Development and characterization of innovative polymeric oil-core nanocarriers for nisin delivery

Abstract

Nisin is an antimicrobial peptide broadly used as a preservative in the food industry. In this study, oil-core polymeric nanocapsules encapsulating nisin were prepared by a nanoprecipitation technique using three different synthetic biodegradable polymers, namely poly(butylene adipate-coterephthalate) (PBAT), Eudragit RS-100® (EUD), and poly(ε-caprolactone) (PCL), and their physical characteristics, thermal resistance and antimicrobial activity against Listeria monocytogenes were investigated. All nanocapsule formulations showed entrapment efficiency superior to 96%. EUD and PCL nanocapsules showed average diameters ranging from 145 to 303 nm, while PBAT-nisin nanocapsules showed larger size and PDI index (556.2 nm and 0.51, respectively), possibly due to changes in the organic phase equilibrium during preparation. The thermogravimetric analysis indicates lower decomposition temperatures in the PCL and EUD nanocapsules containing nisin compared with the unload nanocapsule and the contrary effect in the PBAT. Moreover, all nisin-containing polymeric nanocapsules exhibited antimicrobial activity against L. monocytogenes in both agar diffusion tests and determination of antimicrobial units (AU/mL) in liquid media. Oil-core polymeric nanocapsules have not been previously described as carriers for nisin, and the results suggested that PBAT, EUD, and PCL could be suitable polymers for nisin delivery systems.