Biological imaging with laser-feedback microscopy (LFM)

摘要

Optical laser-feedback microscopy (LFM), a scanning confocal interference microscopy, furnishes nanometer axial and 200 nm lateral resolution of surface topology when examining well-defined reflective hard surfaces such as semiconductors, metals, or other materials. Biological samples (e.g., cells or tissues under physiological conditions) are important objects for examination by LFM as the improved resolution available with this new method of optical microscopy can furnish biological structural information on a scale previously only attainable with electron microscopy but without the necessity for sample fixation or staining or the effect of ionization-produced radiation damage. Although the small refractive-index changes that occur at biological-membrane/water interfaces produce sufficient signal to be useful in LFM- imaging, being able to obtain `optical-sectioning' at a scale of nanometers and derive 3D information at that resolution would allow intracellular biological structures (e.g., organelles, chromosomes) and their functional changes to be determined on physiological-viable samples. By incorporating information from two simultaneously-acquired LFM images (optical phase and amplitude reflectivity), information has been obtained on a variety of biological cells; two examples will be presented, images of a green algae (Chlamydomonas reinhardtii) and of a human erythrocyte.