Biosensor bioreceptor

Biosensors play a significant role in the monitoring of a wide range of diseases and pathogens. A biosensor is an analytical device, which incorporates a biological recognition element or bioreceptor which is capable of sensing the presence. 

J. S. Schultz, Design of fibre-optic biosensors based on bioreceptors, in Biosensors Fundamentals andApplications (A. P. F. Turner, I. Karobe, and G. S. Wilson, eds.), Oxford University Press, New York (1987). 

The analytical device is represented by an amperometric biosensor able to monitor the evolution of photosynthetic 02, obtained by coupling a suited algal bioreceptor to a Clark electrode. The selected algal species is the marine filamentous cyanobacterium Spirulina subsalsa (Campanella [4]). Further details on the application of biosensors for integral toxicity... 

In a typical configuration of a DNA biosensor, the bioreceptor is an ssDNA called the capture probe that is immobilised by one of the methods described above. The analyte, a complementary ssDNA called... 

The reaction between the analjrte and the bioreceptor produces a physical or chemical output signal normally relayed to a transducer, which then generally converts it into an electrical signal, providing quantitative information of analytical interest. The transducers can be classified based on the technique utilized for measurement, being optical (absorption, luminescence, surface plasmon resonance), electrochemical, calorimetric, or mass sensitive measurements (microbalance, surface acoustic wave), etc. If the molecular recognition system and the physicochemical transducer are in direct spatial contact, the system can be defined as a biosensor [76]. A number of books have been published on this subject and they provide details concerning definitions, properties, and construction of these devices [77-82]. 

Biological Biosensors with thermally stable enzyme bioreceptors Quaternary structure modeling of known tertiary structures of related proteins 50... 

Entrapment methods of immobilization of bioreceptors utilized the lattice structure of particular base material. They include such methods as entrapment behind the membrane, covering the active surface of biosensors, entrapment within a self-assembled monolayers on the biosensor surface, as well as on freestanding or supported bilayer lipid membranes, and also entrapment within a polymeric matrix membranes, or within bulk material of sensor. All these mentioned methods are widely employed in design of biosensors. The essential condition of success of these methods of immobilization is preservation of sufficient mobility of substrate or products of biochemical reaction, involved in sensing mechanism, as matrix may act as a barrier to mass transfer with significant implications for... 

Biosensor Detection Systems Engineering Stable, High-Affinity Bioreceptors by Yeast Surface Display... 

Increased thermal stability of proteins used for biosensors is desirable to allow for robust devices that can withstand a variety of storage, assay, and regeneration conditions. In addition, some evidence suggests that starting from the most stable version of a bioreceptor by yeast surface display will aid in later affinity maturation efforts (38-40). In addition, thermally stable mutants can enable higher expression levels as soluble proteins from yeast or E. coli (19, 20, 38). Thermal stability selection rounds have been carried out on many of the proteins that were later mutated for high affinity (17,19-21, 38 2). 

This property has important implications on the characteristics of the biosensor, particularly as related to the supply rate of the analyte to the sensor. Thus for small sample volumes, the analyte may be depleted in the region of the sensor. Further, factors that affect the delivery of the analyte to the sensor, e.g. fouling of the sensor surface, can affect the sensor performance. The bioreceptors identified with cell signaling in immunology and pharmacology are usually nonconsuming in nature, and thus have fewer potential problems due to artifacts related to analyte consumption. 

As bioreceptors with unique recognition properties, this class of materials are becoming likely candidates for use in biosensors. Several research papers... 

Schultz J S 1987 Sensitivity and dynamics of bioreceptor-based biosensors... 

Fig. 5.17. A biosensor is comprised of a bioreceptor with a specific surface and a transducer to pass on a signal when recognition occurs.

The functioning of a biosensor can thus be summarised as shown in Fig. 5.18. The analyte is recognised by the bioreceptor, which is usually a protein such as an enzyme or antibody. The protein is in close proximity to the detector. This transduces the recognition event into a signal, which can be amplified and displayed. 

When the immobilized sensing reagent also contains a bioreceptor, such as an enzyme or an antibody, the device is regarded as a biosensor (23). Such sensors hold great promise as they exploit the inherent ability of the bio molecule to selectively and sensitively recognize a particular chemical spedesln a complex matrix. Enzyme-based sensors produce a signal due to a selective enzyme-catalyzed chemical reaction of an analyte and form a product that is detected by a transduction element in the sensor. The... 

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