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1.
ACS Sens ; 5(3): 781-788, 2020 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-32037789

RESUMO

Enriching and locating target analytes into specific "hot spots" are vital for ultrasensitive molecular identification and detection using plasmonic-based techniques. Inspired by mass transportation in lamp wicks, we develop an effective enrichment strategy for highly diluted analytes in which analytes and Au nanoparticles are transported via a solution microflow under the capillarity driving force of glass fiber papers to a heated region. After evaporation, a large volume of a solution containing analytes and Au nanoparticles is condensed into a very limited area, and thus, analyte molecules are effectively enriched and located into surface-enhanced Raman scattering (SERS) hot spots. Using this enrichment strategy, the sensitivity and detection limits of SERS are remarkably improved. Detection levels of crystal violet and anthracene are down to 10-16 and 10-10 M, respectively. This enrichment strategy is very robust and easy to implement, and it can potentially be exploited in various plasmonic-based molecular detection and identification techniques.

2.
Nanomedicine (Lond) ; 14(11): 1443-1454, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31169451

RESUMO

Aim: To realize the transit and release of cancer drug exactly as well as high drug loading ratio, we reported a biocompatible and temperature responsive controlled drug delivery system based on 3D mesoporous structured Au networks. Materials & methods: Here, we filled the hollow interiors of Au networks with a phase-change material so that the drug release was easily regulated by controlling the temperature only. Results: Thanks to the high near-infrared reflectance absorbance and mesoporous structure, the Au-PEG + lauric acid/doxorubicin system showed a strong photothermal conversion efficiency, high drug-loading ratio (54.2% for doxorubicin) and controlled drug release. Conclusion: This system revealed great advantages in photothermal therapy and chemotherapy, offering an obvious synergistic effect in cancer treatment.

3.
Anal Chem ; 91(7): 4687-4695, 2019 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-30810031

RESUMO

Collecting highly diluted target analytes into specific hot spot regions is vital for ultrasensitive surface-enhanced Raman spectroscopy (SERS) applications. In this work, a hydrophobic slippery platform was employed as a concentrator to construct colloidal SERS-active substrates regardless of the diffusion limits during droplet evaporation. Within only 140 s, sufficient absorption between the analytes and colloidal Au nanoparticles (Au NPs) was observed by fluorescence imaging. This effect resulted in excellent SERS sensitivity and stability. Compared with the common metal colloid-based SERS substrates, e.g., drying on a silicon wafer or detection in colloidal solutions, this preconcentrated method showed lower detection limits and the lowest detection concentration of crystal violet molecule down to 10-12 M with a portable Raman spectrometer. Such high signal enhancement was mainly ascribed to the condensation effect of Au colloids/analytes on the hydrophobic slippery substrate, by which almost all probe molecules were guided into the "hot spot" regions of aggregated Au NPs. Using the SERS platform, various illegal additives in realistic food and health-care products, for example, malachite green (1 ppb) added in fish and morphine (0.1 ppm) added in a chafing dish, could be sensitively detected. Therefore, our protocol is a general SERS platform that may provide a simple, fast, and cost-effective approach for trace molecular sensing.

4.
Zhongguo Zhong Yao Za Zhi ; 43(18): 3756-3763, 2018 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-30384543

RESUMO

To investigate the hepatoprotective effect of Schisandrae Chinensis Fructus (SCF) on CCl4-induced liver injury, observe its effect on serum metabolites, explore its scientific connotation in liver preservation and find the biomarkers for hepatoprotective effect of SCF. Liver injury model was established by using CCl4. The pathological sections of liver tissues were observed and the contents of alanine transaminase (ALT) and aspartate transaminase (AST) in serum were determined. The metabolic skills were adopted based on ultra performance liquid chromatography time-of-flight mass spectrometry (UPLC-Q-TOF-MS), principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) for screening and identification of biomarkers related to liver injury. The results showed the metabolites in blank group, model group and administration group could be easily distinguished, 50 differential compounds were identified and 7 possible metabolic pathways of liver protection were enriched. In this experiment, the hepatoprotective effect of SCF was verified, and the related metabolic pathways such as amino acid metabolism, vitamin metabolism and glycerophospholipid metabolism were discussed.


