Award Information
Agency: Department of Health and Human Services
Branch: N/A
Contract: 2R44GM062100-02
Agency Tracking Number: GM062100
Amount: $1,037,403.00
Phase: Phase II
Program: SBIR
Awards Year: 2002
Solicitation Year: N/A
Solicitation Topic Code: N/A
Solicitation Number: N/A
Small Business Information
HUBZone Owned: N
Woman Owned: N
Socially and Economically Disadvantaged: N
Principal Investigator
 (919) 845-6324
Business Contact
Phone: (631) 205-9490
Research Institution
Molecular beacons are hairpin loops of DNA, conjugated to a fluorescent label at one end and a quencher at the other. Upon binding to a complementary target, the beacon opens, the fluorophore and quencher move apart, and fluorescence appears. Sensitivity is dependent upon the "signal-to-noise ratio" of fluorescence intensities in the open and closed conformations. Conventional dabcyl-quenched beacons give intensity ratios up to 100. However, the 1.4 nM Nanogold cluster yields intensity ratios up to several thousand, and since it absorbs over a wide range of wavelengths, can quench a variety of fluorophores. Improved gold nanoparticle quenchers will be prepared, using larger gold particles to achieve more effective quenching through surface plasmon coupling. Fluorescence quenching properties of these labels will be made reproducible through the synthesis of modified ligands which increase the solubility, stability and biological compatibility of he beacon, while introducing specific affinities for fluorophores to hold the gold particle and quencher closer together and increase quenching in the closed configuration. Purification methods will be developed and gold quenched DNA and PNA beacons will be compared with conventional analogs for rapid bacterial characterization. Prototype reusable biosensors will be fabricated by immobilizing gold-quenched beacons on fiber optic cables.

* Information listed above is at the time of submission. *

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