Two approaches for addressing electrochemical electrode arrays with reduced external connections

Abstract

Although patterning hundreds or thousands of electrochemical electrodes on lab-on-a-chip devices is straightforward and cost-effective using photolithography, easily making connections between hundreds of electrodes and external amplifiers remains a bottleneck. Here we describe two electrode addressing approaches using multiple fluid compartments that can potentially reduce the number of external connections by ~100-fold. The first approach enables all compartments on the device to be filled with solution at the same time, and then each fluid compartment is sequentially electrically activated to make the measurements. The second approach achieves lower measurement noise by sequentially filling recording chambers with solution. We propose an equivalent circuit to explain measurement noise in these recording configurations and demonstrate application of the approaches to measure quantal exocytosis from individual cells. A principle advantage of using these approaches is that they reduce the fraction of the microchip area that needs to be dedicated to making external connections and therefore reduces the cost per working electrode.

Surface-modified CMOS IC electrochemical sensor array targeting single chromaffin cells for highly parallel amperometry measurements

“…Although the devices enable amperometry and TIRF imaging simultaneously, these arrays rely on external amplifiers and are not suitable for large scale parallel recordings of many cells. Two approaches were developed to multiplex the outputs and reduce external connections [49]. However, the approaches still require external amplifiers and due to the need of external connections, the size of the array is not scalable.…”

A sandwich-type bacteriophage-based amperometric biosensor for the detection of Shiga toxin-producing Escherichia coli serogroups in complex matrices

“…The dimension of the working electrode strongly inuenced the noise and stability of the sensor, such as the noise was directly proportional to the electrode area. 51,52 Though the working electrode had a diameter of only 4 mm, the transducer-induced noise highly likely originated from the thermal motion of ions in the electrolyte-electrode interface where electrode pores created a frictional environment. 53 Another possibility was power line interference pickup, which contributed to the overall background noise; therefore, it was recommended to insulate all microelectrode connections.…”

Electrochemical measurement of quantal exocytosis using microchips

“…In the case when the potentiostats are external to the chip, there are practical limitations to the number of electrodes that can be recorded from due to the cost and complexity of developing instruments with many dozens of potentiostats as well as making all the connections through microchip bonding pads. Approaches to reduce the number of external connections and amplifiers include placing multiplexer electronics on the microchip (27), or addressing banks of electrodes isolated from each other in separate fluid compartments (95).…”