R. Ubaid, S. Saroj Kumar, S. Hemalatha,
Volume 15, Issue 3 (September 2018)
Abstract
Drug resistant pathogenic microbes have been causing serious health issues resulting in the substantial increase of death rates and morbidity paving the way for nanoparticles to be utilized as antimicrobial agents. This study was performed to evaluate the effectiveness of CuNPs on the growth of drug resistant clinical isolates of Streptococcus pyogenes, Enterococcus faecium and Enterococcus faecalis. Minimum inhibitory concentration of CuNPs against Streptococcus pyogenes, Enterococcus faecium and Enterococcus faecalis was found to be 1.25. 1.25 and 0.625 mg/ml and minimum bactericidal concentration against the same isolates was found to be 2.5, 2.5 and 5 mg/ml respectively. The ratio of MBC/MIC, referred to as tolerance level, was calculated for all the isolates which signifies the bactericidal or bacteriostatic effect of any antimicrobial agent. For Streptococcus pyogenes and Enterococcus faecium, the tolerance level was 2 while as for Enterococcus faecalis, it was 8. Antibiotic susceptibility results were calculated which showed that the isolates were resistant to Ampicillin (10 µg), Amoxycillin (30 µg) and Aztreonam (30 µg). Susceptibility results were followed by calculating multiple antibiotic resistance indices (MARI). MARI is an important tool which gives an idea about the bacterial resistance in a given population. For all the three isolates, MARI results were equivalent to 1 because of their resistance towards all the three antibiotics used. Antimicrobial activity through well-plate method was carried out and inhibitory effect of CuNPs on biofilm formation was evaluated.
Mala Siddaramappa, Haraluru Kamala Eshwaraiah Latha, Haraluru Shankaraiah Lalithamba, Andi Udayakumar,
Volume 18, Issue 4 (December 2021)
Abstract
Indium tin oxide (ITO) nanoparticles were synthesized by green combustion method using indium (In) and tin (Sn) as precursors, and Carica papaya seed extract as novel fuel. This paper highlights effect of tin concentration (5%, 10% and 50%) on microstructural, optical and electrical properties of ITO nanoparticles (NPs). The indium nitrate and tin nitrate solution along with the fuel were heated at 600 °C for 1 h in muffle furnace and obtained powder was calcinated at 650 °C for 3 h to produce ITO NPs. The above properties were investigated using XRD, FTIR, UV-Vis spectroscopy, SEM, TEM and computer controlled impedance analyser. The XRD, SEM and TEM investigations reveals the synthesized NPs were spherical in shape with an increase in average grain size (17.66 to 35 nm) as Sn concentration increases. FTIR investigations confirms the In-O bonding. The optical properties results revealed that the ITO NPs band gap decreased from 3.21 to 2.98 eV with increase in Sn concentration. The ac conductivity of ITO NPs was found to increase with increase in Sn concentration. These synthesised ITO NPs showed the excellent properties for emerging sensor and optical device application.
