Monolayer antigen

I. Willner, R. Blonder, and A. Dagan, Application of photoisomerizable antigenic monolayer electrodes as reversible amperometric immunosensors. J. Am. Chem. Soc. 116, 9365-9366 (1994). 

Plates containing cell-bound antigens- Monolayers of cells grown in 96-well polystyrene (PS) plates (see Methods in Molecular Biology, Volume 5, Chapter 54 for detailed instructions)... 

The association of the DNP-Ab to the antigen-monolayer-functionalized electrode leads to the electrical insulation of the electrode support and to the introduction of an electron barrier at the electrode surface. Thus, in the presence of an electrically wired enzyme (e.g., ferrocene-tethered glucose oxidase), the bioelectrocatalytic current is inhibited upon the formation of... 

Blonder, R., Levi, S., Tao, G., Ben-Dov, L, and Willnet I. Development of anaperometric and microgravimetric immunosensors and reversible immunosensors using antigen and photoisomerizable antigen monolayer electrodes. J. Am. Chem. Soc. 1997, 119, 10467-10478. 

The combination of a photoisomerizable spiropyran and Ab-DNP was also applied in the development of reversible amperometric immunosensors.49 The amperometric immunosensor was based on a 6,8-dinitrospiropyran-assembled monolayer on an Au electrode (Figure 6b). When Ab-DNP associated with the spiropyran monolayer as the electrode, the electrode surface was insulated toward the solubilized redox probe, and its amperometric response decreased. After irradiation (360nmrinsed electrode revealed a high amperometric response, indicating that the Ab-DNP was washed off. Thus, the two-step illumination of the monolayer enables its reversible cyclic performance, which would demonstrate a general means for cyclic operation of an amperometric immunosensor. 

Hapten monolayer electrode sensor assembly was used to detect triazine in a flow injection analysis mode. The interaction of the electrode with different antibody concentrations resulted in the formation of an antibody-antigen (Ab-Ag) complex which insulated the electrode towards the [Fe(CN)6] /Fe(CN)6] " redox probe and diis in turn resulted in no charge transfer. The extent of insulation depends on the antibody concentration and the time of exposure to the antibody solution. The decrease in amperometric response of the antigenic monolayer to corresponding antibody solution for a fixed time produces a quantitative measurement of the antibody concentration. Typical responses obtained for cyanazine-hapten monolayer electrode to different antibody concentrations is shown in Figure 4. The lowest detection limit achieved for cyanazine sensor was 4.0 pg/ml at a response time of few minutes and a less-than 2% cross-reactivity to atrazine, simazine and other metabolites. 

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