title: Synthesis and Characterization of Mn:ZnSe/ZnS/ZnMnS Sandwiched QDs for Multimodal Imaging and Theranostic Applications.
abstract: In this work, a facile aqueous synthesis method is optimized to produce Mn:ZnSe/ZnS/ZnMnS sandwiched quantum dots (SQDs). In this core-shell co-doped system, paramagnetic Mn(2+) ions are introduced as core and shell dopants to generate Mn phosphorescence and enhance the magnetic resonance imaging signal, respectively. T1 relaxivity of the nanoparticles can be improved and manipulated by raising the shell doping level. Steady state and time-resolved optical measurements suggest that, after high level shell doping, Mn phosphorescence of the core can be sustained by the sandwiched ZnS shell. Because the SQDs are free of toxic heavy metal compositions, excellent biocompatibility of the prepared nanocrystals is verified by in vitro MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. To explore the theranostic applications of SQDs, liposome-SQD assemblies are prepared and used for ex vivo optical and magnetic resonance imaging. In addition, these engineered SQDs as nanocarrier for gene delivery in therapy of Panc-1 cancer cells are employed. The therapeutic effects of the nanocrystals formulation are confirmed by gene expression analysis and cell viability assay.
authors.affiliation: School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore.
authors.forename: Yucheng
authors.initials: Y
authors.lastname: Wang
authors.affiliation: School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore.
authors.forename: Bo
authors.initials: B
authors.lastname: Wu
authors.affiliation: School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore.
authors.forename: Chengbin
authors.initials: C
authors.lastname: Yang
authors.affiliation: Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, NY, 14260, USA.
authors.forename: Maixian
authors.initials: M
authors.lastname: Liu
authors.affiliation: School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore.
authors.forename: Tze Chien
authors.initials: TC
authors.lastname: Sum
authors.affiliation: School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore.
authors.forename: Ken-Tye
authors.initials: KT
authors.lastname: Yong
mesh_terms: D045744:Cell Line, Tumor; D006801:Humans; D057446:Hydrodynamics; D008081:Liposomes; D049449:Luminescence; D008279:Magnetic Resonance Imaging; D008345:Manganese / Q000737:chemistry*; D017895:Manganese Compounds / Q000737:chemistry*; D008856:Microscopy, Fluorescence; D015335:Molecular Probes / Q000737:chemistry; D064847:Multimodal Imaging / Q000379:methods*; D010316:Particle Size; D045663:Quantum Dots / Q000737:chemistry* / Q000648:ultrastructure; D034741:RNA, Small Interfering / Q000378:metabolism; D018036:Selenium Compounds / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013440:Sulfides / Q000737:chemistry*; D000068936:Theranostic Nanomedicine / Q000379:methods*; D014162:Transfection; D017967:Zinc Compounds / Q000737:chemistry*
chemical_list: D008081:Liposomes; D017895:Manganese Compounds; D015335:Molecular Probes; D034741:RNA, Small Interfering; D018036:Selenium Compounds; D013440:Sulfides; D017967:Zinc Compounds; D008345:Manganese; C041368:manganese sulfide; C031238:zinc sulfide; C044696:zinc selenide
keywords: cancer therapies; doped quantum dots; gene delivery; magnetic resonance imaging; multimodal imaging