High Concentrations of GdYVO4:Eu3+ Nanoparticles Alter the State of White Blood Cell Membranes by Increasing Their Microviscosity

Aim. To evaluate the effects of GdYVO4:Eu3+ nanoparticles on the state of leukocyte cell membranes upon direct exposure.Materials and methods. The membranotropic fluorescent probe 2-(2’-OH-phenyl)-5-(4’-biphenyl)-1,3-oxazole was incubated directly with leukocyte suspensions obtained from blood treated directly with different concentrations of GdYVO4:Eu3+ nanoparticles (0 μg/ml, 20 μg/ml, 40 μg/ml, 80 μg/ml) during 24 h. The fluorescence of normal and tautomeric forms of the probe was registered using a FL8500 Fluorescence Spectrophotometer (Perkin Elmer, USA).Results. Our findings indicate that the statistically significant elevation in values of the tautomeric form fluorescence intensity-to-normal form fluorescence intensity ratio (IT*/IN*) was observed only for suspensions with the highest concentration of nanoparticles used, while at low concentrations nanoparticles did not alter the state of phospholipid bilayer in the region of membranes where the probe locates.Conclusions. Low concentrations of GdYVO4:Eu3+ nanoparticles don’t alter the lipid order of leukocyte cell membranes, while their high concentrations promote an increase in lipid order suggesting a decrease in fluidity and an increase in microviscosity of the area of phospholipid bilayer where the probe locates.