Hybrid Hollow Nanospheres Research Articles

The thermal/pH-sensitive drug delivery system encapsulated by PAA based on hollow hybrid nanospheres with two silicon source

The synthesis of drug delivery systems based on hollow mesoporous silica nanoparticles (MSNs) is still a major challenge. In this work, the hollow hybrid MSNs were successfully prepared by cetyltrimethylammonium bromide-directed sol-gel process and one-step hydrothermal treatment process. The hollow hybrid MSNs had hybrid ethane-bridged frameworks with the uniform particle size (250 nm) and mesoporous pore diameter (3.7 nm). The polyacrylic acid (PAA) encapsulated drug delivery system based on hollow hybrid MSNs was prepared by using silanization, surface modification, doxorubicin hydrochloride (DOX) loading, and PAA coating. Drug encapsulation and release behavior at different temperatures and pH were studied by using DOX as a model guest molecule. The results displayed that the modified hollow ethane-bridged MSNs possessed good biocompatibility and excellent thermal/pH-dual-sensitive drug release property. This novel thermal/pH-sensitive drug delivery system based on hollow ethane-bridged MSNs has the advantages of feasible synthesis, no cytotoxicity, and good drug loading capacity, which may have potential applications in the anticancer therapy.

The construction of CuCo2O4/N-doped reduced graphene oxide hybrid hollow spheres as anodes for sodium-ion batteries

Hierarchical CuCo2O4/N-doped reduced graphene oxide (CuCo2O4/N-rGO) hollow hybrid nanospheres was constructed and further applied as highly capacity anode materials for SIBs.

Co3O4/carbon hollow nanospheres for resistivemonitoring of gaseous hydrogen sulfide and for nonenzymatic amperometricsensing of dissolved hydrogen peroxide.

Co3O4/carbon hybrid hollow nanospheres (hs-Co3O4/C) with an empty cavity and a thin shell, were synthesized starting from the pectin and cobalt acetate via cross-linking deposition at room temperature and post-calcination. The hierarchical structure is constructed from the interconnected nanoparticles in the residual carbon matrix, and the carbon content can be adjusted by changing the calcination temperature. The gas sensor based on hs-Co3O4/C calcined at 300°C in air shows high response towards 50ppm of H2S (S = 95.5) and good selectivity at a low working temperature (92°C). The detection limit is as low as 0.1ppm. The non-enzymatic glassy carbon electrode basedsensor constructed from the same material exhibits excellent electrocatalytic activity for H2O2 with the sensitivity of 405.8μA∙mM∙cm-2 at 0.3V (vs. SCE) in alkaline solution. The chronoamperometric response time is <3s and the detection limit (at S/N= 3) is 0.30μM. The good sensing performances are attributed to the synergetic effect of unique hollow nanostructure and appropriate amount of carbon in the hybrid material. The porous nanostructure can increase the mass transfer efficiency, and the cross-linked nanoparticles with good crystallinity also improve the conductivity of materials. The presence of carbon enhances the charge transfer ability and increases the specific surface, thereby improving the sensor performance. Graphical abstract Schematic illustration of the formation of hollow Co3O4 nanospheres composited with pectin-derived carbon. The materialdisplays excellent selectivityforH2S gas and in non-enzymaticdetection of dissolved H2O2.

Construction of complex WO3-SnO2 hollow nanospheres as a high-performance anode for lithium-ion batteries

Hollow architectures can greatly enhance diffusion kinetics and structural stability for lithium-ion batteries electrode materials. Herein we develop a simple method to fabricate WO3-SnO2 hybrid hollow nanospheres (WO3-SnO2 HHNs). A possible self-assembly formation process of WO3-SnO2 HHNs have been referring to glucose act as a structure-directing and stabilizing agent. The reversible capacity of WO3-SnO2 HHNs is about 883.9 mAh g−1, and electrode exhibits stable capacity after 500 cycles at 1000 mA g−1. The larger reversible capacity may result from hollow nanospheres, which endow larger surface area that can provide more lithium storage sites. Moreover, the extra Li2O mainly coming from SnO2 may be further reduced to Li by reaction with metallic W nanoparticles. It is also assembling with Li[Ni1/3Co1/3Mn1/3]O2 as full cell, the energy density is about 386.4 Wh kg−1 at 0.1C and maintains about 270 Wh kg−1 at 1 C after 50 cycles. The HHNs present excellent lithium insertion-deinsertion performance, suggesting that it is a promising approach can be applied to other electrodes for high-performance lithium-ion batteries.

