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1.
P Yin  Y Wang  Y Li  C Deng  X Zhang  P Yang 《Proteomics》2012,12(18):2784-2791
In this study, sandwich-structured graphene/mesoporous silica composites (C8-modified graphene@mSiO(2) ) were synthesized by coating mesoporous silica onto hydrophilic graphene nanosheets through a surfactant-mediated cocondensation sol-gel process. The newly prepared C8-modified graphene@mSiO(2) nanocomposites possess unique properties of extended plate-like morphology, good water dispersibility, highly open pore structure, uniform pore size (2.8 nm), high surface area (632 m(2) /g), and C8-modified-interior pore walls. The unique structure of the C8-modified graphene@mSiO(2) composite nanosheets not only provide extended planes with hydrophilic surface that prevents aggregation in solution, but also offer a huge number of C8-modified mesopores with high surface area that can ensure an efficient adsorption of peptides through hydrophobic-hydrophobic interaction between C8-moified pore walls and target molecules. The obtained C8-modified graphene@mSiO(2) materials were utilized for size selectively and specifically enriching peptides in standard peptide mixtures and endogenous peptides in real biological samples (mouse brain tissue).  相似文献   

2.
Liu S  Li Y  Deng C  Mao Y  Zhang X  Yang P 《Proteomics》2011,11(23):4503-4513
In this paper, magnetic mesoporous silica microspheres with C8-modified interior pore-walls were prepared through a facile one-pot sol-gel coating strategy, and were successfully applied for selective enrichment of endogenous peptides in mouse brain for peptidome analysis. Through the one-pot sol-gel approach with surfactant (CTAB) as a template, tetraethyl orthosilicate (TEOS) and n-ctyltriethoxysilane (C8TEOS) as the precursors, C8-modified magnetic mesoporous microspheres (C8-Fe(3)O(4)@mSiO(2)) consisting magnetic core and mesoporous silica shell with C8-groups exposed in the mesopore channels were synthesized. The obtained microspheres possess highly open mesopores of 3.4 nm, high surface area (162.5 m(2)/g), large pore volume (0.17 cm(3)/g), excellent magnetic responsivity (56.3 emu/g) and good dispersibility in aqueous solution. Based on the abundant surface silanol groups, functional C8 groups and the strong magnetic responsivity of the core-shell C8-Fe(3) O(4) @mSiO(2) microspheres, efficient and fast enrichment of peptides was achieved. Additionally, the C8-Fe(3)O(4)@mSiO(2) microspheres exhibit excellent performance in selective enrichment of endogenous peptides from complex samples that are consist of peptides, large proteins and other compounds, including human serum and mouse brain followed by automated nano-LC-ESI-MS/MS analysis. These results indicate C8-Fe(3)O(4)@mSiO(2) microspheres would be a potential candidate for endogenous peptides enrichment and biomarkers discovery in peptidome analysis.  相似文献   

3.
Sandwich‐type hybrid carbon nanosheets (SCNMM) consisting of graphene and micro/mesoporous carbon layer are fabricated via a double template method using graphene oxide as the shape‐directing agent and SiO2 nanoparticles as the mesoporous guide. The polypyrrole synthesized in situ on the graphene oxide sheets is used as a carbon precursor. The micro/mesoporous strcutures of the SCNMM are created by a carbonization process followed by HF solution etching and KOH treatment. Sulfur is impregnated into the hybrid carbon nanosheets to generate S@SCNMM composites for the cathode materials in Li‐S secondary batteries. The microstructures and electrochemical performance of the as‐prepared samples are investigated in detail. The hybrid carbon nanosheets, which have a thickness of about 10–25 nm, high surface area of 1588 m2 g?1, and broad pore size distribution of 0.8–6.0 nm, are highly interconnected to form a 3D hierarchical structure. The S@SCNMM sample with the sulfur content of 74 wt% exhibits excellent electrochemical performance, including large reversible capacity, good cycling stability and coulombic efficiency, and good rate capability, which is believed to be due to the structure of hybrid carbon materials with hierarchical porous structure, which have large specific surface area and pore volume.  相似文献   

