title: Aqueous synthesis of Ag and Mn co-doped In2S3/ZnS quantum dots with tunable emission for dual-modal targeted imaging.
abstract: Here, we present the microwave-assisted synthesis of In2S3/ZnS core/shell quantum dots (QDs) co-doped with Ag+and Mn2+(referred to as AgMn:In2S3/ZnS). Ag+altered the optical properties of the host QDs, whereas the spin magnetic moment (S=5/2) of Mn2+efficiently induced the longitudinal relaxation of water protons. To the best of our knowledge, this is the first report of the aqueous synthesis of color-tunable AgMn:In2S3/ZnS core/shell QDs with magnetic properties. The synthetic procedure is rapid, facile, reproducible, and scalable. The obtained QDs offered a satisfactory quantum yield (45%), high longitudinal relaxivity (6.84s-1mM-1), and robust photostability. In addition, they exhibited excellent stability over a wide pH range (5-12) and high ionic strength (0.15-2.0M NaCl). As seen by confocal microscopy and magnetic resonance imaging, AgMn:In2S3/ZnS conjugated to hyaluronic acid (referred to as AgMn:In2S3/ZnS@HA) efficiently and specifically targeted cluster determinant 44, a receptor overexpressed on cancer cells. Moreover, AgMn:In2S3/ZnS@HA showed negligible cytotoxicity in vitro and in vivo, rendering it a promising diagnostic probe for dual-modal imaging in clinical applications.
  
  
  
  In this manuscript, we reported a facial and rapid method to prepare In2S3/ZnS core/shell quantum dots (QDs) co-doped with Ag+and Mn2+(referred to as AgMn:In2S3/ZnS). Ag+dopants were used to alter the optical properties of the In2S3host, whereas Mn2+co-dopants with their unpaired electrons provided paramagnetic properties. The emission wavelength of the core/shell QDs could be tuned from 550 to 743nm with a maximum PL quantum yield of 45%. The resulting core/shell QDs also maintained a stable emission in aqueous solution at broad ranges of pH (5-12) and ionic strength (0.15-2.0M NaCl), as well as a high photostability under continuous irradiation. In vivo cytotoxicity experiments showed that up to 500μg/mL AgMn:In2S3/ZnS@HA did not cause obvious toxicity to zebrafish embryos. In vitro targeted cell luminescence and magnetic resonance imaging showed that AgMn:In2S3/ZnS conjugated to hyaluronic acid was selectively and efficiently internalized in CD44-expressing tumor cells, confirming that the resultant QDs could function as dual-modal imaging probes for accurate diagnosis.
authors.affiliation: Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan, ROC.
authors.forename: Pei-Yu
authors.initials: PY
authors.lastname: Lai
authors.affiliation: Institute of Bioscience and Biotechnology and Center for Marine Bioenvironment and Biotechnology, National Taiwan Ocean University, Keelung 20224, Taiwan, ROC.
authors.forename: Chih-Ching
authors.initials: CC
authors.lastname: Huang
authors.affiliation: Department of Chemical and Materials Engineering, National Yunlin University of Science and Technology, Yunlin 64002, Taiwan, ROC.
authors.forename: Tzung-Han
authors.initials: TH
authors.lastname: Chou
authors.affiliation: School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan, ROC; Biomedical Engineering Research and Development Center, China Medical University Hospital, Taichung 404, Taiwan, ROC; Department of Dentistry, Taipei Medical University-Shuang Ho Hospital, New Taipei City 235, Taiwan, ROC; 3D Global Biotechnology Inc., New Taipei City 221, Taiwan, ROC; Department of Dentistry, Taipei Medical University Hospital, Taipei 110, Taiwan, ROC. Electronic address: klou@tmu.edu.tw.
authors.forename: Keng-Liang
authors.initials: KL
authors.lastname: Ou
authors.affiliation: Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan, ROC. Electronic address: jychang@mail.ntust.edu.tw.
authors.forename: Jia-Yaw
authors.initials: JY
authors.lastname: Chang
mesh_terms: D000818:Animals; D016923:Cell Death; D003102:Colloids / Q000737:chemistry; D006367:HeLa Cells; D006801:Humans; D006820:Hyaluronic Acid / Q000737:chemistry; D021621:Imaging, Three-Dimensional; D007204:Indium / Q000737:chemistry*; D008280:Magnetics; D008345:Manganese / Q000737:chemistry*; D008546:Melanoma, Experimental; D055620:Optical Phenomena; D045663:Quantum Dots / Q000737:chemistry* / Q000648:ultrastructure; D012834:Silver / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013440:Sulfides / Q000737:chemistry*; D014867:Water / Q000737:chemistry*; D015027:Zebrafish; D017967:Zinc Compounds / Q000737:chemistry*
chemical_list: D003102:Colloids; D013440:Sulfides; D017967:Zinc Compounds; D007204:Indium; D014867:Water; D012834:Silver; D008345:Manganese; D006820:Hyaluronic Acid; C031238:zinc sulfide
keywords: Hyaluronic acid; In(2)S(3); Luminescence probe; Quantum dots; T1-weighted images