Herein, we applied hypericin (Hyp) for the detection of DNA on streptavidin-functionalized magnetic beads (SA-MB) through non-covalent π-π stacking interaction between 1-pyrenebutanoic acid (PBA) and Hyp. Briefly, the target DNA (tDNA) was hybridized to morpholino oligonucleotide (MO) that was immobilized on the surface of SA-MB. PBA was incorporated to the backbone of tDNA by means of phosphate-zirconium-carboxylate coordination reaction. Then, fluorescent Hyp was linked to PBA via π-π stacking interaction. Under the optimal conditions, this biosensor displayed a good linear relationship between the fluorescence intensity and the tDNA concentrations in the range from 1 to 100 nM with a low detection limit of 2.9 nM. The mismatch type in a specific DNA sequence can also be efficiently discriminated. Compared with some other reports, this method is more convenient, and has great potential for practical applications.
2016 by The Japan Society for Analytical Chemistry