Development of Methods for Encapsulation of Viruses into Polymeric Nano- and Microparticles for Aquaculture Vaccines

To meet an urgent need for improved vaccines against viral diseases in aquaculture, encapsulating the viruses into biodegradable and biocompatible polymers was suggested to protect viral antigens from premature degradation and gradually expose them to the immune system. We used water-in-oil-in-water emulsion to first encapsulate model red fluorescent polystyrene (PS) particles and then infectious salmon anemia virus (ISAV) into poly-lactic-co-glycolic acid (PLGA) together with coumarin 6. A milder layer-by-layer method was applied to incorporate both PS and ISAV into chitosan (Cs)-fluorescein isothiocyanate and alginate (Alg) followed by ionic crosslinking. All particles were characterized by dynamic light scattering, zeta-sizer, fluorescence, transmission- and scanning electron microscopy. Successful encapsulation of PS beads and ISAV into PLGA, Cs, and Alg was accomplished. The prepared particles were of different size, surface charge density, and morphology. This yields opportunities for further developments of these structures as vaccine candidates to be delivered by injection or oral administration. (C) 2014 Wiley Periodicals, Inc.