Biological recognition elements

Biological recognition systems offer exquisite selectivity and sensitivity. A vast range of approaches has been described [42,43]. 

Enzyme sensors can measure analytes that are the substrates of enzymatic reactions. Thermometric sensors can measure the heat produced by the enzyme reaction [31], while optical or electrochemical transducers measure a product produced or cofactor consumed in the reaction. For example, several urea sensors are based on the hydrolysis of urea by urease producing ammonia, which can be detected by an ammonium ion-selective ISE or ISFET [48] or a conductometric device [49]. Amperometric enzyme sensors are based on the measurement of an electroactive product or cofactor [50] an example is the glucose oxidase-based sensor for glucose, the most commercially successful biosensor. Enzymes are incorporated in amperometric sensors in functionalised monolayers [51], entrapped in polymers [52], carbon pastes [53] or zeolites [54]. Other catalytic biological systems such as micro-organisms, abzymes, organelles and tissue slices have also been combined with electrochemical transducers. 

Despite their advantages of specificity and selectivity, biosensors suffer from a severe disadvantage, the instability of the biological recognition system, which makes storage and operation in harsh chemical environments problematic. This problem has been addressed using a newly developed sensor with injected recognition element biosensors (whose operational principle is based on the one time use 

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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. 

A biosensor is an analytical device comprising a biological recognition element directly interfaced to a signal transducer, which together relates the concentration of... 

Immobilization of Biological Recognition Elements Over Nanophotonic Biosensors... 

Metal NPs have received tremendous attention in the field of bio-analytical science, in particular the sequence-specific DNA detection [23,24]. This is attributed to their unique properties in the conjugation with biological recognition elements (e.g., DNA oligonucleotide probe) as well as in the signal transduction with optical [22,25], electrical [26], microgravimetric [27] and electrochemical [23,28-30] methods. 

Compound selectivity with the use of a specific biological recognition element... 

Generally, the application of a sensor system is determined by the chemical or biological recognition elements. They have to fulfill the following requirements ... 

Biosensors are particular types of chemical sensors that specifically utilize a biological recognition element, converting biochemical signals into quantifiable electrical signals. In biosensors, the recognition element is typically an immobilized... 

Biological receptors can include chemically and genetically modifled enzymes, new types of antibodies with high afiinity and selectivity for small molecules, natural or artiflcial receptors or complex biological recognition elements. 

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