Two-Photon Fluorescence Microscopy: Capturing Biology in Action
Optical techniques are playing increasingly important roles in biology and medicine. Optical microscopy is a particularly exciting field. The recent advent of two-photon fluorescence microscopy is a particularly important development. Two-photon microscopy has two unique properties. First, two-photon microscopy are significantly less phototoxic than other 3-D imaging methods such as confocal microscopy. The minimally invasive nature of this method allows long term study of biological specimen. Second, the near infrared radiation used in two-photon excitation has lower absorption coefficient in turbid specimens and allows the study of thick tissue physiology. The combination of two-photon imaging and fluorescence spectroscopy further allows the study of tissue biochemistry in vivo. In this presentation, I will provide an overview of two-photon microscopy and spectroscopy techniques. The use of two-photon techniques will be demonstrated in two examples: a study of mechanotransduction in smooth muscle cells, and the development a non- invasive optical biopsy instrument.