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1.
Anal Chim Acta ; 1097: 169-175, 2020 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-31910957

RESUMO

In this work, a label-free electrochemical immunosensor was developed for the detection of procalcitonin (PCT), using toluidine blue functionalized NiFe Prussian-blue analog nanocubes (NiFe PBA nanocubes@TB) as a signal amplifier. NiFe PBA nanocubes was synthesized by a simple and efficient self-templating method in this work. NiFe PBA nanocubes with open-framework construction not only provides a larger specific area to load a mass of antibodies but produces an excellent signal without adding extra reaction reagent. Besides, the electrochemical performance of NiFe PBA nanocubes can be enhanced after functionalized with TB. The developed immunosensor exhibited favorable performance for PCT detection with a linear range from 0.001 to 25 ng mL-1 and a detection limit of 3 × 10-4 ng mL-1. Moreover, the immunosensor with acceptable reproducibility, selectivity, and stability may provide a new strategy in the clinical detection of PCT.


Assuntos
Ferrocianetos/química , Imunoensaio , Ferro/química , Nanocompostos/química , Níquel/química , Pró-Calcitonina/análise , Cloreto de Tolônio/química , Técnicas Biossensoriais , Técnicas Eletroquímicas , Humanos , Tamanho da Partícula , Propriedades de Superfície
2.
Biosens Bioelectron ; 149: 111842, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31726273

RESUMO

Effective detection of cancer biomarkers plays a crucial role in the prevention of early cancer. Here, a sandwich-type electrochemical immunosensor was successfully constructed for sensitive detection of carcinoembryonic antigen (CEA) using MoS2/CuS-Au as sensing platform and mulberry-like Au@PtPd porous nanorods (Au@PtPd MPs) as signal amplifiers. The large surface area and good biocompatibility of MoS2/CuS-Au increased the loading of primary antibody. And the good conductivity of MoS2/CuS-Au accelerated the electron transport rate of the electrode surface. Au@PtPd MPs with large specific surface area and a large number of catalytically active sites showed excellent electrocatalytic performance for hydrogen peroxide reduction. The sandwich-type immunosensor prepared by the signal amplification strategy exhibited a wide linear detection range (50 fg/mL to 100 ng/mL) and a low detection limit of 16.7 fg/mL (S/N = 3), featuring good selectivity, stability and reproducibility. Moreover, the satisfactory results in analysis of human serum samples indicated that it possessed a potential application promising in early clinical diagnoses.


Assuntos
Técnicas Biossensoriais , Antígeno Carcinoembrionário/isolamento & purificação , Neoplasias/diagnóstico , Antígeno Carcinoembrionário/química , Proteínas Ligadas por GPI/química , Proteínas Ligadas por GPI/isolamento & purificação , Ouro/química , Humanos , Peróxido de Hidrogênio/química , Limite de Detecção , Nanopartículas Metálicas/química , Nanotubos/química
3.
Bioelectrochemistry ; 131: 107352, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31494386

RESUMO

The designed synthesis of efficient materials can significantly enhance the performance of electrochemical immunoassay in the detection of diseases, pesticide residues and environmental pollutants. The hollow AgPt@Pt core-shell nanoparticles (AgPt@Pt HNs) have exhibited high catalytic efficiency to the hydrogen peroxide (H2O2) reduction for its high mass activity from their hollow structure. Their limitation of instability can be overcome by loading on polypyrrole nanosheet (PPy NS). Besides, PPy NS exhibits good conductivity, and there exists environmentally-friendly method for its synthetic. Thus, AgPt@Pt HNs loaded on PPy NS (AgPt@Pt HNs/PPy NS) exhibits high catalytic efficiency to the reduction of H2O2 and good stability. Furthermore, the quick electron transfer of AgPt@Pt HNs/PPy NS modified glassy carbon electrode has been evidenced by the finding that the large constant of apparent electron transfer rate has also enlarged the current signal when the amount of electron is invariant. The modified electrode has fabricated a label-free amperometric immunosensor to detect sensitively prostate-specific antigen (PSA) with H2O2 as the electroactive material. The immunosensor in hollow core-shell nanosheet structure exhibiting good detection performance of PSA shows its promising applications in the clinical diagnosis.


