Laccase bioconjugate and multi-walled carbon nanotubes-based biosensor for bisphenol A analysis

Bisphenol A (BPA) is an endocrine disruptor compound that has been detected in aquatic ecosystems. In this work, the development of an electrochemical biosensor for BPA determination based on laccase from Trametes versicolor is reported. A bioconjugate was optimized to maximize the biosensor electrocatalytic activity and stability, which for the first time involved the synergistic effect of this specific enzyme (6.8 UmL(-1)), chitosan (5 mgmL(-1)) and the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate in an optimum 5:5:2 (v/v/v) proportion. This bioconjugate was deposited onto a screen-printed carbon electrode previously modified with multi-walled carbon nanotubes (MWCNTs). Nanostructuration with MWCNTs enlarged the electrocatalytic activity and surface area, thus improving the biosensor performance. The BPA electrochemical reaction follows an EC mechanism at the optimum pH value of 5.0. Linearity up to 12 mu M, a sensitivity of (6.59 +/- 0.04) x 10(-2) mu A mu M-1 and a detection limit of 8.4 +/- 0.3 n M were obtained coupled with high reproducibility (relative standard deviations lower than 6%) and stability (87% of the initial response after one month). The developed biosensor was employed to the analysis of BPA in river water displaying appropriate accuracy (94.6-97.9%) and repeatability (3.1 to 6% relative standard deviations) proving its high potential applicability for in situ environmental analysis. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

In this work, the development of an electrochemical biosensor based on laccase from Trametes versicolor for the determination of BPA in river water was reported. The optimization of a bioconjugate and nanostructuration with multi-walled carbon nanotubes improved the biosensor performance, achieving high sensitivity, linearity, and stability. The developed biosensor showed great potential for in situ environmental analysis.