Poly-Caprolactone Nanocapsules Morphological Features by AtomicForce Microscopy

Extract

Polymeric nanoparticles containing an oily core, named nanocapsules (NCs), have been widely studied in the life sciences field due to their therapeutic potentialities of drug targeting in the body accompanied also by its larger stability in the biological fluids compared to other colloidal carriers. Many studies have shown different applications of nanocapsules for therapeutic use concerning their properties [1] of loading poorly water-soluble drugs, protection drugs from inactivation in the gastro-intestinal tract [2], gastric mucosal toxicity protection [3,4], increased drug permeation through mucous epithelium [5,6] and prolongation of drugs in blood circulation for surface modified nanocapsules [7]. The characterization of the nanocapsules is frequently performed by mean size, surface charge of the particles (zeta potential), hydrophobicity, drug loading yield and release kinetic [8]. These features are of great importance for biodistribution profile and interactions with the cells of mononuclear phagocyte system of any injected particles by intravenous route [1]. However, few data on structural organization of the nanocapsules constituents are available in literature and several hypotheses only suggest the presence of an oil "capsular" structure surrounded by a polymeric envelope. Recently, atomic force microscope (AFM) has been used as a method for imaging the surfaces of colloidal systems, such as liposomes [9,10] and nanospheres [11], supplying high resolution information in nanoscaled dimension. In the present work, unloaded nanocapsules were deposited on mica in order to analyze by AFM the diameter, height, particles polydispersion, and topographic characteristics of nanocapsule surface.