Synthesis, characterization of nisin loaded alginate-chitosan-pluronic composite nanoparticles and evaluation against microbes

•Nanoparticles were synthesized by ionotropic pre-gelation method followed by polycationic cross-linking.•Drug to polymer ratio 1:1, cross linker 0.2%, nisin 1 mg/ml, and 270 min stirring at room temperature found to be best.•Controlled and sustained in vitro release of nisin was achieved.•Polymer and nisin exhibited synergistic antimicrobial activity that was retained over a prolonged period.

Nisin loaded tripolymeric nanoformulation was prepared using three biocompatible polymers i.e. chitosan, sodium alginate and pluronic F68 which are permitted for use in food. The process variables were optimized to obtain efficient encapsulation and appropriate particle size. Mean particle size of nanoparticles was determined to be 208.2 nm with particle size analyzer. TEM (Transmission Electron Microscope) observations revealed spherical shape and size in the range of 130-170 nm. Fourier transform-infrared analysis did not reveal any chemical interaction among the constituents in the composite nanoparticles. In-vitro release studies held for two weeks showed initial burst release followed by a sustained release of nisin from the formulation. Further studies demonstrated that biological activity of nisin was prolonged by its encapsulation in polymeric nanoparticles.