Luminescence properties and cell uptake analysis of Y2O3:Eu, Bi nanophosphors for bio-imaging applications

Abstract

A comparative investigation of nanostructural and photoluminescence properties (PL), functionalization, cytotoxicity and cell uptake of Y2O3:Eu3+,Bi3+ nanoparticles (NPs) fabricated by sol–gel (SG) and combustion synthesis (CS) is reported in this work. A detailed analysis by X-ray diffraction confirmed the formation of pure crystalline cubic phase of Y2O3 and transmission electron microscopy revealed the formation of spheroidal NPs by SG, while CS resulted in NPs with irregular morphology. The photoluminescence analysis of Y2O3: Eu3+,Bi3+ demonstrated red emission from Eu3+ upon near-UV excitation via energy transfer from Bi3+→Eu3+. The Y2O3:Eu3+, Bi3+ (4%, 0.1%) produced by SG approach presented the strongest red emission when excited under 254 and 330 nm excitation-wavelength with quantum yield value of 76% and 22% respectively. SG synthesized Y2O3:Eu3+, Bi3+ (4%, 0.1%) NPs were successfully functionalized with folic acid (FA) for cellular internalization. Cytotoxicity assay and flow cytometry studies of the FA functionalized Y2O3:Eu3+, Bi3+ (4%, 0.1%) NPs in various cancer cells showed good biocompatibility and cellular uptake. Our findings suggest the applicability of sol gel synthesized Y2O3:Eu3+, Bi3+ (4%, 0.1%) NPs for cancer cells bioimaging.