Optogenetics technology uses light-sensitive proteins to achieve cell control by visible light. When genetically engineered cells, such as neurons, expressing a light-sensitive protein, are bombarded with light, a conformational change of the cell channels, or specific signaling pathways, are opened for neural activation. Challenges for biomedical applications include both the synthesis of NaGdF4:Eu nanoparticles (NPs) and control of the NP size, in order for them to be used for optogenetics modulation. The procedure for synthesis of the NaGdF4:Eu NPs is a chemical reaction followed a hydrothermal treatment at 210 oC. The target particle size is around 50 nm to conform with an insertion for biomedical applications. Compositional mappings in Scanning Transmission Electron Microscopy (STEM) indicate that NaGdF4:Eu are fabricated successfully into NPs, Eu atoms are effectively introduced into the NaGdF4 matrix, and not in the form of agglomerated particles. The mapped images of NaGdF4:Eu show that an evolution of NPs size and shape occurred in the hydrothermal step: big spherical particles transformed into dump-bell shapes which then separated at their center to form two smaller particles. The size of the NPs are therefore reduced during this process. The final average sizes of the NaGdF4 NPs are 67±17 nm. A variation of temperatures from 180, 210 to 230 oC was performed and the optimal condition was set at 210 oC. Extended hydrothermal treatment times (2, 4 and 6 hours) under the high temperature (210 oC) did not further improve particle size distributions or decrease the NP sizes significantly. The NaGdF4:Eu NPs were measured by TEM, STEM, ED and XRD. XRD spectra suggest that the crystal structure of the sample fits well to standard crystal data of Na3Gd3F12, and Na3Eu3F12, ie, NaGdF4 and NaEuF4, respectively.

Synthesis, characterization and development of nanostructured materials NaGdF4: Eu for biomedical applications

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.