Antibiotics functionalization intervened morphological, chemical and electronic modifications in chitosan nanoparticles

Abstract

Abstract Applicability and efficacy of chitosan nanoparticles for drug delivery have been widely studied recently. However, the physicochemical effects of antibiotics functionalization in chitosan nanoparticles have not been comprehensively explored. In the current study chitosan nanoparticles have been prepared through an ionic gelation method and subsequently functionalized with antibiotic molecules, namely, Ampicillin, Dalacin (Clindamycin) and Levofloxacin antibiotics. The small angle X – ray scattering studies on these samples inferred that chitosan nanoparticles exhibited spherical morphology with an average size ≈ 90\xa0nm, while antibiotics functionalization interestingly shows diffusion limited aggregation of chitosan nanoparticles to form fractal structures, retaining primary particle radius of chitosan nanoparticles unchanged. These features were further correlated to surface charge using zeta potential measurements and pH of the samples. The interactions between chitosan nanoparticles and antibiotic molecules were corroborated through the optical spectroscopy and Fourier transform infrared spectroscopy measurements. To get a better insight on the above experimental findings and the possible interactions between chitosan nanoparticles and antibiotic molecule, first principles density of states and force field calculations were performed. The calculations show that chitosan nanoparticles exhibit a porous network which can allow a single antibiotic molecule to get incorporated in the single pore. However, this feature was observed to be a function of an antibiotic type. The antibiotic incorporation alters chitosan’s porous network, thereby correlating observation of fractal structure in antibiotic functionalized chitosan nanoparticles. The calculations further show that molecular orbital energy levels and subsequently dipole moments governed experimental observations. Thus our experimental and theoretical studies proved to be complementary offering a new approach to evaluate physicochemical interactions between antibiotic–nanoparticles carrier system crucial for the effective realization of drug delivery.