Characterization and biological investigation of silver nanoparticles biosynthesized from Galaxaura rugosa against multidrug-resistant bacteria

Bacterial drug resistance poses a global challenge to established antibacterial prevention and treatment schemes. Recent approaches focus on raising algal extracts' efficacy by fusing them to other antibacterial agents employing nanotechnology. Here, we successfully biosynthesized AgNPs using Galaxaura rugosa crude methanol extract (AgNP_CR) and raw powder aqueous (AgNP_AQ) solution. The resultant AgNPs were characterized using UV-visible spectroscopy, Fourier-transform infrared spectroscopy, dynamic light scattering, and transmission electron microscopy. The AgNPs were spherical and ranged between 60 to 114.4 nm. The presence of the hydroxyl group and alkenes propped AgNPs biosynthesis. We investigated AgNPs antibacterial and antibiofilm activity against eighteen medically important bacteria, including multidrug-resistant bacteria. The sensitive and resistant Acinetobacter baumannii and Staphylococcus aureus were the most affected strains. The biofilm of MDR strains was mostly disturbed, indicating the reduced bacterial fitness in resistant strains. These results may aid antibacterial agents' development by investing in natural resources available abundantly in our environment.