A novel surface modification strategy of CdTe/CdS QDs and its application for sensitive detection of ct-DNA

A kind of novel Glyp-functionalized-CdTe/CdS Quantum dots (QDs) was successfully synthesized by coating Glyp on the surface of the CdTe/CdS QDs. The fluorescence emission of the modified QDs was enhanced greatly but with a low resonance Rayleigh scattering (RRS). When it interacted with calf thymus DNA (ct-DNA), the fluorescence intensity of the system was obviously quenched and the RRS was enhanced, both in good linear relations. Based on the above, a novel fluorescence biosensor for simple, sensitive and selective detection of ct-DNA was developed. Under the optimized conditions, the linear ranges of the functionalized QDs fluorescence intensity and RRS intensity versus the concentration of ct-DNA were 0.109–70   μg   mL −1 and 0.482–90   μg   mL −1 , respectively. The corresponding detection limits by fluorescence quenching and by RRS enhancing methods were 0.0327   μg   mL −1 and 0.146   μg   mL −1 , respectively. The proposed method was applied to detect ct-DNA in synthetic sample with satisfactory results.