Two - Photon 3 D FIONA of Individual Quantum Dots in an Aqueous

2 Environment 3 Ruobing Zhang,†,‡,r Eli Rothenberg,‡,§,O,r Gilbert Fruhwirth, Paul D. Simonson, Fangfu Ye, 4 Ido Golding, ,§,^ Tony Ng, || Ward Lopes, ,# and Paul R. Selvin* ,‡ ,§ 5 Center for Biophysics and Computational Biology, Center of Physics of Living Cells, and Physics Department, 6 and University of Illinois at Urbana Champaign, Urbana, Illinois 61801, United States 7 The Richard Dimbleby Department of Cancer Research, Randall Division of Cell & Molecular Biophysics, 8 and Division of Cancer Studies, King's College London, London WC2R 2LS, United Kingdom 9 Gerna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030, 10 United States 11 Physics Department, Williams College, Williamstown, Massachusetts 01267, United States