Assuntos
Técnicas Biossensoriais , Eletrodos , Ouro/química , Nanopartículas Metálicas/química , Nanoestruturas/química , Platina/química , Polímeros/química , Pirróis/química , Biomarcadores Tumorais/análise , Catálise , Peróxido de Hidrogênio/química , Limite de Detecção , Oxirredução , Antígeno Prostático Específico/análise
4.
Polymers (Basel) ; 11(10)2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31569813

RESUMO

Four cyanide-bridged FeIII-MnIII complexes {[Fe(qxcq)(CN)3][Mn(L1)(H2O)]}[Mn(L1)(H2O)(CH3OH)](ClO4)·1.5MeOH·0.5H2O (L1 = N,N'-bis(3-methoxy-5-bromosalicylideneiminate) (2), {[Fe(qxcq)(CN)3][Mn(L2)]}2·0.5H2O (L2 = N,N'-ethylene-bis(3-ethoxysalicylideneiminate)) (3), [Fe(qxcq)(CN)3][Mn(L3)] (L3 = bis(acetylacetonato)ethylenediimine) (4), [Fe(qxcq)(CN)3][Mn(L4)]·1.5MeOH·0.5CH3CN·0.25H2O (L4 = N,N'-(1,1,2,2-tetramethylethylene)bis(salicylideneiminate)) (5), were prepared by assembling a new structurally characterized mer-tricyanoiron(III) molecular precursor (Ph4P)[Fe(qxcq)(CN)3]·0.5H2O (qxcq- = 8-(2-quinoxaline-2-carboxamido)quinoline anion) (1) and the corresponding manganese(III) Schiff base compound. Complexes 2and 3containa cyanide-bridged heterobimetallic dinuclear entity, which can be further dimerized by self-complementary H-bond interactions through the coordinated water molecule from one complex and the free O4unit from the adjacent complex. Complexes 4 and 5 area one-dimensional coordination polymer (CP) comprised of the repeated [Mn(Schiffbase)-Fe(qxcq)(CN)3] units. Complex 4 shows a linear-chain conformation with two trans-located cyano groups bridgingthe neighboring Mn units, while complex 5 is a zigzag-like 1D CP, where the two cyano groups in cis configurationfunction as bridges. In bothcomplexes 4 and 5, the inter-chain π-πstack interactions within the aromaticrings of cyanide precursor extend the 1D chain into the supermolecular 2D networks. The magnetic property has been experimentally studied and theoretically fitted over the four Fe(III)-Mn(III) complexes, revealing the antiferromagnetic interaction in complexes 2 and 4 and the unusual ferromagnetic coupling in complexes 3 and 5 between the Fe(III) ion and the Mn(III) ion bridged by the cyano group. Furthermore, the different magnetic coupling nature has been analyzed on the basis of the magneto-structure correlation of the mer-tricyanometallate-based Fe(III)-Mn(III) magnetic system.