Assuntos
Doença Hepática Induzida por Substâncias e Drogas/tratamento farmacológico , Medicamentos de Ervas Chinesas/química , Metabolômica , Schisandra/química , Animais , Biomarcadores , Cromatografia Líquida de Alta Pressão , Frutas/química , Fígado/efeitos dos fármacos , Fígado/metabolismo , Análise de Componente Principal , Espectrometria de Massas em Tandem
5.
Nanotechnology ; 29(42): 425708, 2018 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-30070658

RESUMO

An ideal supporting material improves both activity and durability of noble metal nanoparticles in electrocatalytic reactions. Graphene possesses a high transport rate of electrons in-plane, a low cost, and stability, but, the restacking of graphene layers trap noble metal nanoparticles and make them inaccessible to reactants and results in reduced catalytic activity. Here, holey-graphene as the supporting materials for Pt nanoparticle catalysts is deeply investigated in the electrocatalytic reaction of methanol oxidation. The holey-graphene can be scalable to synthesize using our simple method described herein. The holes on the holey-graphene layer promote the access of reactants with Pt nanoparticle catalysts compared with carbon black and graphene when used as supporting materials. Density functional theory calculations and molecule dynamic simulation further explain the function of holey-graphene in the promotion of electrocatalytic activity. Holey-graphene may open extraordinary possibilities as a supporting material for electrocatalysts.

6.
Sci Rep ; 8(1): 5695, 2018 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-29632384

RESUMO

Experiential quality assessment(EQA) is an important sensory analysis for judging herbal quality grades. Because of the high empirical utility of expert experience, the consistency, science and inheritance of such experience are continuously in dispute. To explore the scientific evidence for this subjective method, we designed a Delphi expert investigation coupled with chemical analysis to evaluate the quality of Schisandrae Chinensis Fructus (SCF). Initially, 13 experts were invited to independently evaluate the grades of 11 batches of SCF. After screening the consistency and repeatability of the evaluation results, typical samples of all quality levels were identified. Seven significant physical characters were detected; colour and size were found to be the key parameters for identifying SCF quality. Based on this correlation, a decision tree model was ultimately established and converted to a quality evaluation card. Over 80% consistency in a novice test demonstrated the technical advantages and application characteristics of the model. Further correlation analysis revealed that EQA quality grades of SCF were positively correlated to the content of polysaccharides and polyphenols, while negatively correlated to the content of lignans. Biological activities were also approving it. In summary, our study proves that subjective EQA is consistency, repeatability and could be inherited.


Assuntos
Lignanas/análise , Polifenóis/análise , Polissacarídeos/análise , Schisandra/química , Cromatografia Líquida de Alta Pressão , Árvores de Decisões , Técnica Delfos , Medicamentos de Ervas Chinesas/química , Humanos , Fenótipo , Controle de Qualidade
7.
Nat Commun ; 9(1): 521, 2018 02 06.
Artigo em Inglês | MEDLINE | ID: mdl-29410431

RESUMO

Metal species have a relatively high mobility inside mesoporous silica; thus, it is difficult to introduce the metal precursors into silica mesopores and suppress the migration of metal species during a reduction process. Therefore, until now, the controlled growth of metal nanocrystals in a confined space, i.e., mesoporous channels, has been very challenging. Here, by using a soft-enveloping reaction at the interfaces of the solid, liquid, and solution phases, we successfully control the growth of metallic nanocrystals inside a mesoporous silica template. Diverse monodispersed nanostructures with well-defined sizes and shapes, including Ag nanowires, 3D mesoporous Au, AuAg alloys, Pt networks, and Au nanoparticle superlattices are successfully obtained. The 3D mesoporous AuAg networks exhibit enhanced catalytic activities in an electrochemical methanol oxidation reaction. The current soft-enveloping synthetic strategy offers a robust approach to synthesize diverse mesoporous metal nanostructures that can be utilized in catalysis, optics, and biomedicine applications.

8.
Small ; 14(8)2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29320611

RESUMO

Precisely engineering the decoration of metal nanoparticles on the special surface of semiconductor represents a promising strategy to design efficient metal-semiconductor heterostructured photocatalysts. This study demonstrates a versatile soft-template method to fabricate a novel nonsymmetrical heterostructured Ag/AgI nanoplate, in which only one side surface of the nanoplate is covered with uniform 2D Ag nanoweb. Compared with symmetrical heterostructure, the nonsymmetrical heterostructure may further facilitate the separation of photogenerated electron-hole pairs and shows a greatly enhanced photocatalytic activity. This study may open up a new way to improve the photocatalytic property by synthesizing nonsymmetrical metal-semiconductor composites.

