Biomacromolecules of chitosan - Bacopa saponin based LipL32 gene delivery system for leptospirosis therapy

Leptospirosis is a severe bacterial infectious disease caused by the organisms belonging to the genus of Leptospira. The chitosan/Bacopa saponin/tripolyphosphate (CS/BS/TPP) nanoparticles conjugated with recombinant DNA vaccines were designed against Leptospirosis. Chitosan, a polysaccharide is suitable for delivery of drug, and gene due to its bio-compatible and biodegradable properties. Bacopa saponins are used for the induction of the immune response against microbial infections. The recombinant DNA vaccine construct was composed of the leptospiral outer membrane LipL32 gene tagged with EGFP and hGMCSF adjuvant in the pVAX1 mammalian expression vector along with the Cytomegalovirus (CMV) promoter. These recombinant DNA vaccine constructs was termed as pVAX1-EGFP-LipL32 and pVAX1-EGFP-hGMCSF-LipL32, and these constructs were conjugated with CS/BS/TPP nanoparticles by using the ionic gelation technique. Thus, CS/BS/TPP conjugated nanoparticle DNA vaccine was confirmed by functionality (FT-IR), crystalline nature (XRD) and surface charge (Zeta potential). The 90% encapsulation efficiency was observed in the conjugated nanoparticle DNA vaccine. In contrast, cell viability analysis validated that the synthesized DNA conjugated CS/BS/TPP nanoparticles showed low cytotoxicity up to 10 mg/mL. The results showed here are the initial establishment of DNA vaccine conjugated nanoparticles, which can be used as a potential anti-leptospiral vaccine.