5.
Biosens Bioelectron ; 142: 111580, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31422222

RESUMO

Medically, the dynamic change of carcinoembryonic antigen (CEA) concentration has been an important indicator for monitoring and diagnosing tumors. The sensitive and early detection of CEA plays a momentous role in the prevention and diagnosis of cancer and the evaluation of treatment efficiency. In this work, a sensitive sandwich-type electrochemical immunosensor was fabricated for the quantitative detection of CEA. The trimetallic yolk-shell Au@AgPt nanocubes (Au@AgPt YNCs) loaded on amino-functionalized MoS2 nanoflowers (MoS2 NFs/Au@AgPt YNCs) were used as the labels to conjugate with secondary antibodies. The Au@AgPt YNCs with internal space and permeable shell improved catalytic active surface area. The nanosheet-based MoS2 NFs with good catalytic activity were used as carriers to load Au@AgPt YNCs effectively. Due to the biphasic synergistic catalysis, MoS2 NFs/Au@AgPt YNCs catalyzed the reduction of H2O2 effectually to amplify the current signal. Besides, Au triangular nanoprisms (Au TNPs) were used as substrate material to increase the effective contact areas with the surface of electrode and accelerate the interface electron transfer. Under the optimal conditions, a broad linear range from 10 fg mL-1 to 100 ng mL-1 with low detection limit of 3.09 fg mL-1 (S/N = 3) for detecting CEA was obtained. Moreover, the detection results of the human serum samples were satisfactory, indicating the fabricated immunosensor had potential application values in the early clinical analysis.


Assuntos
Técnicas Biossensoriais/métodos , Antígeno Carcinoembrionário/sangue , Dissulfetos/química , Nanopartículas Metálicas/química , Molibdênio/química , Anticorpos Imobilizados/química , Técnicas Eletroquímicas/métodos , Ouro/química , Humanos , Imunoensaio/métodos , Limite de Detecção , Platina/química , Prata/química
6.
Biosens Bioelectron ; 142: 111556, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31377574

RESUMO

Nowadays, nanomaterials with enzymatic properties have aroused wide interest because of their special advantages, such as catalytic activity, simple preparation method and high stability. We introduced new nanoenzymes to a label-free electrochemical immunosensor for Hepatitis B surface antigen (HBs Ag) detection. In this study, PtPd nanocubes@MoS2 nanoenzymes (PtPd NCs@MoS2) were prepared by loading PtPd nanocubes (PtPd NCs) on molybdenum disulfide nano-sheet (MoS2) through in situ redox polymerization. The prepared nanoenzymes exhibited enhanced peroxidase-like activity than separate MoS2 and PtPd NCs. The catalytic process of PtPd NCs@MoS2 is in agreement with the Michaelis-Menten kinetic equation. PtPd NCs@MoS2 were used for sensitive detection of HBs Ag, which is ascribed to their superior peroxidase activity, good conductivity and high specific surface area and synergistic amplification for current signals. Compared with the detection limit of colorimetric method (3.3 pg/mL), the electrochemical method (10.2 fg/mL) shows a lower detection limit and a wider linear range from 32 fg/mL to 100 ng/mL, so it is more suitable for quantitative analysis of Hepatitis B. In summary, the prepared immunosensor provides a better opportunity for early diagnosis of Hepatitis B and also has further applications in biosensing and medical diagnostics.


Assuntos
Dissulfetos/química , Antígenos de Superfície da Hepatite B/sangue , Molibdênio/química , Nanoestruturas/química , Paládio/química , Platina/química , Anticorpos Imobilizados/química , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Hepatite B/sangue , Hepatite B/diagnóstico , Antígenos de Superfície da Hepatite B/análise , Vírus da Hepatite B/isolamento & purificação , Humanos , Imunoensaio/métodos , Limite de Detecção , Nanoestruturas/ultraestrutura
7.
Org Biomol Chem ; 17(33): 7669-7673, 2019 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-31384864

RESUMO

A new cycloisomerisation of Z-1-iodo-4-N-methylbenzenesulfonyl-1,6-enynes to functionalized pyrroles was realized in the presence of an organomolecule (4,4'-bis(1,1-dimethylethyl)-2,2'-bipyridine) and KOtBu. The transformations were performed efficiently to produce different kinds of functionalized pyrroles within 10 min. This is the first example of an organomolecule promoted methodology with vinyl iodides from a non-aromatic system to an aromatic system, which offers an excellent option toward establishing a new horizon for cross-coupling reactions of vinyl halides. Preliminary mechanistic studies were performed and a crude radical pathway was proposed.

