Gu, LuoHall, David J.Qin, ZhengtaoAnglin, EmilyJoo, JinmyoungMooney, DavidHowell, Stephen B.Sailor, Michael J.2014-01-272013Gu, Luo, David J. Hall, Zhengtao Qin, Emily Anglin, Jinmyoung Joo, David J. Mooney, Stephen B. Howell, and Michael J. Sailor. 2013. In vivo time-gated fluorescence imaging with biodegradable luminescent porous silicon nanoparticles. Nature Communications 4: 2326.2041-1723http://nrs.harvard.edu/urn-3:HUL.InstRepos:11591711Fluorescence imaging is one of the most versatile and widely used visualization methods in biomedical research. However, tissue autofluorescence is a major obstacle confounding interpretation of in vivo fluorescence images. The unusually long emission lifetime (5–13 μs) of photoluminescent porous silicon nanoparticles can allow the time-gated imaging of tissues in vivo, completely eliminating shorter-lived (<10 ns) emission signals from organic chromophores or tissue autofluorescence. Here using a conventional animal imaging system not optimized for such long-lived excited states, we demonstrate improvement of signal to background contrast ratio by >50-fold in vitro and by >20-fold in vivo when imaging porous silicon nanoparticles. Time-gated imaging of porous silicon nanoparticles accumulated in a human ovarian cancer xenograft following intravenous injection is demonstrated in a live mouse. The potential for multiplexing of images in the time domain by using separate porous silicon nanoparticles engineered with different excited state lifetimes is discussed.en-USchemical sciencesmedicinal chemistrynanotechnologyJournal Article2013-12-01Luo Gu, David J. Hall, Zhengtao Qin, Emily Anglin, Jinmyoung Joo, David J. Mooney, Stephen B. Howell, Michael J. Sailor2014-02-1310.1038/ncomms3326