Antibacterial screening of Amoxiclav functionalized silver nanoparticles synthesized by the microalgae Bryopsis pennata and Caulerpa taxifolia

Abstract

The loss of antibiotics efficacy over common infections has raised concerns and resulted in significant research efforts to the search for new antibiotics or chemically altering existing ones for a better control of infectious diseases. In this study, the aqueous extracts of Bryopsis pennata and Caulerpa taxifolia were used to synthesize silver nanoparticles. These nanoparticles were functionalized with Amoxicillin/Clavulanic acid (amoxiclav). UV/visible spectroscopy was used to monitor the synthesis of the silver nanoparticles. The organic surface groups responsible for the capping and stabilization of the nanoparticles were analyzed using Fourier transmission infrared spectroscopy (FTIR). Scanning Electron Microscopic (SEM) studies showed that the silver nanoparticles formed had sizes in the range of 7 nm to 65 nm. The aqueous extracts of Bryopsis pennata and Caulerpa taxifolia showed very low activity against Escherichia coli, Klebsiella oxytoca and Bacillus mycoides. Salmonella enterica, Pseudomonas aeruginosa and Staphylococus aureus with values for the zone of growth inhibition ranging from 7 mm to 15 mm for both extracts at the maximum concentration of 500 µg/mL. Silver nanoparticles exhibited much higher activity than their respective extracts as the zone of growth inhibition values ranged between 23 mm to 26 mm at the maximum concentration. The activity of Amoxicillin/Clavulanic acid was improved when conjugated with silver nanoparticles with very high values for the zone of growth inhibition ranging from 30 mm to 34 mm at the maximum concentration of 500 µg/mL. Therefore, the functionalization of silver nanoparticles with antibiotics is medicinally important and can be used to improve the activity of existing antibiotics.