8.
Mikrochim Acta ; 186(7): 416, 2019 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-31187243

RESUMO

A voltammetric sandwich immunoassay is described for the biomarker cardiac troponin I (cTnI). The gold nanocube-functionalized graphene oxide (AuNC/GO) is employed as a substrate to accelerate the electron transfer and to immobilize more primary antibodies. It also employs composite materials prepared from bimetallic gold/silver core-shell nanocubes and nitrogen and sulfur co-doped reduced graphene oxide as the signal amplifier. The introduction of N and S into GO enlarges the active surface and accelerates the electron transfer rate. Such unique characteristics render the material an effective support substrate to load more Au@AgNC and to immobilize an increasing number of second antibodies via Ag-N bonds. After specific binding with cTnI, the immunosensor was incubated in a labeled cTnI secondary antibody solution. The amperometric signal change is then measured at 0.34 V (vs. SCE) using o-phenylenediamine and hydrogen peroxide as an electrochemical probe. Response is linear in the concentration range from 100 fg∙mL-1 to 250 ng∙mL-1, and the detection limit is 33 fg∙mL-1. Graphical abstract Schematic presentation of cardiac troponin I (cTnI) electrochemical immunosensor based on gold nanocube-functionalized graphene oxide (AuNC/GO) as substrate material, bimetallic gold/silver core-shell nanocubes and nitrogen and sulfur co-doped reduced graphene oxide (Au@AgNC/N, S-rGO) as signal amplifier, and hydrogen peroxide (H2O2) and o-phenylenediamine (o-PD) as redox probe.


Assuntos
Técnicas Eletroquímicas/métodos , Grafite/química , Imunoensaio/métodos , Nanopartículas Metálicas/química , Troponina I/sangue , Anticorpos Imobilizados/imunologia , Biomarcadores/sangue , Técnicas Eletroquímicas/instrumentação , Eletrodos , Ouro/química , Humanos , Limite de Detecção , Nitrogênio/química , Reprodutibilidade dos Testes , Prata/química , Enxofre/química , Troponina I/imunologia
9.
Anal Chim Acta ; 1069: 117-125, 2019 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-31084737

RESUMO

Sensitive detection of early ovarian cancer is imminent for women's health. Human epididymis specific protein 4 antigen (HE4 Ag), as a novel tumor marker, has good specificity and sensitivity in ovarian cancer markers, especially for the detection of early ovarian cancer. In this work, a novel and ultrasensitive sandwich-type amperometric electrochemical immunosensor was constructed using amine modified graphene supported gold nanorods (Au NRs/NH2-GS) as a sensor platform and core-shell Au@Pd urchin-shaped nanostructures (Au@Pd USs) as a label of the secondary antibodies (Ab2, Au@Pd USs-Ab2) to realize the quantitative determination of HE4 Ag. The Au NRs/NH2-GS were used for increasing the electrode surface area and effectively immobilizing primary antibodies (Ab1) due to its good water-solubility. The Au@Pd USs have special morphology with high crystal surface index and good stability, capable of loading secondary antibodies (Ab2) and providing a larger active site for the catalysis of hydrogen peroxide (H2O2). The proposed immunosensor displays excellent performance for HE4 Ag detection over the range from 1 pmol L-1 to 50 nmol L-1 with a detection limit of 0.33 pmol L-1 (signal-to-noise ratio of 3). Moreover, the designed immunosensor exhibits excellent reproducibility, selectivity, and stability, which shows great potential in clinical diagnosis.


