Unveiling the antibacterial potency of phyto-stabilized silver nanoparticles against MDR uropathogens and exploration of its biocompatibility towards healthy blood cells.

This study illustrates the phyto-synthesis of silver nanoparticles (AgNPs) using the aqueous leaves extract of Carica papaya. The average particle size of AgNPs was approximately 41 nm and the surface charge of approximately -26mV. After being initially validated by UV-Vis on the day of synthesis, the λ value of AgNPs remained constant for six months, showing its stability. The time-dependent degradation of methylene blue dye was also seen after incubation with AgNPs. Multidrug-resistant (MDR) strains of Escherichia coli and Staphylococcus aureus were employed to assess the antibacterial and antibiofilm properties of AgNPs. The MIC of AgNPs was 20 μg/mL for Escherichia coli and 30 μg/mL for Staphylococcus aureus. AgNPs exhibited more potent antibacterial efficacy against the Gram-negative than the Gram-positive strain in MBC and DAD assays that are in accordance with the outcome of MIC. When the specific MIC of AgNPs was applied to each strain, a ≈90 % reduction in biofilm formation was also observed. AgNPs can disintegrate bacterial cell walls, produce a surplus of ROS, and trigger DNA damage. Concerning cytotoxicity, it showed lessened hemolysis and cellular toxicity on RBCs and PBMCs at concentrations of up to 50 μg/mL. Thus, AgNPs may reveal considerable promise as nanotherapeutics for the treatment of a wide range of pathogenic bacteria.