Nona Semana Integrada do Instituto de Física de São Carlos

Two photon absorption of several amino-styryl purines for application in fluorescent probes and biological imaging

Não agendado

20m

Doutorado

Palestrante

Leandro Zucolotto Cocca

Descrição

Organics fluorescent molecules has received great notoriety in last decades due to the wide application range, in specific, purines molecules have photophysical properties, such as high fluorescence quantum yield and considerable Stokes shift, which make them good candidates for applications as fluorescent probes, DNA detection and biological imaging of live cells.(1) Furthermore, push-pull structures can be added in main purine structure, this fact can modify the spectroscopy properties of purines, increasing fluorescence quantum yields and Stokes shift. The determination of two photon absorption (2PA) spectrum is important in view of the applications already mentioned, imaging of cells or fluorescent probes through 2PA can present great advantages over the one photon absorption (1PA). It is due to the ease of filtering between signal and noise and depth of penetration, characteristics of 2PA. Here, we characterized, using linear and nonlinear spectroscopy, nine amino-styryl purines distinguished by distinct push-pull structures. Fluorescence life times, fluorescence quantum yield, permanent and transition dipole moments and molar absorptivity (1PA) were determined through linear optics techniques. 2PA spectra were determined using Z-scan technique.(2) The results showed that changes of push-pull structures modify fluorescence quantum yield and absorption wavelengths windows for 1PA and 2PA. However, fluorescence life time is not suffering considerably modification by changing the push-pull groups. Lastly, 2PA spectra have a shift on the maximum absorption, which varies according to the push-pull structure added to the purine structure, around 750 nm covering the therapeutic window.

Referências

1 VABRE, R. et al. Synthesis and evaluation of spectroscopic properties of newly synthesized push-pull 6-amino-8-styryl purines. Dyes and Pigments, v.105, p.145-151, 2014.doi: 1.1016/j.dyepig.2014.01.025.
2 SHEIK-BAHAE, M. et al. Sensitive measurement of optical nonlinearities using a single beam. Journal of Quantum Electronics,v. 26, n.4,p.760-769, 1990.