Gracilaria salicornia as potential substratum for green synthesis of Cerium Oxide Nanoparticles coupled hydrogel: An effective antimicrobial thin film

Abstract

Sodium alginate based (SA) hydrogel supplemented Cerium Oxide nanoparticles (CeO₂NPs) was produced to fabricate an antimicrobial thin film using an aqueous extract of G. salicornia (Gs). The Gs-CeO₂NPs were characterized via SEM, FT-IR, EDX, XRD and DLS, the particle size was 200 nm, agreed with XRD. Gs-SA powder was extracted and incorporated with CeO₂NPs. The Gs-SA and its composite thin film (Gs-CeO₂NPs-SATF) were characterized including viscosity, FT-IR, TGA, and SEM. The adhesion of Gs-SA coating around Gs-CeO₂NPs confirmed via FTIR. The antimicrobial properties of Gs-CeO₂NPs and CeO₂NPs-SATF were proved in MICs for E. coli and Candida albicans at 62.5 and 250.0 μg/mL. The biofilm inhibition efficiency of CeO₂NPs-SATF was 74.67 ± 0.98% and 65.45 ± 0.40% for E. coli and Candida albicans. The CeO₂NPs-SATF was polydisperse in nature and film structure gets fluctuated with NPs concentration. Increased NPs into SATF enhances pore size of gel and corroborated with viscous behaviour. The cytotoxicity of Gs-CeO₂NP-SA in Artemia salina at higher concentration 100 μg/mL provides less lethal effect into the adult. The antioxidant activity of Gs-CeO₂NP-SA in DPPH assay was noticed at 0.6 mg ml^-1 with radical scavenging activity at 65.85 ± 0.81%. Thus the Gs-CeO₂NP-SATF would be suitable in antimicrobial applications.

Keywords: Antibiofilm; Antimicrobial; CeO(2)NPs; Cytotoxicity; G. salicornia; Thin film.