4.
The MALDI‐TOF MS has already been a main platform for phosphoproteome analysis. However, there are some weaknesses in direct analysis of endogenous phosphopeptides by MALDI‐TOF MS because of the serious suppression effect and poor ionization efficiency, which is brought by the excess of nonphosphopeptides and protein. It is essential to enrich endogenous phosphopeptides from complex biosamples efficiently prior to MALDI‐TOF MS analysis. Herein, we present a time‐saving and detailed protocol for the synthesis of titanium(iv)‐immobilized magnetic mesoporous silica nanoparticles (denoted as Fe3O4@mSiO2‐Ti4+), the subsequent enrichment process, and MALDI‐TOF MS analysis. We tested the LOD, size‐exclusive effect, reproducibility, and stability of Fe3O4@mSiO2‐Ti4+ nanoparticles. Furthermore, the ability of this protocol for identifying endogenous phosphopeptides in healthy human serum and saliva was investigated.  相似文献   

5.
In this work, core‐shell magnetic metal organic framework (MOF) microspheres were successfully synthesized by coating magnetite particles with mercaptoacetic acid and subsequent reactions with ethanol solutions of Cu(OAc)2 and benzene‐1,3,5‐tricarboxylic acid (designated as H3btc) alternately. The resulting Fe3O4@[Cu3(btc)2] possess strong magnetic responsiveness. We applied the novel nanocomposites in the enrichment of low‐concentration standard peptides, peptides in MYO and BSA tryptic digests and in human urine in combination with MALDI‐TOF MS analysis for the first time. In addition, the Cu3(btc)2 MOF shells exhibit strong affinity to peptides, thus providing a rapid and convenient approach to the concentration of low‐abundance peptides. Notably, peptides at an extremely low concentration of 10 pM could be detected by MALDI‐TOF MS after enrichment with the magnetic MOF composites. In brief, the facile synthesis and efficient enrichment process of the Fe3O4@[Cu3(btc)2] microspheres make them promising candidates for the isolation of peptides in even complex biological environments.  相似文献   

6.
Man Zhao  Chunhui Deng 《Proteomics》2016,16(7):1051-1058
In this work, for the first time, perfluorinated magnetic mesoporous microspheres were designed and synthesized for the highly specific enrichment of fluorous‐derivatized phosphopeptides through the unique fluorine–fluorine interactions. The perfluorinated magnetic mesoporous microspheres were prepared through a surfactant‐mediated one‐pot approach and successfully applied to the selective extraction of fluorous‐derivatized phosphopeptides from β‐casein tryptic digest, protein mixtures, and human serum. Thanks to the hydrophilic silanol groups exposed on the surface, perfluorinated groups modified in the pore channels and the magnetic cores, the flourous‐functionalized magnetic microspheres exhibited excellent dispersibility, specificity toward fluorous‐derivatized phosphopeptides while facilitated separation procedures. The novel composites achieved a high selectivity of 1:1000 toward nonphosphorylated peptides and proved to be practicable in the enrichment of endogenous phosphopeptides in the human serum sample.  相似文献   

7.
In this work, we report the development of a novel enrichment protocol for peptides by using the microspheres composed of Fe3O4@nSiO2 Core and perpendicularly aligned mesoporous SiO2 shell (designated Fe3O4@nSiO2@mSiO2). The Fe3O4@nSiO2@mSiO2 microspheres possess useful magnetic responsivity which makes the process of enrichment fast and convenient. The highly ordered nanoscale pores (2 nm) and high‐surface areas of the microspheres were demonstrated to have good size‐exclusion effect for the adsorption of peptides. An increase of S/N ratio over 100 times could be achieved by using the microspheres to enrich a standard peptide, and the application of the microspheres to enrich universal peptides was performed by using myoglobin tryptic digest solution. The enrichment efficiency of re‐used Fe3O4@nSiO2@mSiO2 microspheres was also studied. Large‐scale enrichment of endogenous peptides in rat brain extract was achieved by the microspheres. Automated nano‐LC‐ESI‐MS/MS was applied to analyze the sample after enrichment, and 60 unique peptides were identified in total. The facile and low‐cost synthesis as well as the convenient and efficient enrichment process of the novel Fe3O4@nSiO2@mSiO2 microspheres makes it a promising candidate for selectively isolation and enrichment of endogenous peptides from complex biological samples.  相似文献   

