Abstract
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Silver nanoparticles (Ag NPs) with anti-bacterial effects against the biofilm-producing bacteria Klebsiella pneumoniae (K. pneumoniae) were synthesized using the marine seaweed Gracilaria corticata (G. corticata). Physiochemical characterization using UV-spectrometer, fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) confirmed that the synthesized material consisted of Ag NPs. Morphological analysis using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) with energy-dispersive X-ray (EDX) analysis confirmed the shape, size, surface morphology, and available chemical composition of the Ag NPs. Furthermore, the rich phenolic and flavonoid content of G. corticata has excellent antioxidant activity, which was confirmed through gas chromatography-mass spectrometry (GC–MS) analysis. The highest antibacterial activity and biofilm reduction (88 %) of Ag NPs treated K. pneumoniae was observed at 50 μg/mL and 100 μg/mL concentrations respectively. The bacterial viability and exopolysaccharide production of K. pneumoniae significantly decreased after treatment with Ag NPs. Morphological alterations and intracellular damage were confirmed by SEM and confocal laser scanning microscopy (CLSM). Finally, the toxicity results showed a 90 % inhibitory effect against Artemiafranciscana (A.franciscana) at 100 μg/mL after 24 h of incubation. Based on our results, we propose that the Ag NPs biosynthesized using seaweed are an eco-friendly and effective bio-medical material, unlike those produced via chemical methods.