Enhanced generation of reactive oxygen species and membrane intercalation potency of berberine-based conjugates for efficient photodynamic inactivation against foodborne bacteria

Abstract

Dual-functional photosensitizers (PSs) with enhanced reactive oxygen species generation based on natural aggregation-induced emission (AIE) luminogen and membrane-intercalating ability were fabricated. Specifically, the AIE property of berberine (BBR) was achieved by encapsulating it into the carboxymethyl-β-cyclodextrin (CMCD) cavity to restrict its molecular motion. Meanwhile, the CMCD was decorated with transacting activator of transduction (TAT) peptide to realize the membrane-intercalating function. On this basis, the fabricated BBR/CMCD/TAT conjugates exhibited superior PDI efficiency (>8 Log CFU mL⁻¹) against foodborne bacteria by inducing severe membrane damages. Transcriptomic analysis revealed that the BBR/CMCD/TAT-mediated PDI significantly blocked the biosynthesis of peptidoglycan and lipopolysaccharide, and compromised the energy production pathways, eventually causing cell death. Furthermore, the BBR/CMCD/TAT-mediated PDI efficiently inactivated ∼99 % bacteria on salmon fillets throughout the storage period, consequently extending the shelf life by 3 days. These findings highlight the promising application of dual-functional PS-mediated PDI in combating bacteria and ensuring food microbiological safety.