Tissue electrodes

Enzyme electrodes belong to the family of biosensors. These also include systems with tissue sections or immobilized microorganism suspensions playing an analogous role as immobilized enzyme layers in enzyme electrodes. While the stability of enzyme electrode systems is the most difficult problem connected with their practical application, this is still more true with the bacteria and tissue electrodes. 

F. Massei, F. Botre, G. Lorenti, G. Simonetti, F. Porcelli, G. Sdbona, and C. Botre, Plant tissue electrode for the determination of atrazine. Anal. Chim. Acta 316, 79-82 (1995). 

Tissue electrodes [2, 3, 4, 5, 45,57], In these biosensors, a thin layer of tissue is attached to the internal sensor. The enzymic reactions taking place in the tissue liberate products sensed by the internal sensor. In the glutamine electrode [5, 45], a thick layer (about 0.05 mm) of porcine liver is used and in the adenosine-5 -monophosphate electrode [4], a layer of rabbit muscle tissue. In both cases, the ammonia gas probe is the indicator electrode. Various types of enzyme, bacterial and tissue electrodes were compared [2]. In an adenosine electrode a mixture of cells obtained from the outer (mucosal) side of a mouse small intestine was used [3j. The stability of all these electrodes increases in the presence of sodium azide in the solution that prevents bacterial decomposition of the tissue. In an electrode specific for the antidiuretic hormone [57], toad bladder is placed over the membrane of a sodium-sensitive glass electrode. In the presence of the antidiuretic hormone, sodium ions are transported through the bladder and the sodium electrode response depends on the hormone concentration. 

For electrochemotherapy there is at this point only the Cliniporator equipment available (Carpi, IGEA, Italy). This generator allows simultaneous collection of voltage and current traces, and allows storage of treatment data, and is CE marked for clinical use. It works together with two types of needle electrodes as well as plate electrodes for cutaneous applications. It can also be used with endoscopic electrodes (Section 8.8.1), expandable soft tissue electrodes, and pin electrodes for bone metastases (Section 8.8.2). It can be used for gene therapy, as reviewed in [3]. 

To first obtain an ECG the patient must be physically connected to the amplifier front end. The patient/amplifier interface is formed by a special bioelectrode that converts the ionic current flow of the body to the electron flow of the metallic wire. These electrodes typically rely on a chemical paste or gel with a high ionic concentration. This acts as the transducer at the tissue-electrode interface. For short-term applications the use of silver-coated suction electrodes or sticky metallic foil electrodes are... 

If a repetitive signal is applied to the tissue electrodes via a high-pass filter, no DC polarization is possible. 

Reports on the use of monomeric MPc complexes for the electrocatalysis of phenols are rare, hence the use of some polymeric MPc complexes will be included in this section. Biosensors based on enzymes have been developed for many electrochemical analyses. The use of MPc complexes as part of the enzyme improves the sensitivities of the biosensors. Ozsoz et al. used CoPc monomer dispersed in mushroom tissue electrode as a catalyst for the analysis of phenolic compounds The enzymatic reaction between mushroom and the phenolic compounds was coupled with the catalytic activity of CoPc. The CoPc dispersed electrodes gave shorter response times and lower potentials compared to conventional tissue biosensors . 

Odaci D, Timur S, Telefoncu A (2004) Immobilized Jerusalem artichoke (Helianthus tuberosus) tissue electrode for phenol detection. Artif Cells Blood Substit Biotechnol 32 (2) 315-323. doi 10.1081/bio-120037836... 

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