Dual Screen-Printed Carbon Electrode (2WE-SPCE) as Flexible Electrochemical Biosensors, CFEBDSPCE

A Dual Screen-Printed Carbon Electrode (Dual-SPCE) integrates two independently addressable carbon working electrodes (WE1, WE2) alongside a shared counter electrode (CE) and reference electrode (RE) on a single planar ceramic or polymer (PET) strip. This 4-electrode architecture allows multi-analyte quantification, in-situ background subtraction, or electrochemical signal amplification within a single micro-droplet sample (30–60 uL).

The standard footprint aligns the electrodes within a shared dielectric reaction well: (1) Working Electrodes (WE1 & WE2): High-purity graphite/carbon ink printed as adjacent semicircles, discs, or interdigitated/parallel microbands separated by an insulating gap (typically 0.5–1.5 mm). (2) Shared Counter Electrode (CE): Outer perimeter carbon band sized at 2 times to 4 times the combined area of WE1 + WE2 to avoid limiting the cell's current compliance. (3) Shared Reference Electrode (RE): Screen-printed Ag/AgCl track providing a unified potential baseline for both working channels.

The Primary Operating Modalities: (1) Multiplexed Detection: The dual potentiostat drives WE1 & WE2 at individual target potentials. It can be use for simultaneous quantification of two targets: e.g., WE1 functionalized with Glucose Oxidase and WE2 with Lactate Oxidase, or simultaneous stripping detection of two distinct heavy-metal pairs (Pb^{2+}/Cd^{2+} vs. Cu^{2+}/Hg^{2+}). (2) Differential / Background Subtraction: WE1 = Target sensing surface; WE2 = Non-functionalized or scrambled-probe control. It can eliminates non-specific interferents: In complex matrices (whole blood, saliva, environmental runoff), subtraction of the baseline signal (Δ I = I_WE1 - I_WE2) cancels out charging currents, matrix fouling, and electroactive interferents (ascorbic acid, uric acid). (3) Generator-Collector Mode: WE1 poised at oxidation potential; WE2 poised at reduction potential. An analyte oxidized at WE1 diffuses to the adjacent WE2, where it is reduced back to its original state and diffuses back to WE1. This continuous regenerative loop magnifies Faradaic current by an order of magnitude.

References:

1. H. Beitollahi, et al., Applications of electrochemical sensors and biosensors based on modified screen-printed electrodes: a review, Anal. Methods (2020) 12 (12): 1547–1560.
2. Keiichiro Yamanaka, et al. Printable Electrochemical Biosensors: A Focus on Screen-Printed Electrodes and Their Application, Analytical and Bioanalytical Chemistry, 2005, 382, 884–886.