Electrospray deposition of starch-containing laccase: A green technique for low-cost and eco-friendly biosensors

Recently a laccase-based biosensors with unprecedented reuse and storage capabilities in the detection of catechol compound has been manufactured using ambient Electrospray Deposition (ESD) technique. These biosensors showed to be reused up to 63 measurements on the same electrode just prepared at room temperature and pressure. In this new work the reasons behind such a high-performance functioning have been investigated by analysing the commercial sample of laccase with different chemical physics methods: Electrophoresis, Fourier Transform Infrared Spectroscopy, X-ray Fluorescence and Nuclear Magnetic Resonance Spectroscopy. The analyses reveal the presence of the starch in the sample and its essential role as stabilizing agent. Indeed, comparing the performance of starch/laccase-based biosensors with starch-free/laccase-based biosensors, both produced via ESD, showed that the starch-free biosensors lost about 40% of their performance after just the first wash. This suggests that the presence of starch in the laccase sample is a key factor in providing the high wash and storage resistance, which are essential for the fabrication of such devices.