8.
In this work, for the first time, a novel C60‐functionalized magnetic silica microsphere (designated C60‐f‐MS) was synthesized by radical polymerization of C60 molecules on the surface of magnetic silica microspheres. The resulting C60‐f‐MS microsphere has magnetite core and thin C60 modified silica shell, which endow them with useful magnetic responsivity and surface affinity toward low‐concentration peptides and proteins. As a result of their excellent magnetic property, the synthesized C60‐f‐MS microspheres can be easily separated from sample solution without ultracentrifuge. The C60‐f‐MS microspheres were successfully applied to the enrichment of low‐concentration peptides in tryptic protein digest and human urine via a MALDI‐TOF MS analysis. Moreover, they were demonstrated to have enrichment efficiency for low‐concentration proteins. Due to the novel materials maintaining excellent magnetic properties and admirable adsorption, the process of enrichment and desalting is very fast (only 5 min), convenient and efficient. As it has been demonstrated in the study, newly developed fullerene‐derivatized magnetic silica materials are superior to those already available in the market. The facile and low‐cost synthesis as well as the convenient and efficient enrichment process of the novel C60‐f‐MS microspheres makes it a promising candidate for isolation of low‐concentration peptides and proteins even in complex biological samples such as serum, plasma, and urine or cell lysate.  相似文献   

9.
In this work, for the first time, magnetic binary metal oxides nanocomposites which integrated Zr and Ti into one entity on an atomic scale on polydopamine coated magnetic graphene (magG/PD/(Zr‐Ti)O4) was designed and synthesized, and applied to the enrichment of phosphopeptides. The newly prepared magG/PD/(Zr‐Ti)O4 composites gathered the advantages of large surface area, superparamagnetism, biocompatibility and the enhanced affinity properties to phosphopeptides. MagG/PD/ZrO2, magG/PD/TiO2, as well as the simple physical mixture of them were introduced to compare with magG/PD/(Zr‐Ti)O4 composites. High sensitivity (1 pg/μL or 4.0 × 10–11 M) and selectivity (weight ratio of β‐casein and BSA reached up to 1:8000) toward phosphopeptides were also presented for magG/PD/(Zr‐Ti)O4 composites. Additionally, mouse brain tissue was chose as the real samples to further investigate the phosphopeptides enrichment ability of this new material.  相似文献   

10.
Haizhu Lin  Chunhui Deng 《Proteomics》2016,16(21):2733-2741
In this work, we first immobilized tin(IV) ion on polydopamine‐coated magnetic graphene (magG@PDA) to synthesize Sn4+‐immobilized magG@PDA (magG@PDA‐Sn4+) and successfully applied the material to highly selective enrichment of phosphopeptides. The material gathered the advantages of large surface area of graphene, superparamagnetism of Fe3O4, good hydrophilicity and biocompatibility of polydopamine, and strong interaction between Sn4+ and phosphopeptides. The enrichment performance of magG@PDA‐Sn4+ toward phosphopeptides from digested β‐casein at different concentrations, with and without added digested BSA was investigated and compared with magG@PDA‐Ti4+. The results showed high selectivity and sensitivity of the Sn4+‐IMAC material toward phosphopeptides, as good as the Ti4+‐IMAC material. Finally, magG@PDA‐Sn4+ was applied to the analysis of endogenous phosphopeptides from a real sample, human saliva, with both MALDI‐TOF MS and nano‐LC‐ESI‐MS/MS. The results indicated that the as‐synthesized Sn4+‐IMAC material not only has good enrichment performance, but also could serve as a supplement to the Ti4+‐IMAC material and expand the phosphopeptide coverage enriched by the single Ti4+‐IMAC material, demonstrating the broad application prospects of magG@PDA‐Sn4+ in phosphoproteome research.  相似文献   

