Real-time detection of single quantum dots inside living cells

Amit Agrawal, Shuming Nie

Research output: Contribution to journalConference articlepeer-review


Quantum dots have opened up a plethora of possibilities in biological detection and imaging. Their small size, stable luminescence and resistance to photobleaching make them ideal for intracellular imaging and detection. It is highly desirable to develop tools that will allow detection and imaging of biological processes without disrupting native cellular processes. A significant barrier to use of quantum dots in living cells is ability to deliver and detect single quantum dots inside living cells. In this article we describe a bacterial toxin dependent method that allows delivery of single quantum dots. We also demonstrate use of a single molecule detection system to detect both single and aggregated quantum dots in living cells in real time. We compare results of quantum dot delivery from receptor mediated endocytosis and HIV-TAT peptide mediated delivery methods with the bacterial toxin Streptolysin O. Our results show that Streptolysin O is able to deliver single quantum dots to living cells. Our results also indicate that the mechanism of cargo delivery by HIV-TAT peptide might be endocytosis dependent. Ongoing work in this direction involves showing that single, functional quantum dot probes can also be delivered using the bacterial toxin.

Original languageEnglish (US)
Article number34
Pages (from-to)152-158
Number of pages7
JournalProgress in Biomedical Optics and Imaging - Proceedings of SPIE
StatePublished - 2005
Externally publishedYes
EventNanobiophotonics and Biomedical Applications II - San Jose, CA, United States
Duration: Jan 24 2005Jan 27 2005


  • Pore Forming Toxins
  • Quantum Dots
  • Real-time Detection
  • Receptor Mediated Endocytosis
  • Single Molecule Detection
  • Streptolysin O

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Radiology Nuclear Medicine and imaging
  • Biomaterials


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