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1.
J Colloid Interface Sci ; 569: 277-285, 2020 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-32114106

RESUMO

To explore alkaline fuel cells in practice, searching low-cost and efficient alternatives to Pt-based catalysts is urgent yet challenging for oxygen reduction reaction (ORR). Herein, Co3Fe7 alloy nanoparticles wrapped in N-doped defect-rich carbon nanosheets (Co3Fe7/CNs) were synthesized at 800 °C by a one-step pyrolysis of the mixture (dicyandiamide, iron (II) phthalocyanine (FePc), cobalt (II) phthalocyanine (CoPc) and Fe2O3), defined as Co3Fe7/CNs-800 for simplicity. The pyrolysis temperature and the dosages of dicyandiamide closely correlated to the ORR performance of the resultant catalysts in 0.1 M KOH solution. Significantly, the optimized Co3Fe7/CNs-800 exhibited encouraging onset potential (Eonset = 0.97 V) and half-wave potential (E1/2 = 0.85 V) in the alkaline media, surpassing commercial Pt/C (50 wt%, Eonset = 0.96 V, E1/2 = 0.84 V). This work provides a feasible strategy for developing efficient non-noble metal ORR electrocatalysts in the alkaline condition.

2.
Chem Commun (Camb) ; 2020 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-32159543

RESUMO

In this study, three kinds of CDs with blue, yellow and red emissions were prepared and their luminescence mechanisms through theoretical calculations together with experimental data were further investigated in depth. Afterwards, a sensor array was constructed by using three kinds of CD-metal ions for rapid discrimination of different types of sulfur-containing species.

3.
Anal Chem ; 2020 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-32191435

RESUMO

Nonspecific adsorption is of great concern for electrochemical biosensors performing in complex biological media, and various antifouling materials have been introduced into the sensing interfaces to improve the antifouling capability of different biosensors. However, for most of the biosensors with the antifouling materials and sensing probes coexisted in the sensing interfaces, either the antifouling materials will impair the sensing performances, or the sensing probes will affect the antifouling ability. Herein, a facile and efficient antifouling biosensor was developed based on a newly designed three-in-one peptide with anchoring, antifouling and recognizing capabilities. One end of the designed peptide is a unique anchoring part that is rich in amine groups, and this part can be anchored to the poly (3,4-ethylenedioxythiophene) (PEDOT)-citrate film electrodeposited on a glassy carbon electrode. The other end of the peptide is a recognizing part that can specifically bind to the aminopeptidase N (APN) and human hepatocellular carcinoma cells (HepG2 cells). While the middle part of the peptide, together with the anchoring part, was designed to be antifouling. With this designed multifunctional peptide, highly sensitive and low fouling biosensors capable of assaying targets APN and HepG2 cells in complex biological media can be easily prepared, with detection limits of 0.4 ng·mL-1 and 20 cells·mL-1, respectively. This antifouling biosensor is feasible for practical targets detection in real complex samples, and it is highly expected that this peptide designing strategy may be extended to the development of various antifouling biosensors.

4.
Chem Rev ; 2020 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-32202761

RESUMO

The ability to fabricate sensory systems capable of highly selective operation in complex fluid will undoubtedly underpin key future developments in healthcare. However, the abundance of (bio)molecules in these samples can significantly impede performance at the transducing interface where nonspecific adsorption (fouling) can both block specific signal (reducing sensitivity) and greatly reduce assay specificity. Herein, we aim to provide a comprehensive review discussing concepts and recent advances in the construction of antifouling sensors that are, through the use of chemical, physical, or biological engineering, capable of operating in complex sample matrix (e.g., serum). We specifically highlight a range of molecular approaches to the construction of solid sensory interfaces (planar and nanoparticulate) and their characterization and performance in diverse in vitro and in vivo analyte (e.g., proteins, nucleic acids, cells, neuronal transmitters) detection applications via derived selective optical or electrochemical strategies. We specifically highlight those sensors that are capable of detection in complex media or those based on novel architectures/approaches. Finally, we provide perspectives on future developments in this rapidly evolving field.

