Venom-loaded cationic-functionalized poly(lactic acid) nanoparticles for serum production against Tityus serrulatus scorpion.

Reported accidents involving scorpion poisoning by Tityus serrulatus are the most frequent in Brazil. The only specific treatment for envenomation is the administration of antivenoms associated with traditional adjuvants. Novel adjuvants are studied to reduce or avoid side effects and potentialize the efficacy of conventional serum. In this study, poly(lactic acid) nanoparticles were functionalized with polyethylenimine for loading peptides and proteins of T. serrulatus venom, and their use as a potential immunoadjuvant was evaluated. The protein loading efficiency of about 100% and the polyacrylamide gel electrophoresis assay confirmed the success of venom loading. Dynamic light scattering and zeta potential analysis supported small and narrow-sized cationic functionalized nanoparticles. Atomic force microscopy and scanning electron microscopy images showed nanoparticles with a spherical and smooth shape. The stability of tested formulations was accessed for six weeks, and the sustained release of proteins controlled by diffusion mechanism was also measured. Finally, in vivo immunization in BALB/c mice showed superior efficacy of the T. serrulatus venom protein-loaded nanoparticles compared to the traditional aluminum hydroxide immunoadjuvant. Thus, the formulations shown are promising nanocarriers to be used as a biotechnological approach to immunotherapy against scorpion envenomation.