Ultrasound-assisted preparation of size-controlled chitosan nanoparticles: Characterization and fabrication of transparent biofilms

• Type: Article in International Scientific Journal
• Date: 2013

Authors

Hileia K. S. Souza (Author) FEUP; José M. Campiña (Author) FCUP; Ana M.M. Sousa (Author) FEUP; Fernando Silva (Author) FCUP; Maria P. Gonçalves (Author) FEUP

Journal

Title: Food Hydrocolloids

Vol. 31

Pages: 227-236

ISSN: 0268-005X

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 32 Citations

ISI Web of Science

Scopus - 32 Citations

Scientific classification

FOS: Engineering and technology

Other information

Authenticus ID: P-001-ZTT

DOI: 10.1016/j.foodhyd.2012.10.005

Abstract (EN): The use of biodegradable natural polymers is a suitable alternative for the preparation of more environmentally-friendly plastics and biocompatible nanoparticulated systems. Chitosan is an abundant and inexpensive candidate. However, its transparent films present poor mechanical response and high sensitivity to moisture. Moreover, the findings made by different researchers on the effects of molecular mass and degree of deacetylation (DD) on these properties are still controversial. This paper aims to unveil the separate effects of these parameters on biofilm properties. For these purposes, two aqueous solutions of chitosan (DD = 90 and 95%) were submitted to controlled fragmentation by ultrasonication. The resulting solutions were characterized by rheological techniques and the nanoparticles formed were studied ex-situ by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Irrespective of DD, the application of longer sonication times reduced the viscoelasticity of the solutions and yielded nanoparticles with lower size (and molecular mass). The mechanical strength and stiffness of transparent biofilms fabricated from these solutions, without plasticizers, were determined in stress tests. Sensitivity to moisture was also evaluated through water vapor permeability measurements and water sorption isothermal data. The results showed a significant decrease in the permeability with decreasing the molecular mass. However, the mechanical properties were adversely affected. These findings may be useful for the future design of bioplastics with improved properties but also for the development of biocompatible nanoparticles with tunable size and molecular mass.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10