Nanoplasmonics and surface enhanced spectroscopy

Plasmonic effect of Ag triangular nanoprisms on electronic processes in Ce0.85Tb0.15F3 nanoparticles - CTAB shell - chlorin e6 nanosystem
Losytskyy M.Yu.1, Shcherbakov O.B.2, Yeshchenko O.A.1, Golovynskyi S.3, Berezovska N.I.1, Dmytruk I.M.1, Yashchuk V.M.1 
1 Taras Shevchenko National University of Kyiv, Volodymyrs’ka Str. 64/13, Kyiv-01601, Ukraine. 
E-mail: mlosytskyy@univ.kiev.ua; mlosytskyy@gmail.com
2 Zabolotny Institute of Microbiology and Virology, NAS of Ukraine, Zabolotnogo Str. 154, Kyiv-03680, Ukraine.
3 College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China.

X-ray photodynamic therapy (X-ray PDT) is an approach for cancer treatment, where the sensitizer generating singlet oxygen under X-ray excitation and thus destroying cancer tissue is used. Nanosystems (NS) developed as potential sensitizers contain scintillator part excited by X-rays and sensitizer part generating singlet oxygen; electronic excitation energy transfer (EEET) occurs from the former to the latter. Recently we studied EEET in the NS containing Ce0.85Tb0.15F3 nanoparticles (NP) and chlorin e6 photosensitizer held together with cetrimonium bromide (CTAB) shell, and EEET from Ce3+ to chlorin e6 was shown [1]. 
Here, in order to find the ways to enhance the efficiency of NS for X-ray PDT, we studied the possibility to enhance the electronic processes in Ce0.85Tb0.15F3 NP - CTAB - chlorin e6 NS by the plasmonic effect of silver triangular nanoprisms (AgTNP). Thus, AgTNP were added to the suspension of Ce0.85Tb0.15F3 NP - CTAB - chlorin e6 NS. Fluorescence excitation spectrum of chlorin e6 showed that efficiency of Ce3+-to-chlorin e6 EEET does not change upon addition of AgTNP; at the same time, emission intensity of chlorin e6 increased for 70%. This points to the binding of AgTNP with Ce0.85Tb0.15F3 NP - CTAB - chlorin e6 NS and plasmonic enhancement of chlorin e6 fluorescence. The effect of AgTNP on the singlet oxygen generation by the studied NS should be further investigated. 

1.	Losytskyy M.Yu., Kuzmenko L.V., Shcherbakov O.B., Gamaleia N.F., Marynin A.I., Yashchuk V.M. Energy Transfer in Ce0.85Tb0.15F3 Nanoparticles- CTAB Shell-Chlorin e6 System // Nanoscale Res Lett.-2017.-12.-294.