A New and Facile Method To Prepare Uniform Hollow MnO/Functionalized mSiO(2) Core/Shell Nanocomposites

Department of Chemistry, National Taiwan University, Taipei 106, Taiwan.
ACS Nano (Impact Factor: 12.88). 05/2011; 5(5):4177-87. DOI: 10.1021/nn200928r
Source: PubMed


Trifunctional uniform nanoparticles comprising a manganese nanocrystal core and a functionalized mesoporous silica shell (MnO@mSiO(2)(Ir)@PEG, where Ir is an emissive iridium complex and PEG is polyethylene glycol) have been strategically designed and synthesized. The T(1) signal can be optimized by forming hollow core (H-MnO@mSiO(2)(Ir)@PEG) via a novel and facile etching process, for which the mechanism has been discussed in detail. Systematic investigation on correlation for longitudinal relaxation (T(1)) versus core shapes and shell silica porosity of the nanocomposites (MnO, H-MnO, MnO@SiO(2), MnO@mSiO(2), H-MnO@mSiO(2)) has been carried out. The results show that the worm-like nanochannels in the mesoporous silica shell not only increase water permeability to the interior hollow manganese oxide core for T(1) signal but also enhance photodynamic therapy (PDT) efficacy by enabling the free diffusion of oxygen. Notably, the H-MnO@mSiO(2)(Ir)@PEG nanocomposite with promising r(1) relaxivity demonstrates its versatility, in which the magnetic core provides the capability for magnetic resonance imaging, while the simultaneous red phosphorescence and singlet oxygen generation from the Ir complex are capable of providing optical imaging and inducing apoptosis, respectively.

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Available from: Hsieh-Chih Chen, Oct 13, 2015
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    • "Hollow mesoporous silica particles (H-MSPs) with unique large hollow cavities and mesoporous shells have attracted extensive attention in both fundamental and practical studies because of their unique properties [1], such as low density, large surface area, high cargo-loading capacity, as well as their potential applications in drug/gene delivery [2] [3], biomedical imaging [4] catalysis [5], etc. A recent breakthrough in the field of H-MSP preparation is the so-called 'structural difference-based selective dissolution' strategy which does not need soft/hard templates for templating the hollow cavities [6]. "
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    ABSTRACT: One-pot hard/soft template-free synthesis of hollow structured mesoporous silica particles (H-MSPs) with enlarged pore sizes was developed. By a simplified in situ hydrothermal treatment under mild conditions (70 °C), a hollow interior evolution to a final size of ~150 nm was successfully induced for the as-prepared particles from the sol–gel synthesis solution. The particles were evenly spherical with an average particle diameter of 350 nm, as well as a mean pore size of 5 nm in the mesoporous shell. Pore-swelling agents and aminosilane were demonstrated to contribute to the chemical irregularities in the silica network formation during particle growth, consequently leading to selective dissolution of the interior silica.
    Materials Letters 03/2015; 143:140-143. DOI:10.1016/j.matlet.2014.12.067 · 2.49 Impact Factor
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    • "The iridium complexes have been also conjugated to MnO based mesoporous silicate nanoparticles that exhibit T1 weighted contrast enhancement. The photodynamic therapy effect is proved efficacious at in vitro HeLa cell model (Peng et al., 2011). "
    Smart Nanoparticles Technology, 04/2012; , ISBN: 978-953-51-0500-8
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    • "Indeed, MnO nanoparticles with intact silica coatings only have an r1 of 0.07 mM-1s-1. Such a figure was found increased to 0.16 mM-1s-1 for MnO@mSiO2 and 0.2 mM-1s-1 for H-MnO@mSiO2 32. "
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    ABSTRACT: MRI is one of the most important imaging tools in clinics. It interrogates nuclei of atoms in a living subject, providing detailed delineation with high spatial and temporal resolutions. To compensate the innate low sensitivity, MRI contrast probes were developed and widely used. These are typically paramagnetic or superparamagnetic materials, functioning by reducing relaxation times of nearby protons. Previously, gadolinium(Gd)-based T(1) contrast probes were dominantly used. However, it was found recently that their uses are occasionally associated with nephrogenic system fibrosis (NSF), which suggests a need of finding alternatives. Among the efforts, manganese-containing nanoparticles have attracted much attention. By careful engineering, manganese nanoparticles with comparable r(1) relaxivities can be yielded. Moreover, other functionalities, be a targeting motif, a therapeutic agent or a second imaging component, can be loaded onto these nanoparticles, resulting in multifunctional nanoplatforms.
    Theranostics 01/2012; 2(1):45-54. DOI:10.7150/thno.3448 · 8.02 Impact Factor
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