Rational design of SnO2@C@MnO2 hierarchical hollow hybrid nanospheres for a Li-ion battery anode with enhanced performances

SnO2@C@MnO2 hierarchical hollow hybrid nanospheres have been obtained by coating the MnO2 nanosheet-based hierarchical shell on SnO2@C hollow nanospheres via a redox method. The hierarchical hollow hybrid nanospheres are composed of the SnO2 internal layer with hollow nanostructures, the carbon interlayer and the MnO2 hierarchical nanostructured external layer built from two dimensional nanosheets. SnO2@C@MnO2 nanomaterials exhibit a large initial discharge capacity (1378 mAhg−1), extraordinary cyclic stability (644.5 mAhg−1 after 200 cycles) and rate capability as Li-ion battery anodes. The excellent properties may benefit from the rational design of hierarchical hollow hybrid nanostructures and the synergistic effects between the three layers of SnO2, carbon and MnO2.

MnO2 nanosheets grown on the internal/external surface of N-doped hollow porous carbon nanospheres as the sulfur host of advanced lithium-sulfur batteries

Nanostructured porous carbon materials are widely used as sulfur host materials in order to enhance sulfur utilization and improve electrical performance in Li-S batteries. However, owing to interface incompatibility between the nanocarbon with homogeneous nonpolar surface and intrinsic polar sulfur guests, the cathode materials still face poor stability during the long-term cycling process. Herein, based on a highly effective sulfur host, namely manganese oxide nanosheets grown on both sides of the N-doped hollow porous carbon nanospheres (NHCSs@MnO2), we put forward a rational physical and chemical dual-encapsulation strategy for the application of advanced Li-S batteries. The multifunctional, integrated and hollow hybrid nanospheres can provide efficient electron-modified interface, hold much more active material, and importantly face-to-face effectively prevent polysulfide dissolution and diffusion via the synergistic restriction, thus the developed NHCSs@MnO2/S composite exhibits an initial discharge capacity of 1249 mAh g−1 at 0.5 C and a sustainable cycling stability with ultralow capacity decay of only 0.041% per cycle over 1000 cycles, implying its great prospects for the improved cyclability and electrochemical performance as application of advanced Li-S battery.

A facile synthesis of superparamagnetic hybrid hollow nanospheres based on monodisperse nickel–zinc ferrite/polyethylene glycol and their electromagnetic, microwave absorbing properties

Ni0.3Zn0.5Fe2O4/polyethylene glycol (PEG) hybrid hollow nanospheres have been successfully prepared using a facile synthesis method. Their shape, size and structure have been characterized by transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The determination from inductively coupled plasma (ICP) indicates that the atomic ratio of Ni/Zn/Fe is 3:5:20, the results from fourier transform infrared (FTIR) spectra and thermogravimetric analysis (TGA) show that the PEG is also contained by the nanospheres, and thus an expression of Ni0.3Zn0.5Fe2O4/PEG is presented. A formation mechanism is suggested according to FTIR, XRD, TGA, TEM and selected area electron diffraction (SAED) with different reaction time: 4, 6, 8, 10, and 12h. The magnetic measurement of the Ni0.3Zn0.5Fe2O4/PEG nanospheres reveals that the saturation magnetization is 86.26emug−1. The sample of 35% volume fraction (Ni0.3Zn0.5Fe2O4/PEG/paraffin containing Ni0.3Zn0.5Fe2O4/PEG nanospheres) exhibits a minimum reflection loss (RL) of −50.15dB at about 8.8GHz in the range of 2–18GHz. The Ni0.3Zn0.5Fe2O4/PEG nanospheres show unique morphology, favorable magnetism, as well as excellent microwave absorbing properties.