9.
Small ; 14(4)2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29205816

RESUMO

Nanocasting, using ordered mesoporous silica or carbon as a hard template, has enormous potential for preparing novel mesoporous materials with new structures and compositions. Although a variety of mesoporous materials have been synthesized in recent years, the growth mechanism of nanostructures in a confined space, such as mesoporous channels, is not well understood, which hampers the controlled synthesis and further application of mesoporous materials. Here, the nucleation and growth of WO3 -networked mesostructures within an ordered mesoporous matrix, using an in situ transmission electron microscopy heating technique and in situ synchrotron small-angle X-ray scattering spectroscopy, are probed. It is found that the formation of WO3 mesostructures involves a particle-mediated transformation and coalescence mechanism. The liquid-like particle-mediated aggregation and mesoscale transformation process can occur in ≈10 nm confined mesoporous channels, which is completely unexpected. The detailed mechanistic study will be of great help for experimental design and to exploit a variety of mesoporous materials for diverse applications, such as catalysis, absorption, separation, energy storage, biomedicine, and nanooptics.

10.
J Colloid Interface Sci ; 514: 217-226, 2018 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-29268212

RESUMO

Surface Enhanced Raman Scattering (SERS) has been developed into a powerful vibrational spectroscopy technique for chemical detection. However, the fabrication of colloidal droplets-based SERS substrates with well reproducibility and uniformity still remains challenging. In this paper, colloidal suspensions of hollow Au-Ag alloy nanourchins (HAAA-NUs) and Au nanoparticles (Au NPs) with different morphologies were employed as SERS-active substrates. After evaporation of colloidal suspensions, we evaluated the SERS performance based on the following features: "Coffee Ring Effects", adsorption processes of probe molecule and colloidal NPs, spin coating and morphologies of suspended NPs. The results demonstrated that SERS signals could be enhanced enormously in the marginal region of Coffee Ring patterns. The limit of detection (LOD) for amaranth molecule would be reached 10-8 M. Moreover, by combining the droplets evaporation of HAAA-NUs suspensions with spin coating, the relative standard deviation (RSD) could be down to 3.5%, showing excellent reproducibility. The investigation here would provide a simple, practical and portable SERS detection method with excellent signal uniformity.

11.
Nanoscale ; 7(29): 12318-24, 2015 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-26145709

RESUMO

Surface-enhanced Raman scattering (SERS) substrates with high density and uniformity of nanogaps are proven to enhance the reproducibility and sensitivity of the Raman signal. Up to now, the syntheses of a highly ordered gold or silver superstructure with a controllable nanoparticle size and a well-defined particle gap have been quite limited. Here, we reported an ordered mesoporous silver superstructure replicated by using ordered mesoporous KIT-6 and SAB-15 as templates. By means of a nanocasting process, the ordered mesoporous Ag superstructure was successfully synthesized, which shows uniform distribution of the nanowire diameter (10 nm) and nanogap size (∼2 nm), thus exhibiting a high Raman enhancement of ∼10(9). The finite difference time-domain (FDTD) results indicate that the ordered mesoporous Ag superstructure has a uniform distribution of hot spots. Therefore, the mesoporous silica template strategy presented here could lead to a new class of high quality SERS substrates providing extraordinary potential for diverse applications.

12.
Biomaterials ; 35(13): 4099-107, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24518389

RESUMO

The 'sea urchin'-like nanostructures with particular small size (<100 nm) and abundant multi-tips have not yet been employed for the cancer photothermal therapy (PTT). Here we report sub-100 nm hollow Au-Ag alloy nanourchins (HAAA-NUs) with ultrahigh density of nanotips synthesized via a facile seed-mediated growth. The HAAA-NUs exhibit a remarkably integrated high-quality photothermal feature including well-defined but tunable surface plasmon resonance peak, strong absorption (2.2 × 10(10) M(-1) cm(-1)) as well as high photothermal conversion efficiency (80.4%) in the near-infrared region. Importantly, the HAAA-NUs demonstrate improved photothermal stability verified via continuous exposition and cyclic irradiation of laser beam. The cell assay, in vitro cell ablation and in vivo breast cancer treatment verify that the HAAA-NUs are superior photothermal agent for photothermal tumor ablation therapy owing to low toxicity and high cell destruction capability.


Assuntos
Ligas/química , Ouro/química , Nanoestruturas/química , Fototerapia/métodos , Animais , Neoplasias da Mama/tratamento farmacológico , Feminino , Humanos , Camundongos Endogâmicos BALB C
13.
Adv Mater ; 26(15): 2431-9, 2014 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-24449036

RESUMO

A hierarchical nanoparticle strategy to simultaneously gain super Raman signal amplification, high uniformity, and reproducibility is presented. Using hollow Au-Ag alloy nanourchins, an ultrahigh sensitivity, e.g., down to 1 fM concentrations for DEHP molecule is obtained. A small standard deviation of <10% is achieved by simply dropping and evaporating sub-100 nm nanourchins onto a substrate.


