Novel fluorescent CdTe quantum dot–thymine conjugate—synthesis, properties and possible application

Abstract

Novel, highly fluorescent cadmium telluride quantum dots conjugated with thymine and stabilized with thioglycolic acid were obtained and characterized. Successful formation of the conjugate was confirmed by elemental analysis, and UV-vis, fluorescence and Fourier transform infrared spectroscopies. Crystal structure and composition of the conjugates were characterized with xray diffraction and x-ray photoelectron spectroscopy. The size of the conjugates was 4-6 nm as demonstrated using atomic force microscopy and high resolution transmission electron microscopy imaging. The plasmon resonance fluorescence band at 540 nm on excitation at 351 nm was observed for these nanoparticles. The intensity of this band increased with the increase in the amount of conjugated thymine with no shift in its position. Based on the fluorescence measurements it was found that the CdTe-thymine conjugate interacted efficiently and selectively not only with adenine, a nucleobase complementary to thymine, but also with adenine-containing modified nucleosides, i.e., 5'-deoxy-5'-(methylthio)adenosine and 2'-O-methyladenosine, the urinary tumor markers which allow monitoring of the disease progression. To the best of our knowledge, as yet, there have been no studies presented in literature on that type of the interaction with CdTe-thymine conjugates. Therefore, the system presented can be considered as a working component of a selective adenine/adenosine biosensor with potential application in cancer diagnosis.

Multilayered Membrane Electrolytes Based on Aramid Nanofibers for High-Temperature Proton Exchange Membrane Fuel Cells

“…The appearance of some small peaks at 880 and 745 cm –1 were also indicative of PA molecules in the (Kevlar-CdTe-PA) 4 membrane . Although the peak at 1680 cm –1 caused by COO – groups in thioglycollic acid was found in the (Kevlar-CdTe-PA) 4 membrane, , there was a concern of CO groups in Kevlar nanofibers besides CdTe nanocrystals. Fortunately, the peaks at 890 and 620 cm –1 from −C–S groups provided a strong evidence to determine the existence of CdTe nanocrystals in (Kevlar-CdTe) 4 and (Kevlar-CdTe-PA) 4 membranes …”