5.
Anal Chim Acta ; 1104: 53-59, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32106957

RESUMO

Development of ultra-sensitive and high specific aptasensors is important for early diagnosis of prostate cancer. Herein, ultrasensitive detection of prostate specific antigen (PSA) aptasensor was realized based on the "on-off-on" model via fluorescence (FL) covalent energy transfer between g-C3N4 quantum dot (g-CNQDs) and palladium triangular plates (Pd TPs). Specifically, the Pd TPs were primarily linked with PSA aptamer (PA) as the reporter probe, followed by attaching them onto the g-CNQDs surfaces, causing the highly enlarged FL quenching rate (ca. 75%). After the introduction of PSA, the FL intensities recovered again because of the distinctively stronger affinity of PA to PSA than that of g-CNQDs. The bond of pyridine N with Pd was identified as efficient energy transfer pathway through the X-ray photoelectron spectroscopy (XPS) and FL measurements. The surface plasmon resonance (SPR) experiments certified the remarkably different affinity of PA towards g-CNQDs and PSA. The as-constructed FL aptasensor can accurately quantify PSA with wide linear range of 10 pg mL-1-50 ng mL-1 and ultra-low limit of detection (LOD, 4.2 pg mL-1), indicating the promising applications in clinical assay and biological detection.

6.
J Mater Chem B ; 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-32073101

RESUMO

As nonspecific adsorption or biofouling has obvious side effects on the selectivity, it is a great challenge for cytosensors to detect target cells in practical biological samples. In this study, we first propose the design and synthesis of an antifouling photoelectrode. The antifouling photoelectrode not only has the desired photocurrent response, but also possesses an unexpected antifouling capability of resisting nonspecific adsorption of biomolecules. Herein, the PEDOT-HPG/SnS/ZnO-NT antifouling photoelectrode was formed and a robust photoelectrochemical cytosensor with enhanced sensitivity and selectivity has been demonstrated.

7.
Chem Commun (Camb) ; 56(9): 1413-1416, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-31912820

RESUMO

A novel ratiometric surface-enhanced Raman scattering (SERS) biosensor was constructed based on stimuli-responsive DNA functionalized metal organic frameworks (MOFs) for detection of adenosine triphosphate (ATP). As a result, the detection range of ATP was 1 nM to 200 nM with a detection limit of 0.4 nM. The ratiometric SERS biosensor strategy offers a lower detection limit and exhibits a more enhanced performance than the typical SERS detection based on single signal response, which may have potential for detection of other biomolecules or metal ions.


Assuntos
Trifosfato de Adenosina/química , Técnicas Biossensoriais , DNA/química , Estruturas Metalorgânicas/química , Análise Espectral Raman , Propriedades de Superfície
9.
Anal Chim Acta ; 1097: 78-84, 2020 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-31910972

RESUMO

A biomimetic assembly of per-O-methylated-cyclodextrin dimer with cobalt proto-porphyrin (CoIII-PPIX@Py2CD) was achieved via covalent linkage between CoIII of CoIII-PPIX and pyridine N of Py2CD (primarily synthesized by the acyl chlorination reaction of two ß-CDs monomers with 3,5-bis (bromomethyl) pyridine). Ultraviolet-visible (UV-vis) and circular dichroism (CD) absorption spectroscopy, and NMR hydrogen spectroscopy (H1-NMR) were adopted to carefully characterize the structure of Py2CD and its functional assembly with CoIII-PPIX. X-ray photoelectron spectroscopy (XPS) was employed to affirm the binding of the as-obtained CoIII-PPIX@Py2CD, whose electrochemical kinetics were extensively studied to validate the feasibility in the catalytic reduction of hydrogen peroxide (H2O2). The developed sensor displayed the wide linear range for H2O2 detection and the low detection limit of 2.47 × 10-7 M. This work sheds some constructive lights on rational design and synthesis of preeminently biomimic carrier and high cost-effectiveness catalyst for (bio)analytical applications.

10.
J Colloid Interface Sci ; 565: 35-42, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31931297

RESUMO

Nanoscale ternary chalcogenides have attracted increasing research interest due to their merits of tunable properties and diverse applications in energy and biomedical fields. In this article, silver indium sulfide quantum dots supported by glutathione and polyethyleneimine as dual-ligands have been synthesized through an environmentally friendly and reproducible aqueous method. An emission quantum yield up to 37.2% has been achieved by glutathione as co-ligand bearing electron-rich groups, much higher than that of polyethyleneimine coated quantum dots (4.97%). Both spectroscopic and structural characterizations demonstrate that the photoluminescence enhancement is attributed to change of surface properties by glutathione as co-ligand. Dynamic light scattering (DLS) results and thermogravimetric analysis (TGA) reveal that glutathione covers the QDs with a higher density on the nanocrystal surface than other co-ligands. Therefore, it can effectively passivate the surface trap centers, thus decreasing the non-radiative emission. Moreover, the resultant silver indium sulfide quantum dots present surprisingly long lifetime of 3.69 µs, excellent fluorescent stability and low cytotoxicity, which enables them to be ideal candidate for real-time bioimaging.

