2. Biodistributions of Semiconductor Quantum Dots

2. Biodistributions of Quantum Dots that are Used in Solar Cells

Vincent Rotello (Chemistry) and Richard Vachet (Chemistry)

Quantum dots (QD) are semiconducting nanocrystals that are finding increasing applications in devices such as solar cells [1]. As the use of QDs in solar cells becomes widespread, these nanomaterials will inevitably be released into the environment, and their impact on the health of humans, plants, microbes, and ecological systems could be substantial [2]. Therefore, studies on the environmental impact of QDs are necessary. In particular, studies that relate QD chemical/physical properties to environmental fate, transport, and accumulation are needed [3-5]. In this REU project, students will explore QD stability and how their chemical and physical properties influence biodistributions (Fig. 1).

Fig. 1. Functionalized QD bioavailability

QD stability is important because the core materials of common QDs are selenium and cadmium; the latter of which can be toxic. QD size and surface chemistry are critical parameters that affect their properties in solar cell devices, and these two parameters also control their stability and the availability of the materials in the environment and in biological systems [6,7]. The REU students involved in this project will help obtain quantitative data on the role of size and surface properties on QD stability and biodistributions in model cell-based and animal systems. Specifically, a newly developed approach in our laboratories, which is based on laser desorption/ionization mass spectrometry (LDI-MS), will be further optimized and used [8,9].

  • Design and Synthesis of Model Functionalized Quantum Dots: An REU student in the Rotello group will synthesize QD materials of various sizes and with various chemical functionalities.
  • Develop and Optimize LDI-MS as a Means to Track QDs in Complex Samples.: An REU student in the Vachet group will develop and apply new mass spectrometric methods to track QDs in complex samples.
  • Collaborative Effort: The two REU students will work together and use the model QDs and LDI-MS to investigate the stability and uptake of these materials in cells and animal systems.


  1. I. Robel, V. Subramanian, M. Kuno and P.V. Kamat, “Quantum dot solar cells. Harvesting light energy with CdSe nanocrystals molecularly linked to mesoscopic TiO2 films” J Am Chem Soc, 2006, 128, 2385-2393.
  2. R. Hardman, “A toxicologic review of quantum dots: Toxicity depends on physicochemical and environmental factors” Environ Health Persp, 2006, 114, 165-172.
  3. S.J. Klaine, P.J.J. Alvarez, G.E. Batley, T.F. Fernandes, R.D. Handy, D.Y. Lyon, S. Mahendra, M.J. McLaughlin and J.R. Lead, “Nanomaterials in the environment: Behavior, fate, bioavailability, and effects” Environ Toxicol Chem, 2008, 27, 1825-1851.
  4. Z.J. Zhu, P.S. Ghosh, O.R. Miranda, R.W. Vachet and V.M. Rotello, “Multiplexed Screening of Cellular Uptake of Gold Nanoparticles Using Laser Desorption/Ionization Mass Spectrometry” J Am Chem Soc, 2008, 130, 14139-14143.
  5. Z.J. Zhu, V.M. Rotello and R.W. Vachet, “Engineered nanoparticle surfaces for improved mass spectrometric analyses” Analyst, 2009, 134, 2183-2188.
  6. Z.J. Zhu, R. Carboni, M.J. Quercio, B. Yan, O.R. Miranda, D.L. Anderton, K.F. Arcaro, V.M. Rotello and R.W. Vachet, “Surface Properties Dictate Uptake, Distribution, Excretion, and Toxicity of Nanoparticles in Fish” Small, 2010, 6, 2261-2265.
  7. Z.J. Zhu, Y.C. Yeh, R. Tang, B. Yan, J. Tamayo, R.W. Vachet and V.M. Rotello, “Stability of quantum dots in live cells” Nat Chem, 2011, 3, 963-968.
  8. B. Creran, B. Yan, D.F. Moyano, M.M. Gilbert, R.W. Vachet and V.M. Rotello, “Laser desorption ionization mass spectrometric imaging of mass barcoded gold nanoparticles for security applications” Chem Commun, 2012, 48, 4543-4545.
  9. Z.J. Zhu, R. Tang, Y.C. Yeh, O.R. Miranda, V.M. Rotello and R.W. Vachet, “Determination of the Intracellular Stability of Gold Nanoparticle Monolayers Using Mass Spectrometry” Anal Chem, 2012, 84, 4321-4326.