The Functionalization of Nanostructures and Their Potential Applications in Edible Coatings

Nowadays, edible coatings incorporated with nanostructures as systems of controlled release of flavors, colorants and/or antioxidants and antimicrobial substances, also used for thermal and environmental protection of active compounds, represent a gap of opportunity to increase the shelf life of food highly perishable, as well as for the development of new products. These functionalized nanostructures have the benefit of incorporating natural substances obtained from the food industry that are rich in polyphenols, dietary fibers, and antimicrobial substances. In addition, the polymers employed on its preparation, such as polysaccharides, solid lipids and proteins that are low cost and developed through sustainable processes, are friendly to the environment. The objective of this review is to present the materials commonly used in the preparation of nanostructures, the main ingredients with which they can be functionalized and used in the preparation of edible coatings, as well as the advances that these structures have represented when used as controlled release systems, increasing the shelf life and promoting the development of new products that meet the characteristics of functionality for fresh foods ready to eat.

Hydrophobic amino acids grafted onto chitosan: a novel amphiphilic chitosan nanocarrier for hydrophobic drugs

OBJECTIVE

The objective of this study is to develop a novel biocompatible amphiphilic drug delivery for hydrophobic drugs, chitosan (CS) was grafted to a series of hydrophobic amino acids including l-alanine (A), l-proline (P), and l-tryptophan (W) by carbodiimide mediated coupling reaction.

MATERIALS AND METHODS

Chemical characteristics of the modified polymers were determined and confirmed by FT-IR, ¹H NMR, and UV-vis spectroscopy and the degree of substitution was quantified by elemental analysis. The modified polymers were used to form amphiphilic chitosan nanocarriers (ACNs) by the conventional self-assembly method using ultrasound technique. The morphology and the size of ACNs were analyzed by scanning electron microscope (SEM) and Dynamic light scattering (DLS).

RESULTS AND DISCUSSION

The sizes of spherical ACNs analyzed by SEM were obviously smaller than those of determined by DLS. The ACNs effectively surrounded the hydrophobic model drug, letrozole (LTZ), and demonstrated different encapsulation efficiencies (EE), loading capacities (LC), and controlled drug release profiles. The characteristics of ACNs and the mechanism of drug encapsulation were confirmed by molecular modeling method. The modeling of the structures of LTZ, profiles of A, P, and W grafted onto CS and the wrapping process around LTZ was performed by quantum mechanics (QM) methods. There was a good agreement between the experimental and theoretical results. The cell viability was also evaluated in two cell lines compared with free drug by MTT assay.

CONCLUSION

The hydrophobic portion effects on ACNs' characteristics and the proper selection of amino acid demonstrate a promising potential for drug delivery vector.