Biodegradable dextran vesicles for effective haemoglobin encapsulation

Biodegradable dextran vesicles were developed based on dextran and poly(L-lactide) (PLA). The amphiphilic graft copolymer dextran-g-poly(L-lactide) (dextran-g-PLA) was obtained by coupling carboxyl-terminated PLA to dextran. The copolymer was induced to self-assemble to form nanoparticles using a dialysis procedure. The morphology and size of the nanoparticles were examined by transmission electron microscopy (TEM) and dynamic light scattering (DLS). An alternative morphology could be induced by varying the relative mass ratio of dextran to PLA. The vesicles produced showed high stability. In order to encapsulate haemoglobin (Hb), the lyophilized dextran-g-PLA was dispersed in a Hb phosphate buffer solution (PBS) and free Hb removed by centrifugation. The oxygen affinity of haemoglobin vesicles (HbVs) was close to that of pure Hb, suggesting that HbVs have considerable future potential as a blood substitute