Assuntos
Antígenos/análise , Técnicas Biossensoriais , Técnicas Eletroquímicas , Imunoensaio , Proteínas/análise , Anticorpos Imobilizados/química , Reações Antígeno-Anticorpo , Catálise , Ouro/química , Humanos , Peróxido de Hidrogênio/química , Nanoestruturas/química , Paládio/química , Tamanho da Partícula , Sensibilidade e Especificidade , Propriedades de Superfície , Proteína 2 do Domínio Central WAP de Quatro Dissulfetos
10.
Bioelectrochemistry ; 128: 140-147, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30991310

RESUMO

A sandwich-type electrochemical immunosensor was fabricated for the quantitation of alpha fetoprotein (AFP). To this end, the Au@Pt dendritic nanorods loaded with amino functionalized molybdenum selenide nanosheets (Au@Pt 41 DNRs/NH2-MoSe2 NSs) with enhanced peroxidase-like properties were selected as the secondary antibody label (Ab2) to achieve signal amplification. The as-obtained Au@Pt DNRs/NH2-MoSe2 NSs exhibited better catalytic activity toward hydrogen peroxide reduction and offered rich anchors for bioconjugation. Meanwhile, gold nanoparticles anchored on an amino functionalized graphene (Au NPs/NH2-GS) composite with admirable conductivity and biocompatibility was used as the matrix material to improve sensitivity. Under optimal conditions, amperometric current responses had a good linear relationship with the logarithm values of AFP concentration in the range 10 fg mL-1 to 200 ng mL-1 with a detection limit of 3.3 fg mL-1 (S/N = 3). Additionally, the immunosensor had excellent reproducibility, selectivity, and stability, which indicated superior performance for AFP detection compared with previous reports. The satisfactory results of human serum samples analysis showed that the designed immunosensor has potential applicability for the sensitive detection of other tumor markers.


Assuntos
Anticorpos Imobilizados/química , Técnicas Biossensoriais , Técnicas Eletroquímicas/instrumentação , Ouro/química , Nanopartículas Metálicas/química , Molibdênio/química , Nanocompostos/química , Platina/química , Compostos de Selênio/química , alfa-Fetoproteínas/análise , Biomarcadores Tumorais/análise , Grafite/química , Peróxido de Hidrogênio/química , Limite de Detecção , Microscopia Eletrônica de Transmissão , Oxirredução , Reprodutibilidade dos Testes
11.
Chem Commun (Camb) ; 55(30): 4355-4358, 2019 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-30911748

RESUMO

A novel palladium-catalyzed regiocontrollable hydroarylation reaction of allenamides with B2pin2/H2O has been disclosed. H2O as an ideal hydrogen source was activated by B2pin2 to furnish allylamines or enamines with a broad functional group tolerance. The regioselectivity for both of the two products was up to 99 : 1 for most of the examples, which was achieved by adjusting the addition order of the catalyst and iodobenzene derivatives. The tentative investigation of the mechanism proved the reaction to be a non-radical process and the deuterium-labeled experiments indicated that the hydrogen was from H2O.

12.
Biosens Bioelectron ; 133: 72-78, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30909015

RESUMO

A sensitive sandwich-type electrochemical immunosensor was established by employing Au@Pt core-shell multi-branched nanoparticles, and thionin functionalized nitrogen/sulfur co-doped graphene oxide (N/S-cGO/L-lys/Au@Pt MBs/Thi) as a double signal label to detect cardiac troponin I (cTnI). In this work, Au nanorods functionalized polydopamine (Au NR@PDA) with high adsorption capacity and superior electroconductivity can provide an efficient substrate for immobilizing primary antibodies (Ab1). In the proposed N/S-cGO/L-lys/Au@Pt MBs/Thi, an electrochemically active molecule, Thi was covalently bonded in the N/S-cGO/L-lys/Au@Pt MBs. It presented a strong differential pulse voltammetry (DPV) current signal without electron transfer mediators, and showed a high electrocatalytic activity toward H2O2 reduction by using amperometric i-t (i-t). Impressively, with the synergistic effect of N/S-cGO/L-lys/Au@Pt MBs/Thi and Au NR@PDA, the developed dual-mode electrochemical immunosensor for cTnI detection showed a wide linear concentration range (50 fg/mL to 250 ng/mL, 750 fg/mL to 100 ng/mL) and a low detection limit (16.7 fg/mL, 250 fg/mL) via i-t and DPV, respectively. Furthermore, this immunosensor exhibited acceptable reproducibility, high sensitivity and good stability under optimal conditions. More importantly, the satisfactory results were obtained in detection of cTnI-spiked human serum samples, and the presented method may be a promising application in clinical bioanalysis.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Imunoensaio , Troponina I/isolamento & purificação , Ouro/química , Grafite/química , Humanos , Limite de Detecção , Nanopartículas Metálicas/química , Fenotiazinas/química , Troponina I/química
13.
Inorg Chem ; 58(7): 4067-4070, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30895784

