Plasmon-Enhanced Electrochemical Biosensing of Hydrogen Peroxide from Cancer Cells by Gold Nanorods

The direct exploitation of generated hot charge carriers originating by localized surface plasmon resonance (LSPR) from a plasmonic metal nanostructure has been an important topic for enhancing the electrocatalytic activity; however, the influence of direct plasmon-accelerated electrocatalytic activity on biosensor device fabrication has not yet been well explored. In this work, cetyltrimethylammonium bromide-capped gold nanorods (AuNRs) were immobilized on a glassy carbon (GC) electrode to fabricate a biosensor device (AuNRs/GC) for the electrocatalytic detection of hydrogen peroxide (H2O2) under LSPR excitation (808 nm, 2 W cm–2). The sensor device exhibited dramatic improvement in the biosensing properties (∼2–4-fold) with a wide linear range from 5.0 μM to 5.0 mM, a lower detection limit of 1.8 μM, and sensitivity of 1.6 μA mM–1cm–2. The hot charge carriers were produced during plasmon decay and are one of the main reasons for the superior electrocatalytic activity, which directly related to the light wavelength, intensity, and solution pH, along with the attentive photothermal effect for enhanced electrocatalysis. The AuNRs/GC device was finally employed for cancer cell detection by detecting trace amounts of H2O2 released from cervical cancer cells (HeLa). The finding and concept reveals enhanced electrocatalytic performances by gold nanostructures under LSPR excitation and therefore assures it as a decent candidate for electrochemical energy conversion and electrochemical devices.