Forthcoming Events

26.10.2020 - 28.10.2020, Paul Scherrer Institut (PSI), Villigen,Switzerland

Jean-Pierre Wolf and co-workers: A biophotonics approach based on the nonlinear optical process of second harmonic generation

January 30, 2014

Deep UV generation and direct DNA photointeraction by harmonic nanoparticles in labelled samples.

Wolf and co-workers demonstrate a diagnostic and therapeutic protocol based on the nonlinear optical process of non phase-matched second harmonic (SH) generation by harmonic nanoparticles (HNPs). Previously, the doubling of any incoming frequency has not been employed for therapeutic use, although the SH-HNP approach has several straightforward advantages, including (i) the possibility of direct interaction with DNA of malignant cells in the absence of photosensitizing molecules, (ii) fully independent access to imaging and therapeutic modalities, and (iii) the complete absence of risk of spontaneous activation by natural or artificial light sources other than pulsed femtosecond lasers.

Here they show that by tuning the frequency of ultrashort laser pulses from infrared (IR) to visible, SH generation leads respectively to diagnostics (imaging) and therapy (localized phototoxicity). Specifically, we report in situ generation of deep ultraviolet (DUV) radiation (270 nm) in human-derived lung cancer cells treated with bismuth ferrite (BiFeO3, BFO) HNPs upon pulsed laser irradiation in the visible spectrum, at 540 nm. They observe and quantify the appearance of double-strand breaks (DSBs) in the DNA and cell apoptosis, in the area of the laser beam. They show that DNA damage is dependent on irradiation- time, laser intensity, and NP concentration.

Staedler, D., Magouroux, T., Passemard, S., Schwung, S., Dubled, M., Schneiter, G.S., Rytz, D., Gerber-Lemaire, S., Bonacina, L., and Wolf, J.-P. (2014) Deep UV generation and direct DNA photo-interaction by harmonic nanoparticles in labelled samples. Nanoscale 6: 2929-2936 (10.1039/C3NR05897B) Staedler-2014 (4.77 MB).

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