Synthesis of biocompatible and bioresorbable composite materials such as “polymer matrix-mineral constituent,” which stimulate the natural growth of living tissues and the restoration of damaged parts of the body, is one of the challenging problems in regenerative medicine and material science. Composite films of bioresorbable polymer of polyvinylpyrrolidone (PVP) and hydroxyapatite (HA) were obtained. HA was synthesized in situ in a solution of polymer mixture. We applied electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) approaches to study their properties. EPR in two frequency ranges allowed to derive spectroscopic parameters of the nitrogen-based light and radiation-induced paramagnetic centers in HA, PVP and PVP-HA with high accuracy. It was shown that PVP did not significantly affect the EPR spectral and relaxation parameters of the radiation-induced centers in HA. Magic angle spinning (MAS) 1H NMR shows the presence of two signals at 4.7 ppm and -2.15 ppm attributed to “free” water and hydroxyl groups, while the single line - to 31P. NMR relaxation measurements for 1H and 31P show that the relaxation decays are a multicomponent process that can be described by three components of the transverse relaxation times. The obtained results demonstrated that the applied magnetic resonance methods can be used for the control of quality of the synthesis of the PVP-HA composites and, potentially, for the development of analytical tools to follow the processes of the sample treatment, resorption, and degradation.

The Ce0.5Y0.35Tb0.15F3 nanoparticles with CeF3 hexagonal structure were synthesized by co-precipitation technique. The average nanoparticle diameter was 14±1 nm. The luminescence decay curves of Ce0.5Y0.35Tb0.15F3 nanoparticles (λem = 541 nm, 5D4 – 7F5 transition of Tb3+) conjugated with Radachlorin by means of polyvinylpyrrolidone coating as well as without Radachlorin were detected. Efficient nonradiative energy transfer from Tb3+ to the Radachlorin was demonstrated. The maximum energy transfer coefficient for nanoparticles conjugated with Radachlorin via polyvinylpyrrolidone and without the coating were 82% and 55%, respectively. The average distance between nanoparticle surface and Radachlorin was R0 =4.5 nm. The best results for X-ray induced cytotoxicity was observed for NP-PVP-Rch sample at the lowest Rch concentration. In particular, after X-ray irradiation the survival A 549 human lung carcinoma cells decreased by ~12%.