Preparation, characterization, and in vitro activity evaluation of triblock copolymer-based polymersomes for drugs delivery

CORTIZO, M. SUSANA; CORTIZO, ANA M.; BESADA, LUCAS N.; PERUZZO, PABLO

JOURNAL OF NANOPARTICLE RESEARCH

SPRINGER

Año: 2018 vol. 20

1388-0764

Polymersomes are polymer-based vesiclesthat form upon hydration of amphiphilic block copolymersand display high stability and durability, due totheir mechanical and physical properties. They havehydrophilic reservoirs as well as thick hydrophobicmembranes; allowing to encapsulate both watersolublebioactive agent and hydrophobic drugs. In thisstudy, poly ethylene glycol (PEG3350 and PEG6000)were used as hydrophilic part and poly(vinyl benzoate)(PVBz) as hydrophobic block to synthesize amphiphilictriblock copolymers (PVBz-b-PEG-b-PVBz). Differentproportions of hydrophilic/hydrophobic part wereassayed in order to obtain polymersomes by solventinjection method. For the synthesis of the copolymers,the initial block of PEG was derived to obtain amacroinitiator through a xanthate functional group(PEGX3 or PEGX6) and the polymerization of vinylbenzoate was carried out through reversible additionfragmentationchain transfer polymerization (RAFT).The structure of PEGX and copolymers was confirmedby Infrared, 1H-NMR and UV-Vis spectrometry, whilethe average molecular weight (Mw) and polydispersityindex (PI) were determined by size exclusion chromatography(SEC). The structures adopted by the copolymersin aqueous solution by self-assembly were investigatedusing transmission electron microscopy (TEM),dynamic light scattering (DLS) and small-angle X-rayscattering (SAXS). Both techniques confirm thatpolymersomes were obtained for a fraction of hydrophilicblock (f) ≈ 35 ± 10%, with a diameter of38.3 ± 0.3 nm or 22.5 ± 0.7 nm, as determined byTEM and according to the Mw of the precursor blockcopolymer. In addition, we analyzed the possible cytotoxicityin view of its potential application as biomedicalnanocarrier. The results suggest that polymersomesseem not induce cytotoxicity during the periods of timetested.