Electrochemical immunoassays

D Orazio P (2003) Biosensors in cUnical chemistry, din Chim Acta 334 41-69 Warsinke A, Benkert A, ScheUer FW (2000) Electrochemical immunoassays. Fresenius J... 

Four major areas of electrochemistry related to medical diagnostics have been reviewed. Blood pH and gas measurements as well as ISE s represent relatively mature areas which enjoy widespread commercialization. New approaches should yield devices which have superior performance and which are less expensive to produce. Enzyme electrodes and electrochemical immunoassay arc still largely experimental, but the intense level of current research effort coupled with some interesting recent developments should lead to commercial success over the next decade. 

There are many other examples of competitive electrochemical immunoassays and immunosensors for detecting clinically important analytes [12-14], Despite simplicity, a disadvantage of competitive immunoassays is that labeling the analyte may reduce, or totally remove, its binding affinity for antibody. This would occur if the analyte were labeled at a site that is closely associated with an epitope. 

N.J. Ronkainen-Matsuno, J.H. Thomas, H.B. Halsall, and W.R. Heineman, Electrochemical immunoassay moving into the fast lane. TrAC, Trends Anal. Chem. 21, 213-225 (2002). 

M.S. Wilson and R.D. Rauh, Hydroquinone diphosphate an alkaline phosphatase substrate that does not produce electrode fouling in electrochemical immunoassays. Biosens. Bioelectron. 20, 276-283 (2004). 

L. Wu, J. Chen, D. Du, and H. Ju, Electrochemical immunoassay for CA125 based on cellulose acetate stabilized antigen/colloidal gold nanoparticles membrane. Electrochim. Acta 51, 1208-1214 (2006). 

FIGURE 14.4 (a) Particle-based electrochemical immunoassay protocol (i) introduction of antibody-... 

FIGURE 14.7 Schematic illustration of an electrochemical immunoassay based on die poly[G]-func-tionalized silica NPs on carbon electrode. Diamond stands for die mouse IgG Y shape for mouse antibody red strings for poly[G] (reproduced from [62] with permission) (see Plate 16 for color version). 

X. Mao, J.H. Jiang, J.W. Chen, Y. Huang, G.L. Shen, and R.Q. Yu, Cyclic accumulation of nanoparticles a new strategy for electrochemical immunoassay based on the reversible reaction between dethio-biotin and avidin. Anal. Chim. Acta 557, 159-163 (2006). 

Warsinke, A., Benkert, A., and ScheUer, F. W. (2000). Electrochemical immunoassays. Frese-nius J. Anal. Chem. 366, 622-634. 

Figure 11.15 Noncompetitive heterogeneous electrochemical immunoassay based on gold NP label and using ASV detection. Adapted from Ref. 50 with permission.

The reactive NP core provides an alternate use for catalytic NPs as sensitive electrocatalytic tags for biosensors. Brozik and coworkers have developed a reagentless electrochemical immunoassay by using electrocatalytic NP modified antibodies that are sensitive to the oxygen reduction reaction.74 Gold/palladium core-shell... 

Transducer materials for electrochemical immunoassay and analytical strategies... 

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