Electrochemical characterization of PVA/SA nanofibers obtained by electrospinning processing

Sodium alginate (SA), a linear polysaccharide which is present in different forms, is commonly used for tissue engineering. One of the main challenges of using SA in tissue engineering consists of the fabrication of nanoparticles/nanofibres for cell culture scaffolds. Because SA has been developed for medical purposes, it is necessary to measure, among others, the electrochemical properties because they provide information of biological activity related to metabolic behaviour. This work focuses on the measurement, interpretation, and characterization of electrochemical properties by means of electrochemical impedance spectroscopy of SA electrospun fibres mixed with poly(vinyl alcohol) (PVA) at different PVA/SA concentration ratios (3.5, 4, and 5 wt.%). To stabilize the PVA/SA systems, a calcium chloride solution was used for the cross‐linking process. The electrochemical impedance spectroscopy results show that PVA/SA nanofibres immersed in calcium chloride react instantly and the dielectric properties of the PVA/SA system change until the cross‐linking process is stabilized in time. The overall cross‐linking time depends on the PVA/SA ratio which means, the more SA concentration mixed in PVA solution, the shorter the cross‐linking time needed for a stabilization plateau. The 5 wt.%, PVA/SA gives not only the highest impedance values after cross‐linking treatment, but also the more constant and reproducible electrochemical features in time, in conjunction with a more homogeneous, compact and low porous nanofibre.