A novel Quantum Dots (QDs)-based biosensor was developed by the research group headed by Dr. TANG Fangqiong from Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, a step forward in the detection of lactate dehydrogenase (LDH).

LDH is one of the Nicotinamide Adenine Dinucleotide (NAD) dependent enzymes, detection of which plays a significant role in clinical diagnostics of various diseases. Thus, a number of detection techniques including optical analysis have been developed for the evaluation of enzyme activities. Most of these techniques, however, are expensive, time-consuming, and inadequate for in situ monitoring. Therefore, a novel QDs-based biosensor comes into being.

The QDs-based biosensor is developed by the research group to detect the activity of LDH by the change of fluorescence intensities of the QDs. In this system, the fluorescence intensities of the QDs are quenched by NAD first and then intensified with increasing amounts of the LDH because of the consumption of NAD in the biocatalyzed reaction. A linear calibration plot of the activity of LDH is obtained in wide amounts range from 150 to 1500 U/L and the lowest detection limit is 75 U/L.

The technique is also used to detect the density of glucose in serum and realizes simultaneous detection for both of them. Compared to previous biosensors, the novel QDs-based biosensor enjoys a greater prospect due to its promise for simple procedure.

The research has received support from National Natural Science Foundation of China. Its findings have been published in Biosensors and Bioelectronics.