title: Magnetic-luminescent YbPO4:Er,Dy microspheres designed for tumor theranostics with synergistic effect of photodynamic therapy and chemotherapy.
abstract: In this paper, magnetic and fluorescent bifunctional YbPO4:Er,Dy microspheres were synthesized via a simple solvothermal method. The prepared microspheres exposed to 980 nm near-infrared (NIR) laser light emitted bright upconversion fluorescence (450-570 nm) after calcination at high temperatures (>800°C). Results of magnetic resonance studies demonstrated that the YbPO4:Er,Dy microspheres are more suitable to be used as a transverse relaxation time (negative) contrast magnetic resonance imaging agent. The microspheres successfully entered the human hepatocellular carcinoma cells and presented low toxicity. A well-selected photodynamic therapy (PDT) drug, merocyanine 540 (MC540) with an ultraviolet-visible spectroscopy absorption maximum of 540 nm, was loaded onto the microspheres to obtain YbPO4:Er,Dy-MC540. Since the upconversion fluorescence emitting from the microspheres could be absorbed by MC540 with a small absorption/emission disparity, YbPO4:Er,Dy-MC540 could kill the hepatocellular carcinoma cells via PDT mechanism effectively. In other words, being upconverting particles, the prepared microspheres acted as light transducers in the NIR light-triggered PDT process. A chemotherapy drug, doxorubicin, was further loaded onto YbPO4:Er,Dy-MC540 to achieve enhanced antitumor effect based on synergistic therapeutic efficacy of PDT and chemotherapy. It is expected that the prepared YbPO4:Er,Dy microspheres have applications in tumor theranostics including magnetic-fluorescent bimodal imaging and NIR light-triggered PDT.
authors.affiliation: Lab of Functional and Biomedical Nanomaterials, College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Lab of Functional and Biomedical Nanomaterials, College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, People's Republic of China.
authors.forename: Dong
authors.initials: D
authors.lastname: Xu
authors.affiliation: Lab of Functional and Biomedical Nanomaterials, College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, People's Republic of China.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Wei
authors.affiliation: Lab of Functional and Biomedical Nanomaterials, College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, People's Republic of China.
authors.forename: Kezheng
authors.initials: K
authors.lastname: Chen
mesh_terms: D001672:Biocompatible Materials; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D004357:Drug Synergism; D056945:Hep G2 Cells; D006801:Humans; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008027:Light; D049408:Luminescent Agents / Q000737:chemistry; D008280:Magnetics; D008863:Microspheres; D010778:Photochemotherapy; D011744:Pyrimidinones / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology*
chemical_list: D001672:Biocompatible Materials; D028581:Lanthanoid Series Elements; D049408:Luminescent Agents; D011744:Pyrimidinones; C003954:merocyanine dye
keywords: fluorescent; lanthanide; upconversion