Nanodrugs: optimism for emerging trend of multidrug resistance

Study of synthesis, structural, optical and magnetic characterizations of iron/copper oxide nanocomposites: A promising novel inorganic antibiotic

This paper reports the development of inorganic nanoparticles based novel antibiotic. Inorganic nanoparticles have the potential of being used as bactericidal agent due to their effective antimicrobial activity, colloidal aqueous stability and comparatively low toxic profile. Among them, iron oxide and copper oxide were chosen for this study because of the nascent bactericidal properties of both iron and copper. In this work, along with the pure samples of iron oxide and copper oxide nanoparticles, hybrid magnetic nanocomposites of iron oxide and copper oxide with varying molar concentrations of copper precursor were produced by wet-chemical approach. Structural, physical and chemical properties of the prepared samples were investigated using spectroscopic and microscopic techniques like XRD, SEM, TEM, EDAX, Raman, VSM and TGA-DTA. The antibacterial activity of the samples were established against pathogenic strains of bacteria E. coli, B. subtilis, S. aureus and S. typhi by using two different methods. The prepared nanomaterials were very adequate to combat the bacterial growth and their bactericidal efficiency was comparable to the commercial antibiotic gentamycin. Thus these non-toxic hybrid nanocomposites can be used as the potential antibiotic to counter the diseases caused by normal and multi drug resistant pathogenic bacterial strains.

Biofabrication of broad range antibacterial and antibiofilm silver nanoparticles

Silver nanoparticles (AgNPs) were biosynthesized via a green route using ten different plants extracts (GNP1- Caryota urens, GNP2-Pongamia glabra, GNP3- Hamelia patens, GNP4-Thevetia peruviana, GNP5-Calendula officinalis, GNP6-Tectona grandis, GNP7-Ficus petiolaris, GNP8- Ficus busking, GNP9- Juniper communis, GNP10-Bauhinia purpurea). AgNPs were tested against drug resistant microbes and their biofilms. These nanoparticles (NPs) were characterised using UV-vis spectroscopy, transmission electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction and Image J software. Most of the AgNPs were distributed over a range of 1 of 60 nm size. The results indicated that AgNPs were antibacterial in nature without differentiating between resistant or susceptible strains. Moreover, the effect was more prominent on Gram negative bacteria then Gram positive bacteria and fungus. AgNPs inhibited various classes of microbes with different concentration. It was also evident from the results that the origin or nature of extract did not affect the activity of the NPs. Protein and carbohydrate leakage assays confirmed that the cells lysis is one of the main mechanisms for the killing of microbes by green AgNPs. This study suggests that the action of AgNPs on microbial cells resulted into cell lysis and DNA damage. Excellent microbial biofilm inhibition was also seen by these green AgNPs. AgNPs have proved their candidature as a potential antibacterial and antibiofilm agent against MDR microbes.

Nanoparticles vs. biofilms: a battle against another paradigm of antibiotic resistance

Microbes form surface-adherent community structures called biofilms and these biofilms play a critical role in infection.

Nanotechnology as a therapeutic tool to combat microbial resistance

Use of nanoparticles is among the most promising strategies to overcome microbial drug resistance. This review article consists of three parts. The first part discusses the epidemiology of microbial drug resistance. The second part describes mechanisms of drug resistance used by microbes. The third part explains how nanoparticles can overcome this resistance, including the following: Nitric oxide-releasing nanoparticles (NO NPs), chitosan-containing nanoparticles (chitosan NPs), and metal-containing nanoparticles all use multiple mechanisms simultaneously to combat microbes, thereby making development of resistance to these nanoparticles unlikely. Packaging multiple antimicrobial agents within the same nanoparticle also makes development of resistance unlikely. Nanoparticles can overcome existing drug resistance mechanisms, including decreased uptake and increased efflux of drug from the microbial cell, biofilm formation, and intracellular bacteria. Finally, nanoparticles can target antimicrobial agents to the site of infection, so that higher doses of drug are given at the infected site, thereby overcoming resistance.