Intracellular Nanotransducers for Photobiomodulation Applications




Tek, Sumeyra

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Upconversion nanoparticles (UCNPs) are trivalent lanthanide ion doped rare-earth crystalline materials that convert NIR light into high energy photons throughout the UV-Visible range as multiple sharp emission peaks. The use of NIR irradiation for intracellular photon emission provides a non-invasive optical biomodulation platform that employs UCNPs as on-demand remote controlled intracellular nanotransducers (ICNTs) for desired modulation on cell function. The opportunities that are offered by various crystal designs include tuning their upconversion emission properties, color sensitive emission enhancement, surface decoration for specific applications and even shifting the excitation wavelength that is more desirable for biomedical applications. In this study, we achieved color sensitive upconversion enhancement through fine tuning of the lanthanide dopant ions in core-shell designs. The use of a facile microwave-assisted polyol synthesis method allows the use of green organic solvents and biocompatible surfactants that makes bright, small size, non-toxic core and core-shell nanoparticles. In this work, polyvinylpyrrolidone (PVP)-coated LaF3 core-shell UCNPs are synthesized, and elucidation of the optical enhancement mechanism with active and inert shell homo-epitaxial designs is achieved through detailed crystal analysis at the atomic level and employed these nanoparticles as intracellular nanotransducers for photobiomodulation of ARPE-19 retina epithelial cells. Another in-vitro cell study is conducted with the use of polyethylenimine (PEI)-coated NaYF4 upconversion nanoparticles, synthesized with the same method, for optical stimulation of neuronal NG108-15 cells through a combination of NIR and upconversion light therapy. Modulatory effects are analyzed through cell viability measurements, two-photon/confocal microscopy, fluorescence microscopy and SEM whole cell imaging.


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biomedical, core-shell, microwave-assisted synthesis, nanoparticle, photobiomodulation, upconversion



Physics and Astronomy