Preparation and characterization of dendronized chitosan/gelatin-based nanogels

Abstract

The composition, functionality and morphological structure of biomaterials control their properties, such as the hydrophilic/hydrophobic character, the magnitude of the inter/intramolecular interaction, and architecture and size, which determine their potential applications. The adequate combination of nanoscale with natural polymers could then yield nanogels (NGs) with greater relevance for biomedicine. Also, the dendritic structures can be combined with NGs to improve their applications. Then, the dendronized NGs combine the advantages of hydrogels, the nanoscale and multifunctionality, generating composite materials with synergic properties. Dendronized natural polymer-based NGs were prepared by inverse nanoemulsion. Gelatin and chitosan were crosslinked with 0.3, 0.6 and 0.9 wt% of tannic acid, and dendronized with weisisocyanate dendron. The NGs were characterized using infrared microscopy, thermogravimetric analysis and dynamic light scattering. IR spectra and thermic analysis allowed confirming the crosslinking reaction with tannic acid and dendronization of NGs. The systems are sized in the nanometric scale within 100 and 500 nm, and polydispersity index (PDI) values between 0.2 and 0.5. In all cases, an increase in the hydrodynamic diameter of the NGs was observed with the increase in the degree of crosslinking and a reduction in size after dendronization of up to 100 nm. NGs with low polydispersity were obtained, showing a hydrodynamic diameter value regulated by the crosslinker percentage, and an hydrophilic/hydrophobic character governed by the dendritic moiety.