Wavelength-Selective Nonlinear Imaging and Photo-Induced Cell Damage by Dielectric Harmonic Nanoparticles

Abstract

We introduce a nonlinear all-optical theranostics protocol based on the excitation wave- length decoupling between imaging and photo-induced damage of human cancer cells labelled by Bismuth Ferrite (BFO) harmonic nanoparticles (HNPs). To characterize the damage pro- cess, we rely on a scheme for IN SITU temperature monitoring based on upconversion nanopar- ticles: by spectrally resolving the emission of silica coated NaGdF4: Yb3+/Er3+ nanoparticles in close vicinity of a BFO HNP, we show that the photo-interaction upon NIR-I excitation at high irradiance is associated with a temperature increase > 100 C. The observed laser-cell interaction implies a permanent change of the BFO nonlinear optical properties which can be used as a proxy to read-out the outcome of a theranostics procedure combining imaging at 980 nm and selective cell damage at 830 nm. The approach has potential applications to monitor and treat lesions within NIR light penetration depth in tissues.