i-Diagnostics and TIRF Analytix – technologies empowering Apollo Program for Biodefense

     TIRF geometries. In prism- and lightguide-TIRF geometries the excitation lightpath is separated from the emission channel, which enables a set of advantages. UV light can be used for excitation in prism- and lightguide-TIRF, a feature not available in objective-TIRF. Large area of the evanescent wave up to 20 mm X 50 mm can be used in lg-TIRF geometry  for real-time TIRF microarray studies to detect proteins, nucleic acids, and metabolites simultaneously. In p-TIRF and lg-TIRF the intensity of stray light is minimal and the TIRF effect is clean. In the o-TIRF geometry the evanescent wave is contaminated with ~10-15% of stray light. lg-TIRF and p-TIRF are exceptionally flexible geometries that can be used with dry, water-, and oil-immersion objectives, low and high numerical aperture, while o-TIRF only with specialized high NA, large magnification objectives, which is not suitable for certain applications, including real-time TIRF microarrays. 

     Selecting TIRF geometry. If you perform in vitro studies,  prism-TIRF is the first geometry to consider, as it  provides the cleanest TIRF effect. For studies with live cells that require open perfusion chambers, lg-TIRF will be the best geometry from the standpoint of signal-to-background ratio. If you intend to detect single molecules, you will need ~1kiloWatt/cm2 excitation power, objectives with NA 1.0 or more to collect enough fluorescence, and a low light camera.  Both p-TIRF and lg-TIRF are well-suited for single molecule detection studies. lg-TIRF is compatible with  AFM, electrophysiology, and electric field control. TIRF Labs supplies p-TIRF and lg-TIRF systems as factory-aligned add-on accessories. It takes no time to install/uninstall p-TIRF and lg-TIRF; they fit onto virtually all microscopes. See White Papers “Selecting the Optimal TIRF geometry...”, "Compare TIRF microscopy geometrics", "Minimize stray light in TIRF microscopy", Application Notes and Literature references to articles of our customers.