Individually addressable

OFETs constructed on a silicon wafer do not lake advantage of one of the main interest of organic materials, namely the possibility of building electronic devices on plastic substrates. A second important drawback of the silicon-based structure is the difficulty to individually address the gale of transistors built on the same wafer, which would prevent the achievement of integrated circuits. 

Electrochemical experiments have been carried out on materials deposited by PVD on silicon microfabricated arrays of Au pad electrodes [Guerin et al., 2006a]. The substrate is made up of a square silicon wafer capped with silicon nitride (31.8 mm x 31.8 mm), which has an array of 100 individually addressable Au pad electrodes. These electrodes make up a square matrix on the wafer, which can be masked when placed in a PVD chamber, allowing deposition of thin films on the Au electrodes. Figure 16.3 is a schematic drawing of the configuration. Small electrical contact pads in Au for the individual addressing of electrodes (0.8 mm x 0.8 mm) are placed on the boundaries. 

Figure 16.3 Silicon nitride pacified silicon wafer with an array of 100 individually addressable square Au electrodes.

K. Ramanathan, M.A. Bangar, M. Yun, W. Chen, A. Mulchandani, and N.V. Myung, Individually addressable conducting polymer nanowires array. Nano Lett. 4, 1237-1239 (2004). 

An isotopic labeling scheme based on pseudo-enantiomers that enabled the diastereomeric receptors to be individually addressed (by LC-MS) was also examined. This methodology enabled the direct identification of the amplified diastereomer and the measurement of its selectivity over the competing stereoisomers (Fig. 5.12). 

Electronically active chips (e.g.. Nanogen s NanoChip Electronic Microarray) are true microchips in which microelectrodes (pads) become elements of the array (Figure 2.13). The microelectrodes are covered with materials that allow immobilization of probes. Each electrode is individually addressable so that specific probes can be attached to different electrodes. Hybridization is accelerated by electromotive force (emf) on the target. Enhanced stringency is also achieved by modulation of the emf (Heller et al., 2000). 

Bompart et al. [125] reported the synthesis of composite nanoparticles of approximately 500 nm diameter consisting of a polymer core, a layer of gold nanoparticles attached to the core, and a few nanometers thick MIP outer layer (Fig. 13). These particles were used as individually addressable nanosensors, where surface-enhanced Raman spectroscopy was used to detect the binding of the target analyte, the beta-antagonist propranolol. A l,000x improved detection limit was... 

Different methods are described to construct ultramicro electrodes48-62 such as insulation in glass or epoxy resin, the construction of ultramicro electrode arrays (an array of individual ultramicro electrodes to increase the current signal without losing the benefits of ultramicro electrode behaviour) by template synthesis, metal depositions in pores of membranes and by using the connecting wires in microchips. The latter has the advantage that each ultramicro electrode is individually addressable. 

The specific electrochemical behaviour of IDAs is result of its design [97], i.e. two arrays intercalated and individually addressed in a bipotentiostatic system where reversible redox species can be cycled between one array (generator) and the other array (collector) (Fig. 32.3). The feedback obtained, greatly enhances the current and high sensitive detection can be achieved. An important application of IDAs is the electrochemical detection of p-aminophenol when it is generated from p-aminophenyl phosphate, by enzymatic reaction with alkaline phosphatase (like enzymatic label), in geno- [98-100] and immunoassays [101-103]. Another interesting feature of IDAs is the possibility of... 

As an example, Fig. 36.5 presents a calibration curve for the determination of Interleukin IB in plasma sample. The insert in Fig. 36.5 shows the row data obtained for the parallel detection of p-aminophenol in a series of eight individually addressable microchannels as a function of time, and the resulting calibration points are given by the slope at the origin of these different curves. 

Fig. 11.2 A 64-element, individually addressable, Ti electrode array on a 3" diameter quartz wafer for the synthesis of electrocatalyst libraries.

Using the solution-based procedure, we obtain fully covered substrates, while by the //CP-based procedure, discrete areas of coverage are patterned on the substrate, which is convenient in terms of microarray fabrication because different fluorophore probes can be placed on specific, discrete regions of the same glass substrate. Such an array could then be exposed to a guest solution and subsequently the surface fluorescence emission scanned by a confocal microscope for the simultaneous acquisition of the optical data from the individually addressable areas [60-63]. 

An individually addressable double-sided 1.5 inch AM-OLED display was recently presented by AU Optronics these are the thinnest OLED devices for mobile applications [60]. Samsung SDI has demonstrated a 17 inch UXGA-AMOLED display suitable for HDTV application in home entertainment [61]. 

Arrays of microelectrodes are being developed which may have individually addressable elements. For example, Kakerow et al. (1994) have produced arrays with as many as 400 individually accessible working microelectrodes in a chip with centimetre dimensions. These advances coupled with the... 

Ros, R., Schwesinger, F., Anselmetti, D., Kubon, M., Schafer, R., Pliickthun, A. and Tiefenauer, L. (1998) Antigen binding forces of individually addressed single-chain Fv antibody molecules. Proc. Nad Acad. Sci. U.S.A. 95, 7402-7405. 

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