Ratiometric fluorescence biosensor based on CdTe quantum and carbon dots for double strand DNA detection

A ratiometric fluorescence biosensor was developed for detection of double strand DNA (dsDNA). The sensor consists of water-soluble fluorescent carbon dots (CDs) and 3-mercapropionic acid-coated cadmium telluride (CdTe) quantum dots exhibiting emissions peaks at 435 and 599 nm, respectively, under single-wavelength excitation (360 nm). CdTe QDs fluorescence was quenched by mitoxantrone via electron transfer and was restored in the presence of dsDNA, while the fluorescence intensity of CDs remained almost constant, providing a ratiometric means of dsDNA detection. The relative fluorescence intensity ration is directly proportional to the concentration of dsDNA between 0 and 50 nM, and the detection limit is 1.0 nM. Meanwhile, common organic compounds including amino acids, nucleotides, bovine serum albumin, single strand DNA and RNA had not significant interference in the detection mode. The novel nanosensor is simple, rapid, and convenient since it does not require modification or separation procedures, and was applied to the detection of HIV dsDNA in synthetic samples and human serum samples with satisfactory results. (C) 2017 Elsevier B.V. All rights reserved.