Designed synthesis of sulfonated polystyrene/mesoporous silica hollow nanospheres as efficient solid acid catalysts

We report the successful synthesis of hybrid hollow nanospheres with sulfonated polystyrene aligned in the mesoporous channels of a silica shell.

A new inorganic–organic hybrid In2Se3(en) as hollow nanospheres: hydrothermal synthesis and near-infrared photoluminescence properties

A new inorganic-organic hybrid In(2)Se(3)(en) was synthesized as hollow nanospheres via a facile and controllable hydrothermal method in a system containing ethylenediamine (en) and hydrazine hydrate. These as-obtained hybrid hollow nanospheres with an average diameter of 200 nm were assembled by irregularly small-sized (ca. 20 nm) nanoparticles. These hollow nanospheres were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The surface chemical composition of the In(2)Se(3)(en) hollow nanospheres were studied by X-ray photoelectron spectroscopy (XPS). The possible gas bubble-template growth mechanism is proposed to understand the formation of In(2)Se(3)(en) hollow nanospheres. Room-temperature UV-vis diffuse reflection spectra and photoluminescence (PL) spectra indicate that the as-obtained hybrid nanospheres possess a maximum absorption at 470 nm and single strong near-infrared emission peak centered at 1092 nm. The near-infrared luminescence endows the hybrid nanospheres with potential application in telecommunications, biolabeling and biomedical imaging, etc.

Effects of preparation parameters on the morphology of chitosan‐silica hybrid hollow nanospheres

PurposeThe purpose of this paper is to investigate the effects of preparation process and amounts of starting materials on the morphology of chitosan‐silica (CS‐silica) hybrid hollow nanospheres.Design/methodology/approachA simple method coupling sol‐gel process and in situ self‐assembly was used to prepare CS‐silica nanospheres from the solution containing chitosan‐poly (acrylic acid) (CS‐PAA) nanoparticles, tetraethoxyorthosilicate (TEOS) and polyvinylpyrrolidone (PVP). The morphology of CS‐silica hybrid hollow nanospheres was studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The chemical structures of CS‐PAA nanoparticles and CS‐silica nanospheres were characterised by FT‐IR spectra.FindingsThe size and morphology of CS‐silica nanospheres was largely dependent on the starting amounts of TEOS, PVP and ammonia. Moreover, the reaction time can also affect the structures of the hybrid nanospheres.Research limitations/implicationsThe dispersibility of CS‐silica nanospheres was not good enough and the conglutination was inevitable to some extent.Practical implicationsThe coupling of sol‐gel technology and in situ self‐assembly opened a new gateway for preparing other organic/inorganic composite nanoparticles. This kind of material could be used as a slow release agent for biocides in coatings/paints.Originality/valueThe hybrid CS‐silica nanospheres showed obvious hollow structures. The morphology of nanospheres can be efficaciously controlled via adjusting the starting amounts of PVP, TEOS and ammonia, and the stirring time. The obtained CS‐silica hybrid nanospheres will have potential applications in such as drug delivery and controlled release.

Carbon nanospheres-promoted electrochemical immunoassay coupled with hollow platinum nanolabels for sensitivity enhancement

