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1.
Inorg Chem ; 58(16): 11076-11084, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31393117

RESUMO

Platinum drugs including cisplatin are widely used in clinics to treat various types of cancer. However, the lack of cancer-cell selectivity is one of the major problems that lead to side effects in normal tissues. Luteinizing hormone-releasing hormone (LHRH) receptors are overexpressed in many types of cancer cells but rarely presented in normal cells, making LHRH receptor a good candidate for cancer targeting. In this study, we report the synthesis and cytotoxic study of a novel platinum(IV) anticancer prodrug functionalized with LHRH peptide. This LHRH-platinum(IV) conjugate is highly soluble in water and quite stable in a PBS buffer. Cytotoxic study reveals that the prodrug selectively targets LHRH receptor-positive cancer cell lines with the cytotoxicities 5-8 times higher than those in LHRH receptor-negative cell lines. In addition, the introduction of LHRH peptide enhances the cellular accumulation in a manner of receptor-mediated endocytosis. Moreover, the LHRH-platinum(IV) prodrug is proved to kill cancer cells by binding to the genomic DNA, inducing apoptosis, and arresting the cell cycle at the G2/M phase. In summary, we report a novel LHRH-platinum(IV) anticancer prodrug having largely improved selectivity toward LHRH receptor-positive cancer cells, relative to cisplatin.


Assuntos
Antineoplásicos/farmacologia , Platina/farmacologia , Pró-Fármacos/farmacologia , Receptores LHRH/antagonistas & inibidores , Antineoplásicos/síntese química , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Relação Dose-Resposta à Radiação , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Estrutura Molecular , Platina/química , Pró-Fármacos/síntese química , Pró-Fármacos/química , Receptores LHRH/metabolismo , Relação Estrutura-Atividade
2.
J Agric Food Chem ; 67(34): 9658-9666, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31381330

RESUMO

The biomimetic enzyme-linked immunosorbent assay (BELISA) is widely used for detection of small-molecule compounds as a result of low cost and reagent stability of molecularly imprinted polymers (MIPs). However, enzyme labels used in BELISA still suffer some drawbacks, such as high production cost and limited stability. To overcome the drawbacks, a biomimetic nanozyme-linked immunosorbent assay (BNLISA) based on MIPs and nanozyme labels was first proposed. For nanozyme labels, platinum nanoparticles (PtNPs) acted as peroxidase by catalyzing the oxidation of colorless 3,3',5,5'-tetramethylbenzidine (TMB) into an ideal surface-enhanced Raman scattering (SERS) marker. Blue TMB2+ and bovine serum albumin (BSA)-hapten showed superior selectivity when competing with targets for binding sites on MIPs, named the Pt@BSA-hapten probe. The BNLISA method was employed to detect triazophos with a limit of detection of 1 ng mL-1 via colorimetric and SERS methods. Replacing traditional enzymes with nanozymes for combination with MIPs may bring about a new prospect for other compound analyses.


Assuntos
Colorimetria/métodos , Organotiofosfatos/análise , Praguicidas/análise , Análise Espectral Raman/métodos , Triazóis/análise , Benzidinas/química , Materiais Biomiméticos/química , Colorimetria/instrumentação , Frutas/química , Ouro/química , Imunoadsorventes/química , Nanopartículas Metálicas/química , Platina/química , Pyrus/química , Sensibilidade e Especificidade , Análise Espectral Raman/instrumentação , Poluentes Químicos da Água/análise
3.
Phys Chem Chem Phys ; 21(31): 17142-17151, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31339149

RESUMO

In this work we compute high-coverage hydrogen adsorption energies and geometries on the stepped platinum surfaces Pt(211) and Pt(533) which contain a (100)-step type and the Pt(221) and Pt(553) surface with a (111) step edge. We discuss these results in relation to ultra-high-vacuum temperature programmed desorption (TPD) data to elucidate the origin of the desorption features. Our results indicated that on surfaces with a (100)-step type, two distinct ranges of adsorption energy for the step and terrace are observed, which mirrors the TPD spectra for which we find a clear separation of the desorption peaks. For the (111) step type, the TPD spectra show much less separation of the step and terrace features, which we assign to the low individual adsorption energies for H atoms on this step edge. From our results we obtain a much clearer understanding of the surface-hydrogen bonding at high coverages and the origin of the different TPD features present for the two step types studied.


