Assaying of Cu²⁺ with near‐infrared l‐cysteine‐capped CdSeTe/CdS quantum dots and its effect on cell imaging

Abstract

Near‐infrared (NIR) core–shell CdSeTe/CdS quantum dots (QDs) modified with l‐cysteine were synthesized in aqueous solution. The QDs had a special NIR‐emitting spectrum, high fluorescence stability and low cytotoxicity. In addition, they exhibited an obvious fluorescence quenching when Cu2+ was present. An NIR nanosensor was prepared for rapidly, sensitively, and selectively determining Cu2+ in solution quantitatively and monitoring the changes in Cu2+ in cells with fluorescence imaging in a semiquantitative way. The linear relationship between the relative fluorescence intensity (F0/F) and the concentration of Cu2+ from 5.12 × 10−8 M to 2.56 × 10−5 M in solution was observed using an NIR fluorescence spectrophotometer with R2 equal to 0.9958. Moreover, in the experiment with the fluorescence microscope, F0/F versus the concentration of Cu2+ from 5.00 × 10−8 M to 7.68 × 10−6 M also showed a good linear relationship with R2 equal to 0.9817. Practical water sample ion detecting experiments had good accuracy and recovery rates. Cell experiments showed that the NIR imaging intensity of cells was inversely proportional to the concentration of copper ions, therefore NIR QDs have great potential for detection of metal ions in solution and in cells.

One-pot hydrothermal synthesis of high quantum yield orange-emitting carbon quantum dots for sensitive detection of perfluorinated compounds

“…Even after incubation with a higher concentration of CQDs (60 mg mL À1 ) for 24 h, the survival rate of Hep-2 cells can still reach about 80%. The cytotoxicity of as-prepared CQDs is lower than that of some previously reported CQDs 43 and conventional QDs, 44 though it is higher than some other reported CQDs reported. 20 The observed cytotoxicity probably results from the positively charged amine groups on the CQDs surface.…”

SDS‐capped 1‐pyrenecarboxaldehyde nanoprobe for selective detection of Cu2+ ion from water samples: Spectroscopic approach

“…Therefore the development of a sensory system to detect Cu 2+ metal ions is essential for environmental and biological systems. Various analytical techniques have been used to detect Cu 2+ ions, including electrochemical methods, atomic emission spectroscopy, inductively coupled mass spectroscopy, chemiluminescence immune assays and surface‐enhanced Raman scattering [11, 19–22]. Furthermore, these methods involve sophisticated instrumentation, multiple steps and the use of high‐cost chemicals [23].…”