Assuntos
Ligas/química , Ouro/química , Nanopartículas Metálicas/química , Prata/química , Levodopa/química , Nanopartículas Metálicas/ultraestrutura , Oxirredução , Tamanho da Partícula , Análise Espectral Raman
14.
Nanoscale ; 6(5): 2567-72, 2014 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-24463635

RESUMO

Ideally, a SERS substrate should possess super signal amplification, high uniformity and reproducibility. Up to now, an emphasis on reproducibility and uniformity has been crucial to ensure consistent chemical detection sensitivity across the surface of a SERS substrate. Here we demonstrate a simple and facile double sided tape-assisted transfer method to fabricate surface enhanced Raman scattering (SERS) substrates with prominent performance using hollow Au-Ag alloy nanourchins (HAAA-NUs). Such a large area, closely-packed flat film of the HAAA-NUs with a high density of "hot spots" exhibits a high SERS activity and reproducibility, simultaneously. The AFM-correlated nano-Raman and the point by point scanning of SERS signals verify the excellent spatial uniformity and reproducibility with a low relative standard deviation (RSD) less than 15% using crystal violet as probe molecule at the concentrations of 1 × 10(-8) M and 1 × 10(-10) M. The SERS signals of Sudan dye at a 1 × 10(-8) M concentration also show high reproducibility with a low RSD of 13.8%. This facile protocol presented here could lead to a high quality SERS substrate and open tremendous potential for various applications.

15.
Analyst ; 139(2): 455-63, 2014 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-24303521

RESUMO

Somatic mutations in the epidermal growth factor receptor (EGFR) gene were associated with sensitivity to small molecule tyrosine kinase inhibitors for patients with lung adenocarcinomas. In this research, EGFR mutation status was analyzed by DNA sequencing in 153 lung adenocarcinoma tissues. Of these, 75 samples carried EGFR mutations, including 29 with E19del mutation, 33 with L858R mutation, 7 with T790M mutation, and 6 with multiple mutations. Then, 30 samples including 10 with wild type (wt)-EGFR, 10 with L858R and 10 with E19del mutations were selected for Raman and immunohistochemistry (IHC) analyses. After removing the spectra from normal and non-mutated regions, 441 spectra were found appropriate for Raman analysis: 149 from wt-EGFR, 135 from L858R and 157 from E19del mutations. The Raman peaks at 675, 1107, 1127 and 1582 cm(-1) were significantly increased in wt-EGFR tissues which can be attributed to specific amino acids and DNA. The Raman peaks at 1085, 1175 and 1632 cm(-1) assigned to arginine were slightly increased in L858R tissues. The overall intensity of E19del tissues was weaker than others due to exon 19 deletion that removes residues 746-750 of the expressed protein. Principal component analysis (PCA) and support vector machine (SVM) were applied for final prediction. The PCA/SVM algorithm yielded an overall accuracy of 87.8% for diagnosing L858R or E19del from wt-EGFR tissues. Finally, RS provides a simple, rapid and low-cost procedure based upon the molecular signatures for predicting EGFR mutation status.


Assuntos
Adenocarcinoma/genética , Análise Mutacional de DNA/métodos , Receptores ErbB/genética , Neoplasias Pulmonares/genética , Análise Espectral Raman/métodos , Adenocarcinoma de Pulmão , Algoritmos , Carcinoma Pulmonar de Células não Pequenas/genética , Linhagem Celular Tumoral , Éxons/genética , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Componente Principal , Máquina de Vetores de Suporte
16.
ACS Appl Mater Interfaces ; 4(12): 6942-8, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23176064

RESUMO

Controlling the morphology and size of Pt nanostructures can provide a great opportunity to improve their electrocatalytic properties and durability toward methanol oxidation. We successfully synthesized well-defined hollow coral-like Pt mesocrystals via a facile replacement reaction, using hierarchically structured Ag nanoparticles as the template. The as-synthesized coral-like Pt mesocrystals had hollow structures composed of porous walls that were 5-7 nm thick, which were constructed from numerous pores (~2 nm) and small (~5 nm) Pt nanoparticle building units. These hollow and porous structures exhibited large electrochemical surface areas. The Pt mesostructures that have single-crystal inherence as well as hollow and porous features possess improved performance with respect to electrocatalytic activity (2.72 mA/cm(2) at peak potential, which is 2.1 times greater than that of Pt black) and durability toward methanol oxidation.

