Biosensors/biosensing

In Vivo Biosensing. In vivo biosensing involves the use of a sensitive probe to make chemical and physical measurements in living, functioning systems (60—62). Thus it is no longer necessary to decapitate an animal in order to study its brain. Rather, an electrochemical biosensor is employed to monitor interceUular or intraceUular events. These probes must be small, fast, sensitive, selective, stable, mgged, and have a linear response. 

NADH. Immobilized redox mediators, such as the phenoxazine Meldola Blue or phenothiazine compoimds, have been particularly useful for this purpose (20) (see also Figure 4-12). Such mediation should be useful for many other dehydrogenase-based biosensors. High sensitivity and speed are indicated from the flow-injection response of Figure 3-21. The challenges of NADH detection and the development of dehydrogenase biosensors have been reviewed (21). Alcohol biosensing can also be accomplished in the presence of alcohol oxidase, based on measurements of the liberated peroxide product. 

Mainly, two principles are used in electrochemical pesticide biosensor design, either enzyme inhibition or hydrolysis of pesticide. Among these two approaches inhibition-based biosensors have been widely employed in analysis due to the simplicity and wide availability of the enzymes. The direct enzymatic hydrolysis of pesticide is also extremely attractive for biosensing, because the catalytic reaction is superior and faster than the inhibition [27],... 

The applications of nanoparticles in biosensors can be classified into two categories according to their functions (1) nanoparticle-modified transducers for bioanalytical applications and (2) biomolecule-nanoparticle conjugates as labels for biosensing and bioassays. We intend to review some of the major advances and milestones in biosensor development based upon nanoparticle labels and their roles in biosensors and bioassays for nucleic acids and proteins. Moreover, we focus on some of the key fundamental properties of certain nanoparticles that make them ideal for different biosensing applications. 

Hu, Y., et al., Green-synthesized gold nanoparticles decorated graphene sheets for label-free electrochemical impedance DNA hybridization biosensing. Biosensors and Bioelectronics,... 

Gutes, A., C. Carraro, and R. Maboudian, Single-layer CVD-grown graphene decorated with metal nanoparticles as a promising biosensing platform. Biosensors and Bioelectronics,... 

Figure 3.1 — (A) Configuration of p-nitrophenyl phosphate biosensor (a) common end of bifurcated bundle b) retaining 0-ring (c) inner nylon mesh with enzyme (d) outer nylon mesh (not drawn to scale). (B) Processes occurring at the biosensing tip a enzyme/scatter layer S enzymatic substrate P light absorbing product. (Reproduced from [34] with permission of the American Chemical Society).

Qian Z, Tan TC (1998) A model for multicomponent biosensing and its application to dead-base BOD biosensor. Chem Engineer Science 53 3281-3294... 

---