Assuntos
Teoria da Densidade Funcional , Hidrogênio/química , Platina/química , Adsorção , Cristalização , Ligações de Hidrogênio , Temperatura Ambiente , Termodinâmica
4.
Anal Chim Acta ; 1078: 161-167, 2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31358215

RESUMO

Sarcosine is a recently identified biomarker for prostate cancer. However, the rapid detection methods for sarcosine are relatively lack because of the low concentration and the presence of complicated interfering substances in serum or urine. In this manuscript, hollow nanospheres of Fe3O4 was synthesized and used as carrier to disperse Pt (Pt) nanoparticles. In order to achieve excellent electron transfer ability, we use polyaniline to coat Pt-Fe3O4 nanoparticles, and pyrolyze the polyaniline to carbon (C). Thus, hollow magnetic Pt-Fe3O4@C nanocomposites with good electron transfer ability are formed. The Pt-Fe3O4@C nanocomposites have high catalytic activity and stability. The nanocomposites were immobilized on glassy carbon electrode (GCE) to construct a nonenzyme hydrogen peroxide (H2O2) sensor (Pt-Fe3O4@C/GCE). We further construct a sensitive sarcosine biosensor by immobilizing sarcosine oxidase (SOx) on the Pt-Fe3O4@C/GCE. The high catalytic activity and good biocompatibility of Pt-Fe3O4@C nanocomposites greatly retained the bioactivity of immobilized SOx, and the prepared sarcosine biosensor has good electrocatalytic performance towards sarcosine. It has a linear detection range between 0.5 and 60 µM with a limit of detection (LOD) of 0.43 µM (the signal to noise ratio is 3), and the sensitivity is 3.45 nA µM-1 (48.8 nA µM-1 cm-2), which has the potential to be used for rapid screening of prostate cancer.


Assuntos
Nanopartículas de Magnetita/química , Nanocompostos/química , Sarcosina/sangue , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Carbono/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Enzimas Imobilizadas/química , Humanos , Limite de Detecção , Platina/química , Sarcosina Oxidase/química
5.
Food Chem ; 300: 125190, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31330375

RESUMO

Technologies for monitoring meat spoilage are important to ensuring consumer safety. As dimethyl sulfide (DMS) is a reliable marker for meat freshness, sensitive and selective DMS sensors are of great interest. Herein, two trinuclear cyano-bridged bimetallic donor-acceptor ensembles, FeII(bpy)2(CN)2-[PtII(DMSO)Cl2]2 (1) and FeII(bpy)2(CN)2-[AuICl]2, were synthesized, and corresponding solid-supported sensors were fabricated to determine the effect of the acceptor metal (MA) on DMS detection. Changing MA from AuI to PtII improved the sensitivity and selectivity owing to changes in the relative thermodynamic stabilities of the complex and MA-DMS adduct. When applied to real meat samples, 1 exhibited a linear spectroscopic response to DMS, even in the presence of interfering compounds, with a method detection limit of 1.0 ppm. The total bacteria count and gas chromatography-mass spectrometry results revealed that the spectroscopic signal generated by 1 correlated with the microbial growth level and DMS concentration during meat spoilage.


Assuntos
Complexos de Coordenação/química , Análise de Alimentos/métodos , Carne/análise , Sulfetos/análise , Complexos de Coordenação/síntese química , Análise de Alimentos/instrumentação , Microbiologia de Alimentos , Ouro/química , Limite de Detecção , Carne/microbiologia , Platina/química , Sensibilidade e Especificidade , Compostos Orgânicos Voláteis/análise
6.
Analyst ; 144(12): 3817-3825, 2019 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-31086898

RESUMO

Herein, an ultrasensitive and label-free electrochemical biosensor was developed for microRNA (miRNA) based on rolling circle amplification (RCA)-mediated palladium nanoparticles (PdNPs). The sensor was fabricated by immobilizing dual-functionalized hairpin probes onto an electrode. The specific recognition of target miRNA-21 by the hairpin probes could trigger the RCA reaction, which produced numerous guanine (G)-rich long single-stranded DNAs (ssDNAs). Based on the interaction of the PdII species with the nitrogen atoms of the G bases, these G-rich long ssDNAs served as specific templates in the in situ synthesis of massive PdNPs as electrochemical indicators. The formation of PdNPs was demonstrated to be exactly along the RCA products by high-resolution transmission electron microscopy. Using this cascade signal amplification strategy, the developed biosensor achieved a linear range of 50 aM-100 fM with an ultralow detection limit of 8.6 aM miRNA-21. Furthermore, the developed biosensor exhibited good selectivity, reproducibility, stability and satisfactory feasibility for miRNA-21 detection in human serum samples; this ensured significant potential of this biosensor in disease diagnosis and prognosis applications.


