A new fluorometric enzyme immunoassay for 17beta-estradiol (E2) using biotinylated estradiol (BE) as a probe ligand, is described. In this method, E2 is detected indirectly by a solid-phase avidin-biotin binding assay, in which the biotin is immobilized on a microtiter plate (biotin-plate). After the competitive reaction between E2 and BE for the anti-E2 antibody in solution, the free E2 and BE...

We describe a method for the preparation of novel long (hundreds of nanometers), uniform, inter-molecular G4-DNA molecules composed of four parallel G-strands. The only long continuous G4-DNA reported so far are intra-molecular structures made of a single G-strand. To enable a tetra-molecular assembly of the G-strands we developed a novel approach based on avidin-biotin biological recognition. ...

An electrotextile with a biosensing focus composed of conductive polymer coated microfibers that contain functional attachment sites for biorecognition elements was developed. Experiments were conducted to select a compound with a pendant functional group for inclusion in the polymer, a fiber platform, and polymerization solvent. The effects of dopant inclusion and post-polymerization wash step...

Metalloenzymes and electron transfer proteins influence the electrochemical properties of metal cofactors by controlling the second-sphere environment of the protein active site. Properties that tune this environment include the dielectric constant, templated charge structure, van der Waals interactions, and hydrogen bonds. By systematically varying the binding of a redox-active ligand with a p...

Calmodulin derivatives, specifically biotinylated in domains I and III, were synthesized to address the structures of calmodulin necessary for binding to its target enzymes in active conformations. By binding avidin to these biotinylated calmodulins, the role of specific sequences of the calmodulin molecule in target enzyme interactions could then be evaluated. The role of domain I in these int...

Biotinylated anti-C-reactive protein (CRP) species were attached to the surface of streptavidin-coated magnetic beads (MB) and avidin-coated polystyrene microspheres/beads (PSB) entrapping a large number of electrogenerated chemiluminescence (ECL) labels ( approximately 10(9) Ru(bpy)(3)[B(C(6)F(5))(4)](2)/bead) to form anti-CRP<-->MB and Ru(II) subsetPSB/avidin<-->anti-CRP conjugates, respectiv...

Dual labeled liposomes, carrying both paramagnetic and fluorescent lipids, were recently proposed as potent contrast agents for MR molecular imaging. These nanoparticles are coated with poly(ethylene glycol) (PEG) to increase their blood circulation half-life, which should allow extensive accumulation at the targeted site. To eliminate nonspecific blood pool signal from the MR images, the circu...

Fluorescence resonance energy transfer (FRET) using biotinylated β-galactosidase (βGAL) as a donor and Alexa Fluor 350 (AF350) labeled avidin as an acceptor has been investigated by means of steady-state fluorescence and time-resolved fluorescence spectroscopy. The donors are readily paired with acceptors through the well-established binding affinity of biotin and avidin. The fluorescence energ...

The avidin-biotin interaction permits rapid and nearly irreversible noncovalent linkage between biotinylated molecules and avidin-modified substrates. We designed a biotinylated radioligand intended for use in the detection of avidin-modified polymer nanoparticles in tissue with positron emission tomography (PET). Using an F-18 labeled prosthetic group, [(18)F]4-fluorobenzylamine, and a commerc...

In this work, we have prepared three types of aptamer-conjugated Rubpy-doped silica nanoparticles for Human breast carcinoma MCF-7 cells labeling. Probe A is prepared through covalent conjugation between amine-labeled MUC-1 aptamer and carboxyl-modified Rubpy-doped NPs (NPs-aptamer). Probe B is prepared based on the interaction between biotin-labeled MUC-1 aptamer and avidin-conjugated Rubpy-do...