Preparation and characterization of decyl-terminated silicon nanoparticles encapsulated in lipid nanocapsules.

In this Article, we report on the encapsulation of decyl-modified silicon nanoparticles (decyl-SiNPs) into ∼80 nm lipid nanocapsules (LNCs). The decyl-SiNPs were produced by thermal hydrosilylation of hydride-terminated SiNPs (H-SiNPs) liberated from porous silicon. Various techniques, including Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), UV-vis absorption, dynamic light scattering (DLS), and photoluminescence (PL), were used to characterize their size, shape, colloidal, and optical properties. The results indicate that these nanocapsules feature controllable size, good dispersity, high loading rate of SiNPs, colloidal stability in various media, and bright PL. The PL of decyl-SiNPs loaded LNCs was stable upon heating to 80 °C, but was sensitive to basic solutions due to proton-gated emission of the SiNPs arranged at the LNCs interface between the oil phase and the hydrophilic polyethylene glycol moieties of the surfactant. These luminescent nanocapsules are therefore promising candidates as cellular probes for fluorescence imaging. In addition, it was found that TEM imaging of small-sized decyl-SiNPs could be greatly improved by preliminary negative staining of TEM grids with phosphotungstic acid.

[1]  Mark T. Swihart,et al.  Propionic-acid-terminated silicon nanoparticles : Synthesis and optical characterization , 2006 .

[2]  Eli Ruckenstein,et al.  Water-Soluble Poly(acrylic acid) Grafted Luminescent Silicon Nanoparticles and Their Use as Fluorescent Biological Staining Labels , 2004 .

[3]  B. Cheng,et al.  Origin and evolution of photoluminescence from Si nanocrystals embedded in a SiO2 matrix , 2005 .

[4]  Matthew S Rosen,et al.  Silicon nanoparticles as hyperpolarized magnetic resonance imaging agents. , 2009, ACS nano.

[5]  M. Swihart,et al.  Surface functionalization of silicon nanoparticles produced by laser-driven pyrolysis of silane followed by HF-HNO3 etching. , 2004, Langmuir : the ACS journal of surfaces and colloids.

[6]  Michael J Sailor,et al.  Biodegradable luminescent porous silicon nanoparticles for in vivo applications. , 2009, Nature materials.

[7]  A. Marcelis,et al.  Synthesis and cytotoxicity of silicon nanoparticles with covalently attached organic monolayers , 2009 .

[8]  R. Boukherroub,et al.  Silica cross-linked micelles loading with silicon nanoparticles: preparation and characterization. , 2013, ACS applied materials & interfaces.

[9]  S. Bhatia,et al.  Probing the Cytotoxicity Of Semiconductor Quantum Dots. , 2004, Nano letters.

[10]  Warren C. W. Chan,et al.  Quantum Dots in Biological and Biomedical Research: Recent Progress and Present Challenges , 2006 .

[11]  J. Benoit,et al.  A Novel Phase Inversion-Based Process for the Preparation of Lipid Nanocarriers , 2002, Pharmaceutical Research.

[12]  Hong Ding,et al.  Bioconjugation of luminescent silicon quantum dots to gadolinium ions for bioimaging applications. , 2012, Nanoscale.

[13]  T. Hasegawa,et al.  Size-tunable UV-luminescent silicon nanocrystals. , 2010, Small.

[14]  Jonathan K. M. Chun,et al.  Proton Gated Emission from Porous Silicon , 1993 .

[15]  Ken-Tye Yong,et al.  Biocompatible luminescent silicon quantum dots for imaging of cancer cells. , 2008, ACS nano.

[16]  Mark T Swihart,et al.  Efficient surface grafting of luminescent silicon quantum dots by photoinitiated hydrosilylation. , 2005, Langmuir : the ACS journal of surfaces and colloids.

[17]  Uli Lemmer,et al.  Colloidally stable silicon nanocrystals with near-infrared photoluminescence for biological fluorescence imaging. , 2011, Small.

[18]  Silicon nanocrystals dispersed in water: Photosensitizers for molecular oxygen , 2010 .

[19]  Z. Popović,et al.  Amine-terminated silicon nanoparticles: synthesis, optical properties and their use in bioimaging , 2009 .

[20]  R. Boukherroub,et al.  Alkyl passivation and SiO2 encapsulation of silicon nanoparticles: preparation, surface modification and luminescence properties , 2013 .

[21]  Zhenhui Kang,et al.  Small-sized silicon nanoparticles: new nanolights and nanocatalysts. , 2011, Nanoscale.

[22]  R. F. Pinizzotto,et al.  A Comparison of Porous Silicon and Silicon Nanocrystallite Photoluminescence Quenching with Amines , 1996 .

