Droplet array on local redox cycling-based electrochemical (LRC-EC) chip device

Abstract

We have previously reported a local redox cycling-based electrochemical (LRC-EC) system for the incorporation of many electrochemical sensors into a small chip device. In the present study, a new type of LRC-EC chip device was fabricated for the detection of a droplet array. To detect electrochemically redox compounds in droplets, Pt pseudo-reference/counter electrodes were incorporated into the individual sensors of the LRC-EC chip device. Cyclic voltammetry for the LRC-EC chip device with internal Pt pseudo-reference electrodes indicated well-defined voltammograms based on redox cycling for the individual sensor points. The device was successfully applied to the addressable detection of alkaline phosphatase (ALP) activity of HeLa cells in single droplets on the sensor points. Therefore, the LRC-EC chip device is considered to be a useful device for the bioanalysis of droplet systems.

Microchemistry- and MEMS-based Integrated Electrochemical Devices for Bioassay Applications

“…The development of several types of electrochemical devices for bioassay applications, including analyses of yeast and mammalian cells, has been reported. [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] IDA electrodes were incorporated to amplify signals from cells and provide highly sensitive assays. Yeast cellbased IDA electrodes were utilized for the detection of hormone active chemicals.…”

“…To overcome this difficulty, we proposed a novel electrochemical approach based on redox cycling, the local redox cycling-based electrochemical (LRC-EC) system. [33][34][35][36][37][38][39][40][41][42][43][44] In the LRC-EC system, two arrays of electrodes (n rows and n columns of electrodes) are orthogonally placed to produce n 2 crossing points (Fig. 4).…”

“…To address these problems, planar comb-type IDA electrodes were incorporated into the LRC-EC device, which allowed for all electrodes to be arranged on a single substrate. [34][35][36][37][38][39][40] One of the LRC-EC devices has 1,024 sensors/41 mm 2 , 39 making the device well-suited for high-throughput amperometric detection and rapid electrochemical imaging. In addition, vertically separated electrodes were incorporated into the LRC-EC device to further increase the sensor density.…”

Molecular electrochemical switching element based on diffusive molecular competition for multipoint electrochemical detection of respiration activity of cell aggregates

“…Previously, we proposed a novel type of switching element based on molecular diffusion and an electrochemical reaction, andapplied it to an electrochemical imaging system [9][10][11][12][13].The switching element consists of twoelectrodes and a solution containing target molecules. One of the electrodes acts as a sensor for detection of the target molecules.…”

Nanocavity crossbar arrays for parallel electrochemical sensing on a chip

“…Implementations include systems, which consist of two wafers of parallel bar electrodes that are glued face-to-face to each other [17–18], arrays of ring–ring-based sensors with orthogonal feed lines [19], and designs featuring interdigitated electrodes at the intersections [20]. Reported applications include gene-function analysis [18], electroluminescence detection [21], mapping of cell topographies [22], detection of cellular enzyme secretion [19,23], detection of DNA hybridization [24], and evaluation of embryoid bodies [25]. …”