Kosuke Ino

We propose a novel electrochemical detection system for alkaline phosphatase (ALP) activity using the difference in water and oil solubilities between the substrate, ferrocene ethyl phosphate ester (FcEtOPO(3)(2-)), and the enzymatic product, ferroceneethanol (FcEtOH). In this system, water droplets containing ALP and FcEtOPO(3)(2-) were placed on a Pt disk microelectrode and surrounded by a mineral oil. By the ALP-catalyzed reaction, FcEtOPO(3)(2-) was converted to FcEtOH, which was then transf

We present a chip device with an array of 900 gourd-shaped microwells designed to pair single cells of different types. The device consists of interdigitated array (IDA) electrodes and uses positive dielectrophoresis to trap cells within the microwells. Each side of a microwell is on a different comb of the IDA, so that cells of different types are trapped on opposite sides of the microwells, leading to close cell pairing. Using this device, a large number of cell pairs can be formed easily and

Monitoring cellular activity: A local redox-cycling-based electrochemical chip device (see picture) has been used to entrap three-dimensional culture cells and evaluate their activity. Deep microwells were incorporated into the chip device for the trapping of embryoid bodies. This chip device is useful for the evaluation of 3D organ tissues.

In this study, we developed a novel method for fabricating microwell arrays constructed from alginate gels, and the alginate gel microwells were used for three-dimensional (3D) cell culture. The alginate gel microwells were fabricated on a patterned ITO electrode using alginate gel electrodeposition. Embryonic stem (ES) cells or hepatocellular carcinoma cells (HepG2) were cultured in the alginate gel microwells containing 3T3 cells. During the culture, embryoid bodies (EBs) or HepG2 spheroids we

Cell aggregates have attracted much attention owing to their potential applications in tissue engineering and drug screening. To evaluate cellular respiration of individual cell aggregates in these applications, noninvasive and on-chip high-throughput analytical tools are necessary. Electrochemical methods for detecting oxygen concentrations are useful because of their noninvasiveness. However, these conventional methods may be unsuitable for high-throughput detection because it is difficult to

An electrochemical device is proposed for high-throughput electrochemical detection that consists of 32 row and 32 column electrodes on a single glass substrate. The row and column electrodes are connected to interdigitated array (IDA) electrodes to form 1024 (32 × 32) addressable sensor points in the device. Electrochemical responses from each of the 1024 sensors were successfully acquired on the device within 1 min using redox cycling at individual IDA electrodes, which ensures application of

To investigate the effects of cell-cell interactions on cellular function, the microenvironment surrounding cells should be precisely controlled. Here, we describe a cell patterning technique, which utilizes magnetic force and magnetite nanoparticles. This method was used to develop cell culture arrays for investigation of cell behaviors in angiogenesis. Pin holder devices that contain more than 6,000 pillars on the surface are used for fabricating the cell culture arrays by setting it on a magn

Endocrine disruptors that act like hormones in the endocrine system might have toxic effects. Therefore, it is important to develop a portable device that can detect hormone active chemicals in samples rapidly and easily. In this study, a microfluidic device was developed for the detection of hormone active chemicals using genetically engineered yeast cells. The yeast cells were used as biosensors since they were genetically engineered to respond to the presence of hormone active chemicals by sy

A lab-on-a-chip device is described for the electrochemical detection of alkaline phosphatase (ALP) secreted by transformed single HeLa cells. Detection on the chip device is based on local redox cycling at 256 individually addressable sensor points. Ring-disk electrodes (generator/collector) are arranged at individual sensor points to amplify the signal due to redox-cycling with only 32 connector pads. The surface of each sensor point is modified with antibodies for secreted alkaline phosphatas

This review summarizes recent research progress in the development of micro/nanoelectrochemical probe and chip devices for the evaluation of three-dimensional (3D) cultured cells.

An electrochemical device, which consists of electrode arrays, nanocavities, and microwells, was developed for multi-electrochemical detection with high sensitivity. A local redox cycling-based electrochemical (LRC-EC) system was used for multi-electrochemical detection and signal amplification. The LRC-EC system consists of n(2) sensors with only 2n bonding pads for external connection. The nanocavities fabricated in the sensor microwells enable significant improvement of the signal amplificati

A new local redox cycling-based electrochemical (LRC-EC) device integrated with many electrochemical sensors has been developed into a small chip device. The LRC-EC chip device was successfully applied for detection of alkaline phosphatase and horseradish peroxidase activity in substrate generation/chip collection (SG/CC) and extended feedback modes, respectively. The new imaging approach with extended feedback mode was particularly effective for sharpening of the image, because this mode uses f

Here we propose a novel electrochemical lithography methodology for fabricating calcium-alginate hydrogels having controlled shapes. We separated the chambers for Ca²⁺ production and gel formation with alginate with a semipermeable membrane. Ca²⁺ formed in the production chamber permeated through the membrane to fabricate a gel structure on the membrane in the gel formation chamber. When the calcium-alginate hydrogels were modified with collagen, HepG2 cells proliferated on