INDEX transduction mechanisms

Apart from the classification based on sensing mechanisms, biosensors are classified into three categories considering the transduction mechanism used. They are optical, electrochenfical, or electrical. The optical transduction mechanism includes fluorescence, chemilununescence, interferometry, and surface plasmon resonance. These techniques involve either the production of light from chemical reactions or the change in refractive index at the interface of biosensing materials. 

Noble metal nanoparticles can go beyond acting as labels recent advances show that changes in nanoparticle optical properties can act as the signal transduction mechanism in chemosensing and biosensing events. Van Duyne and coworkers have exploited the extreme LSPR sensitivity of NSL-fabricated nanoparticles to changes in local refiactive index in order to sense small molecules, amino acids, proteins, and antibodies. The LSPR shifts systematically to lower energies as the local dielectric constant increases ... 

Many bixxer compounds contain both hydrophobic and hydrophilic sites which can alter cell membranes through penetration. There is a correlation between bitter intensity and hydrophobicity-solubility indexes such as fee octanol/water partition coefficient, lo (7). Penetration may directly affect cAMP phosphodiesterase as part of fee transduction process (see below). A bitter receptor protein may be involved wife certain bitters, such as specific structural requirements wife fee bitter tasting dipeptides and denatonium salts (27). The latter is used in some consumer products to avoid accidental ingestion. A receptor mechanism is also supported by fee existence of a genetic "taste blindness" for some bitter materials (see below). 

---