPs was the effective mechanism in the bacterial inactivation.

Antibacterial effects of gold nanoparticles functionalized with the extracted peptide from Vespa orientalis wasp venom

“…16 It has been demonstrated that NPs interact with the bacterial cell's basic components such as lysosomes, DNA, ribosomes, and enzymes leading to heterogeneous alterations, oxidative stress, electrolyte balance disorders, changes in cell membrane permeability, protein deactivation, enzyme inhibition, and changes in gene expression. 36 The strong affinity of AuNPs for disulfide bonds in bacteria were found to affect the metabolism of bacterial cells. Moreover, the NPs attack the potential protein fucoidan and disrupt the integrity of the cell membrane.…”

The antimicrobial activity of nanoparticles: present situation and prospects for the future

“…85 NPs need to be in contact with bacterial cells to achieve their antibacterial function. The accepted forms of contact include electrostatic attraction, 86 van der Waals forces, 87 and receptor-ligand 88 and hydrophobic interactions. 89 NPs then cross the bacterial membrane and gather along the metabolic pathway, influencing the shape and function of the cell membrane.…”

Synthesis, toxicity, biocompatibility, and biomedical applications of graphene and graphene-related materials

“…Graphene effectively inhibited the growth of Gram-negative E. coli and Grampositive Bacillus subtilis at a concentration of 1 mg/mL. 150 Li et al 151 investigated a large-area monolayer graphene film manipulated by charge transfer from a conductor (Cu), a semiconductor (Ge), or an insulator (SiO 2 ). Graphene films on Cu and Ge inhibited the growth of bacteria by membrane damage and destroying membrane integrity.…”