Anti-quorum Sensing and Anti-biofilm Activity of Zinc Oxide Nanospikes

Abstract

This study evaluates the impact of two separate incubation periods (4 and 6 weeks) on the morphology of sol–gel-fabricated ZnO nanospikes (ZNs), that is, ZN1 and ZN2, respectively. We further analyzed the inhibitory effects of ZN1 and ZN2 on quorum sensing (QS) and biofilm formation in Pseudomonas aeruginosa (PAO1) and Chromobacterium violaceum (strains 12472 and CVO26). The size of the synthesized ZNs was in the range of 40–130 nm, and finer nanoparticles were synthesized after an incubation period of 6 weeks. Treatment with ZNs decreased the production of violacein in the pathogen without affecting the bacterial growth, which indicated that ZNs inhibited the QS signaling regulated by N -acyl homoserine lactone. ZN2 had a higher inhibitory action on the virulence factor productivity than ZN1. Furthermore, ZN2-treated cells displayed a substantial decrease in azocasein-degrading protease activity (80%), elastase activity (83%), and pyocyanin production (85%) relative to untreated P. aeruginosa PAO1 cells. Treatment with ZN2 decreased swarming motility and exopolysaccharide production by 89 and 85%, respectively. ZN2 was effective against both the las & pqs systems of P. aeruginosa and exhibited broad-spectrum activity. Additionally, ZN2 was more efficient in inhibiting the biofilm formation at the attachment stage than ZN1. These findings revealed that in P. aeruginosa , ZN2 demonstrated inhibitory effects on QS as well as on the development of biofilms. Thus, ZN2 can be potentially used to treat drug-resistant P. aeruginosa infections.

Microwave-Assisted Rapid Green Synthesis of Gold Nanoparticles Using Seed Extract of Trachyspermum ammi: ROS Mediated Biofilm Inhibition and Anticancer Activity

“…Highest decrease of 58% and 64% in the swarming behavior of L. monocytogenes and S. marcescens respectively, was recorded as compared to their untreated controls. Our results find support from the observations made with sub-MICs of AgNPs, ZnO nanoparticles and ZnO-xanthan gum nanocomposite, wherein a significant drop in the swarming motility behavior was recorded in test pathogens [ 49 , 56 , 57 , 58 ].…”

Facet-Dependent Bactericidal Activity of Ag3PO4 Nanostructures against Gram-Positive/Negative Bacteria

“…The bacterial strain’s cell membrane integrity and viability were evaluated by staining them with acridine orange (AO) and propidium iodide (PI) dye using confocal laser scanning microscopy (CLSM). 23 First, the bacteria were cultured in MHB in CLSM dishes (SPL Scientific, Gyeonggi-do, South Korea) for 48 h at 37 °C; thereafter, the bacterial strains were treated with APNs for 12 h, and the untreated group was used as the control. 2 μL of each of the AO and PI mixture was added and incubated for 20 min at room temperature, and then they were visualized using an Eclipse Ti confocal laser scanning microscope (Nikon Corporation, Tokyo, Japan) interfaced with an argon-ion laser at the green and red channels.…”

“…The bacterial strain’s cell membrane integrity and viability were evaluated by staining them with acridine orange (AO) and propidium iodide (PI) dye using confocal laser scanning microscopy (CLSM) . First, the bacteria were cultured in MHB in CLSM dishes (SPL Scientific, Gyeonggi-do, South Korea) for 48 h at 37 °C; thereafter, the bacterial strains were treated with APNs for 12 h, and the untreated group was used as the control.…”

Anticancer effect of zinc oxide nanoparticles prepared by varying entry time of ion carriers against A431 skin cancer cells in vitro

“…Various physico-chemical methods ( Krol et al, 2017 ; Jin and Jin, 2019 ); such as sol-gel ( Khan et al, 2014 , 2016 , 2020 ), solution precipitation ( Thein et al, 2015 ), electrochemical synthesis ( Chandrappa and Venkatesha 2012 ), co-precipitation ( Adam et al, 2018 ), hydrothermal precipitation ( Li et al, 2017 ), sonochemical ( Noman and Petrů 2020 ), mechanochemical ( Otis et al, 2021 ) microemulsions ( Han et al, 2016 ), thermal evaporation ( Stanković et al, 2013 ), spray pyrolysis ( Ebin et al, 2012 ) and microwave-assisted methods ( Shinde et al, 2014 ; Wojnarowicz et al, 2020 ) have been implemented for the preparation of ZRTs resulting in a wide range of shapes and sizes of NPs. Our previous approaches used for synthesis of ZRTs involved variation in temperatures and stirring speeds, while avoiding sophisticated equipment.…”