RESUMO

A flexible-ligand-based metal-organic cage containing functional amide and secondary amino groups as guest-interacted sites has been synthesized. The synergistic effect between the size-defined cavity and self-adaptive backbone endows the cage excellent properties for the selective recognition of specific natural guests over other similar molecules via fluorescent response.

14.
Org Biomol Chem ; 17(10): 2651-2656, 2019 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-30778484

RESUMO

A highly chemo- and regioselective [4 + 2] formal cycloaddition of (Z)-3-iodo allylic nucleophiles and allenamides catalyzed by palladium is reported. The methodology proceeds under mild reaction conditions and is tolerant of alkyl and aryl functional groups. The SN2' substitution at the proximal C[double bond, length as m-dash]C bond performed against the Heck or SN2 pathway delivered a variety of 2-amino-dihydropyrans and 2-amino-tetrahydropiperidines in moderate to satisfactory yields. The [4 + 2] formal cycloaddition derivatives are convertible to interesting scaffolds 2,6,7,7a-tetrahydropyrano[2,3-b]pyrrole and 2,6,7,7a-tetrahydro-1H-pyrrolo[2,3-b]pyridine derivatives via ring-closing metathesis (RCM) with Grubbs catalyst II.

15.
Biosens Bioelectron ; 127: 174-180, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30605806

RESUMO

A label-free electrochemical immunosensor for quantitative detection of human epididymis specific protein 4 antigen (HE4 Ag) was developed by a novel multi-amplification signal system. The multi-amplification signal system was formed by loading bimetallic Au@Pd holothurian-shaped nanoparticles (Au@Pd HSs) on titanium oxide nanoclusters functionalized nitrogen-doped reduced graphene oxide (TiO2-NGO). The Au@Pd HSs were obtained via seed-mediated approach with in-situ grown palladium nanoarms on gold nanorods (Au NRs) surfaces, which possessed good electrocatalysis for hydrogen peroxide (H2O2) reduction and excellent biocompatibility. The TiO2-NGO with the high catalytic activity and large specific surface area was synthesized by hydrothermal method. Using H2O2 as an electrochemically active substrate, the prepared label-free electrochemical immunosensor based on the TiO2-NGO/Au@Pd HSs hetero-nanostructures as the signal amplification platform exhibited excellent selectivity, reproducibility and stability for the detection of HE4 Ag. Meanwhile, the linear range from 40 fM to 60 nM with the detection limit of 13.33 fM (S/N = 3) was obtained, indicating the immunosensor offers a promising method for clinical detection of HE4 Ag.


Assuntos
Antígenos/isolamento & purificação , Técnicas Biossensoriais , Imunoensaio , Proteínas/isolamento & purificação , Anticorpos Imobilizados/química , Antígenos/química , Antígenos/imunologia , Catálise , Ouro/química , Grafite/química , Humanos , Peróxido de Hidrogênio/química , Limite de Detecção , Nanopartículas Metálicas/química , Paládio/química , Proteínas/química , Proteínas/imunologia , Titânio/química , Proteína 2 do Domínio Central WAP de Quatro Dissulfetos
16.
Bioelectrochemistry ; 126: 92-98, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30530260

