Which microscopy allows imaging of a single molecule near the coverslip surface using evanescent waves?
Total Internal Reflection Fluorescence microscopy exploits total internal reflection at glass-water interface. When incident light exceeds critical angle, an evanescent field penetrates only 100-200 nanometers into specimen, selectively exciting fluorophores immediately adjacent to coverslip. Shallow illumination eliminates background from deeper cytoplasm, yielding exceptional signal-to-noise for single-molecule events like membrane receptor binding, vesicle fusion, and cytoskeletal polymerization at cell surface. Objective-based configurations confine excitation axially, making TIRF indispen
Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.