Local hydrogel fabrication based on electrodeposition with a large-scale integration (LSI)-based amperometric device

Abstract

Addressable electrode arrays are widely used in a number of applications, such as electrochemical imaging and high-throughput assays. Recently, large-scale integration (LSI) technologies have been used to prepare electrochemical devices containing signal amplifiers and switching elements, such that multiple highly sensitive sensors can be incorporated into these devices. Because these devices induce chemical reactions at the target electrodes, biomaterials such as hydrogels can be electrochemically fabricated. In this study, we present a new biofabrication strategy using the electrochemical device. We used an LSI device to locally electrodeposit chitosan hydrogels at the target electrodes, with the goal of fabricating the designed hydrogels. The hydrogels were fabricated via the generation of Cl2 at the anodes where a potential of 0.95 V was applied. The biofabrication method was utilized for three bioapplications. First, three-dimensionally designed chitosan hydrogels, for example apple-shaped and layered hydrogels were fabricated on this device by electrodepositing them for 10–30 s. In order to demonstrate biosensing, glucose oxidase and horseradish peroxidase were modified at the target electrodes through hydrogel electrodeposition; consequently, droplets containing glucose and H2O2 were electrochemically imaged at the same time using the electrochemicolor imaging technique we developed. Since this system can be used to fabricate hydrogels containing enzymes only at the target sensors, glucose and H2O2 were separately monitored. The detection limit of glucose was less than 0.5 mM. In addition, the chitosan hydrogels were electrodeposited only in the target areas such that cells only adhering at unmodified areas, resulting in cell patterning. We show that the LSI device is useful for the fabrication of local hydrogels for several bioapplications such as biosensing and cell culturing.