RESUMO

In this work, a sandwich-type electrochemical immunosensor was fabricated to quantitatively detect hepatitis B surface antigen (HBsAg). The immunosensor was based on Rh core and Pt shell nanodendrites loaded onto amino group functionalized graphene nanosheet (RhPt NDs/NH2-GS) as label and gold nanoparticles loaded onto polypyrrole nanosheet (Au NPs/PPy NS) as platform. RhPt NDs with abundant catalytic active sites because of the branched core-shell structure, RhPt NDs/NH2-GS as the label displayed high catalytic activity, amplifying the current signal of the immunosensor. Additionally, Au NPs/PPy NS enhanced the electron transfer and provided a good microenvironment to immobilize antibodies effectively, thus improving the sensitivity of the immunosensor. Based on above advantages, the immunosensor emerged a linear concentration ranging from 0.0005 to 10 ng/mL, a low detection limit of 166 fg/mL for HBsAg (S/N = 3) and good stability, selectivity, reproducibility. Furthermore, the satisfactory accuracy in analysis of actual serum samples implied the immunosensor had promising prospect in clinical analysis applications.


Assuntos
Anticorpos Imobilizados/química , Técnicas Eletroquímicas/métodos , Antígenos de Superfície da Hepatite B/sangue , Nanoestruturas/química , Polímeros/química , Pirróis/química , Técnicas Biossensoriais/métodos , Ouro/química , Grafite/química , Hepatite B/sangue , Hepatite B/imunologia , Antígenos de Superfície da Hepatite B/imunologia , Vírus da Hepatite B/imunologia , Humanos , Imunoensaio/métodos , Limite de Detecção , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Nanoestruturas/ultraestrutura , Platina/química , Ródio/química
17.
Biosens Bioelectron ; 126: 785-791, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30557837

RESUMO

An ultrasensitive sandwich-type electrochemical immunosensor was designed by using gold nanoparticles (Au NPs) as the substrate material and microporous carbon spheres (CS) loading silver nanoparticles (Ag NPs) spaced Hemin/reduced graphene oxide (Hemin/rGO) porous composite materials (Ag NPs@CS-Hemin/rGO) as the detection antibodies (Ab2) label for detecting carcinoembryonic antigen (CEA). The Au NPs with good electrical conductivity and biocompatibility could accelerate the electron transfer on the electrode interface and enhance the load capacity of capture antibodies (Ab1). Hemin is peroxidase-like substance which has excellent catalytic ability for H2O2 reduction but easy to molecular aggregation and oxidative self-destruction. Reduced graphene oxide (rGO) is a good supporting material for Hemin to mitigate this disadvantage. CS loading Ag NPs (Ag NPs@CS) as the spacer inserts into Hemin/rGO sheet can overcome the irreversible stacking of rGO, and form complex porous structure which exposes more active sites of Hemin. Moreover, Ag NPs loaded on CS also has catalytic ability for H2O2 reduction. Thus the Ag NPs@CS-Hemin/rGO used as the Ab2 label has a large working surface area and high utilization rate, which heightens the catalytic ability for H2O2 reduction to amplify the current signal effectually. The current signal and the logarithm of CEA concentration presented a wide linear response range of 20 fg/mL to 200 ng/mL, and the detection limit of CEA was 6.7 fg/mL. Furthermore, the designed immunosensor exhibited a good reproducibility, selectivity and stability, which confirms a broad development prospect when applying it in early clinical detection.


Assuntos
Técnicas Biossensoriais , Antígeno Carcinoembrionário/isolamento & purificação , Técnicas Eletroquímicas , Neoplasias/diagnóstico , Antígeno Carcinoembrionário/química , Ouro/química , Grafite/química , Humanos , Imunoensaio , Limite de Detecção , Nanopartículas Metálicas/química
18.
Org Biomol Chem ; 16(40): 7356-7360, 2018 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-30280178

RESUMO

A palladium-catalyzed heck-type cascade cyclization of (Z)-1-iodo-1,6-dienes with N-tosyl hydrazones is reported. The alkylpalladium intermediate coupled with the diazo compound, generating the second alkylpalladium species bearing two ß-H, which generated a terminal alkene as the major products in the anti-Zaitsev way via the highly regioselective ß-H elimination. It provided a new way to synthesize tetrahydropyridine derivatives bearing a terminal alkene.

