Colloid detection protocol

FIGURE 14.5 Multiprotein electrical detection protocol based on different inorganic colloid nanocrystal tracers, (a) Introduction of antibody-modified magnetic beads (b) binding of the antigens to the antibodies on the magnetic beads (c) capture of the nanocrystal-labeled secondary antibodies (d) dissolution of nanocrystals and electrochemical stripping detection (reproduced from [29] with permission). 

This protocol was extended to other inorganic colloids (e.g., ZnS, PbS), and it was pointed out that such extension paves the way to an electrochemical coding technology for the simultaneous detection of multiple DNA targets based on nanocrystal tags with diverse redox potentials [148]. 

Protein-labeled colloidal gold probes suit as well as for immuno-histochemistry in electron microscopy as for detection of antigens or glycoproteins on blots. There are several protocols for enhancement of electron density and visible color resulting in higher sensitivity. 

Much more work has been undertaken with colloidal nanoparhcles over the past decades for developing various protocols for detecting neurochemicals and their metabolites. Recently it has even been shown that this SERS strategy can be used to image dopamine and norepinephrine release in cells [318] demonstrahng the potential of the technique. However, issues with fast detechon for five cell work and selectivity shll remain. 

The protocol is similar to that described in Subheading 3.1, and differences are clarified as below. In this case, anti-CL mAb IgG is conjugated with colloidal gold and the hapten conjugate, BSA-CL, is used on the test line. A positive standard sample of the hapten is required for the quantitive detection. 

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