Assuntos
Técnicas Biossensoriais/métodos , Sondas de DNA/química , Ácidos Nucleicos Imobilizados/química , Nanopartículas Metálicas/química , MicroRNAs/sangue , Platina/química , Calibragem , Sondas de DNA/genética , Técnicas Eletroquímicas/métodos , Humanos , Ácidos Nucleicos Imobilizados/genética , Sequências Repetidas Invertidas , Limite de Detecção , MicroRNAs/genética , Técnicas de Amplificação de Ácido Nucleico/métodos , Hibridização de Ácido Nucleico , Reprodutibilidade dos Testes
7.
Analyst ; 144(12): 3773-3781, 2019 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-31089613

RESUMO

MDM2 is a well-known oncoprotein overexpressed in a variety of cancers, and the identification of inhibitors that disrupt the MDM2/p53 interaction is of great interest in anticancer drug development. Here we designed a platform for the facile and visualizable identification of inhibitors of MDM2 using co-expressed protein complexes of MDM2/p53. A hexahistidine-tag on MDM2 allows the binding of the protein complex to the Ni-NTA affinity resin, while the fluorescent protein fused to p53 enables the direct visualization of the interaction of p53 with MDM2. Hence, the inhibition of the MDM2/p53 interaction can be observed with the naked eye. The assay can be set up by directly loading cell lysate to the Ni-NTA affinity resin, and no chemical modification of proteins is needed. In addition to the qualitative analyses, the binding affinity of inhibitors to the MDM2 protein can be quantified by fluorescence titration. The applications of this system have been verified using small molecules and peptide inhibitors. As a proof of concept, we screened a small library using this platform. Interestingly, two types of novel inhibitors of MDM2, including cyclohexyl-triphenylamine derivatives and platinum complexes, were identified and their binding affinities were obtained. Quantitative measurements show that these new types of inhibitors demonstrate a high binding affinity (up to Kd = 51.9 nM) to MDM2.


Assuntos
Bioensaio/métodos , Proteínas Luminescentes/metabolismo , Ligação Proteica/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Sequência de Aminoácidos , Compostos de Anilina/química , Cromatografia de Afinidade/métodos , Complexos de Coordenação/química , Escherichia coli/genética , Histidina/genética , Histidina/metabolismo , Humanos , Medições Luminescentes/métodos , Proteínas Luminescentes/genética , Simulação de Acoplamento Molecular , Oligopeptídeos/genética , Oligopeptídeos/metabolismo , Peptídeos/química , Platina/química , Estudo de Prova de Conceito , Proteínas Proto-Oncogênicas c-mdm2/química , Proteínas Proto-Oncogênicas c-mdm2/genética , Proteína Supressora de Tumor p53/genética
8.
Analyst ; 144(11): 3659-3667, 2019 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-31074478

