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SHG nanoprobes: Advancing harmonic imaging in biology
Author(s) -
Dempsey William P.,
Fraser Scott E.,
Pantazis Periklis
Publication year - 2012
Publication title -
bioessays
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.175
H-Index - 184
eISSN - 1521-1878
pISSN - 0265-9247
DOI - 10.1002/bies.201100106
Subject(s) - second harmonic generation , second harmonic imaging microscopy , signal (programming language) , fluorescence , optics , materials science , autofluorescence , microscopy , photon , two photon excitation microscopy , harmonic , nanotechnology , optoelectronics , physics , laser , computer science , quantum mechanics , programming language
Second harmonic generating (SHG) nanoprobes have recently emerged as versatile and durable labels suitable for in vivo imaging, circumventing many of the inherent drawbacks encountered with classical fluorescent probes. Since their nanocrystalline structure lacks a central point of symmetry, they are capable of generating second harmonic signal under intense illumination – converting two photons into one photon of half the incident wavelength – and can be detected by conventional two‐photon microscopy. Because the optical signal of SHG nanoprobes is based on scattering, rather than absorption as in the case of fluorescent probes, they neither bleach nor blink, and the signal does not saturate with increasing illumination intensity. When SHG nanoprobes are used to image live tissue, the SHG signal can be detected with little background signal, and they are physiologically inert, showing excellent long‐term photostability. Because of their photophysical properties, SHG nanoprobes provide unique advantages for molecular imaging of living cells and tissues with unmatched sensitivity and temporal resolution.