11.
The quaternary oxide CsTaWO6 exhibits a very high activity for photocatalytic hydrogen generation and water splitting. To improve its properties with regard to photocatalytic applications, it is prepared with mesoporous morphology for the first time, utilizing a template‐based evaporation‐induced self‐assembly process. The resulting material exhibits a median mesopore size of 10 nm, a surface area of 60 m2 g?1, and high crystallinity after preparation at 550 °C with phase‐pure defect‐pyrochlore structure. To further improve the textural properties of mesoporous CsTaWO6, the addition of additives to the synthesis procedure is also investigated. By using H2SO4/HCl and a carbonization/oxidation procedure, the surface area of the resulting mesoporous CsTaWO6 is increased to 78 m2 g?1, which is a 20‐fold increase compared to a nonporous reference via sol‐gel preparation, also leading to improved photocatalytic activity. By investigating the ability for photocatalytic hydrogen generation, the importance of high surface area and pore diameter of the resulting materials in comparison to nonporous materials is presented. Interestingly, the photocatalytic activity does not increase linearly with surface area, due to a strong influence of the pore diameter on the photocatalytic activity.  相似文献   

12.
Graphitic carbons with ordered mesostructure and high surface areas (of great interest in applications such as energy storage) have been synthesized by a direct triblock‐copolymer‐templating method. Pluronic F127 is used as a structure‐directing agent, with a low‐molecular‐weight phenolic resol as a carbon source, ferric oxide as a catalyst, and silica as an additive. Inorganic oxides can be completely eliminated from the carbon. Small‐angle XRD and N2 sorption analysis show that the resultant carbon materials possess an ordered 2D hexagonal mesostructure, uniform bimodal mesopores (about 1.5 and 6 nm), high surface area (~1300 m2/g), and large pore volumes (~1.50 cm3/g) after low‐temperature pyrolysis (900 °C). All surface areas come from mesopores. Wide‐angle XRD patterns demonstrate that the presence of the ferric oxide catalyst and the silica additive lead to a marked enhancement of graphitic ordering in the framework. Raman spectra provide evidence of the increased content of graphitic sp2 carbon structures. Transmission electron microscopy images confirm that numerous domains in the ordered mesostructures are composed of characteristic graphitic carbon nanostructures. The evolution of the graphitic structure is dependent on the temperature and the concentrations of the silica additive, and ferric oxide catalyst. Electrochemical measurements performed on this graphitic mesoporous carbon when used as an electrode material for an electrochemical double layer capacitor shows rectangular‐shaped cyclic voltammetry curves over a wide range of scan rates, even up to 200 mV/s, with a large capacitance of 155 F/g in KOH electrolyte. This method can be widely applied to the synthesis of graphitized carbon nanostructures.  相似文献   

13.
In this work we investigate a mesoporous silica (MS) decorated with dipyridyl‐pyridazine (dppz) ligands and further grafted with a mixture of Eu3+/Tb3+ ions (28.45%:71.55%), which was investigated as a potential thermometer in the 10–360 K temperature range. The MS material was prepared employing a hetero Diels–Alder reaction: 3,6‐di(2‐pyridyl)‐1,2,4,5‐tetrazine was reacted with the double bonds of vinyl‐silica (vSilica) followed by an oxidation procedure. We explore using the dppz‐vSilica material to obtain visible emitting luminescent materials and for obtaining a luminescent thermometer when grafted with Eu3+/Tb3+ ions. For the dppz‐vSilica@Eu,Tb material absolute sensitivity Sa of 0.011 K?1 (210 K) and relative sensitivity Sr of 1.32 %K?1 (260 K) were calculated showing good sensing capability of the material. Upon temperature change from 10 K to 360 K the emission color of the material changed gradually from yellow to red.  相似文献   