RESUMO

We report a highly sensitive and rapid electrochemical method for the detection of endotoxin, based on a Limulus amebocyte lysate (LAL) assay using redox cycling at a pair of electrodes in a nanocavity for electrochemical signal amplification. We have previously developed Boc-Leu-Gly-Arg-p-aminophenol (LGR-pAP) as a substrate for the amperometric LAL assay, and in this work, Z-Leu-Gly-Arg-aminomethylferrocene (LGR-AMF) was newly prepared. They were examined as substrates for a LAL-based endotoxin assay using a nanocavity device. During the last step of the endotoxin-induced LAL cascade reaction, pAP or AMF is generated from the substrate, which can be detected electrochemically with efficient signal amplification by redox cycling between the two electrodes in the nanocavity. A device with a 190 nm-high nanocavity was fabricated by photolithography. With the fabricated device in model assay solutions prepared by mixing LGR-pAP and pAP, we demonstrated that pAP could be quantitatively detected from the difference in oxidation potentials between LGR-pAP and pAP. For LGR-AMF and AMF, a difference in the formal potential of 0.1 V was obtained which was considered to be insufficient to distinguish AMF from LGR-AMF. However, we showed for the first time that analytes such as AMF can be detected by differences in diffusion coefficients between the analyte and coexisting molecules (such as LGR-AMF) using a device with high redox-cycling efficiency. Next, the endotoxin assay was performed using the fabricated nanocavity device. Using this method, endotoxin was detected at concentrations as low as 0.2 and 0.5 EU L-1 after LAL reaction times of 1 h and 30 min, respectively, using the LGR-pAP substrate. However, the endotoxin assay using LGR-AMF was not successful because the clotting enzyme did not react with LGR-AMF. This problem might be solved by further design of the substrate. Our nanocavity device represents an effective platform for the simple and rapid detection of endotoxin with high sensitivity.


Assuntos
Endotoxinas/análise , Nanoestruturas/química , Aminofenóis/química , Animais , Proteínas de Artrópodes/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Endopeptidases/química , Endotoxinas/química , Precursores Enzimáticos/química , Desenho de Equipamento , Compostos Ferrosos/química , Caranguejos Ferradura/enzimologia , Oligopeptídeos/química , Oxirredução , Platina/química , Serina Endopeptidases/química , Titânio/química
9.
Talanta ; 200: 472-479, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31036211

RESUMO

A new kind of nanoscale MOFs probe for nitric oxide (NO) sensing has been successfully constructed by a one-pot strategy, in which the chemically stable UiO-66 crystal structure was achieved using platinum meso-tetra(4-carboxyphenyl)porphyrin (Pt-TCPP), 1,1,2,2-Tetra(4-carboxylphenyl)ethylene (H4TCPE) and 1,4-dicarboxybenzene (BDC) as co-linkers (Pt-TCPP/H4TCPE@UiO-66). Pt-TCPP was verified to serve as a signal reporter in NO sensing fields for the first time while H4TCPE worked as a luminescence reference to build a ratiometric sensor. The integration of luminescent dyes in nanoscale MOFs effectively avoided their aggregation-caused quenching effect and poor aqueous dispersibility to rationalize NO detection in the aqueous phase. The obtained Pt-TCPP/H4TCPE@UiO-66 nanoparticles (NPs) exhibited an excellent sensing property toward NO with an ultrahigh linear correlation of the Stern-Volmer equation and a rapid response time as short as 2 min. Moreover, the elaborated sensor could work under a wide pH window (7.4, 5.6 and 0) and the limit of detection (LOD) reached as low as 0.1420 µg mL-1. The specificity of the obtained Pt-TCPP/H4TCPE@UiO-66 NPs toward NO sensing was scarcely affected by other possibly coexistent species in biological system. The in vitro monitoring for NO in living cells was also testified with these Pt-TCPP/H4TCPE@UiO-66 NPs.


Assuntos
Sobrevivência Celular , Substâncias Luminescentes/química , Estruturas Metalorgânicas/química , Metaloporfirinas/química , Óxido Nítrico/análise , Platina/química , Zircônio/química , Citometria de Fluxo , Células HeLa , Humanos , Medições Luminescentes , Imagem Óptica , Tamanho da Partícula , Propriedades de Superfície
10.
Talanta ; 200: 503-510, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31036215

RESUMO

In this work, an ultrasensitive aptasensor for the detection of Mucin 1 (MUC1) was presented based on the target-induced catalytic hairpin assembly combined with excellent mimic peroxidase performance of PtPd bimetallic nanoparticles (PtPdNPs). Traditionally, the cyclic reuse of target protein was achieved by protein conversion with enzyme cleavage or polymerization, which is costly and complex. However, in this work, it can be performed by simple strand displacement. In addition, PtPdNPs, a mimic peroxidase, was used a probe to catalyze the oxidation of tetramethylbenzidine (TMB) by H2O2, leading to the electrochemical signal amplification. With this ingenious design, the prepared aptasensor for MUC1 detection showed a favorable linear response from 100 fg mL-1 to 1 ng mL-1 and a relatively low detection limit of 16 fg mL-1. The proposed biosensor possessed acceptable stability, selectivity and reproducibility for MUC1 assay. Additionally, the fabricated aptasensor has been successfully applied to detect MUC1 in serum samples with satisfactory results. This new strategy supplied one efficient approach to improve signal amplification, which also open an avenue for sensitivity enhancement in targets detection.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Eletroquímicas , Nanopartículas Metálicas/química , Mucina-1/análise , Benzidinas/química , Técnicas Biossensoriais , Catálise , Humanos , Peróxido de Hidrogênio/química , Oxirredução , Paládio/química , Peroxidase/química , Peroxidase/metabolismo , Platina/química
11.
Int J Nanomedicine ; 14: 2451-2464, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31040668