Two nanostructures including carbon nanospheres-graphene hybrid nanosheets (CNS-GNS) and hollow platinum nanospheres (HPtNS) were first synthesized by using direct electrolytic reduction and wet chemistry methods, respectively. Thereafter, a specific sandwich-type electrochemical immunoassay was designed for determination of carcinoembryonic antigen (CEA) by using HPtNS-labeled horseradish peroxidase-anti-CEA conjugates (HRP-anti-CEA) as molecular tags and anti-CEA-assembled CNS-GPS as sensing probes. Compared with pure graphene nanosheets, the presence of carbon nanospheres on the graphene increased the surface coverage of the substrate, and enhanced the immobilized amount of primary antibodies. Several labeling protocols, such as HRP-anti-CEA, solid platinum nanoparticle-labeled HRP-anti-CEA, and hollow platinum nanospheres-labeled HRP-anti-CEA, were investigated for determination of CEA and improved analytical features were obtained with hollow platinum nanosphere labeling. With the HPtNS labeling method, the effects of incubation time and pH on the current responses of the immunosensors were also studied. The strong attachment of biomolecules to the CNS-GPS and HPtNS resulted in a good repeatability and intermediate precision down to 10.2%. The dynamic concentration range spanned from 0.001ngmL−1 to 100ngmL−1 CEA with a detection limit of 1.0pgmL−1 at the 3Sblank level. No significant differences at the 0.05 significance level were encountered in the analysis of 10 clinical serum samples between the developed immunoassay and the commercially available electrochemiluminescent method for determination of CEA.

Facile synthesis of hybrid hollow mesoporous nanospheres with high content of interpenetrating polymers for size-selective peptides/proteins enrichment

A facile synthesis of polymer-inorganic hybrid hollow mesoporous nanospheres was developed based on the entrapment of a dissolved polymer core template in the framework during the assembly process of the hybrid hollow nanospheres for efficient and size-selective enrichment of target peptides/proteins from complex biosamples.

Preparation and Characterization of Acrylated-SiO&lt;SUB&gt;2&lt;/SUB&gt;@TiO&lt;SUB&gt;2&lt;/SUB&gt; Hollow Hybrid Nanospheres

Novel inorganic-organic hybrid hollow nanospheres, acrylated SiO2 and SiO2@TiO2, were synthesized via a sol-gel polymerization, using crown-appended sugar gelator 1 as an organic template for the unique nanospherical structures in demand for a fast expanding area in nanomaterial research. In this work, hollow SiO2 nanospheres were obtained by a simple sol-gel method followed by calcination and rather rough TiO2 nanolayers were coated onto the highly dispersed surface of SiO2 nanospheres and further copolymerization of MPA on the surface of SiO2 and SiO2@TiO2 nanosphseres was successfully conducted. The morphological properties of those hollow nanospheres were characterized by TEM, SEM and powder-XRD. Furthermore, the physical and chemical properties of the synthesized nanocomposites were characterized by the analysis of EDX, FT-IR, TGA and ESCA.

Synthesis and characterization of fluorescent chitosan-ZnO hybrid nanospheres

Hybrid hollow nanospheres of chitosan-ZnO (CS-ZnO Nps) with fluorescence were successfully prepared by the in situ growing of ZnO quantum dots (QDs) in an aqueous solution consisting of a cationic polymer CS and an anionic monomer acrylic acid (AA), followed by the polymerization of AA and selectively crosslinking of CS with glutaraldehyde. ZnO QDs were dispersed evenly in the shell of hybrid nanospheres, with its dimension less than 5 nm. These fluorescent CS-ZnO Nps were expected to be simultaneously used as biological fluorescent labeling and carrier for guest materials. Hybrid hollow nanospheres of chitosan-ZnO (CS-ZnO Nps) were successfully prepared by the in situ growing of ZnO quantum dots (QDs) in an aqueous solution consisting of a cationic polymer CS and an anionic monomer acrylic acid (AA), followed by the polymerization of AA and selectively crosslinking of CS with glutaraldehyde. The as-prepared nanospheres were characterized by transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), UV–visible spectrometer (UV) and fluorescence spectrophotometer (PL). ZnO QDs were dispersed evenly in the shell of hybrid nanospheres, with its dimension less than 5 nm. These fluorescent CS-ZnO Nps were expected to be simultaneously used as biological fluorescent labeling and a carrier for guest materials.

