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A New Nanoparticle Design for Imaging with Ultralow Powers of Near Infrared Light
Foundry staff and users have developed alloyed upconverting nanoparticles (UCNPs) that can be excited with low-powered lasers for sensitive and non-toxic imaging.
Significance and Impact
The nanocrystals can be imaged with low-energy light at laser intensities over 300-fold lower than needed for previous comparably sized UCNPs, leading to advanced imaging of light-sensitive systems, such as high-precision surgeries.
- Researchers discovered that UCNPs with fully alloyed lanthanide compositions produce the brightest emissions, overturning decades of previous work which suggested low lanthanide doping levels are superior.
- It was determined that the lanthanide erbium, commonly used in UCNPs to emit light, can adopt a second role to enhance the UCNP absorption. The new UCNPs are brighter over a 10,000-fold range of excitation powers.
- The UCNPs are 12-15 nm in diameter, allowing them to penetrate deep into tissue. The team showed nanoparticles can be imaged several millimeters deep in live mice at excitation intensities well below those known to cause physiological damage.
B. Tian, A. Fernandez-Bravo, H. Najafiaghdam, N.A. Torquato, M.V. Altoe, A. Teitelboim, C.A. Tajon, Y. Tian, N.J. Borys, E.S. Barnard, M. Anwar, E.M Chan, P.J. Schuck, B.E. Cohen. Nat. Comm. (2018). 9 3082.