Streptavidin gold labeling

Fig. 34 Functionalisation of bait peptides. I Gold-labelled streptavidin is attached directly. 2 Biotin-labelled anti-FLAG antibody is bound to the FLAG on the peptide (reaction b) and this is used to attach gold-labelled streptavidin (reaction d). Reprinted with permission from Ryadnov and Woolfson [76]. Copyright 2004 American Chemical Society...

Tris(hydroxymethyl)methylamine (TRIS), sodium chloride, sodium citrate, ethylenediamine tetraacetic acid disodium salt (EDTA), lithium chloride, Tween 20, streptavidin 10 nm colloidal gold labelled, hydrochloric acid (37%), nitric acid, streptavidin-coated paramagnetic beads (MB) with a diameter of 2.8 pm, Dynabeads M-280 Streptavidin (Dynal Biotech, Oslo, Norway) biotinylated probe oligonucleotides which sequences are shown in Table 53.1. 

Add to the previous suspension (50 pL of MB/BC-A conjugate) the desired amount of BC-T (target DNA). Incubate at 42°C for 15 min and 800 rpm in TS-100 Thermo Shaker in order to carry out the hybridization reaction. Wash the formed MB/BC-A/BC-T conjugate twice with 100 pL of TT buffer and resuspend in 20 pL of TTL buffer. It is ready for adding streptavidin-gold nanoparticles (Au-NPs) label. 

Gold labeling may be used in the recently introduced catalyzed reporter deposition-immunogold technique where biotinylated tyramide molecules are attached the antibody-antigen complex site the biotinylated sites are visualized by interaction with streptavidin-gold (46,47). 

Briefly, the sandwich type assay consists in the incubation of streptavidin-coupled-MB with an antihuman IgG biotin conjugate, and then, the immunological reaction with the human IgG antigen takes place. After that, a gold labeled anti-human IgG reacts with the antigen, and finally the AuNPs are elec-trochemically detected. 

Figure 3.9 Schematic representation of the typical noncovalent CNT functionalizations and the hybrid approach by using pyrene linkers. The figure also shows transmission electron images of SWNT modified with streptavidin labeled with 10 nm gold nanoparticles that were covalently coupled to pyrene linkers that were stacked on...

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