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An integrated device consisting of a biological recognition element and a transducer capable of detecting the biological reaction and converting it into a signal which can be processed. Ideally, the sensor should be self-contained, so that it is not necessary to add reagents to the sample matrix to obtain the desired response. There are a number of analytes (the target substances to be detected) which are measured in biological media: pH, partial pressure of carbon dioxide (pCO2), partial pressure of oxygen (pO2), and the ionic concentrations of sodium, potassium, calcium, and chloride. However, these sensors do not use biological recognition elements, and are considered chemical sensors. Normally, the biological recognition element is a protein or protein complex which is able to recognize a particular analyte in the presence of many other components in a complex biological matrix. This definition has since been expanded to include oligonucleotides. The recognition process involves a chemical or biological reaction, and the transducer must be capable of detecting not only the reaction but also its extent. An ideal sensor should yield a selective, rapid, and reliable response to the analyte, and the signal generated by the sensor should be proportional to the analyte concentration.

Biosensors are typically classified by the type of recognition element or transduction element employed. A sensor might be described as a catalytic biosensor if its recognition element comprised an enzyme or series of enzymes, a living tissue slice (vegetal or animal), or whole cells derived from microorganisms such as bacteria, fungi, or yeast. The sensor might be described as a bioaffinity sensor if the basis of its operation were a biospecific complex formation. Accordingly, the reaction of an antibody with an antigen or hapten, or the reaction of an agonist or antagonist with a receptor, could be employed. In the former case, the sensor might be called an immunosensor.

Since enzyme-based sensors measure the rate of the enzyme-catalyzed reaction as the basis for their response, any physical measurement which yields a quantity related to this rate can be used for detection. The enzyme may be immobilized on the end of an optical fiber, and the spectroscopic properties (absorbance, fluorescence, chemiluminescence) related to the disappearance of the reactants or appearance of products of the reaction can be measured. Since biochemical reactions can be either endothermic (absorbing heat) or exothermic (giving off heat), the rate of the reaction can be measured by microcalorimetry. Miniaturized thermistor-based calorimeters, called enzyme thermistors, have been developed and widely applied, especially for bioprocess monitoring.

In the case of affinity biosensors, as is true of catalytic biosensors, many physical techniques can be used to detect affinity binding: microcalorimetry (thermometric enzyme-linked immunosorbent assay, or TELISA), fluorescence energy transfer, fluorescence polarization, or bioluminescence.

The quality of the results obtained from sensors based on biological recognition elements depends most heavily on their ability to react rapidly, selectively, and with high affinity. Antibodies and receptors frequently react with such high affinity that the analyte does not easily become unbound. To reuse the sensor requires a time-consuming regeneration step. Nonetheless, if this step can be automated, semicontinuous monitoring may be possible.

McGraw-Hill Concise Encyclopedia of Bioscience. © 2002 by The McGraw-Hill Companies, Inc.


(analytical chemistry)
An analytical device that converts the concentration of an analyte in an appropriate sample into an electrical signal by means of a biologically derived sensing element intimately connected to, or integrated into, a transducer.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.


A device that detects a person's body movement, temperature, pulse rate and other physical characteristics, which it converts into electronic signals. See lab on a chip, smart clothes, biowearable and data glove.
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References in periodicals archive ?
The report on the global Biosensors Development and Demand Market covers historical market trends, current market dynamics, market valuation by segmentation as well as region, country-level analysis for every segment, key player's market share analysis, competitive landscape and supply chain analysis.
Biosensors are devices that combine the sensing element (e.g.
THURSDAY, May 24, 2018 (HealthDay News) -- An ingestible micro-bio-electronic device (IMBED) could be used for in situ biomolecular detection based on environmentally resilient biosensor bacteria and luminescence readout electronics, according to a study published in the May 25 issue of Science.
A review of enzymatic uric acid biosensors based on amperometric detection.
Using antibodies as biosensors greatly reduces the time required for early detection.
Electrochemical biosensors are then a subclass of chemical sensors that use a biological recognition element (an enzyme, a protein, an antibody, etc.), which reacts selectively with the target analyte producing an electrical signal related to its concentration.
Understanding the redox behaviour and adsorption process of the DNA probe at electrochemical transducers is critical for the design and successful application of DNA-electrochemical biosensors [2-7, 9-11, 38-46].
Passive RF biosensors utilize either metamaterial elements such as ring resonators or rectangular/cylindrical cavity resonators [9, 10].
To date, very few studies on electrochemical biosensors for JE diagnosis have been reported.
Lately, photonic crystals biosensors have attracted intensive researches because ultra-compact size, high measurement sensitivity, flexibility in structural design, and more suitable for monolithic integration.
Recently, nanowires, nanotubes, and nanospheres as donors of electrical responses have been studied for minimized nanostructures in a field of biosensors. Nanoscaled biosensor devices can support in vivo applications, high sensitivity, and low limit concentration of detection [8].
Maryland Heights, MO, September 17, 2016 --( Biosensors Market 2013-2020 report estimates the global biosensors market to reach nearly USD 18.5 Billion in 2020, at a CAGR of 5.7% from 2016 to 2020 - iHealthcareAnalyst, Inc.