Rapid preparation of self-assembled CdTe quantum dots used for sensing of DNA in urine

Abstract

In this article, the authors report a systematic study of the self-assembly of CdTe quantum dots (QDs) stabilized by mercaptosuccinic acid (MSA) at laboratory temperature (25 °C) or after thermal treatment (90 °C). It was found that QD/MSA can be synthesized spontaneously under mild laboratory conditions (25 °C and 70 hours) without any further instrumentation or they can be treated using an increased temperature (90 °C and 8 min) to achieve the same fluorescence intensity. These QDs were used for the preparation of a fluorescent (off–on) probe based on methylene blue as a quencher for the specific determination of nucleic acid from urine. The whole process was monitored using stationary spectroscopy (absorbance and fluorescence measurement) and capillary electrophoresis (CE) with laser-induced fluorescence detection. The average size of the prepared QDs (approximately 3 nm) was determined using transmission electron microscopy and it was proven that the presented fluorescent probe combined with the CE method can be used for the sensitive determination of DNA (LOD 3 ng mL⁻¹).