11.
Colloids Surf B Biointerfaces ; 186: 110706, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31838270

RESUMO

m-Aminobenzoic acid (ABA) is one popular derivative of highly conductive monomer of aniline, which contains a carboxyl (COOH) group in its skeleton that is beneficial to various bio-interface and bio-analysis. Hence, Poly(m -aminobenzoic acid) (PABA) membrane was firstly electrochemical deposited onto bare electrode surface using a straightforward cyclic voltammetry (CV) method. PABA membrane exhibited excellent electrochemical stability and apparent wrinkle morphology that could effectively enhance response signal and immensely increase specific surface area of electrode. Next, PABA membrane was decorated with well-designed hairpin aptamer and preferred antifouling peptide in sequence to construct a two-layer architectural bio-interface that could present both sensitive target recognition capability and excellent antifouling ability. Benefiting from the electrodeposited PABA membrane to enhance electrochemical response signal, the developed biosensor performed excellent sensitivity toward target protein, meanwhile, associated with good selectivity and reproducibility attributing to the favored peptide that was able to decline nonspecific protein adsorption and improve target recognition.

12.
Biosens Bioelectron ; 147: 111779, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31630031

RESUMO

In this study, a coumarin-appended cyclometalated iridium (III) complex was prepared and demonstrated to be an efficient photoelectrochemical (PEC) active species with stable and reproducible cathodic photocurrent illuminated by visible light. A gold nanoparticles (AuNPs)-based PEC probe was assembled using the as-prepared iridium (III) complex as signal reporter. Integrating aptamer/protein proximity binding-triggered strand displacement and catalytic hairpin assembly (CHA) amplification strategy, an enzyme-free and sensitive PEC assay was developed. Benefiting from superior photon-to-current conversion character of the iridium (III) complex and effective amplification strategy, the proposed assay exhibited enhanced sensitivity for thrombin detection with a detection limit of 23 fM. It also showed a high specificity in serum samples. This study further demonstrated that cyclometalated iridium (III) complexes could be adopted as favorable photoactive material for bioanalysis by improving their ability of absorbance in the visible region.

13.
ACS Appl Mater Interfaces ; 12(1): 373-379, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31840494

RESUMO

A simple and label-free sensing platform with low background based on the chain-displacement triggered self-assembly of Ag NCs was developed for ratiometric visual analysis of intracellular miRNA-21. Based on this sensitively ratiometric sensing approach, a picomole limit detection for miRNA-21 can be obtained. Most importantly, compared with the traditional single base mismatch detection method, our proposed method can realize single base mismatch detection according to the remarkable fluorescence color conversion, rather than simple fluorescence intensity change, which can obviously improve the accuracy and reliability. In addition, successful multicolor real-time monitoring of intracellular miRNA-21 makes the probe a potential candidate for miRNA-21 inhibiting drug screening. Furthermore, MCF-7, HeLa, and normal L02 cells can also be visually differentiated according to the fluorescence color by using the label-free sensing platform, showing its potential prospect in target visual analysis.

