A method for the convenient detection of lead at the parts-per-billion (ppb)-level has been developed; it uses a conventional compact disc (CD) as the platform for preparing DNAzyme assays and an unmodified optical drive of ordinary desktop/laptop computers as the readout device. In particular, by immobilization of Pb2+-specific DNAzyme sensing constructs on the “transparent side” of a conventional CD-R via mild surface reactions, the Pb2+ concentration can be determined by a free diagnostic program that checks the error distribution on the CD (i.e., it extracts the number of errors in a prerecorded audio file). The reading errors increase monotonically over a wide range of Pb2+ concentrations (from 10 nM to 1 mM), and the selectivity is confirmed by testing several other divalent cations (Zn2+, Ba2+, Mg2+, Ca2+, Cu2+, and Hg2+).
Figure. (a) Surface immobilization and reaction of DNAzyme sensors in the presence/absence of Pb2+.
(b) Digital reading with a conventional optical drive: the nanoparticles accumulated
at the binding sites block the reading laser and generate significant errors at zero or low Pb2+ concentrations.
Additional Information:
1 Author Information:Honglun Wang, Lily M. L. Ou, Yourui Suo, and Hua-Zhong Yu, Correspondence: hogan_yu@sfu.ca.
2 Published : February 10, 2011,Chemical Society, 2011, 83 (5), pp 1557–1563.