Colloidal stability and physicochemical characterization of bombesin conjugated biodegradable nanoparticles

The aim of this investigation was to explore the potential of bombesin (BBN) peptide conjugated biodegradable polymeric nanoparticles as cancer targeting system. Poly (lactic-co-glycolic) acid nanoparticles were prepared using different concentration of surfactants. Nanoparticles, prepared with 0.25% sodium cholate (PNP), showed the smallest size (86.15 nm) and good zeta potential value (−34.2 mV). Bombesin was covalently conjugated to the nanoparticle surface by amide bonding. The surface conjugation was confirmed by change in surface potential and Fourier transform infrared analysis. Slight change in pH and buffer medium did not show significant effect on conjugation efficiency. Colloidal stability of nanoparticles was evaluated with respect to time, salt induced aggregation, storage medium and release of BBN from nanoparticle surface. The stability factor was determined by change in optical density and particle size with time. Nanoparticles were found to be more stable in phosphate buffer saline and serum when compared to that in normal saline and distilled water. Bombesin conjugated nanoparticles (BPNP) showed more stability in both PBS and serum than PNP which may be due to steric stabilization of nanoparticles by the peptide. Similarly, in aggregation resistance studies, BPNP were stable up to 0.7 M concentration of sodium sulphate. Bombesin was released only 12.76% in 24 h under acceleration conditions, showing the stability of amide bond formed between nanoparticles and peptide. Conclusively, the bombesin peptide conjugated PLGA nanoparticle could be a promising drug delivery system for targeting of anticancer drugs.