Affinity biosensors derivatives

Antibodies, owing to their unparalleled ability to bind a diverse array of antigens with high affinity and specificity, are essential recognition reagents for numerous biosensor platforms. Most diagnostic immunoassays rely upon monoclonal or polyclonal antibodies derived from animals, and this source of recognition... 

A similar strategy was employed for an IP3 biosensor Pleckstrin homology (PH) domain of phospholipase C (PEG) 5i, which binds IP3 with a submicromolar affinity, was mutated to incorporate a cysteine residue next to the anion-binding site. Labeling with thiol-reactive fluorescein or aminonaphthalene derivatives gave anion... 

In the application of this biosensor to the detection of urinary metabolites of cocaine, there are certain advantages and limitations compared to standard chromatographic analysis. Although speed, convenience, and sensitivity are some of the advantages, the cross-reactivities of several cocaine metabolites and derivatives must be considered. It is evident that this mAb, if used in commercial kits for urine analysis, could detect cocaine at a 6-fold lower concentration than it would BE, against which the mAb was raised. The urine of a cocaine user contains primarily the major metabolite BE and very little cocaine (Devine et al., 1995). In addition, if the user ingests alcohol with cocaine the urine would also contain cocaethylene. In this situation, the high affinity that this mAb has for cocaethylene would result in as much as a 6-fold overestimate of the amount of BE in urine and consequently of cocaine administered by the user. The limited... 

As shown above, a broad optimization effort for the 9-position had led to the identification of p-chlorobenzamide as the best substituent ( 147, entry 63 in Table 7). Because the sheer enlargement of the hydrophobic group in the 2-position did not exhibit improved affinities (entries 6-12 in Table 7), the electron densities of the aromatic aglycones were altered in a next step (entries 4-9, Table 8) [81]. Then, with the substituents in the 2- and 9-positions set, a further optimization of the acyl group in the 5-position was conducted (entries 10-16). The binding properties of the neuraminic acid derivatives 155-167 again were evaluated with the hapten binding assay relative to sialoside 147. In addition, the dissociation constants Kjj were determined in a surface plasmon resmiance (SPR) based biosensor (Biacore) experiment [70]. 

Chemoreceptors are important bioanalytical tools because of their specific abilities in molecular recognition. Associated with a suitable receptor, a biosensor can detect proteins, toxins, hormones, chemical derivatives, or living cells, in both gaseous or liquid media. The weak dissociation constant of the complex formed (K 10 for the cobratoxin/acetylcholine-receptor complex, and K 10 ° for the insulin/insulin-receptor complex) means that such biosensors can be purified by affinity chromatography, and detect a specific ligand associated with the bioreceptor at extremely low concentrations. 

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