Dual Gold-Nanoslit Electrodes for Ultrasensitive Detection of Antigen–Antibody Reactions in Electrochemical Surface Plasmon Resonance

Abstract

We present the use of surface charges in dual gold-nanoslit electrodes to improve the surface plasmon resonance (SPR) detection limit by several orders of magnitude. The SPR is directly generated by gold-nanoslit arrays in the two electrodes. The SPR shifts for both nanoslit arrays are measured simultaneously with a simple hyperspectral setup. When biomolecules are captured by specific antibodies on the dual electrodes, the surface charge is changed during the electrochemical process due to the increase in surface impedance. The push–pull-type electrodes generate opposite surface charges. Using the differences in both spectral shifts, the change in surface charge is detected sensitively. We demonstrate that using a [Fe­(CN)6]3–/4– redox process after antigen–antibody interactions, the dual nanoslit electrodes show an enhancement of the detection limit from 1 μg/mL to 10 pg/mL.

Design and Analysis of PtSe2 and Blue Phosphorus/MoS2 Heterostructure-Based SPR Biosensor

“…Surface plasmon resonance (SPR) sensors have received significant attention recently due to their profound influence on many scientific and industrial domains. , Due to their enhanced sensitivity in detecting even the slightest variations in refractive index (RI), these technologies have become essential in various applications, from biology to environmental monitoring. − The absence of labeling in SPR sensing streamlines experimental protocols and reduces the likelihood of modifying the characteristics of the analyte . This characteristic makes SPR sensing economically efficient and adaptable to many applications. , The capacity to see and analyze real-time interactions has significantly transformed drug development and molecular biology. − In addition, continuous progress in materials science and nanotechnology has enhanced sensor designs and performance, expanding their applications. Multiplexing capabilities allow for the concurrent detection of numerous analytes, augmenting their effectiveness in diagnostic applications and high-throughput screening processes; − the evolution of healthcare needs using SPR sensors has become indispensable in sensitive and expeditious diagnostics.…”

Non-fouling polymer brush grafted fluorine-doped tin oxide enabled optical and chemical enhancement for sensitive label-free antibody microarrays

“…[13][14][15] Even compared with the angle-scanning SPR based label-free immunoassay, the sensitivity of the OIRD chip is generally lower. [16][17][18] Therefore, it is of utmost importance to enhance the performance of OIRD based microarrays.…”