Functionalized semiconductor nanocrystals for ultrasensitive detection of peptides

Semiconductor CdS nanoparticle have been prepared and modified with thiovanic acid. The functionalized nanoparticles are water-soluble. They were used as the fluorescence probes in the ultrasensitive detection of peptides. This method is based on the fluorescence enhancement of functionalized nano-CdS in the presence of peptide with mercapto groups (GN-9) and the fluorescence quenching of functionalized nano-CdS in the presence of peptide (GA-8 and MT-25). Excitation and emission wavelengths were 360 and 530 nm, respectively. Under optimum conditions, the calibration graphs are linear over the range of 0.15-3.5, 0.2-4.0, and 0.2-3.8 μg ml−1 for GN-9, GA-8 and MT-25, respectively. The corresponding detection limits were 0.010 μg ml−1 for GN-9, 0.018 μg ml−1 for GA-8 and 0.022 μg ml−1 for MT-25, respectively. This method has been proved to be a simple, rapid and sensitive method.