Total internal reflection fluorescence microscopy (TIRFM) is a special technique in fluorescence microscopy developed by Daniel Axelrod at the University of Michigan, Ann Arbor in the early 1980s. TIRFM-based biological images are obtained with an outstandingly high axial resolution below 100 nm. This allows the observation of membrane-associated processes, such as cell-surface receptors’ dynamics, cell adhesion to surfaces or viral infection (e.g., HIV-1 early entry and infection (Valenzuela-Fernandez A and Machado JD et al. research team; MBoC 2011)). This is achieved by employing an evanescent wave for excitation of the fluorophores instead of direct illumination via light delivered by an arc lamp, LEDs or lasers. The evanescent field occurs if incident light is totally reflected at the interface of two transparent media with different refractive indices.
TIRFM is a useful and accessible imaging technique that will lead to great advances in our understanding of cell biology.