Study of antimicrobial properties of Piper betel coated nanozirconium on cotton gauze

Harnessing selenium nanoparticles (SeNPs) for enhancing growth and germination, and mitigating oxidative stress in Pisum sativum L

Selenium, an essential micronutrient for plants and animals, can cause selenium toxicity as an oxyanion or at elevated doses. However, the toxic selenite (SeO32-) oxyanion, can be converted into less harmful elemental nano-selenium (Se0), with various practical applications. This research aimed to investigate two methods for reducing SeO32-: abiotic reduction using cell-free extract from Enterococcus spp. (abiotic-SeNPs) and chemical reduction involving L-ascorbic acid (chemical-SeNPs). Analysis with XPS confirmed the presence of Se0, while FTIR analysis identified surface functional groups on all SeNPs. The study evaluated the effects of SeO32-, abiotic-SeNPs, and chemical-SeNPs at different concentrations on the growth and germination of Pisum sativum L. seeds. SeO32- demonstrated detrimental effects on germination at concentrations of 1 ppm (germination index (GI) = 0.3). Conversely, both abiotic- and chemical-SeNPs had positive impacts on germination, with GI > 120 at 10 ppm. Through the DPPH assay, it was discovered that SeNPs exhibited superior antioxidant capabilities at 80 ppm, achieving over 70% inhibition, compared to SeO32- (less than 20% inhibition), therefore evidencing significant antioxidant properties. This demonstrates that SeNPs have the potential to be utilized as an agricultural fertilizer additive, benefiting seedling germination and development, while also protecting against oxidative stress.

Bandage modified with antibacterial films of quaternized chitosan & sodium carboxymethyl cellulose microgels/baicalein nanoparticles for accelerating infected wound healing

Wound dressings capable of sterilizing pathogenic bacteria and scavenging free radicals are important to inhibit bacterial invasion and accelerate wound healing. The target of this work is to develop an antibacterial dressing by modifying bandages with films composed of biological macromolecule microgels and baicalein@tannic acid (Bai@TA) nanoparticles (NPs). Firstly, hydrophobic Bai was made into water soluble Bai@TA NPs using a solvent exchange method with TA as stabilizer. Polymeric microgels of sodium carboxymethyl cellulose (CMC)&hydroxypropyltrimethyl ammonium chloride chitosan (HACC) were then prepared by a simple blending method. Further, CMC&HACC/Bai@TA multilayer films were deposited on medical bandages by using a layer-by-layer assembly technique to obtain an antibacterial dressing. The as-prepared dressings showed great antibacterial ability against E. coli, S. aureus and methicillin resistant Staphylococcus aureus (MRSA), excellent antioxidant activity and good biological safety. In addition, compared to conventional medical bandages, the dressings could efficaciously diminish inflammation in the wound, accelerate skin regeneration and functional restoration, and promote the in vivo healing speed of full-thickness skin wounds infected by MRSA. We believe that as a low-cost but effective wound dressing, the antibacterial bandage modified with CMC&HACC/Bai@TA films has potentials to replace traditional dressings in the clinical management of infected wounds.

Enterococcus spp. Cell-Free Extract: An Abiotic Route for Synthesis of Selenium Nanoparticles (SeNPs), Their Characterisation and Inhibition of Escherichia coli

Selenite (SeO₃²⁻), the most toxic and most reactive selenium (Se) oxyanion, can be reduced to elemental selenium (Se⁰) nanoparticles by a variety of bacteria, including Enterococcus spp. Previously, the orthodox view held that the reduction of SeO₃²⁻ to Se⁰ by a wide range of bacteria was solely accomplished by biological processes; however, recent studies have shown that various bacterial strains secrete metal-reducing metabolites, thereby indirectly catalysing the reduction of these metal species. In the current study, selenium nanoparticles were synthesised from the abiotic reduction of selenite with the use of Enterococcus spp. cell-free extract. Once separated from the cell-free extract, the particles were analysed using Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Transmission electron microscopy (TEM) and a Zetasizer. The results revealed that the SeNPs were spherical in shape, containing both amorphous and crystalline properties, and the sizes with the highest frequency ranged close to 200 nm. Additionally, the obtained nanoparticles exhibited antimicrobial properties by directly inhibiting the viability of an E. coli bacterial strain. The results demonstrate not only the potential of abiotic production of SeNPs, but also the potential for these particles as microbial inhibitors in medical or similar fields.