Hollow chitosan–silica nanospheres for doxorubicin delivery to cancer cells with enhanced antitumor effect in vivo

Here we report the synthesis of hybrid hollow chitosan–silica nanospheres (CS–Silica NPs) with chitosan–polyacrylic acid (CS–PAA) nanoparticles as the template and doxorubicin (DOX) delivery based on CS–Silica NPs. The morphology and the microstructure of CS–Silica NPs were characterized by field emission scanning electron microscopy (FESEM) and X-ray photoelectron spectroscopy (XPS). The confocal laser scanning microscopy (CLSM) and flow cytometry experiments showed that the cellular uptake of the DOX-loaded CS–Silica NPs was time dependent. In addition, cellular internalization and intracellular distribution of DOX-loaded CS–Silica NPs indicated that the DOX was mainly distributed in the cell nucleus while the carriers were primarily located in the cytoplasm. In vivo antitumor response indicated that the DOX loaded CS–Silica hybrid hollow nanospheres exhibited superior antitumor effect over the free drugin vivo, which might be ascribable to the enhanced cellular uptake efficiency and the effective delivery of drug to the cell nucleus.

Hollow Ferrocenyl Coordination Polymer Microspheres with Micropores in Shells Prepared by Ostwald Ripening

Hollow microspheres with pores in their shells have received much attention owing to their hierarchically porous structures and advanced applications in electrochemical capacitive energy storage, hydrogen storage, drug delivery, sensing, and catalysis. For example, Lou et al. reported that hollow SnO2 nanospheres with nanoporous shells showed high reversible charge capacity and good cycling performance. Zhu et al. investigated the drug-delivery properties of hollow silica spheres with mesoporous shells and found that the hollow microspheres were able to store significantly more molecules with higher release rates than conventional mesoporous silica. Template synthesis is one of the most-used strategies to prepare hierarchically hollow microspheres, especially for pores inside the shells. Braun and co-workers have prepared hollow ZnS microspheres with mesoporous shells using dual templates assembled by lyotropic liquid crystals on the surfaces of silica or polystyrene colloidal templates. Liu et al. have produced organic–inorganic hybrid hollow nanospheres with microwindows on the shells templated by tricopolymer aggregates. The template method is general to prepare hollow microspheres with pores in the shells, but expensive and tedious post-treatment processes, such as solvent extraction, thermal pyrolysis, or chemical etching, and resultant fragile frameworks, limit or even impair its applicability. 3, 4] As a result, it remains an important challenge to develop a convenient and template-free method to prepare hollow microspheres with porous shells. Porous coordination polymers are highly ordered porous multifunctional materials prepared by linking metal ions or metal oxide clusters with multidentate organic ligands without any additional template. Construction of shells of hollow materials with porous coordination polymers is an especially promising approach to design hollow microspheres with porous shells through a template-free method and to endow materials with multifunctionality, such as electric, magnetic, and optical properties. Herein, we report the formation of hollow coordination polymer microspheres with microporous shells by a one-pot solvothermal reaction without any additional template; the shells are constructed of iron-based ferrocenyl coordination polymers. We confirm that the Ostwald ripening mechanism is responsible for the formation of hollow cavities with controllable size. Hollow iron-based ferrocenyl coordination polymer microspheres (Fe-Fc-HCPS) were synthesized by a solvothermal reaction of FeCl3·6H2O with 1,1’-ferrocenedicarboxylic acid (H2FcDC) in N,N-dimethyl formamide (DMF; Figure 1a). The precipitate was collected by centrifugation and washed several times with DMF and CHCl3. The reaction temperature, reaction time, and molar ratio of reactants play important roles in the formation of hollow spherical particles. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and optical microscopy (OPM) were

Synthesis of raspberry-like monodisperse magnetic hollow hybrid nanospheres by coating polystyrene template with Fe3O4@SiO2 particles

