Streptavidin-gold

Fig. 35 TEM image of peptide fibres coated with streptavidin-gold nanoparticles, (a, b) Peptides with biotin directly attached (using SAF-pl-biotin) particles are 10 nm, (c) Peptide fibre with biotinylated anti-FLAG antibody attached that was then bound to gold-labelled streptavidin particles are 5 nm. Reprinted with permission from Ryadnov and Woolfson [76]. Copyright 2004 American Chemical Society...

A similar protocol has been used by Bonnard et al. (1984) in the preparation of streptavidin-gold probes. 

Centrifuge the streptavidin-gold suspension at a minimum of 50,000 g for several hours to remove excess protein solution. 

Streptavidin-gold conj ugate. streptavidin conjugated to 1.0-nm gold particles... 

Add 100 pL of TBST containing 1 ng/mL of streptavidin-gold, and incubate at room temperature for 30 min. 

Preparation of Avidin-Gold or Streptavidin-Gold Complexes... 

Avidin-gold or streptavidin-gold conjugates can be used to detect, localize, or quantify the binding of biotinylated molecules in cells, tissue sections, or blots (Morris and Saelinger, 1984 Bonnard et al., 1984 Gillitzer etal., 1990 Bronckers et al., 1987)... 

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). 

---