The electrospinning of xanthan gum: from solution to nanofiber formation

The interest on electrospinning of individual polysaccharides has been growing in the last years. Xanthan gum, an extracellular heteropolysaccharide produced by the bacterium Xanthomonas campestris, has been largely used and... [ view full abstract ]

The interest on electrospinning of individual polysaccharides has been growing in the last years. Xanthan gum, an extracellular heteropolysaccharide produced by the bacterium Xanthomonas campestris, has been largely used and investigated in areas such as food, pharmaceutical, cosmetics, biomedical and tissue engineering industries. However the electrospinning of xanthan gum to produce nanofibers has never been reported. 

In the present study we report for the first time the formation of electrospun xanthan nanofibers using formic acid as a solvent.  The correlation between the concentration and the rheological properties of xanthan solutions, with the spinability (production of uniform nanofibers) of the nanofibers was investigated (Figure 1). Morphological studies by scanning electron microscopy show that uniform fibers with average diameters ranging from 128 ± 36.7 to 240 ± 80.7 nm are formed depending on the polysaccharide concentration  (0.5 to 2.5 wt/vol%) The typical “weak gel-like” and thixotropic properties known for aqueous xanthan solutions, are not observed for the xanthan solutions in formic acid. The Fourier transform infrared spectroscopic and circular dichroism studies verify that an esterification reaction takes place, where formic acid reacts with the pyruvic acid groups of xanthan. Moreover, the results obtained from size-exclusion chromatography reveal a small difference in the molecular weight of the polysaccharide when dissolved in distilled water or in formic acid.    

We are currently investigating the utilisation of these electrospun xanthan nanofibers as a carrier for the encapsulation of bioactive compounds. Moreover due to the low cost, biocompatibility of xanthan nanofiber mats, we expect that a broad range of other applications within life sciences will benefit from the use of these novel nanofibers.