In this paper, we present a novel method for the preparation of raspberry-like monodisperse magnetic hollow hybrid nanospheres with γ-Fe(2)O(3)@SiO(2) particles as the outer shell. PS@Fe(3)O(4)@SiO(2) composite nanoparticles were successfully prepared on the principle of the electrostatic interaction between negatively charged silica and positively charged polystyrene, and then raspberry-like magnetic hollow hybrid nanospheres with large cavities were achieved by means of calcinations, simultaneously, the magnetite (Fe(3)O(4)) was transformed into maghemite (γ-Fe(2)O(3)). Transmission electron microscopy (TEM) demonstrated that the obtained magnetic hollow silica nanospheres with the perfect spherical profile were well monodisperse and uniform with the mean size of 253nm. The Fourier transform infrared (FTIR) spectrometry, energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) provided the sufficient evidences for the presence of Fe(3)O(4) in the silica shell. Moreover, the magnetic hollow silica nanospheres possessed a characteristic of superparamagnetic with saturation magnetization value of about 7.84emu/g by the magnetization curve measurement. In addition, the nitrogen adsorption-desorption measurement exhibited that the pore size, BET surface area, pore volume of magnetic hollow silica nanospheres were 3.5-5.5nm, 307m(2)g(-1) and 1.33cm(3)g(-1), respectively. Therefore, the magnetic hollow nanospheres possess a promising future in controlled drug delivery and targeted drug applications.

Gold Encapsulated Chitosan‐Poly(acrylic acid) Hybrid Hollow Nanospheres

Chitosan-poly(acrylic acid)-gold (CS-PAA-Au) hybrid hollow nanospheres were prepared by reducing gold salts to gold nanoparticles in chitosan-acrylic acid (CS-AA) aqueous solution, followed by polymerization of AA monomer and selectively crosslinking chitosan at the end of polymerization. The payload of Au nanoparticles within the CS-PAA hollow nanospheres could be controlled by varying the addition amount of gold salts in the reaction system. Transmission electron microscopy (TEM) revealed that multi-crystal gold nanoparticles were encapsulated inside the CS-PAA nanospheres. TEM and scanning electron microscopy (SEM) indicated that these hybrid nanospheres had a hollow structure. Energy-dispersive X-ray (EDX) spectroscopy confirmed the existence of gold nanoparticles inside the CS-PAA-Au hybrid nanospheres. These hollow CS-PAA-Au hybrid nanospheres showed a typical surface plasmon resonance (SPR) band of gold nanoparticles around 526 nm, and offered excellent stability at different temperatures and in acidic media. Also, no inhibition of cell proliferation and no cytotoxic effects were observed in the presence of CS-PAA-Au hybrid nanospheres, which renders them good candidates for potential application in biomedical fields.

Polymer/silica hybrid hollow nanospheres with pH-sensitive drug release in physiological and intracellular environments

Hybrid hollow nanospheres of chitosan-silica templated by chitosan-poly(acrylic acid) nanoparticles are fabricated in a complete aqueous system, which provide a pH-sensitive switch in physiological and sub-cell environments for the release of loaded drug.

Organic−Inorganic Hybrid Hollow Nanospheres with Microwindows on the Shell

We demonstrate, for the first time, that organic−inorganic hybrid hollow nanospheres with controllable size (12−20 nm) and shell thickness (4−7 nm) can be successfully synthesized through the condensation of 1,2-bis(trimethoxysilyl)ethane (BTME) around an inorganic-electrolyte-stabilized F127 micelle under a mild buffer condition (NaH2PO4−Na2HPO4, pH ∼7.0). The hollow spheres feature microwindows with pore size about 0.5−1.2 nm on the shell, which allow the guest molecules to diffuse into the hollow cavities. It was found that the concentration of the buffer solution in the synthesis was crucial to the formation of hollow nanosphere. At a low buffer concentration (20−100 mM), the surfactant exists as individual micelle. A core/shell nanocomposite was formed by the deposition of BTME at the corona of individual micelle, which leads to the formation of organic−inorganic hybrid nanoparticles with hollow interior after the extraction of the surfactant. The aggregation of individual micelles was observed at higher buffer concentration (>200 mM), which favors the formation of irregularly shaped particles with ordered mesostructure. This work presents a novel and facile strategy to fabricate hollow nanospheres with microwindows, which provides a versatile platform for practical applications of organic−inorganic hybrid materials in a broad range of fields such as catalysis, encapsulation, and drug delivery, etc.