19.
Biosens Bioelectron ; 122: 231-238, 2018 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-30267981

RESUMO

The quantitative detection of carcinoembryonic antigen (CEA) is significant to assess tumor status and therapeutic efficiency. In this study, a sandwich-type amperometric immunosensor for CEA detection sensitively was fabricated by novel signal amplification system. The signal amplification system was formed by gold nanoparticles loaded on amino functionalized graphene sheet (Au NPs/NH2-GS) and gold@palladium nanodendrites loaded on ferrous-chitosan functionalized polypyrrole nanotubes (Au@Pd NDs/Fe2+-CS/PPy NTs). Au NPs/NH2-GS as platform enhanced the electron transfer proven by apparent electron transfer rate constant. Au@Pd NDs/Fe2+-CS/PPy NTs nanocomposite as label appeared high catalytic activity to hydrogen peroxide reduction. Thus, the immunosensor showed wide linear concentration range (50 fg/mL to 50 ng/mL) and low detection limit of 17 fg/mL via amperometric i-t curve (i-t). Significantly, the nanocomposite can act as electroactive substance, which provided a good method to detect CEA without additional electroactive substance via square wave voltammetry (SWV). An overlapping linear concentration range (500 fg/mL to 5.0 ng/mL) was obtained compared i-t with SWV. The good reliability was verified mutually by i-t and SWV in actual sample analysis under overlapping linear concentration range. The detection method of without additional electroactive substance has vast potential for future development, due to simple testing condition.


Assuntos
Técnicas Biossensoriais/métodos , Antígeno Carcinoembrionário/sangue , Quitosana/análogos & derivados , Ouro/química , Nanoestruturas/química , Paládio/química , Polímeros/química , Pirróis/química , Anticorpos Imobilizados/química , Técnicas Eletroquímicas/métodos , Grafite/química , Humanos , Imunoensaio/métodos , Limite de Detecção , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Nanoestruturas/ultraestrutura
20.
Biosens Bioelectron ; 112: 1-7, 2018 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-29680701

RESUMO

Effective treatment of cancer depends upon the early detection of the tumor marker. Here, we report on the development of a new immunosensor for early detection of carcinoembryonic antigen (CEA). Cubic Au@Pt dendritic nanomaterials functionalized nitrogen-doped graphene loaded with copper ion (Au@Pt DNs/NG/Cu2+) with enhanced peroxidase-like properties was synthesized as labels to effectively capture and immobilize secondary anti-CEA. The Au@Pt DNs with more active surface area could efficiently enhance electrocatalysis for reduction of hydrogen peroxide (H2O2). Meanwhile, with good conductivity and large specific surface area, NG can immobilize a large amount of Au@Pt DNs. Furthermore, after adsorbed Cu2+ can further promote the redox of H2O2 and amplify the signal of the immunosensor. For the immobilization of primary antibodies, Au nanoparticles functionalized polydopamine (Au@PDA) were used as transducing materials to modify glassy carbon electrodes and enhance the electron transfer efficiently. Under optimal conditions, the immunosensor exhibited a satisfactory response to CEA with a limit detection of 0.167 pg/mL and linear detection range from 0.5 pg/mL to 50 ng/mL. Based on the high sensitivity and specificity of the immunosensor, we propose this multiple amplified biosensor for early detection of CEA.


Assuntos
Técnicas Biossensoriais , Antígeno Carcinoembrionário/isolamento & purificação , Técnicas Eletroquímicas , Nanopartículas Metálicas/química , Anticorpos Imobilizados/química , Antígeno Carcinoembrionário/química , Ouro , Grafite/química , Humanos , Peróxido de Hidrogênio/química , Limite de Detecção , Peroxidase/química
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