Time-Resolved Fluorescence Detection of Mosaic DNA Chip

We demonstrated a time-resolved fluorescence (TRF) label and detection of mosaic DNA chip in this paper. We synthesized oligonucleotide sequences in situ on glass slides directly, and then sliced them up into small pieces and patched up the pieces bearing different sequences to generate a mosaic DNA chip. With multiple 4, 7-bis(chlorosulfophenyl)-1, 10-phenanthroline-2, 9-dicarboxylic acid (BCPDA, abbreviated as BCPDA) labeling method based on avidin-biotin amplification, we established a TRF detection format on the mosaic DNA chip. The detection method allows discriminatory signals for perfect match, one-base mismatch, two-base mismatch, and three-base mismatch by TRF labeled DNA hybridization, whereby Europium (III, Eu³⁺) was captured and released on the principle of complexation and dissociation interaction between BCPDA and Eu³⁺ solution when the BCPDA-tagged avidin and biotin-capped oligonucleotide sequence linked. The fluorescence spectra and related lifetimes were determined. We also compared the TRF detection mode with the conventional fluorescence one. These results showed the former is a potential alternative replacement of the latter, especially for labeling the mosaic DNA chip. The discovery is of fundamental interest and has significant implications to biochips and biosensors based on time-resolved-fluorescence detection.