Lanthanide-containing Nanomaterials and Complexes: Utilizing Lanthanide Luminescence for a Broad Range of Application

Combining materials on the nanoscale (1 - 1000 nanometers) with luminescent lanthanide cations has far-reaching implications for exploring the size regime where fundamental biological interactions take place. Nanomaterials such as nanocrystals (NCs), dendrimers, metal-organic frameworks (MOFs) and micelles are uniquely suited for locating lanthanide cations and lanthanide sensitizers in close proximity of one another to stimulate the so-called antenna effect. This approach is necessary to take advantage of the numerous and complementary photophysical properties of luminescent lanthanide cations because lanthanide luminescence is inherently difficult to stimulate and observe for practical applications. A secondary yet equally important feature of nanomaterials is the ability to maximize the number of lanthanide cations and sensitizers per unit volume to increase the overall number of emitted photons and hence sensitivity of the detection platform. State-of-the art spectroscopic techniques have been employed to characterize the properties of lanthanide-containing nanomaterials towards the development of biological reporters and sensors. In particular, a combination of luminescence intensity and lifetime measurements provide sensitive and real-time information on the local environment experienced by the detection platform. This information provides valuable insight for researchers interested in the understanding of diseases and diagnosticians interested in making early and accurate assessments of disease. Using the above-mentioned techniques, we have demonstrated the usefulness of lanthanide luminescence in biological applications and for sensing biologically relevant species such as molecular oxygen. Moreover, our polymetallic nanomaterial approach has allowed us to develop strategies that the lanthanide chemistry community can use to quickly identify lanthanide sensitizers that are adaptable to their respective lines of research. The lanthanide-containing nanomaterial systems have potential applications in the field of chemical sensors and biological imaging, and a fundamental understanding of the energy transfer processes may lead to better sensors and imaging agents.