Synthesis and in vitro characterization of a pH-responsive chitosan- polyethylenimine nanosystem for the delivery of therapeutic proteins

The purpose of this study was to design and characterize Bovine Serum Albumin (BSA)-loaded chitosan (CHT)-based nanoparticles for the potential delivery of therapeutic proteins. Tripolyphosphate (TPP) was used as a polyanionic agent to synthesize the nanosystem that was characterized for its structural integrity, functional modification, particle size, morphology, zeta potential, thermal stability, protein-loading efficiency and protein release kinetics. H1NMR and FT-IR confirmed grafting of co-polymers to the CHT moiety. The average size and morphology of the BSA-loaded nanoparticles - confirmed by TEM, DLS and SEM-showed that the nanoparticles were spherically shape with a narrow particle size distribution (polydispersity index (PDI) = 0.232) and a size of 63.14 ± 31.31 nm. Both TGA and DSC results confirmed the thermal stability of the BSA-loaded nanoparticles compared with native polymers. Protein loading efficiency was 77.2% with an initial burst release due to surface protein desorption and subsequent prolong release through diffusion from sublayers after 2 h up to 30 h at varying pH conditions. The release kinetics at pH 6.8 was higher than at pH 7.4. Conclusively, this nanosystem may be explored as a vehicle for pH-responsive targeting of therapeutic proteins in cancer nanomedicine where tumors are known to have varying pH micro-environments.

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