Microelectrode array structures

The diamond growth can also be patterned to produce microelectrode array structures [18,19]. Several possible microstructures are possible, such as microbands, microdiscs, and microcolumns. Micropyramids are another microstructure that can be produced, and an image of such an array is shown in Fig. 5. The SEM image reveals a monolithic diamond-tip array. The tips are ca. 2 pm in base diameter and are equally positioned over the surface with a spacing of ca. 5 pm. 

The strong and specific biotin-streptavidin binding was used to assemble biomolecule-functionalized nanoparticles in multilayered structures.67 Application of an electrical field allowed the assembly of multilayer structures by using extremely low concentrations of nanoparticles with minimal nonspecific binding. A microelectrode array was used to facilitate the rapid parallel electrophoretic transport and binding of biotin- and streptavidin-functionalized fluorescent nanoparticles to specific sites. By controlling the current, voltage, and activation time at each nanoparticle adsorption step, the directed assembly of more than 50 layers of nanoparticles was accomplished within an hour. 

Bai, Q., Wise, K.D., and Anderson, D.J. A high-yield microassembly structure for three-dimensional microelectrode arrays. IEEE Trans. Biomed. Eng. 2000 47 281-289. 

A minimally invasive microelectrode array intended for high-resolution multichannel recordings of electromyographic signals has been developed [88]. As the structural substrate parylene-C was chosen, the device should be extremely flexible. The steps of fabrication are shown in Figure 2.12. 

Figure 5.4 All-diamond coplanar micro-and macroelectrodes, (a) Multiple microelectrode array formed from machining pillar structures in free-standing BDD, overgrowing with insulating diamond, and then polishing flat to reveal a coplanar structure. SEM side on view of cross-sectioned microelectrode array. (Taken from Ref. [50] with permission.) (b) Atomic Force Microscopy (AFM) topography image of one of the electrodes in the array the location of the BDD microdisk ultramicroelectrode is clearly visible. (Taken...

Fig. 2 A planar 64-microelectrode array, similar to those used in the development of the electronic Petri dish, with a series of connectors allowing electrical signals to be obtained from the central cellular playground. The device was produced using the methods shown in Fig. 1 in order to develop structures of the type shown in Fig. 3.

James, C. D., R. Davis et al. 2000. Ahgned microcontact printing of micrometer-scale poly-L-lysine structures for controlled growth of cultured neurons on planar microelectrode arrays. IEEE Transactions on Biomedical Engineering 47(1) 17-21. 

In Situ Characterization of Stimulating Microelectrode Arrays Study of an Idealized Structure Based on Argus II Retinal implants... 

In order to further characterize the Argus II electrode array, we fabricated a 9-electrode array structure that mimics any subset of 9 (3 x 3) electrodes in the Argus II pattern (Fig. 5). However, unlike the Argus n which contains closely packed microelectrode traces that are in the plane of the array, the traces of the... 

Metal nanoparticles housed in zeolites and aluminosilicates can be regarded as arrays of microelectrodes placed in a solid electrolyte having shape and size selectivity. Remarkably, the chemical and electrochemical reactivity of metal nanoparticles differ from those displayed by bulk metals and are modulated by the high ionic strength environment and shape and size restrictions imposed by the host framework. In the other extreme end of the existing possibilities, polymeric structures can be part of the porous materials from electropolymerization procedures as is the case of polyanilines incorporated to microporous materials. The electrochemistry of these types of materials, which will be termed, sensu lato, hybrid materials, will be discussed in Chapter 8. 

Figure 14.2.4 More complex modified electrode structures based on electroactive polymers, (a) Sandwich electrode (b) array electrode (c) microelectrode d, e) bilayer electrodes if) ion-gate electrode. [Reprinted with permission from C. E. D. Chidsey and R. W. Murray, Science, 231, 25 (1986), copyright 1986, American Association for the Advancement of Science.]...

Richard Normann from the University of Utah spoke about his electrode arrays, which have been used to record both acute and chronic electrophysiological recordings from various brain structures in monkeys, cats, and rats [5]. The standard array is a 4.2-mm square grid with 100 silicon microelectrodes, 1.0 mm long, and a spacing of 0.4 mm (see Figure 35.3). Dr. Normann also spoke about his new Utah Slant Array (USA) electrodes, which have been used to record signals from peripheral nerve. 

Figure 2.30. Design of microelectrodes. Left needle with a microdisk centre interdigitated structure right stiletto shaped array...

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