Two-Photon Kidney Cells

Two-photon kidney cells

 

Kidney cells seen using two-photon excitation microscopy. This is a variant of fluorescence microscopy in which the fluorescent dye emits light once two photons of infrared light have been absorbed. Infrared is used as it has better penetration in biological tissues than ultraviolet and also has less background noise. Managing to get two photons to be absorbed within a short enough time that their energies add together requires the use of very bright pulsed lasers. Here the laser is used to excite quantum dots that bind to specific proteins. Quantum dots are nanocrystals, normally of cadmium sulphide, that can be made to bind to specific proteins and that fluoresce at wavelengths determined only by the crystal size.

Image © Thomas Deerinck, NCMIR

 

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