14.
The exploration of sodium ion batteries (SIBs) is a profound challenge due to the rich sodium abundance and limited supply of lithium on earth. Here, amorphous SnO2/graphene aerogel (a‐SnO2/GA) nanocomposites have been successfully synthesized via a hydrothermal method for use as anode materials in SIBs. The designed annealing process produces crystalline SnO2/graphene aerogel (c‐SnO2/GA) nanocomposites. For the first time, the significant effects of SnO2 crystallinity on sodium storage performance are studied in detail. Notably, a‐SnO2/GA is more effective than c‐SnO2/GA in overcoming electrode degradation from large volume changes associated with charge–discharge processes. Surprisingly, the amorphous SnO2 delivers a high specific capacity of 380.2 mAh g?1 after 100 cycles at a current density of 50 mA g?1, which is almost three times as much as for crystalline SnO2 (138.6 mAh g?1). The impressive electrochemical performance of amorphous SnO2 can be attributed to the intrinsic isotropic nature, the enhanced Na+ diffusion coefficient, and the strong interaction between amorphous SnO2 and GA. In addition, amorphous SnO2 particles with the smaller size better function to relieve the volume expansion/shrinkage. This study provides a significant research direction aiming to increase the electrochemical performance of the anode materials used in SIBs.  相似文献   

15.
Na3V2(PO4)3 (denoted as NVP) has been considered as a promising cathode material for room temperature sodium ion batteries. Nevertheless, NVP suffers from poor rate capability resulting from the low electronic conductivity. Here, the feasibility to approach high rate capability by designing carbon‐coated NVP nanoparticles confined into highly ordered mesoporous carbon CMK‐3 matrix (NVP@C@CMK‐3) is reported. The NVP@C@CMK‐3 is prepared by a simple nanocasting technique. The electrode exhibits superior rate capability and ultralong cyclability (78 mA h g?1 at 5 C after 2000 cycles) compared to carbon‐coated NVP and pure NVP cathode. The improved electrochemical performance is attributed to double carbon coating design that combines a variety of advantages: very short diffusion length of Na+/e? in NVP, easy access of electrolyte, and short transport path of Na+ through carbon toward the NVP nanoparticle, high conductivity transport of electrons through the 3D interconnected channels of carbon host. The optimum design of the core–shell nanostructures with double carbon coating permits fast kinetics for both transported Na+ ions and electrons, enabling high‐power performance.  相似文献   

16.
Mesoporous silica particles for immobilization of lipase from Candida rugosa were prepared by precipitation and aggregation of primary particles from highly basic sodium silicate solution but without addition of templates. The average pore size of the material was 15.8 nm, which allowed enzyme adsorption inside the pores and high enzyme loading. Specific surface area of the material was found to be 359 m2g?1. A loading of 100 mglipasegdrysilica?1 was obtained at initial enzyme concentration of 1.8 mgmL?1 by physical adsorption. The FTIR spectrum showed the structural conformation of lipase to be retained after adsorption into the mesoporous silica support. Although the efficiency of the mesoporous biocatalyst was shown to be lower than that of the free enzyme, the immobilized enzyme showed enhanced thermal stability and could be desorbed with Triton X-100, indicating the hydrophobic nature of the adsorption.  相似文献   

