Targeting microbial biofilms: by Arctium lappa l. synthesised biocompatible CeO2-NPs encapsulated in nano-chitosan

This study is planned to synthesise new biocompatible, nano antimicrobial formulation against biofilm producing strains. Aqueous root extract of Arctium lappa l. was used to synthesise ceria nanoparticles (CeO2-NPs). The synthesised nanoparticles were encapsulated with nano-chitosan by sol-gel method and characterised using standard techniques. Gas chromatography-mass spectrometer of Arctium lappa l. revealed the presence of ethanol, acetone, 1- propanol, 2-methylethane, 1,1-di-ethoxy, 1-Butanol, and oleic acid acted as reducing and surface stabilising agents for tailoring morphology of CeO2-NPs. Erythrocyte integrity after treatment with synthesised nanomaterials was evaluated by spectrophotometer measurement of haemoglobin release having biocompatibility. Scanning electron microscopy revealed the formation of mono dispersed beads shaped particles with mean particle size of 26.2 nm. X-ray diffractometry revealed cubic crystalline structure having size of 28.0 nm. After encapsulation by nano-chitosan, the size of CeO2-NPs enhances to 48.8 nm making average coverage of about 22.6 nm. The synthesised nanomaterials were found effective to disrupt biofilm of S. aureus and P. aeruginosa. Interestingly, encapsulated CeO2-NPs revealed powerful antibacterial and biofilm disruption activity examined by fluorescent live/dead staining using confocal laser scanning microscopy. The superior antibacterial activities exposed by encapsulated CeO2-NPs lead to the conclusion that they could be useful for controlling biofilm producing multidrug resistance pathogens.

Green synthesis of Ce2O3 NPs and determination of its antioxidant activity

In this study, the authors presented synthesis of ceria nanoparticles (NPs) by the bio-reduction method and their antioxidative activity. Aqueous extract of Euphorbia (Euphorbia amygdaloides) was used as reducing and stabilising agents. They used aqueous extract of Euphorbia (E. amygdaloides) as reducing and stabilising agent. Ultraviolet-visible (UV-vis) absorption spectroscopy was used to monitor the quantitative formation of ceria NPs. They also addressed the characteristics of the obtained ceria NPs using scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmitting electron microscope (TEM). The synthesised cerium (III) oxide (Ce2O3) NPs were initially noted through visual colour change from colourless pale yellow cerium (III) to light yellow cerium (IV) and further confirmed the band at 345 nm employing UV-vis spectroscopy. The average diameter of the prepared NPs was about 8.6-10.5 nm. In addition, the synthesised Ce2O3 NPs were tested for antioxidant and anti-bacterial activities using ferric reducing antioxidant power, cupric reducing antioxidant capacity, ferrous ions chelating activity, superoxide the anion radical scavenging and 2, 2'-azinobis 3-ethylbenzothiazol to-6-sulphonic acid scavenging activity. It could be concluded that Euphorbia (E. amygdaloides) extract can be used efficiently in the production of potential antioxidant and anti-bacterial Ce2O3 NPs for commercial applications.