Room-Temperature Phosphorescence Turn-on Detection of DNA Based on Riboflavin-Modulated Manganese Doped Zinc Sulfide Quantum Dots.

A sensitive phosphorescent sensor based on riboflavin (RF)-modulated mercaptopropionic acid (MPA)-capped Mn-doped ZnS quantum dots (QDs) was developed and utilized as room-temperature phosphorescence (RTP) sensor for DNA detection. The RTP of the MPA-capped Mn-doped ZnS QDs was stored via photoinduced electron transfer by RF, and formed an electrochemically nonactive QDs/RF nanohybrids through electrostatic attraction. In the presence of DNA, RF could bind with DNA, which has a double helical structure, via electrostatic interaction and intercalation. RF can be removed from the surface of the QDs, thus releasing the RTP of the QDs. On the basis of this principle, an RTP sensor for DNA detection was developed. Under optimal conditions, the detection limit for DNA was 15 μg mL(-1), the relative standard deviation was 1.9 %, and the method recovery ranged from 97 % to 103 %. The proposed method was applied to biological fluids, in which satisfactory results were obtained.