[23]  A. Barras,et al.  Formulation and characterization of polyphenol-loaded lipid nanocapsules. , 2009, International journal of pharmaceutics.

[24]  Charles M Marcus,et al.  Synthesis of long T₁ silicon nanoparticles for hyperpolarized ²⁹Si magnetic resonance imaging. , 2013, ACS nano.

[25]  Michael J Sailor,et al.  Porous silicon nanoparticle photosensitizers for singlet oxygen and their phototoxicity against cancer cells. , 2011, ACS nano.

[26]  E. Gratton,et al.  Carboxyl functionalization of ultrasmall luminescent silicon nanoparticles through thermal hydrosilylation , 2006 .

[27]  Yi Yang,et al.  Assessing clinical prospects of silicon quantum dots: studies in mice and monkeys. , 2013, ACS nano.

[28]  Mark T Swihart,et al.  Energy transfer from a dye donor to enhance the luminescence of silicon quantum dots. , 2012, Nanoscale.

[29]  Lorenzo Pavesi,et al.  Photoluminescence of hydrophilic silicon nanocrystals in aqueous solutions , 2011, Nanotechnology.

[30]  C. M. Marcus,et al.  In vivo magnetic resonance imaging of hyperpolarized silicon particles. , 2013, Nature nanotechnology.

[31]  M. Sailor,et al.  Photoluminescence‐Based Sensing With Porous Silicon Films, Microparticles, and Nanoparticles , 2009 .

[32]  Mark T. Swihart,et al.  Process for preparing macroscopic quantities of brightly photoluminescent silicon nanoparticles with emission spanning the visible spectrum , 2003 .

[33]  Hong Ding,et al.  Biocompatible magnetofluorescent probes: luminescent silicon quantum dots coupled with superparamagnetic iron(III) oxide. , 2010, ACS nano.

[34]  K. Kolasinski,et al.  Dynamics of porous silicon formation by etching in HF + V2O5 solutions , 2010 .

[35]  T. Emrick,et al.  PEGylated silicon nanoparticles: synthesis and characterization. , 2008, Chemical communications.

[36]  Uwe R. Kortshagen,et al.  Silicon nanocrystals with ensemble quantum yields exceeding 60 , 2006 .

[37]  Mark T. Swihart,et al.  Luminescent Colloidal Dispersion of Silicon Quantum Dots from Microwave Plasma Synthesis: Exploring the Photoluminescence Behavior Across the Visible Spectrum , 2009 .

[38]  Rebecca J. Anthony,et al.  Temperature dependent photoluminescence of size-purified silicon nanocrystals. , 2013, ACS applied materials & interfaces.

[39]  Vincent Noireaux,et al.  In Vivo Imaging of Quantum Dots Encapsulated in Phospholipid Micelles , 2002, Science.

[40]  Xueyuan Chen,et al.  Upconversion nanoparticles in biological labeling, imaging, and therapy. , 2010, The Analyst.

[41]  Hong Ding,et al.  In vivo targeted cancer imaging, sentinel lymph node mapping and multi-channel imaging with biocompatible silicon nanocrystals. , 2011, ACS nano.

[42]  H. Zuilhof,et al.  Efficient Energy Transfer between Silicon Nanoparticles and a Ru−Polypyridine Complex , 2009 .

[43]  Matthew G. Panthani,et al.  Graphene-Supported High-Resolution TEM and STEM Imaging of Silicon Nanocrystals and their Capping Ligands , 2012 .

[44]  Tim Liedl,et al.  Cytotoxicity of colloidal CdSe and CdSe/ZnS nanoparticles. , 2005, Nano letters.

[45]  S. N. Bhatia,et al.  Hyperpolarized Long-T1 Silicon Nanoparticles for Magnetic Resonance Imaging , 2009, 0902.0269.

[46]  B. Horrocks,et al.  A miniemulsion polymerization technique for encapsulation of silicon quantum dots in polymer nanoparticles. , 2011, Nanoscale.

[47]  J. Veinot,et al.  Exploration of organic acid chain length on water-soluble silicon quantum dot surfaces. , 2010, Langmuir : the ACS journal of surfaces and colloids.

[48]  J. L. Hueso,et al.  Alkyl passivation and amphiphilic polymer coating of silicon nanocrystals for diagnostic imaging. , 2010, Small.

[49]  Akiyoshi Hoshino,et al.  Water-soluble photoluminescent silicon quantum dots. , 2005, Angewandte Chemie.

[50]  J. Benoit,et al.  Lipid nanocapsules: a new platform for nanomedicine. , 2009, International journal of pharmaceutics.