14.
Anal Chem ; 91(24): 15846-15852, 2019 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-31736309

RESUMO

Sensitive and selective detection of target analytes in complex biological samples is currently a major challenge. Herein we constructed a dual-mode antifouling electrochemical sensing platform for the detection of prostate-specific antigen (PSA) based on two kinds of antifouling peptides functionalized with a graphene oxide-Fe3O4-thionine (GO-Fe3O4-Thi) probe and internal reference ferrocene (Fc), respectively. The longer peptide (Pep1) modified with the GO-Fe3O4-Thi probe was designed to contain a peptide sequence (HSSKLQK) capable of being recognized and cut by PSA. The GO-Fe3O4-Thi probe functions not only as a peroxidase mimick (GO-Fe3O4) but also works as an electrochemical probe due to the presence of thionine (Thi). The concentration of PSA can be measured through both the increase of differential pulse voltammetry (DPV) signal change of Thi and the decrease of chronoamperometry (CA) signal of the reduction of H2O2 electrocatalyzed by GO-Fe3O4. The shorter peptide (Pep2) was tagged with Fc, whose DPV signal remained constant and was independent of the presence of PSA, and it was used as an internal reference to ensure the reliability and accuracy of the measurement. The dual-mode PSA sensor exhibits a wide linear range from 5 pg/mL to 10 ng/mL, with low detection limits of 0.76 and 0.42 pg/mL through DPV and CA modes, respectively. More importantly, owing to the antifouling capability of the designed peptides, the biosensor performances remained operable even in human serum, indicating feasibility of the electrochemical biosensor for practical PSA quantification in complex samples.

15.
Chem Commun (Camb) ; 55(100): 15053-15056, 2019 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-31777878

RESUMO

The present study reports an aqueous synthesis approach towards off-stoichiometric copper indium sulfide quantum dots with emissions in the near-infrared spectral range. The photoluminescence properties of the dots, and in particular the appearance of dual emission at high Cu deficiency, were studied with temperature-dependent steady-state and transient photoluminescence spectroscopy.


Assuntos
Materiais Biocompatíveis/química , Pontos Quânticos/química , Materiais Biocompatíveis/farmacologia , Sobrevivência Celular , Cobre/química , Células HeLa , Humanos , Índio/química , Medições Luminescentes , Pontos Quânticos/toxicidade , Temperatura Ambiente , Raios Ultravioleta
16.
Biosens Bioelectron ; 145: 111638, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31574352

RESUMO

By integrating the amplified electrochemical signals and effective capture of antibodies together, advanced multimetallic superstructured nanocrystals endow label-free immunosensors promising applications in early diagnosis and monitoring of diseases. Herein, four-metallic PtCoCuPd hierarchical branch-like tripods (HBTPs) were directly synthesized by a green one-pot aqueous method without any seed or organic solvent involved, which were applied to construct a novel label-free immunosensor for detecting cardiac troponin I (cTnI). The specific hierarchical micro/nanostructures greatly improved the immobilization of antibodies and enhanced the catalytic activity for K3Fe(CN)6, which would effectively amplify the electrochemical signals, thereby improving the detection sensitivity. Under the optimal conditions, the as-developed immunosensor exhibited a wide linear range (0.001-100.0 ng mL-1) and a low detection limit (0.2 pg mL-1, S/N = 3) for the assay of cTnI. The immunosensor provides a powerful platform for quantitative detection of cTnI, which can be explored to detect other tumor markers in actual sample analysis.

17.
J Mater Chem B ; 7(38): 5842-5847, 2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31506652

RESUMO

Low fouling electrochemical immunosensors with both "signal-off" and "signal-on" analytical methods were developed for the highly sensitive and efficient detection of cancer antigen 15-3 (CA 15-3) in human serum samples. The antifouling sensing interfaces were constructed by assembling multifunctional polyethylene glycol on gold electrodes, followed by covalent conjugation with CA 15-3 antibody. Pure antigens and Fe3O4@Ag will competitively bind to the immobilized antibody on the electrode. Fe3O4 magnetic nanoparticles attached to the working electrode and collected by a magnetic electrode were treated via electrochemical conversion to generate electroactive Prussian blue as a signal readout. Therefore, these two signals measured independently were complementary, and this design allowed one to choose the assay method according to real situations so as to ensure accuracy of the immunosensor. Moreover, owing to its good antifouling property, the immunosensor was capable of detecting CA 15-3 even in complex human serum samples, demonstrating potential application in quantitative analysis of real patient serum samples.

