May 5, 2011
Nanobelts provide platform for fluorescent DNA detection
Researchers from China West Normal University have prepared uniform co-ordination polymer nanobelts on a large scale by mixing AgNO3 and 4,4'-bipyridine in solution. In further work, the team has demonstrated the great application of this striking material as an effective sensing platform for fluorescence-enhanced DNA detection.
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.
About the author
Dr Xuping Sun is a chemistry professor at Changchun Institute of Applied Chemistry, Chinese Academy of Sciences. He is also an adjunct professor at China West Normal University. His research interests include DNA nanotechnology, DNA detection and biochip, supramolecular chemistry, electroanalytical chemistry, polymer and material chemistry. This work was supported by National Basic Research Program of China (No. 2011CB935800).