Applications of Two-Photon Absorption in Medicine and Biology Enabled by Specially Designed Biological Molecules

COFFEE_KLATCH · Invited

Abstract

We quantitatively study how the two-photon absorption (2PA) properties of biological molecules depend on their structure. 2PA is advantageous over regular one-photon absorption because of deeper penetration and more localized excitation in biological tissues. However, 2PA cross sections of biological chromophores are usually rather small to be useful in real life applications. Using quantum-mechanical few-level description of molecular electronic states, we interpret our data and predict new structures with considerably increased 2PA cross sections. These new materials either synthesized or genetically engineered make 2PA-based techniques applicable in medicine and biology. We show how our new porphyrin photosensitizers with drastically enhanced 2PA ($\sim$1000 times compared to regular porphyrins) can be used for in vivo two-photon-induced closing of blood vessels in Age-Related Macular Degeneration. The second example describes the application of fluorescent proteins in two-photon laser microscopy of biological cells. We demonstrate how the 2PA properties of fluorescent proteins can be considerably improved by smart mutations of the environment of chromophore inside the protein.

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Authors

  • Ernest Henley

    Green River College, University of British Columbia, Pacific Northwest National Laboratory, BYU-Idaho Dept. of Physics, University of Washington, Applied Physics Technologies, Inc., Montana State University, Universidade Estadual de Campinas, Southern Oregon University, Oregon State University Department of Physics, Oregon State University Department of Chemistry, National Institute of Standards and Technology Center for Neutron Research, Physics Department, Oregon State University, University of Idaho, University of Wyoming, Department of Physics, Montana State University, University of Portland, Idaho State University, WWU, Advanced Light Source, Lawrence Berkeley National Laboratory, Oregon Center for Optics and Department of Physics, University of Oregon, Lewis and Clark, Queen's University, University of Notre Dame, Idaho National Lab, TRIUMF, RCNP, Japan, University of Guelph, Mexico University, St. Mary's University, University of Montreal, Deep River, Dept. of Physics; Montana State University, Dept. of Plant Sciences and Pathology, Dept. of Chem. and Biochem.; Montana State University, Department of Physics, Shandong University, P. R. China, Department of Physics, University of Idaho, USA, Dept. of Physics, Simon Fraser University, Burnaby, BC V5A 1S6 Canada, University of Calgary