17.
A novel ligand‐assisted assembly approach is demonstrated for the synthesis of thermally stable and large‐pore ordered mesoporous titanium dioxide with a highly crystalline framework by using diblock copolymer poly(ethylene oxide)‐b‐polystyrene (PEO‐b‐PS) as a template and titanium isopropoxide (TIPO) as a precursor. Small‐angle X‐ray scattering, X‐ray diffraction (XRD), transmission electron microscopy (TEM), high‐resolution scanning electron microscopy, and N2‐sorption measurements indicate that the obtained TiO2 materials possess an ordered primary cubic mesostructure with large, uniform pore diameters of about 16.0 nm, and high Brunauer–Emmett–Teller surface areas of ~112 m2 g?1, as well as high thermal stability (~700 °C). High resolution TEM and wide‐angle XRD measurements clearly illustrate the high crystallinity of the mesoporous titania with an anatase structure in the pore walls. It is worth mentioning that, in this process, in addition to tetrahydrofuran as a solvent, acetylacetone was employed as a coordination agent to avoid rapid hydrolysis of the titanium precursor. Additionally, stepped evaporation and heating processes were adopted to control the condensation rate and facilitate the assembly of the ordered mesostructure, and ensure the formation of fully polycrystalline anatase titania frameworks without collapse of the mesostructure. By employing the obtained mesoporous and crystallized TiO2 as the photoanode in a dye‐sensitized solar cell, a high power‐conversion efficiency (5.45%) can be achieved in combination with the N719 dye, which shows that this mesoprous titania is a great potential candidate as a catalyst support for photonic‐conversion applications.  相似文献   

18.
Sodium ion batteries (NIBs) have become attractive promising alternatives to lithium ion batteries in a broad field of future energy storage applications. The development of high‐performance anode materials has become an essential factor and a great challenge toward satisfying the requirements for NIBs, advancement. This work is the first report on GeS2 nanocomposites uniformly distributed on reduced graphene oxide (rGO) as promising anode materials for NIBs prepared via a facile hydrothermal synthesis and a unique carbo‐thermal annealing. The results show that the GeS2/rGO hybrid anode yields a high reversible specific capacity of 805 mA h g?1 beyond the theoretical capacity, an excellent rate capability of 616 mA h g?1 at 5 A g?1, and a cycle retention of 89.4% after 100 cycles. A combined ex situ characterization study reveals that the electrochemically driven amorphization plays a key role in achieving efficient sodium storage by accommodating excess sodium ions in the electrode materials. Understanding the sequential conversion‐alloying reaction mechanism for GeS2/rGO hybrid anodes provides a new approach for developing high‐performance energy storage applications.  相似文献   

19.
Prostate-specific antigen (PSA), as the specificity of prostate cancer markers, has been widely used in prostate cancer diagnosis and screening. In this study, we fabricated an electrochemical immunosensor for PSA detection using the amino-functionalized graphene sheet–ferrocenecarboxaldehyde composite materials (NH2-GS@FCA) and silver hybridized mesoporous silica nanoparticles (Ag@NH2-MCM48). Under optimal conditions, the fabricated immunosensor showed a wide linear range with PSA concentration (0.01–10.0 ng·ml−1). Low detection limit (2 pg·ml−1) proved the high sensitivity. In addition, the immunosensor possessed good stability and reproducibility. Moreover, the application to PSA analysis in serum samples yielded satisfactory results.  相似文献   

20.
The synergistic adsorption of heavy metal ions and humic acid can be very challenging. This is largely because of their competitive adsorption onto most adsorbent materials. Hierarchically structured composites containing polyethylenimine-modified magnetic mesoporous silica and graphene oxide (MMSP-GO) were here prepared to address this. Magnetic mesoporous silica microspheres were synthesized and functionalized with PEI molecules, providing many amine groups for chemical conjugation with the carboxyl groups on GO sheets and enhanced the affinity between the pollutants and the mesoporous silica. The features of the composites were characterized using TEM, SEM, TGA, DLS, and VSM measurements. Series adsorption results proved that this system was suitable for simultaneous and efficient removal of heavy metal ions and humic acid using MMSP-GO composites as adsorbents. The maximum adsorption capacities of MMSP-GO for Pb(II) and Cd (II) were 333 and 167 mg g−1 caculated by Langmuir model, respectively. HA enhances adsorption of heavy metals by MMSP-GO composites due to their interactions in aqueous solutions. The underlying mechanism of synergistic adsorption of heavy metal ions and humic acid were discussed. MMSP-GO composites have shown promise for use as adsorbents in the simultaneous removal of heavy metals and humic acid in wastewater treatment processes.  相似文献   

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