Deep, high contrast microscopic cell imaging using three-photon luminescence of beta-(NaYF4:Er3+/NaYF4) nanoprobe excited by 1480-nm CW laser of only 1.5-mW

• It is challenging to achieve deep microscopic imaging for the strong scattering in biotissue. An efficient three-photon luminescence can effectively increase the penetration depth. Here we report that beta-NaYF4: Er3+/NaYF4 UCNPs were excited by a 1480-nm CW-laser and emitted 543/653-nm light through a three-photon process. With the merit of the hexagonal crystal phase, sub-milliwatt laser power was utilized to excite the UCNP-probed cells to minimize the heating effect. The polymer-coated UCNPs were shown to be harmless to cells. The deep, high contrast in vitro microscopic imaging was implemented through an artificial phantom. Imaging depth of 800 mu m was achieved using only 1.5 mW excitation and a 0.7 NA objective. The green/red emission intensities ratio after penetrating the phantom was studied, indicating that longer emission wavelength is preferred for deep multiphoton microscopy. The proposed and demonstrated beta-UCNPs would have great potential in three-photon microscopy. (C) 2015 Optical Society of America

Ämnesord

NATURVETENSKAP  -- Biologi -- Biokemi och molekylärbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biochemistry and Molecular Biology (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Radiologi och bildbehandling (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Radiology, Nuclear Medicine and Medical Imaging (hsv//eng)

Nyckelord

Up-Conversion Nanoparticles

Upconverting Nanoparticles

Multiphoton Microscopy

High-Resolution

NM

Excitation

Nanocrystals

Lanthanide

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