Journal of Biotechnology & Biomaterials
Open Access

Abstract

Trivalent rare earth lanthanide ions (Re3+) are used as dopants in specific inorganic ceramics because of their unique luminescence characteristic known as photon upconversion (UC) process. In UC process long wavelength excitation radiations in infrared (IR) or near IR (NIR) are absorbed and shorter wavelengths, higher energy, radiations from ultraviolet (UV) to IR are emitted. UC nanoparticles (UCNPs) have several advantages over conventional luminescent materials like organic dyes or semiconductor quantum dots (QDs) for bioimaging applications. These materials exhibit excellent photostability, continuous emission capability, sharp emission bands, longer luminescence lifetime and low cytotoxicity. Moreover, NIR excitation source used in UC process, compared to UV excitation used in conventional luminescent materials, reduces the photodamage to living organisms and minimizes the autofluorescence from biological samples, along with enhanced tissue penetration depth. Here, we report on the fabrication of well dispersed, spherical Y₂O₃:Tm3+, Yb3+ UCNPs with average size of 70±8 nm using microwave assisted heating method. This is a green, energy efficient and highly reproducible method. X-Ray powder diffraction analysis confirmed the highly crystalline cubic Y2O3 phase structure of synthesized UCNPs. Photoluminescence analysis of Y₂O₃:Tm3+, Yb3+ nanoparticles showed that in 980 nm laser diode excitation nanoparticles emit strong blue, weak red and NIR emissions attributed to the 1G4→3H6, 1G4→3F4 and 3H4→3H6 transitions of Tm3+ ion, respectively. Further, the effect of the molar concentration of Tm3+ and Yb3+ on UC intensity of nanoparticles has been investigated. Due to the enhanced characteristics and expected low toxicity the Y2O3:Tm3+, Yb3+ UCNPs are promising alternatives to conventional luminescent probes for bioimaging.

Biography

Adrine Malek Khachatourian has completed her BSc degree in Material Science Engineering and MSc degree in Materials Engineering-Ceramic in 2010 from Iran University of Science and Technology (IUST). She has spent two years on her PhD at IUST and currently she is pursuing her PhD study at the Department of Materials and Nano Physics from KTH Royal Institute of Technology, Stockholm, Sweden under the guidance of Professor Muhammet S Toprak. Her research interest focuses on synthesis and characterization of various rare earth doped Yttrium oxide luminescent nanoparticles for fluorescence bioimaging via microwave assisted heating method.

Email: adrine@kth.se