Metal Ion Sensor with Catalytic DNA in a Nanofluidic Intelligent Processor
Abstract
Due to the numerous toxicological effects of lead, its presence in the environment needs to be effectively monitored. Incorporating a biosensing element within a microfluidic platform enables rapid and reliable determinations of lead at trace levels. This work pro-duced a microchip-based lead sensor that employs a lead-specific DNAzyme (also called catalytic DNA or deoxyribozyme) as a recognition element that cleaves its complementary substrate DNA strand only in the presence of cationic lead (Pb2+). Fluorescent tags on the DNAzyme translate the cleavage events to measurable, optical signals proportional to Pb2+ concentration. The DNAzyme responds sensitively and selectively to Pb2+, and immobilizing the DNAzyme in the sensor permits both sensor regeneration and lo-calization of the detection zone. The immobilized DNAzyme retains its Pb2+ detection activity in the microfluidic device and can be regenerated and reused. The particular DNAzyme shows no response to other common metal cations and the presence of these con-taminants does not interfere with the lead-induced fluorescence signal. Attempts were made to incorporate a second DNAzyme with selectivity for uranium in the same microfluidic chip sensor, to demonstrate multiplexing capabilities for multiple metal analytes in a single injection. Crosstalk between the lead DNAzyme and the uranium DNAzyme severely limited the utility of this multi-analytic chip.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 2011
- Accession Number
- ADA575220
Entities
People
- Donald M. Cropek
- Jonathan V. Sweedler
- Mark A. Shannon
- Paul Bohn
- Tulika S. Dalavoy
- Yi Lu
Organizations
- Engineer Research and Development Center