The antibacterial and anticorrosion activity of sodium alginate-chitosan cryogels and hydrogels loaded with Satureja montana essential oil and Monarda didyma hydrolate
Imane Haddadou, Amina Ami, Jonathan Gagnon, Claudiane Ouellet‐Plamondon
Abstract
This study develops chitosan-alginate (CS/SA) cryogels incorporating Satureja montana essential oil (EO) and Monarda didyma hydrolate for antibacterial and anticorrosion applications. Cryogels with a CS:SA ratio of 3:1 achieved 78.7 % encapsulation efficiency (EE), driven by electrostatic interactions between chitosan's protonated amine (-NH 3 + ) and alginate's carboxyl (-COO - ) groups, forming a dense polyelectrolyte network that entraps EO (FTIR/SEM evidence). Structural analysis revealed alginate-enhanced porosity (50–200 μm pores) and EO-induced densification, critical for controlled release. The cryogels inhibited Staphylococcus aureus (58.8 ± 2.3 %) and Pseudomonas aeruginosa (41.7 ± 3.0 %) and suppressed corrosion-associated strains: acid-producing bacteria (APB, 91.92 ± 0.16 %) and thiosulfate-reducing bacteria (BTR, 97.76 ± 0.27 %). Hydrolate-EO synergy enhanced anticorrosion performance, with CS/SA (3:1) cryogels retaining 90 % zinc on steel surfaces. This work demonstrates a sustainable strategy for dual-functional coatings, leveraging natural extracts to address industrial and environmental challenges. • Synergistic use of chitosan-alginate in cryogelsenhances bioactivity and stability. • Novel combination of hydrolate and essential oil improves antibacterial performance. • Cryogels achieve 78.7 % essential oil encapsulation efficiency with reduced leakage. • Antibacterial efficacy demonstrated against S. aureus and P. aeruginosa. • Superior anticorrosion activity minimizes biofilm formation and metal degradation.