Bioluminescence-based electrochemical sensor for dual-mode direct hydrocarbon detection in saline water utilizing...

Early detection of hydrocarbon pollution in saline ecosystems faces challenges due to their complexity and the limitations of current detection methods. Salinity, temperature variations, the presence of other organic matter, and weathering processes hinder the effectiveness of traditional techniques, while the cost and complexity of some advanced detection technologies limit their widespread application. In this study, a gold screen-printed electrode (Au-SPE) modified with d-luciferin was developed to monitor the metabolic response of Photobacterium leiognathi to hexane and aromatic hydrocarbons in saline water and seawater. The sensor works by capturing adenosine triphosphate (ATP)-dependent electron release associated with bacterial bioluminescence, which varies according to the type of hydrocarbon. D-luciferin was immobilized on the Au-SPE via a self-assembled monolayer using ethylenediamine and EDC/NHS coupling to create a biocompatible interface. CV analysis revealed time-dependent shifts of anodic and cathodic peaks from -0.5 V to +0.5 V. The presence of aromatic hydrocarbons increased both bioluminescence light emission and current, indicating metabolic stimulation. In contrast, hexane suppressed bioluminescence and decreased current, indicating metabolic inhibition. These distinct responses enable rapid and selective differentiation between different types of hydrocarbons. The developed biosensor exhibits strong potential for real-time monitoring of oil contamination and assessing water quality in saline ecosystems.