CdTe nanocrystals as luminescent probes for detecting ATP, folic acid and l-cysteine in aqueous solution

CdTe quantum dots capped by short-chain thioglycolic acid (TGA) are prepared in aqueous solution. In this study, we report the effect of adenosine 5′ triphosphate (ATP), folic acid and l-cysteine on the photoluminescence intensity of CdTe nanocrystals in pH 7.4 Tris-HCl buffer solutions. The luminescence of CdTe nanocrystals is quenched in the presence of ATP or folic acid, which is related to their concentrations. The relationship between the luminescence intensity of CdTe nanocrystals and the concentration of ATP or folic acid is described by the Stern–Volmer equation. The emission intensity of CdTe nanocrystals is enhanced in the presence of l-cysteine. The relationship between the emission intensity of CdTe nanocrystals and the concentration of l-cysteine agrees with Langmuir binding isotherm equation in the range of 5 × 10−6 to 2 × 10−4 mol/L. These results show that CdTe nanocrystals can be potentially used as luminescence probes for detecting ATP, folic acid and l-cysteine.