Ricerc@Sapienza

Enzymes immobilisation represents a critical issue in the design of biosensors to achieve standardization as well
as suitable analytical performances in terms of sensitivity, selectivity, and stability. In this work electrospray
deposition (ESD) has been exploited as a novel technique for the immobilisation of laccase enzyme on carbon
black modified screen-printed electrodes. The aim is to fabricate an amperometric biosensor for phenolic compound
detection. The electrodes produced by ESD have been analysed by scanning electron microscopy and
characterised electrochemically to prove that this immobilisation technique is suited to manufacture high performance
biosensors. The results show that the laccase enzyme maintains its activity after undergoing the
electrospray ionisation process and deposition and the fabricated biosensor has improved performances in terms
of storage (up to 3 months at room temperature) and working (up to 25 measurements on the same electrode)
stability. The laccase-based biosensor has been tested for phenolic compound detection, with catechol as target
analyte, in the linear range 2.5–50 μM, with 2.0 μM limit of detection, without interference from lead, cadmium,
atrazine, and paraoxon, and without matrix effect in drinking, surface, and wastewater.