18.
Anal Chem ; 91(21): 13947-13952, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31558029

RESUMO

Gold nanoclusters (Au NCs) coated with various peptides have been widely used as fluorescent probes, and nowadays the most commonly used are cysteine (C) and tyrosine (Y) based ones. Herein, we report the preparation and clinical application of highly efficient and stable fluorescent Au NCs protected by screened peptides with a specific amino acid sequence Cys-Met-Met-Met-Met-Met (CMMMMM). Compared with traditional C, Y based peptide (CYYYYY) protected Au NCs, the fluorescence intensity of the CMMMMM-Au NCs increased by 230%, and the photobleaching resistance or stability of the CMMMMM-Au NCs increased by about 300% (after continuous ultraviolet irradiation for 60 min, the fluorescence of the CMMMMM-Au NCs remained more than 90% of their initial intensity, while the CYYYYY-Au NCs remained less than 30%). Assaying arrays based on CMMMMM protected Au NCs with different positive or negative charges as sensing receptors were developed through regulating different pH values, and multivariate analysis on the patterns obtained by these arrays allowed effective identification of not only ten proteins separately but also complex protein mixtures with subtly diverse compositions. The docking simulation and isothermal titration confirmed that target proteins interacted with CMMMMM-Au NCs mainly through electrostatic interactions and partly hydrophobic interactions, which affected the binding energy and fluorescence lifetime of CMMMMM-Au NCs, resulting in the unique fingerprint-like recognition patterns. Furthermore, serums from breast cancer, severe osteoarthritis, and rectal cancer patients can be effectively identified with healthy people using this CMMMMM-Au NCs based sensor array.

19.
Anal Chim Acta ; 1079: 192-199, 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31387710

RESUMO

Herein, a zinc ion (Zn2+)-triggered aggregation induced emission enhancement (AIEE) fluorescence "on-off-on" nanoswitch was fabricated for inorganic pyrophosphate (PPi) and inorganic pyrophosphatase (PPase) activity detection. Dual ligand functionalized Au NCs were utilized as the substrate of the AIEE nanoswitch. The introduction of Zn2+ can cause Au NCs aggregated along with the enhanced fluorescence. After the addition of PPi, aggregated Au NCs disaggregated along with decreased fluorescence due to the competitive combination between PPi and Zn2+ (on-off). When PPase was introduced, PPi was hydrolyzed and release Zn2+, resulting in aggregated Au NCs along with enhanced fluorescence again (off-on). On the basis of this, highly selective and sensitive detection PPi (liner range from 0.1 to 300 µM) and PPase activity (liner range from 0.1 to 10 mU) can be achieved. The detection limits are 0.04 µM for PPi and 0.03 mU for PPase, respectively. Furthermore, the as-prepared Zn2+-triggered AIEE nanoswitch was successfully used for quantitative analysis of PPase activity in human serum with satisfactory spiked recoveries, and applied for the inhibitors screening.


Assuntos
Difosfatos/sangue , Pirofosfatase Inorgânica/sangue , Nanopartículas Metálicas/química , Zinco/química , Ensaios Enzimáticos/métodos , Fluorescência , Ouro/química , Humanos , Limite de Detecção , Espectrometria de Fluorescência/métodos
20.
Biosens Bioelectron ; 142: 111553, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31377575

RESUMO

In this work, an antifouling electrochemiluminescent (ECL) ratiometric biosensor is designed for the accurate, selective and sensitive detection of DNA methyltransferase (MTase) activity based on a dual-signaling strategy. Briefly, an ITO electrode is used to construct the anti-fouling interfaces with the modification of polyaniline (PANI), AuNPs and peptide. Hairpin DNA molecules containing the symmetric sequence of 5'-CATC-3' are attached onto the modified ITO electrode and the ds-DNA can be cut off in the presence of Dam MTase and DpnI. The residual DNA and two hairpin DNA could lead to the extension of ds-DNA due to the Hybridization Chain Reaction (HCR). ECL signal is amplified significantly with the insertion of PTC-NH2 molecules into the dsDNA grooves. The ECLPTC-NH2/ECLAu@luminol is found in a logarithmic linear relation with the concentration of Dam MTase. Moreover, owing to the presence of antifouling peptide on the sensing interface, the ECL biosensor was capable of sensing MTase activity in complex biological media, such as FBS samples and human serum with significantly reduced nonspecific adsorption effect. Assaying Dam MTase in complex sample mixture containing 5% calf serum and 5% human serum further proved the feasibility of this ECL biosensor for early clinical diagnosis.


Assuntos
Compostos de Anilina/química , Técnicas Biossensoriais/métodos , Medições Luminescentes/métodos , Peptídeos/química , DNA Metiltransferases Sítio Específica (Adenina-Específica)/análise , Animais , Incrustação Biológica/prevenção & controle , Bovinos , Eletrodos , Ensaios Enzimáticos/métodos , Células HeLa , Humanos , DNA Metiltransferases Sítio Específica (Adenina-Específica)/sangue
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