Editing Lipid bilayer (section)

===Fluorescence microscopy===

[[File:Sedimented red blood cells.jpg|right|thumb|210px|Human red blood cells viewed through a fluorescence microscope. The [[cell membrane]] has been stained with a fluorescent dye. Scale bar is 20μm.]]

A lipid bilayer cannot be seen with a traditional microscope because it is too thin, so researchers often use [[fluorescence microscopy]]. A sample is excited with one wavelength of light and observed in another, so that only fluorescent molecules with a matching excitation and emission profile will be seen. A natural lipid bilayer is not fluorescent, so at least one fluorescent dye needs to be attached to some of the molecules in the bilayer. Resolution is usually limited to a few hundred nanometers, which is unfortunately much larger than the thickness of a lipid bilayer.<ref name="Crane Tamm 2007">{{cite book |last=Crane |first=Jonathan M. |last2=Tamm |first2=Lukas K. |title=Methods in Membrane Lipids |chapter=Fluorescence Microscopy to Study Domains in Supported Lipid Bilayers |publisher=Humana Press |publication-place=Totowa, NJ |volume=400 |date=2007 |isbn=978-1-58829-662-7 |doi=10.1007/978-1-59745-519-0_32 |page=481–488}}</ref>