DEVELOPMENT OF POLYHYDROXYBUTYRATE NANOPARTICLES (NanoPHB) FOR ANTIVIRAL DRUG DELIVERY

DANIELA S ALVAREZ ; MARIELA P MEZZINA ; ROCÍO DÍAZ PEÑA ; CYBELE GARCÍA; DIANA WETZLER ; KARINA D MARTÍNEZ; OSCAR E PÉREZ; M JULIA PETTINARI

San Luis

Congreso; XIII Congreso Argentino de Microbiología General; 2018

Asociación Civil de Microbiología General

Polyhydroxyalkanoates (PHAs) are biodegradable polymersproduced by a wide range of microorganisms as intracellular carbon and energy storage compounds. Its thermoplastic properties make them attractive candidates for the replacement of traditional plastics, and their biodegradability and biocompatibility allow them tobe exploitedin numerous biomedical applications. Poly(3-hydroxybutyrate) (PHB) was the first PHA discovered and it is still the most common and widely researched member of PHA family. PHB has been shown to be fully biocompatible and non-immunogenic, and has been used in drug delivery systems to improve the release of antibiotics and anticancer drugs.In the present work we aim to develop PHB nanoparticles for antiviral drug delivery.Viral infections pose significant global health challenges, complicated by the limited effectiveness of many antiviral therapies.Among the problems described for antiviral drugsare poor aqueous solubility, short half-life and bioavailability issues.In this context, a PHB-nanoparticle delivery system can help to increase the effectiveness of these drugsby controlling the release and increasing their solubility and stability. We designed reproducible PHB nanoparticles with precise dimensions using the emulsification method. Particles showed an average size of 180nm, as assessed by dynamic light scattering. Nanoparticles  potential values denoted colloidal stability. The size of the nanoparticles allowed us to sterilize the suspension by filtration with 0.22 µm filters. Concentration of the nanoparticles was determined by gas chromatography, after lyophilization and methanolysis of a suspension sample. Precipitation of the nanoparticles was achieved via ultracentrifugation; after which we were able to resuspend the PHB pellet and retrieve the nanoparticles. This step was fundamental for nanoparticle drug loading, in order to analyze the entrapment efficiency. Cytotoxicity assays were performed in Vero cells using crystal violet staining and MTT methods in order to evaluate cell viability in the presence of the hydrophobic polymer nanoparticles. Viability of Vero cells did not appear to be affected by our nanoparticlesin the range of usage concentration reported in bibliography.We also evaluated the effect of the PHB nanoparticles on Vero cells infected with Zika virus. No differences were observed on infection and virus replication between cells treated with nanoparticles and untreated control cells.Finally, as proof of concept, we developed PHB nanoparticles loaded with rhodamine B isothiocyanate (RBITC).The RBITC-loaded nanoparticles were observed by fluorescence microscopy to co-localize within two cell types. Taken together, these results open the road for the application of the PHB nanoparticles as delivery systems for antiviral drugs and other substances of biomedical relevance.