Nanocomposites and nanomaterials

Synthesis and properties of nanodisperse scintillators for photodynamic therapy of tumors of the cranial cavity and bone tissue
Kusyak A.P. 1, Petranovska A.L.1, Shuba Y.M.2, Kravchuk D.I.2, Kravchuk L.I.2, Bur'yanov O.A.3, Chornyi V.S.3, Sobolevsky Y. L.3, Gorbyk P.P.1
1 Chuiko Institute of Surface Chemistry of the NAS of Ukraine.
 General Naumov Str., 17, Kyiv - 03164, Ukraine.
E-mail: a_kusyak@ukr.net
2 Bogomolets Institute of Physiology of the NAS of Ukraine.
 Bogomoletz Str., 4, Kyiv - 01601, Ukraine.
3 Bogomolets National Medical University.
 Taras Shevchenko Boulevard, 13, Kyiv - 02000, Ukraine.

The direction of solving the problems of minimally invasive treatment of malignant tumors located in hard-to-reach areas of the bodycan be the synthesis of highly efficient nanodispersed scintillators, the study of their properties and prospects for use in photodynamic and optopharmacological therapy of tumors in conditions of excitation by "soft" X-rays.
The aim of this work is to develop a promising method for the synthesis of nanosized scintillators, active in a wide range of electromagnetic radiation - from X-ray to infrared. The development of a relatively simple, economical and well-reproducible method for the synthesis of nanosized scintillators based on lanthanum fluoride doped with terbium was chosen.
LaF3 crystals doped with Tb3+ (LaF3:Tb) were selected as scintillation nanoparticles. The conversion of X-rays to fluorescents  is based on the mechanism by which Tb3+ electrons exhibit transitions in the “blue” (transitions 5D3 → 7Fj) and “green” (transitions 5D4 → 7Fj) regions of the spectrum, accompanied by photoluminescent effects at  = 487, 542, 582 and 620 nm, and the mechanism of resonant fluorescence energy transfer (FRET) can lead to the activation of a photosensitizer, with an energy transfer efficiency of up to 56.7%, which induces agents for the treatment of cancer.
Scintillation nanoparticles of LaF3: Tb up to 30 nm in size were synthesized by coprecipitation from an aqueous solution. The particles are well dispersed in aqueous solution and are characterized by high biocompatibility.