(357ar) Liposome and Polyelectrolyte Layers Derived Single Shot Vaccine Platform for Controlled Release of Inactivated Chikungunya Virus

Inactivation of live virus is a commonly used technique to enhance safety in

development of vaccines for infectious diseases. Multi-dose requirement for such

vaccines often lead to missing or mistimed doses thereby limiting their potency. This in

particular can have an adverse effect in controlling an outbreak of vaccine preventable

infectious disease such as that of chikungunya (CHIKV) virus in a place without herd

immunity. Single shot vaccines capable of releasing the antigen intermittently can

potentially be employed to overcome the shortcomings of multi-dose vaccines. A

controlled release of antigen here at different time intervals can help in maintaining

adequate concentration of antibodies in the system and programmed delayed release

can help with increasing or rejuvenating the previous dose. In this study, we are

engineering a delivery platform comprising of CHIKV antigen encapsulated lipid

nanoparticles (HALNP) embedded in biodegradable polymer films to achieve a

sustained spatiotemporal release kinetics of the antigen. The CHIKV virus inactivated

using γ-radiations in presence of MDP complex (MDP-iCHIKV) was encapsulated in

fluorescently tagged lipid nanoparticles. Several formulations were prepared with

particles embedded in polyelectrolyte multilayer (PEM) films so as to obtain an early

and a second phase delayed release of the antigen. In-vivo studies were performed

where these formulations were injected in mice and the concentration of anti-CHIKV

IgG in serum was quantified at different time points. The characterization of liposomes

and liposome embedded PEM formulations (HALNP-PEM) was performed using

dynamic light scattering to obtain particle size and zeta potential measurements to

determine the surface charge. Analysis of encapsulation and released CHIKV antigen

concentration was performed using ELISA. Preliminary studies showed that MDP

complex protected CHIKV viral envelop proteins while destruction of its genome by γ-

radiation and also induced anti-CHIKV IgG response upon injection in mice. In previous

studies we have obtained a controlled and linear release profile of therapeutic cargo in

HALNP-PEM platform. The encapsulation efficiency of CHIKV antigen in liposomes

was nearly 75%. Upon quantifying the fluoresce using plate reader, we obtained about

80% adsorption efficiency of HALNP on PEMs. In-vivo studies with liposome PEM

formulations initially showed higher production of anti-CHIKV IgG in early release

groups in comparison to delay release groups and then gradual increase in antibody

concentration in delay release groups indicating towards intermittent release of antigen

due to presence of PEM layers. We are further working towards optimizing the process

for multiple controlled release phases and testing long term immune response against

CHIKV immunization in mice.