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Bio-FETs couple a transistor device with a bio-sensitive layer that can specifically detect bio-molecules such as nucleic acids and proteins. A Bio-FET system consists of a semiconducting field-effect transistor that acts as a transducer separated by an insulator layer (e.g. SiO 2) from the biological recognition element (e.g. receptors or probe molecules) which are selective to the target ...
Biosensors based on type of biotransducers. A biotransducer is the recognition-transduction component of a biosensor system. It consists of two intimately coupled parts; a bio-recognition layer and a physicochemical transducer, which acting together converts a biochemical signal to an electronic or optical signal.
Biosensors used for screening combinatorial DNA libraries. In a biosensor, the bioreceptor is designed to interact with the specific analyte of interest to produce an effect measurable by the transducer. High selectivity for the analyte among a matrix of other chemical or biological components is a key requirement of the bioreceptor.
Various materials can be made into the transduction element, including silver, gold, graphite or nanoparticle variations of such materials. Detection of electrochemical property changes allows for real-time analysis and kinetics data, an advantage biosensor methods such as optical biosensors lack.
An electro-switchable biosurface is a biosensor that is based on an electrode (often gold) to which a layer of biomolecules (often DNA molecules) has been tethered. An alternating or fixed electrical potential is applied to the electrode which causes changes in the structure and position (movement) of the charged biomolecules.
Invented in 1970, the ISFET was the first biosensor FET (BioFET). The schematic view of an ISFET. Source and drain are the two electrodes used in a FET system. The electron flow takes place in a channel between the drain and source. The gate potential controls the flow of current between the two electrodes.
To prepare for BLI analysis between two unique biomolecules, the ligand is first immobilized onto a bio compatible biosensor while the analyte is in solution. [5] Shortly after this, the biosensor tip is dipped into the solution and the target molecule will begin to associate with the analyte, producing a layer on top of the biosensor tip.
Amperometric biosensors have been used in bio-MEMS for detection of glucose, galactose, lactose, urea, and cholesterol, as well as for applications in gas detection and DNA hybridization. [11] In potentiometric biosensors, measurements of electric potential at one electrode are made in reference to another electrode. [ 11 ]