In principle, the DNA detection is accomplished by two steps (see image, right). First, adsorption of fluorescent-labeled single-stranded DNA onto the material leads to substantial fluorescence quenching, which can be ascribed to photoinduced electron transfer when the sensing surface and target are brought into close proximity. Second, the following specific hybridization of the probe with its target produces a DNA duplex, liberating the dye-labeled probe and thus leading to fluorescence recovery.

The constructed biosensor is endowed with high sensitivity and selectivity down to single-base mismatch, and the team's results provide a new direction for exploring the application of co-ordination polymers.

However, the current sensing system has some drawbacks: (1) the dye fluorescence can't be completely quenched by these quenchers, leading to strong background fluorescence; and (2) such nanobelts are tens of micrometers in length and tend to sink in the aqueous solution due to gravity, which can cause stability problems in detection.

Back in the lab, the group is developing new fluorescent sensing platforms that overcome all of the above-mentioned shortcomings. Further studies also include: (1) exploring the possible use of this sensing platform for clinical sample detection; and (2) designing new strategies to achieve simultaneous multiple-target detection with a single wavelength excitation.

More details can be found in the journal Nanotechnology.