Multimodal silica-shelled quantum dots: direct intracellular delivery, photosensitization, toxic, and microcirculation effects

Bioconjug Chem. 2008 Jun;19(6):1135-42. doi: 10.1021/bc700431c. Epub 2008 May 22.


In the present study, we describe a multimodal QD probe with combined fluorescent and paramagnetic properties, based on silica-shelled single QD micelles with incorporated paramagnetic substances [tris(2,2,6,6-tetramethyl-3,5-heptanedionate)/gadolinium] into the micelle and/or silica coat. The probe was characterized with high photoluminescence quantum yield and good positive MRI contrast, low cytotoxicity, and easy intracellular delivery in viable cells. The intravenous administration of the probe in experimental animals did not affect significantly the physiological parameters and microcirculation (e.g., heart rate, blood pressure, diameter and shape of blood vessels), which makes it appropriate for tracing of blood circulation and in vivo multimodal imaging using fluorescent confocal microscopy, two-photon microscopy, and MRI.

MeSH terms

  • Animals
  • Biocompatible Materials / metabolism
  • Biocompatible Materials / toxicity
  • Blood Pressure / drug effects
  • Brain / blood supply*
  • Brain / drug effects*
  • Contrast Media / metabolism
  • Contrast Media / toxicity
  • Fluorescent Dyes / metabolism
  • Fluorescent Dyes / toxicity
  • Gadolinium / chemistry
  • HeLa Cells
  • Heart Rate / drug effects
  • Humans
  • Intracellular Space / metabolism*
  • Magnetics*
  • Micelles
  • Microcirculation / drug effects
  • Photosensitizing Agents / metabolism*
  • Photosensitizing Agents / toxicity
  • Quantum Dots*
  • Rats
  • Silicon Dioxide / chemistry*


  • Biocompatible Materials
  • Contrast Media
  • Fluorescent Dyes
  • Micelles
  • Photosensitizing Agents
  • Silicon Dioxide
  • Gadolinium