ABSTRACT
Le Qiu and Lev T. Perelman Biomedical Imaging and Spectroscopy Laboratory, Beth Israel Deaconess Medical Center, Harvard University, Boston, Massachusetts 02215 USA
18.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 465 18.2 Light Scattering Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 467 18.3 Confocal Microscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 468 18.4 CLASS Microscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 469 18.5 Imaging of Live Cells with CLASS Microscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 473 18.6 Characterization of Single Gold Nanorods with CLASS Microscopy . . . . . . . . . . . . . . . . . . . . . . 474 18.7 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 477
Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 477 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 478
This chapter reviews biomedical applications of confocal light absorption and scattering spectroscopic microscopy, an optical imaging technique that uses light scattering spectra as a source of the highly specific native contrast of internal cell structures. Confocal light absorption and scattering spectroscopic microscopy (CLASS) combine the principles of microscopy with light scattering spectroscopy (LSS), an optical technique that relates the spectroscopic properties of light elastically scattered by small particles to their size, refractive index, and shape. The multispectral nature of LSS enables it to measure internal cell structures much smaller than the diffraction limit without damaging the cell or requiring exogenous markers, which could affect cell function. CLASS microscopy approaches the accuracy of electron microscopy but is nondestructive and does not require the contrast agents common to optical microscopy. In this chapter we discuss basic physical principles of LSS and CLASS microscopy. We also devote a significant amount of space to the discussion of applications of CLASS microscopy in such diverse areas as obstetrics, neuroscience, ophthalmology, cellular and tissue imaging with nanoparticulate markers, and drug discovery.
