Exploring the multifaceted bioactivities of silver nanoparticles synthesized from red algae Hypnea pannosa: Antimicrobial, antibiofilm, and insecticidal potentials

Background: The emergence of microbial resistance to conventional antibiotics and the environmental impact of chemical pesticides necessitates the search for alternative and sustainable solutions. This study explores the utilization of the dried biomass of the red algae Hypnea pannosa to synthesize silver nanoparticles (AgNPs) using a green and eco-friendly method. Results: The synthesized AgNPs displayed sizes ranging from 15 to 60 nm with polydispersed shapes and a face-centered cubic crystalline structure, confirmed through characterization techniques including transmission electron microscopy (TEM), dynamic light scattering (DLS), and X-ray diffraction (XRD). Stability assessments via zeta potential measurements and docking studies of oleic acid and 9,12-octadecadienoic acid against Gyrase B and GST proteins were also conducted. The nanoparticles demonstrated potent antibacterial and antibiofilm activities, particularly against Staphylococcus epidermidis. Both the algal extract and the AgNPs exhibited significant larvicidal and adulticidal effects against Culex pipiens, with the nanoparticles showing superior efficacy, indicated by lower LC50 and LC90 values. The highest larvicidal effectiveness achieved was 93.33% for algal extract at 600 mg/L and 100% for AgNPs at 100 mg/L. Conclusions: This study provides a sustainable method for producing AgNPs with diverse applications in medical and mosquito control fields, highlighting their potential as effective and safe alternatives to conventional antibacterial and insecticidal agents.How to cite: Bashar MA, Attia EM, Mekky AE, et al. Exploring the multifaceted bioactivities of silver nanoparticles synthesized from red algae Hypnea pannosa: Antimicrobial, antibiofilm, and insecticidal potentials. Electron J Biotechnol 2025;74. https://doi.org/10.1016/j.ejbt.2024.12.001.