Fabrication of curcumin conjugated self-assembled lysozyme nanoparticle as potential food additive with enhanced antibiofilm and antioxidant activity

Food contamination has recently emerged as a major global challenge. Due to the potential side effects of synthetic preservatives, natural-based alternatives with antimicrobial and antibiofilm properties have been developed to prevent food spoilage. This approach involves utilizing biomolecules like proteins, which can undergo self-assembly to form stable nanostructures with enhanced functionalities. Here, we prepared self-assembled nanostructured lysozyme (SaLyz) using two different crosslinkers: Sodium tripolyphosphate (STPP) and Glutaraldehyde (GTD). SaLyz₁, prepared with a single crosslinker (STPP), had a size of 80 nm, while SaLyz₂, prepared with a double crosslinker (GTD + STPP), had a size of 60 nm. SaLyz₂, with a zeta potential of −29 mV, showed greater stability at high pH and temperature. To enhance the antibacterial and antibiofilm activity of SaLyz, the natural polyphenol curcumin was loaded onto SaLyz₁ and SaLyz₂. SaLyz₂-Cur exhibited the highest antibacterial efficacy, with growth inhibition rates of 91% against E. coli and 93.7% against B. subtilis. Additionally, this formulation demonstrated excellent antibiofilm activity, inhibiting over 86% and 88% of E. coli and B. subtilis biofilm formation, respectively. Furthermore, the particles eradicated preformed mature biofilms of E. coli and B. subtilis at rates of 74% and 80%, respectively. The developed SaLyz possessed significant antioxidant properties, which were further enhanced after curcumin loading. In vitro hemocompatibility and cytocompatibility studies showed that SaLyz and SaLyz-Cur were highly biocompatible, indicating their safety for consumption. Hence, the prepared formulations, with their strong antibacterial, antibiofilm, and antioxidant activities, can be utilized as natural food preservatives to prevent food spoilage.