Optical detection of lead and potassium ions using a quantum-dot-based aptamer nanosensor.
Quantum-dot (QD) based nanosensors can be used to detect a wide range of molecules. This study examined a nanosensor comprised of thrombin binding aptamer (TBA) with 700NC InGaP QD on the 5 (') terminus and an Au nanoparticle quencher on the 3 (') terminus. Both K(+) and Pb(2+) bind to TBA, resulting in a conformational change that brings the Au quencher closer to the QD. Photoluminescence measurements indicated a decrease in fluorescence corresponding to an increase in either K(+) or Pb(2+) concentration. For healthy blood serum K(+) concentrations (3.5-5 mM), the beacon exhibited 15-17% quenching efficiency. Pb(2+) concentration of 0.48 μM, the threshold for toxicity in serum, yielded 14% quenching. The beacon's ability to detect changes in ion levels in a critical range of concentrations can make it an effective diagnostic tool.
Xenia
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Meshik
Ke
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Xu
Mitra
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Dutta
Michael A
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Stroscio
D052157:Aptamers, Nucleotide / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D006801:Humans; D007854:Lead / Q000097:blood* / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry*; D055620:Optical Phenomena; D000073718:Pancreatitis-Associated Proteins; D011188:Potassium / Q000097:blood* / Q000737:chemistry; D045663:Quantum Dots / Q000737:chemistry*
D052157:Aptamers, Nucleotide; D000073718:Pancreatitis-Associated Proteins; C000612141:REG3A protein, human; C081676:thrombin aptamer; D007854:Lead; D006046:Gold; D011188:Potassium