17.
Nanotechnology ; 23(16): 165604, 2012 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-22469765

RESUMO

Self-assembling Au mesoflower arrays are prepared using a polymethylmethacrylate (PMMA) template on an iron substrate via a combined top-down/bottom-up nanofabrication strategy. The PMMA template with the holes around 300-500 nm in diameter is first fabricated by using polymer blend lithography on iron substrates, and the highly homogeneous Au mesoflower arrays with less than 10 nm intraparticle gaps are subsequently obtained by an in situ galvanic reaction between HAuCl4 solution and the iron substrate under optimal stirring of the solution as well as reaction time. Owing to the unique mesostructures and uniformity, Raman measurements show that the gold mesoflower arrays obtained demonstrated a strong and reproducible surface enhanced Raman scattering (SERS) enhancement on the order of ∼10(7)-10(8). The development of a SERS substrate based on the Au mesoflowers with high spatial density of hot spots, relatively low cost and facial synthesis provides a novel strategy for applications in chemical and biomolecular sensing.


Assuntos
Cristalização/métodos , Ouro/química , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Análise Espectral Raman/métodos , Ressonância de Plasmônio de Superfície/métodos , Luz , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Tamanho da Partícula , Espalhamento de Radiação , Propriedades de Superfície
18.
ACS Nano ; 5(12): 9442-9, 2011 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-22059897

RESUMO

Using three-dimensional finite-difference time-domain (FDTD) simulation, we described a systematic investigation on the electric field enhancement of the silver corrugated nanowires. The enhancement factor (EF) of surface-enhanced Raman scattering (SERS) for corrugated nanowires can be markedly increased by 1 or 2 orders of magnitude as compared with the smooth nanowires. Moreover, the EF can be further increased with nanoparticle attachment on the corrugated Ag nanowires owing to the coupling between the discrete plasmon state of the nanoparticles and continuum plasmon states of the corrugated nanowire or the crossed corrugated nanowires. The surface plasmonic field distribution of Ag nanowires can be effectively controlled by the polarization of the incident light. Raman spectrum measurements show that the relatively dense corrugated nanowires exhibit a relatively high reproducibility and SERS enhancement attributed to the elimination of polarization-dependent SERS-anisotropic enhancement via the overlapping of randomly distributed Ag nanowires. Such nanostructures as potential nanoantennas offer a route to optimize plasmon coupling for designing miniaturization integration.


Assuntos
Modelos Químicos , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Prata/química , Análise Espectral Raman/métodos , Simulação por Computador , Luz , Teste de Materiais , Tamanho da Partícula , Espalhamento de Radiação
19.
Chem Soc Rev ; 40(11): 5347-60, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21769374

RESUMO

Self-assembly of nanoparticles has emerged as a powerful technique to integrate nanoparticles into well-defined ensembles with collective properties that are different from those of individual nanoparticles and bulk materials with the same chemical composition. Compared with the classical ion/molecule-mediated crystal growth, particle-mediated crystallographically ordered self-assembly is considered as "non-classical crystallization" and the resultant product is termed a "mesocrystal". In this tutorial review, we begin by summarizing the progresses of this field during last decade. Secondly, we outline developments in related fields such as grain rotation and oriented attachment as well as mesocrystals. Thridly, the recent progress in the syntheses of mesocrystals particularly in metals, and the related properties are introduced. Finally, some of the current open questions are discussed.

20.
Biomaterials ; 32(21): 4877-84, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21492933

RESUMO

Surface-enhanced Raman scattering-based signal detection and molecular identification faces the lack of reproducibility and reliability thus hampers its practical applications. Here, we demonstrate a facile particle mediated aggregation protocol to synthesize highly roughened mesosuperstructure--silver polyhedral mesocages. The individual silver octahedral mesocage, owing to highly-roughed surface topography, anisotropic growth as well as intraparticle effect, creates homogenously distributed multiple effective hot spots on the surface of single mesoparticle, hereby exhibits a high reproducibility and an unusual SERS enhancement, i.e., ∼ 10(8)-10(9) magnitude. As such, the current protocol opens avenues for the fabrication of structurally reproducible mesosuperstructure-based SERS sensors.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Prata/química , Análise Espectral Raman/métodos , Teste de Materiais , Tamanho da Partícula , Propriedades de Superfície , Difração de Raios X
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