Electrochemical Arrays for Bioassay Applications

Abstract

This chapter presents a survey of developments and bioassay applications of individually addressable electrochemical arrays covering the past two decades and including over 90 references. Many different array designs have been fabricated, from macroscopic devices that have two to four sensing elements to ultramicroelectrode arrays containing as many as 12,000 individually addressable micrometer-sized working electrodes. Some inexpensively fabricated arrays are intended for single sample analysis and are disposable, while others are encapsulated for incorporation into reusable microfluidic systems. Devices and assays are grouped according to the types of modifications done to the sensing elements, and sections are included to consider unmodified elements as well as modifications with enzymes, antibodies or antigens, nucleic acids, in addition to viable cells and tissues. Some trends have been identified, and possible future directions are suggested.

Electrochemical Microscopy Based on Spatial Light Modulators: A Projection System to Spatially Address Electrochemical Reactions at Semiconductors

“…All the ON statuses after crossing the polarizer beam splitter are collected by the focus lens ( 6) and finally projected onto the substrate situated in a three electrodes electrochemical cell (( 9) and ( 10) in Figure 2 and Figure 3). The focus lens (6) and the cell holder (9) sit on x-y-z traveling stages (8) to allow focusing and/or magnification/reduction of the projected image. To prevent damages to the liquid crystals, the net bias across it must equal zero over time, that is to say each ferroelectric liquid crystal micromirror must be switched ON and OFF intermittently.…”

“…[1][2][3][4][5] Addressing an electrochemical reaction with spatial resolution was originally done by the construction of individually-addressable electrochemical arrays, where each electrode is individually connected to an external power source or measuring instrument. 6 These arrays use considerable space for the pad connections and the geometry is pre-defined and restricted by the array design, giving limited flexibility to the experimentalist. Moreover, the construction of individually-addressable electrochemical arrays is an expensive and laborious task.…”