Office of Technology Transfer – University of Michigan

Luminescent Heteromatallic Metallacrown Complexes for Biological Assays and Imaging

Technology #6312

Sensitized lanthanides are becoming increasingly important across multiple scientific industries because of their stability, long luminescence lifetimes, and narrow emission bands. In the growing field of biological assays there has been demonstrated need for luminescent dyes that emit outside of the visible range where traditional fluorescence measurements suffer from high levels of interference. To address this problem we have developed a series of robust, self-assembled gallium/lanthanide metallacrown complexes that show exceptional luminescence properties in the visible and near-infrared regions with many options for multiplex analysis. In addition to their promise for luminescence bioassays, gallium/lanthanide metallacrowns can be designed to leverage the radioisotopes of gallium for extended applications in biomedical imaging and radiotherapy.

Metallacrown Sensitized Lanthanides Exhibit Exceptional Luminescence Properties

Electronic transitions between the f orbitals in lanthanides are forbidden in the traditional fluorescence mechanism that dominates the field of biological assays. To circumvent this problem, organic antennae are used to absorb light and transfer energy to the lanthanide so luminescence can be observed. Using our metallacrown antennae technology, the highest quantum efficiencies ever reported for a solid-state Yb3+ or Er3+ complex were achieved and excellent photophysical data were reported for several other lanthanides. In addition, the metallacrown is capable of sensitizing Ho3+ and Tm3+ which are known to be refractory to luminescence sensitization. This data taken together with the long luminescence lifetimes and narrow emission bands associated with lanthanides make this technology an excellent tool for time resolved, low-background, multiplexed assays and biomedical imaging.


  • Luminescent dye for time-resolved and multiplexed biological assays
  • Combined radio-luminescent imaging agent
  • Combined radio-luminescent theragnostic agent
  • Signal conversion/transduction in fiber optic technologies
  • Authentication technology
  • Energy conversion technology


  • Facile and cost effective one-pot synthesis
  • Long luminescence lifetimes for time-resolved, low background assays
  • Incorporation of Ga isotopes for radioimaging or radiotherapy
  • Extremely high quantum efficiency
  • Multiple Lanthanides can be used for multiplexed analysis
  • Sensitization of traditionally difficult lanthanides