Biomedical electrodes

Platiaum and its alloys are also used as biomedical electrodes, eg, platiaum—indium wires for permanent and temporary pacemaker leads and defibrillator leads. Electrophysiology catheters, which contain platinum electrodes and marker bands, have been used to map the electrical pathways of the heart so that appropriate treatment, such as a pacemaker, can be prescribed. 

Since the 1970s, nerve surrounding electrodes have become the most successful types of implantable biomedical electrodes in clinical use. For example, they have been used for stimulation of the lower limb [12], the urinary bladder [13], and for recording neural signals [14,15]. Some electrodes have been safely in use for over 15 years [16]. They have been investigated intensively and many efforts have been made in respect to spatial selectivity and nerve fiber recruitment. 

Reference electrodes Biomedical electrodes Apphcations to cations, anions Coated wire/hybrids ISFETs and related Biosensors Gas sensors Amperometric sensors Modified electrodes Gas sensors Biosensors... 

Miller, H.A., Harrison, D.C., 1974. Biomedical Electrode Technology. Theory and Practice. Acad. Press. Morucci, J.-R, Valentinuzzi, M.E., Rigaud, B., Felice, C.J., Chauveau, N., Marsili, P.-M., 1996. Bioelectrical impedance techniques in medicine. Crit. Rev. Biomed. Eng. 24, 223—681. 

Figure 1. Components of Resting and Monitoring Biomedical Electrodes.

Free radicd polymerization of 2-acrylamido-2-methyl propane sulfonic add (Lubtizol s AMPs monomer) or its soluble salt also yields sheet form, ionically conductive adhesive for use in biomedical electrodes (13). This mat ial exhibits uniform conductivity preventing the hot spots associate with localized current Additionally, the AMPs -based materials are inheroitly electrically conductive, not requiring the use of additional additives (e.g., salts). 

Partially neutndized carboxylated polymer solutions can also be reacted with polyepoxides to crosslink via chemical bond formation yielding tacky electrically conductive hydrogels for biomedical electrodes (31). Low molecular weight di-, tri-, or tetraaldehydes react with N-(3-aminopropyl)methacrylamide/N-vinyl pyrrolidone copolymers to form chemically bonded crosslinks giving hydrogels, adhesives, and coatings (52). 

Uy, R. Dietz, T.M. Solid State Conductive Polymer Compositions, Biomedical Electrodes Containing Such Compositions, and Method of Preparing Same. U.S. Patent 5,385,679, Jan. 31, 1995. 

Dietz, T.M. Asmus, R.A. Uy, R. Two-Phase Composites of Icnically-Conductive Pressure-Sensitive Adhesive, Bimnedical Electrodes Using the Composites, and Methods of Preparing the Composite and the Biomedical Electrodes. U.S. Patent 5338,490, Aug. 16,1994. 

Czech, Z. Electrically Conductive Transient Pressure-Sensitive Adherive Hlms Process for their Production and Their Use in die Production of Biomedical Electrodes. U.S. Patent 5,433,892, July 18,1995. 

Meyerhoff, M. E. Fu, B. Bakker, E. et al. Polyion-Sensitive Membrane Electrodes for Biomedical Analysis, Anal. Chem. 1996, 68, 168A-175A. 

J Koryta (Ed), Use of Enzyme Electrodes in Biomedical Investigations, Wiley, Chichester, 1980... 

Most phenolic compounds are readily oxidized at carbon electrodes. The oxidation potentials vary widely depending upon the number of ring hydroxyl groups and their positions on the ring. Many compounds of biomedical and industrial interest are phenolic and LCEC based trace determinations are quite popular. 

Solsky, R. L. Ion-Selective Electrodes in Biomedical Analysis, in CRC Critical Reviews in Analytical Chemistry 14, 1 (1982)... 

Most important biomedical applications of ion-selective electrodes... 

Ion-selective electrode research for biomedical analysis is no longer the relatively narrow, focused field of identifying and synthesizing ionophores for improved selectivity and the integration of ion-selective electrodes into clinical analyzers and portable instruments. These efforts have matured now to such an extent that they can teach valuable lessons to other chemical sensing fields that are just emerging technologies. 

This field is therefore at an exciting stage. Ion-selective electrodes have a proven track record in terms of clinical and biomedical analysis, with a well-developed theory and a solid history of fundamental research and practical applications. With novel directions in achieving extremely low detection limits and instrumental control of the ion extraction process this field has the opportunity to give rise to many new bioana-lytical measurement tools that may be truly useful in practical chemical analysis. 

With the introduction of modern electronics, inexpensive computers, and new materials there is a resurgence of voltammetric techniques in various branches of science as evident in hundreds of new publications. Now, voltammetry can be performed with a nano-electrode for the detection of single molecular events [1], similar electrodes can be used to monitor the activity of neurotransmitter in a single living cell in subnanoliter volume electrochemical cell [2], measurement of fast electron transfer kinetics, trace metal analysis, etc. Voltammetric sensors are now commonplace in gas sensors (home CO sensor), biomedical sensors (blood glucose meter), and detectors for liquid chromatography. Voltammetric sensors appear to be an ideal candidate for miniaturization and mass production. This is evident in the development of lab-on-chip... 

Recently, our laboratory produced a foldable, bendable, and cutable postage-stamp-sized battery (Fig. 12.2). The device looks like a simple sheet of black paper, but it could spell a revolution in implantable battery technology (Pushparaj et al., 2007). The paper battery, a one-piece-integrated device is made of cellulose with CNT and lithium electrodes. The device is flexible, rechargeable, and has the ability to function over a wide range of temperatures giving it a wide variety of potential biomedical applications. As a biomaterial, this paper battery may be useful as a pacemaker because it could easily be inserted under a patient s skin. 

The most important applications of Ca " ISEs are in biomedical practice, especially in the determination of ionized calcium in serum. A pioneer work in this field was that by Moore [149] (see also [110,111]). At present the Ca ISE is used in the solvent polymeric version in a number of automatic devices for determining ionized calcium in serum, usually with periodic recalibration of the electrode and thermostatting to 37 °C. It should be noted that ISEs measure... 

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