Howard Bell

In vivo multiple color lymphatic imaging using upconverting nanocrystals

Upconverting nanocrystals are unique nano-sized particles that emit light at shorter wavelengths (visible and near infrared) after excitation in the near infrared that dramatically reduces background autofluorescence in in vivo two color lymphatic imaging for depicting the lymphatic channels and nodes.

Infrared light utilized for photodynamic therapy by activation of rare earth phosphors for visible light generation.

Introduction: Photodynamic therapy (PDT) is a treatment for cancer requiring activation of a photosensitizer for light-mediated tumor cytotoxicity. PDT is limited by tissue penetration because visible light is required for photosensitizer activation. SunstonesTM are rare-earth phosphors which up-convert energy from infrared wavelengths to emit higher energy in the visible spectrum. We utilized this unique characteristic to generate light of appropriate intensity and wavelength for photosensitizer activation and subsequent tumor cell eradication. Methods: SunstonesTM with infrared absorption at 808 and 980nm and visible two-photon emission at 549.9 and 663.1nm were used. A murine NSCLC line was used to determine in vitro toxicity of SunstonesTM and dose response curves for SunstonesTM-mediated PDT. Human NSCLC cells were incubated with/without PhotofrinTM (photosensitizer). Experimental groups included: Infrared light treatment (IR), IR+PhotofrinTM, IR+SunstonesTM, and IR+SunstonesTM+PhotofrinTM. Groups were exposed to 2.5W of 808nm light and assayed for metabolic activity. Results: In vitro toxicity assays showed no significant toxicological side effects after 1 week incubation with SunstonesTM and demonstrated linear response in cytotoxicity as treatment times and infrared dose increased. IR+SunstonesTM+PhotofriTM group showed significantly decreased metabolic activity compared to control cells, cells treated with IR+SunstonesTM, and IR alone. Conclusion: SunstonesTM are nontoxic nanocrystals capable of activating photosensitizers for PDT. Future directions include conjugation of up-converters to a novel photosensitizer and managing the selective uptake of conjugate by tumor cells.

Intelligent material advances energy technologies

On the most basic level, our world functions on the conversion of energy and the interpretation of that energy as information. The ability of a species to use these energies efficiently in an always-changing environment is a significant determinant of evolutionary success. As technologies rapidly advance, so does our knowledge, and many prevailing truths and realities are found to be wrong: Helios does not take the Sun across the sky on his chariot, and the world is not flat. One might assume that, similarly, what we perceive as reality in 2014 will seem absurd a thousand years from now. The Roman poet Ovid metaphorically described the declines in human civilizations in terms of the decreasing value of metals: gold, silver, bronze, and iron. History may describe our current period as an age of hydrocarbons: i.e., petroleum, which underlies our economy and our society. We pump it from the ground and refine it to power cars and airplanes, shape it into plastic bottles and other materials, and fight wars over its sources. These sources are finite, however, and will ultimately have to be replaced with other forms of energy. Thus, much like sequoia trees that live thousands of years, human survival and evolution will be based on new ways of converting energy and interpreting the knowledge derived. Photons, elementary particles encompassing the electromagnetic spectrum, travel through space in a wave that provides energy. Currently, we perceive only a minuscule portion of the wavelength’s spectrum, but the ability to perceive regions currently out of reach (see Figure 1) will provide us with a deeper understanding of how to live longer, healthier lives. Indeed, we may be just a few generations away from this goal. This potential lies in technologies that can be derived from the ability of rare-earth metals to process energy from the electromagnetic spectrum. Rare earths are indispensable components across many industries, and they facilitate major technological advances. Figure 1. The electromagnetic spectrum. Human perception is limited to only a few small regions of the spectrum, but rare-earth elements allow us to perceive and process larger areas of it.