title: Fluorescent Heterodoped Nanotetrapods as Synergistically Enhancing Positive and Negative Magnetic Resonance Imaging Contrast Agents.
abstract: In this work, we report Mn-Fe heterodoped ZnSe tetrapod nanocrystals (NCs) synthesized to synergistically enhance contrast in both T1- and T2-weighted magnetic resonance imaging (MRI). The proposed NCs were prepared using a customized heteroarchitecture such that the manganese (Mn) is confined in the core and iron (Fe) in the branches of the tetrapods. The elemental composition and profile of these NCs were studied using X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, and inductively coupled plasma mass spectroscopy. Photoluminescence quantum yield of these heterodoped NCs in water is ∼30%. Magnetic measurements reveal the simultaneous presence of superparamagnetic and paramagnetic behavior in these NCs because of the coexistence of Mn(2+) and Fe(2+) dopants. Their potential as simultaneous positive and negative MRI contrast agents was demonstrated by relaxivity measurements and in vivo MRI. From the in vivo studies, we also found that these NCs (with a hydrodynamic diameter of 20 nm) are excreted from the body within 24 h after the injection. Therefore, these heterodoped tetrapods NCs, while being fluorescent and safe, hold great future as a synergistically enhancing dual-modal MRI contrast agent.
authors.affiliation: LUMINOUS! Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 639798, Singapore.|UNAM-Institute of Materials Science and Nanotechnology, UMRAM-National Magnetic Resonance Research Center, Department of Electrical and Electronics Engineering, Department of Physics, and Department of Molecular Biology and Genetics, Bilkent University , Ankara 06800, Turkey.
authors.forename: V K
authors.initials: VK
authors.lastname: Sharma
authors.affiliation: LUMINOUS! Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 639798, Singapore.
authors.forename: A
authors.initials: A
authors.lastname: Alipour
authors.affiliation: LUMINOUS! Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 639798, Singapore.
authors.forename: Z
authors.initials: Z
authors.lastname: Soran-Erdem
authors.affiliation: LUMINOUS! Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 639798, Singapore.
authors.forename: Y
authors.initials: Y
authors.lastname: Kelestemur
authors.affiliation: LUMINOUS! Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 639798, Singapore.
authors.forename: Z G
authors.initials: ZG
authors.lastname: Aykut
authors.affiliation: LUMINOUS! Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 639798, Singapore.|UNAM-Institute of Materials Science and Nanotechnology, UMRAM-National Magnetic Resonance Research Center, Department of Electrical and Electronics Engineering, Department of Physics, and Department of Molecular Biology and Genetics, Bilkent University , Ankara 06800, Turkey.
authors.forename: H V
authors.initials: HV
authors.lastname: Demir
keywords: contrast agents; fluorescence imaging; heterodoped ZnSe nanocrystals; magnetic resonance imaging; nanotetrapods