Portable FRET Sensing of Proteins, Hormones, and Toxins Using DNA Aptamers and Quantum Dots
G.W. Jackson, U. Strych, E. Frank, R.C. Willson, R. Ballerstadt, R.J. McNichols
BioTex, Inc., US
Keywords: aptamers, quantum dots, insulin, thyroxine, anatoxin, sensing
Abstract:There is an urgent need to develop methods and devices that make the monitoring of any compound of interest in the public water system more reliable, more sensitive and more economical. We are developing a sensing chemistry based on rapidly responsive fluorescent resonance energy transfer, or FRET. In particular, we are using highly stable, highly fluorescent quantum dots for a variety of diagnostic and environmental sensing applications and have implemented the sensing chemistry in a format compatible with the parallel readout by an inexpensive, portable, and sensitive fluorometer. In our sensor, aptamers, small nucleic acid molecules, serve as the molecular recognition elements. These versatile DNA or RNA molecules can be obtained to any arbitrary target in a powerful in vitro process termed SELEX, or Systematic Evolution of Ligands by EXponential enrichment. The selected nucleic acid aptamers have a number of advantages over other molecular recognition elements such as antibodies. To demonstrate the feasibility of our sensing approach, we have evaluated a variety of compounds of concern, the protein insulin, the small molecule hormone, thyroxine (T4), and the potent cyanobacterial toxin, anatoxin-a. At present, we are implementing a sensor using recently selected aptamers against anatoxin-a, a potent neurotoxin produced by algal blooms of cyanobacteria and a concern for its potential use as a weapon of bioterrorism.