Nanotechnology for healthcare

GdYVO4:Eu3+ nanoparticles-triggered effects on cultured dermal fibroblasts
Prokopyuk V.Yu.1, Onishchenko A.I.1, Yefimova S.L.2, Maksimchuk P.O.2, Tkachenko A.S.1
1 Research Institute of Experimental and Clinical Medicine, Kharkiv National Medical University, Nauky ave. 4, Kharkiv-61022, Ukraine. 
E-mail: as.tkachenko@knmu.edu.ua 
2 Yu.V. Malyukin Department of Nanostructured Materials, Institute for Scintillation Materials National Academy of Sciences of Ukraine, Nauky ave. 60, Kharkiv-61072, Ukraine. 

Biomedical application of nanomaterials has been expanding for decades. In particular, scintillating nanomaterials can be used to enhance the effects of photodynamic and radiation therapies in cancer. 
The aim of this study was to compare the effects of UV light-activated and non-activated gadolinium-yttrium orthvanadate nanoparticles (GdYVO4:Eu3+) used in various concentrations on cultured dermal fibroblasts. 
Materials and methods. Nanoparticles were synthesized in accordance with the previously developed approach. They are characterized by a spherical shape with a diameter of 1-2 nm. Fibroblasts isolated from rat embryos and cultured in culture flasks were incubated with various concentrations of nanoparticles (0 - 320 µg/ml) either treated with UV-light (40 minutes) for 24 h or not treated. The effects of direct exposure to nanoparticles were assessed by microscopic examination and cytotoxicity tests, including the MTT and neutral red uptake assays. 
	Results. The concentrations of both UV light-activated and not activated nanoparticles below 40 µg/ml were found to affect neither fibroblast monolayer visually, nor the results of cytotoxocity tests suggesting that nanoparticles are safe towards dermal fibroblasts. The concentrations of 80 µg/ml and above increased the metabolic activity of cells with no statistically significant (p above 0.05) differences between the UV light-exposed and not exposed nanoparticles. The cell viability was not compromised even in case of the exposure to the highest concentration used in this study, evidenced by the outcome of neutral red uptake assay. However, it is worth emphasizing that the cells start losing their adhesive properties after being exposed to at least 80 µg/ml nanoparticles. UV light-treated nanoparticles were observed to alter fibroblast adhesion more significantly compared with the untreated ones. 
Conclusions. GdYVO4:Eu3+ nanoparticles are cytotoxic towards fibroblasts when their content in the culture exceeds 80 µg/ml with stronger damaging effects provided by the UV light-exposed particles.