Fluorescent Detection Methods

Fluorescence is used as a detection method in many chemical and biological molecular characterization techniques.

Fluorescence Basics

• A material that contains fluorescent molecules can appear to "glow in the dark."

  Fluorescence occurs when light of a certain wavelength (often ultraviolet) is directed at a material that can absorb this light and emit light at a different, longer wavelength. Often this emission is visible light, making the material appear to glow.

Direct Fluorescence

• A molecule's fluorescence can change depending on how close it is to others.

  Some molecules are naturally fluorescent and can be studied using direct fluorescence. Factors including nearness to other molecules and solvent interactions can change a molecule's fluorescent properties. These changes give information about molecular interactions, aggregation and self-assembly.

Immunofluorescence

• Fluorescence can be used to visualize cell structures.

  In immunofluorescence, fluorescent antibodies are used to reveal certain cellular structures. This can be used to identify cells of different types, visualize particular cell organelles, measure cell metabolism and for many other purposes.

Fluorescent Labeling of DNA

• DNA can form fluorescent complexes.

  Although DNA itself is only weakly fluorescent, many molecular biology techniques rely on preparing fluorescent complexes of DNA for quantification, sequencing and tracking.

Other Methods

• Fluorescent proteins can be used to determine their function inside an organism.

  The list of fluorescent detection methods is long and varied. Proteins can be engineered to contain fluorescent domains, enabling them to be tracked within cells and even inside organisms. Fluorescence can be used in chromatography to separate a molecule of interest from a mixture and in biophysics to determine the rate of conformational change of a single molecule.