Mikhaylov Alexander, de Reguardati Sophie, Pahapill Jüri, Callis Patrik R, Kohler Bern, Rebane Aleksander
Department of Physics, Montana State University, Bozeman, MT 59717, USA.
National Institute of Chemical Physics and Biophysics, Tallinn 12618, Estonia.
Biomed Opt Express. 2018 Jan 5;9(2):447-452. doi: 10.1364/BOE.9.000447. eCollection 2018 Feb 1.
Fluorescent DNA base analogs and intrinsic fluorophores are gaining importance for multiphoton microscopy and imaging, however, their quantitative nonlinear excitation properties have been poorly documented. Here we present the two-photon absorption (2PA) spectra of 2-aminopurine (2AP), 7-methyl guanosine (7MG), isoxanthopterin (IXP), 6-methyl isoxanthopterin (6MI), as well as L-tryptophan (L-trp) and 3-methylindole (3MI) in aqueous solution and some organic solvents measured in the wavelength range 550 - 810 nm using femtosecond two-photon excited fluorescence (2PEF) and nonlinear transmission (NLT) methods. The peak 2PA cross section values range from 0.1 GM (1 GM = 10 cm s photon) for 2AP to 2.0 GM for IXP and 7MG. Assuming typical excitation conditions for a scanning 2PEF microscope, we estimate a maximum image frame rate of ~175 frames per second (FPS).
荧光DNA碱基类似物和固有荧光团在多光子显微镜和成像中变得越来越重要，然而，它们的定量非线性激发特性却鲜有文献记载。在此，我们展示了2-氨基嘌呤（2AP）、7-甲基鸟苷（7MG）、异黄蝶呤（IXP）、6-甲基异黄蝶呤（6MI）以及L-色氨酸（L-trp）和3-甲基吲哚（3MI）在水溶液和一些有机溶剂中的双光子吸收（2PA）光谱，该光谱是在550 - 810 nm波长范围内使用飞秒双光子激发荧光（2PEF）和非线性透射（NLT）方法测量得到的。2PA截面峰值从2AP的0.1 GM（1 GM = 10 cm s光子）到IXP和7MG的2.0 GM不等。假设扫描2PEF显微镜的典型激发条件，我们估计最大图像帧率约为每秒175帧（FPS）。
