Anionic conjugated polyelectrolyte

Microsphere coated with Ga and an anionic-conjugated polyelectrolyte... 

Recently another approach for the detection of protease activity by using fluorescent quenching of a conjugated polyelectrolyte was reported [52] (Figure 13.9). This assay utilizes a covalent attachment of the quencher-labeled peptide substrate to the anionic-conjugated polyelectrolyte and combines the... 

FIGURE 13.16 Description of the detection of amyloid fibrils in proteins with an anionic conjugated polyelectrolyte. (From Nilsson, K.P.R., Herland, A., Hammarstiom, R, and Inganas, O., Biochemistry, 44, 3718, 2005.)... 

Schanze et al. have described the layer-by-layer (LBL) fabrication of multilayer films and photovoltaic cells using poly(phenylene ethynylene)-based anionic conjugated polyelectrolytes as electron donors and water-soluble cationic fuUerene C ) derivatives as acceptors [44]. LBL film deposition was found to be linearly related to the number of bUayers, as monitored by UV/vis absorption. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) of the mtiltilayer... 

Similar assays for measuring protease activity were also reported by Whitten and coworkers [49], These assays utilize polystyrene microspheres that are coated with streptavidin (a biotin-binding protein) and a biotinylated anionic fluorescent conjugated polyelectrolyte or a cationic polyelectrolyte, A biotinylated quencher-labeled peptide serves as a substrate for the enzyme and when mixed with the microspheres, a strong complex similar to the one in the DNA assays described in Section 13,3,1, through the biotin-avidin interaction is created [49], A schematic drawing of the assay is shown in Figure 13,7,... 

Microspheres coated with streptavidin and biotinylated anionic-conjugated electrolytes are presented to a quencher-labeled biotinylated peptide substrate. Quenching of the fluorescence from the conjugated polyelectrolyte occurs as the peptide binds to the microsphere. The quencher is removed when the peptide is cleaved by the protease, detected as enhancement of the fluorescence from the conjugated polyelectrolyte. The assay can also be used with a cationic-conjugated polyelectrolyte and solution sensors based on a polyelectrolyte--avidin ensemble were also reported [49], These... 

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