Multiphoton Microscopy of Nonfluorescent Nanoparticles In Vitro and In Vivo.
Nanotechnology holds great promise for a plethora of potential applications. The interaction of engineered nanomaterials with living cells, tissues, and organisms is, however, only partly understood. Microscopic investigations of nano-bio interactions are mostly performed with a few model nanoparticles (NPs) which are easy to visualize, such as fluorescent quantum dots. Here the possibility to visualize nonfluorescent NPs with multiphoton excitation is investigated. Signals from silver (Ag), titanium dioxide (TiO2 ), and silica (SiO2 ) NPs in nonbiological environments are characterized to determine signal dependency on excitation wavelength and intensity as well as their signal stability over time. Ag NPs generate plasmon-induced luminescence decaying over time. TiO2 NPs induce photoluminescent signals of variable intensities and in addition strong third harmonic generation (THG). Optimal settings for microscopic detection are determined and then applied for visualization of these two particle types in living cells, in murine muscle tissue, and in the murine blood stream. Silica NPs produce a THG signal, but in living cells it cannot be discriminated sufficiently from endogenous cellular structures. It is concluded that multiphoton excitation is a viable option for studies of nano-bio interactions not only for fluorescent but also for some types of nonfluorescent NPs.
Walter-Brendel-Zentrum für Experimentelle Medizin, Ludwig-Maximilians-Universität München, 81377, München, Germany.
Steffen
S
Dietzel
Walter-Brendel-Zentrum für Experimentelle Medizin, Ludwig-Maximilians-Universität München, 81377, München, Germany.
Stefanie
S
Hermann
Walter-Brendel-Zentrum für Experimentelle Medizin, Ludwig-Maximilians-Universität München, 81377, München, Germany.
Yan
Y
Kugel
Walter-Brendel-Zentrum für Experimentelle Medizin, Ludwig-Maximilians-Universität München, 81377, München, Germany.
Sabine
S
Sellner
Walter-Brendel-Zentrum für Experimentelle Medizin, Ludwig-Maximilians-Universität München, 81377, München, Germany.
Bernd
B
Uhl
Walter-Brendel-Zentrum für Experimentelle Medizin, Ludwig-Maximilians-Universität München, 81377, München, Germany.
Stephanie
S
Hirn
Walter-Brendel-Zentrum für Experimentelle Medizin, Ludwig-Maximilians-Universität München, 81377, München, Germany.
Fritz
F
Krombach
Walter-Brendel-Zentrum für Experimentelle Medizin, Ludwig-Maximilians-Universität München, 81377, München, Germany.
Markus
M
Rehberg
D053768:Metal Nanoparticles / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D045663:Quantum Dots; D012822:Silicon Dioxide / Q000737:chemistry; D014025:Titanium / Q000737:chemistry
C009495:titanium dioxide; D012822:Silicon Dioxide; D014025:Titanium
multiphoton microscopy; silica nanoparticles; silver nanoparticles; titanium dioxide nanoparticles