Monitoring leaching of Cd2+ from cadmium-based quantum dots by an Cd aptamer fluorescence sensor

Shanni Hong, Zhenglin Yang, Quanbing Mou, Yunxia Luan, Bingbo Zhang, Renjun Pei, Yi Lu

Research output: Contribution to journalArticlepeer-review


Quantum Dots (QDs) have been demonstrated with outstanding optical properties and thus been widely used in many biological and biomedical studies. However, previous studies have shown that QDs can cause cell toxicity, mainly attributable to the leached Cd2+. Therefore, identifying the leaching kinetics is very important to understand QD biosafety and cytotoxicity. Toward this goal, instrumental analyses such as inductively coupled plasma mass spectrometry (ICP-MS) have been used, which are time-consuming, costly and do not provide real-time or spatial information. To overcome these limitations, we report herein a fast and cost-effective fluorescence sensor based a Cd2+-specific aptamer for real-time monitoring the rapid leaching kinetics of QDs in vitro and in living cells. The sensor shows high specificity towards Cd2+ and is able to measure the Cd2+ leached either from water-dispersed CdTe QDs or two-layered CdSe/CdS QDs. The sensor is then used to study the stability of these two types of QDs under conditions to mimic cellular pH and temperature and the results from the sensor are similar to those obtained from ICP-MS. Finally, the sensor is able to monitor the leaching of Cd2+ from QDs in HeLa cells. The fluorescence aptamer sensor described in this study may find many applications as a tool for understanding biosafety of numerous other Cd-based QDs, including leaching kinetics and toxicity mechanisms in living systems.

Original languageEnglish (US)
Article number114880
JournalBiosensors and Bioelectronics
StatePublished - Jan 15 2023


  • Aptamer sensor
  • Cadmium-based quantum dots
  • Real-time monitoring

ASJC Scopus subject areas

  • Biotechnology
  • Biophysics
  • Biomedical Engineering
  • Electrochemistry


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