17G-29 Production of antimicrobial electrospun PEO-chitosan fibers

T. SAMS¹, J. Rodriguez¹, S. Zivanovic¹, K. Kit², and J. Weiss¹. (1) Dept. of Food Science & Technology, Univ. of Tennessee, Food Chemistry &Biophysics Labs, 2605 River Road, Knoxville, TN 37996, (2) Department of Material Science and Engineering, 510 Dougherty Engineering, 1512 Middle Drive, Knoxville, TN 37996

Chitosan, a polycationic polysaccharide from crustacean shells, offers promising possibilities for applications in the area of food safety. Chitosan films and fibers have shown excellent antimicrobial properties for use in membranes and filters or antimicrobial packaging materials. Electrospinning produces nanoscale fibers with superior mechanical properties.

The objective of this study was to produce fibers with high surface to volume ratios and diameters in the nanometer range by electrostatic spinning.

Chitosan with molecular weight of 150kDa and degree of acetylation of 15% was dispersed in 1% acetic acid. Polyethyleneoxide (PEO) with a molecular weight of 900kDa was dispersed in aqueous solutions containing ethanol, acetic acid and acetone. Solutions were blended to produce uniform biopolymer dispersions. A laboratory scale electrospinning unit consisted of a variable high voltage power supply, a syringe pump, and a copper collector plate. Deposited fibers were characterized using a 5kV scanning electron microscope (SEM).

Initial electrospinning experiments with pure chitosan solutions at concentrations ranging from 0.1 to 4 wt% were unsuccessful at voltages between 8 and 20kV. The applied external electric field did not result in ejection of a biopolymer-containing liquid jet from the tip of a capillary that could be collected on the grounded receptor plate. Viscosity of chitosan solutions was either too high or concentration of biopolymer was too low. Addition of acetone or ethanol did not reduce solution viscosity sufficiently to initiate fiber production. However, co-spinning of chitosan and PEO both dispersed in 1% acetic acid solution at a ratio of 1:2.25 resulted in nanoscale fibres with beadlike morphologies. SEM images indicated an average fiber diameter of 7-8nm. Success was establish with chitosan/PEO solution viscosity at η=0.2 Pas.

Our results demonstrate for the first time successful production of chitosan-containing electrospun nanoscale fibers suitable for use in food, pharmaceutical, biomedical and biochemical applications.