Surfactant-free fabrication of SiO2-coated negatively charged polymer beads and monodisperse hollow SiO2 particles

Chen, Wanghui; Takai, Chika; Khosroshahi, Hadi Razavi; Fuji, Masayoshi; Shirai, Takashi

doi:10.1016/j.colsurfa.2015.06.008

Cited by 15 publications

(10 citation statements)

References 19 publications

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“…For consistent formation of disordered structures, it is important to make monodisperse hollow particles with controlled shell thickness. There are many experimental approaches to prepare uniform hollow silica particles, − which mostly involve sol–gel reactions on latex particles. However, it is still challenging to prepare dispersions of monodisperse hollow spheres because the particles may aggregate into dimers during shell growth or during the calcination process that removes the cores.…”

Section: Resultsmentioning

confidence: 99%

Inverse Photonic Glasses by Packing Bidisperse Hollow Microspheres with Uniform Cores

Kim

Magkiriadou

Rhee

et al. 2017

ACS Appl. Mater. Interfaces

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A major fabrication challenge is producing disordered photonic materials with an angle-independent structural red color. Theoretical work has shown that such a color can be produced by fabricating inverse photonic glasses with monodisperse, nontouching voids in a silica matrix. Here, we demonstrate a route toward such materials and show that they have an angle-independent red color. We first synthesize monodisperse hollow silica particles with precisely controlled shell thickness and then make glassy colloidal structures by mixing two types of hollow particles with the same core size and different shell thicknesses. We then infiltrate the interstices with index-matched polymers, producing disordered porous materials with uniform, nontouching air voids. This procedure allows us to control the light-scattering form factor and structure factor of these porous materials independently, which is not possible to do in photonic glasses consisting of packed solid particles. The structure factor can be controlled by the shell thickness, which sets the distance between pores, whereas the pore size determines the peak wave vector of the form factor, which can be set below the visible range to keep the main structural color pure. By using a binary mixture of 246 and 268 nm hollow silica particles with 180 nm cores in an index-matched polymer matrix, we achieve angle-independent red color that can be tuned by controlling the shell thickness. Importantly, the width of the reflection peak can be kept constant, even for larger interparticle distances.

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Section: Resultsmentioning

confidence: 99%

Inverse Photonic Glasses by Packing Bidisperse Hollow Microspheres with Uniform Cores

Kim

Magkiriadou

Rhee

et al. 2017

ACS Appl. Mater. Interfaces

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“…Taking further into account that a considerably large number of ammonium ions is present in the system, we tentatively ascribe the association of smaller SiO 2 NPs (with a higher net surface charge) onto the more negatively charged PS10 to a higher concentration of NH 4 + ions in the interlayer between PS/PVP beads and SiO 2 NPs, in accordance with recent findings by Fuji's group. 45 As a result, smaller SiO 2 NPs assemble on PS10 due to electrostatic effects, forming a more densely packed monolayer and hence smoother coating.…”

Section: Langmuirmentioning

confidence: 99%

Polystyrene Core–Silica Shell Particles with Defined Nanoarchitectures as a Versatile Platform for Suspension Array Technology

2016

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The need for rapid and high-throughput screening in analytical laboratories has led to significant growth in interest in suspension array technologies (SATs), especially with regard to cytometric assays targeting a low to medium number of analytes. Such SAT or bead-based assays rely on spherical objects that constitute the analytical platform. Usually, functionalized polymer or silica (SiO2) microbeads are used which each have distinct advantages and drawbacks. In this paper, we present a straightforward synthetic route to highly monodisperse SiO2-coated polystyrene core-shell (CS) beads for SAT with controllable architectures from smooth to raspberry- and multilayer-like shells by varying the molecular weight of poly(vinylpyrrolidone) (PVP), which was used as the stabilizer of the cores. The combination of both organic polymer core and a structurally controlled inorganic SiO2 shell in one hybrid particle holds great promises for flexible next-generation design of the spherical platform. The particles were characterized by electron microscopy (SEM, T-SEM, and TEM), thermogravimetry, flow cytometry, and nitrogen adsorption/desorption, offering comprehensive information on the composition, size, structure, and surface area. All particles show ideal cytometric detection patterns and facile handling due to the hybrid structure. The beads are endowed with straightforward modification possibilities through the defined SiO2 shells. We successfully implemented the particles in fluorometric SAT model assays, illustrating the benefits of tailored surface area which is readily available for small-molecule anchoring. Very promising assay performance was shown for DNA hybridization assays with quantification limits down to 8 fmol.

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“…SF electrospinning fibers contain a large number of –OH, –NH 2 , and –COOH on their surface, and the presence of Ca 2+ in the fibers make the surface of the fiber have good hydrophilicity, which provides a great possibility for inducing hydrolysis tetraethoxysilane (TEOS) to condense on its surface [ 33 , 36 , 37 ]. By soaking SF fiber templates in Söber-type sol-gel solution, the silica shell was successfully formed on the surface of SF fibers without adding any surfactant or coupling agent.…”

Section: Resultsmentioning

confidence: 99%

A Facile Strategy for Fabrication Lysozyme-Loaded Mesoporous Silica Nanotubes from Electrospun Silk Fibroin Nanofiber Templates

Zhu

Wang

et al. 2021

Molecules

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This paper presents a facile and low-cost strategy for fabrication lysozyme-loaded mesoporous silica nanotubes (MSNTs) by using silk fibroin (SF) nanofiber templates. The “top-down method” was adopted to dissolve degummed silk in CaCl2/ formic acid (FA) solvent, and the solution containing SF nanofibrils was used for electrospinning to prepare SF nanofiber templates. As SF contains a large number of -OH, -NH2 and -COOH groups, the silica layer could be easily formed on its surface by the Söber sol-gel method without adding any surfactant or coupling agent. After calcination, the MSNTs were obtained with inner diameters about 200 nm, the wall thickness ranges from 37 ± 2 nm to 66 ± 3 nm and the Brunauer–Emmett–Teller (BET) specific surface area was up to 200.48 m2/g, the pore volume was 1.109 cm3/g. By loading lysozyme, the MSNTs exhibited relatively high drug encapsulation efficiency up to 31.82% and an excellent long-term sustained release in 360 h (15 days). These results suggest that the MSNTs with the hierarchical structure of mesoporous and macroporous will be a promising carrier for applications in biomacromolecular drug delivery systems.

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Surfactant-free fabrication of SiO2-coated negatively charged polymer beads and monodisperse hollow SiO2 particles

Cited by 15 publications

References 19 publications

Inverse Photonic Glasses by Packing Bidisperse Hollow Microspheres with Uniform Cores

Inverse Photonic Glasses by Packing Bidisperse Hollow Microspheres with Uniform Cores

Polystyrene Core–Silica Shell Particles with Defined Nanoarchitectures as a Versatile Platform for Suspension Array Technology

A Facile Strategy for Fabrication Lysozyme-Loaded Mesoporous Silica Nanotubes from Electrospun Silk Fibroin Nanofiber Templates

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