RESUMO

Background: Acute myocardial infarction (AMI), usually caused by atherosclerosis of coronary artery, is the most severe manifestation of coronary artery disease which results in a large amount of death annually. A new diagnosis approach with high accuracy, reliability and low measuring-time-consuming is essential for AMI quick diagnosis. Purpose: The objective of this study was to develop a new point-of-care testing system with high accuracy and reliability for AMI quick diagnosis. Patients and methods: 50 plasma samples of acute myocardial infarction patients were analyzed by developed Smartphone-Assisted Pressure-Measuring-Based Diagnosis System (SPDS). The concentration of substrate was firstly optimized. The effect of antibody labeling and matrix solution on measuring result were then evaluated. And standard curves for cTnI, CK-MB and Myo were built for clinical sample analysis. The measuring results of 50 clinical samples were finally evaluated by comparing with the measuring result obtained by CLIA. Results: The concentration of substrate H2O2 was firstly optimized as 30% to increase measuring signal. A commercial serum matrix was chosen as the matrix solution to dilute biomarkers for standard curve building to minimize matrix effect on the accuracy of clinical plasma sample measuring. The standard curves for cTnI, CK-MB and Myo were built, with measuring dynamic range of 0-25 ng/mL, 0-33 ng/mL and 0-250 ng/mL, and limit of detection of 0.014 ng/mL, 0.16 ng/mL and 0.85 ng/mL respectively. The measuring results obtained by the developed system of 50 clinical plasma samples for three biomarkers matched well with the results obtained by chemiluminescent immunoassay. Conclusion: Due to its small device size, high sensitivity and accuracy, SPDS showed a bright potential for point-of-care testing (POCT) applications.


Assuntos
Pressão Sanguínea , Infarto do Miocárdio/diagnóstico , Infarto do Miocárdio/fisiopatologia , Smartphone , Anticorpos/metabolismo , Biomarcadores/sangue , Catálise , Feminino , Humanos , Peróxido de Hidrogênio/análise , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/sangue , Nanopartículas/química , Platina/química , Padrões de Referência , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Eletricidade Estática
12.
J Photochem Photobiol B ; 195: 27-32, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31051327

RESUMO

Platinum and Curcumin conjugation using green chemistry is an attempt to enhance the curcumin effectiveness as an anti-fibrosis. In this study, Platinum and curcumin were conjugated to direct curcumin into the liver. Curcumin platinum nanoparticles (C-PtNPs) were formed by changing curcumin concentration at pH 10. The successful formation of C-PtNPs was recognized with the help of Fourier transform infrared (FTIR) and UV-visible spectrophotometers. The particle size and morphology were studied with the help of dynamic light scattering (DLS) and High-resolution transmission electron microscopy (HR-TEM) respectively. The antimicrobial activity of C-PtNPs, was examined against gram positive and gram negative bacteria. Moreover, the NIH/3 T3 cells were used to test the C-PtNPs activity of modifying initial fibrosis indication. The favorable condition for the synthesis of CPt-NPs was by using curcumin 1.5 mM at pH 10. When compared with free curcumin, C-Pt-NPs exhibited higher activity for decreased production of collagen by NIH/3 T3 cells. Altogether, the formation of C-PtNPs by conjugation of platinum to curcumin is assuring for the curcumin directing to treat the hepatic fibrosis.


Assuntos
Anti-Infecciosos/síntese química , Curcumina/química , Nanopartículas Metálicas/química , Platina/química , Animais , Anti-Infecciosos/farmacologia , Sobrevivência Celular , Curcumina/farmacologia , Curcumina/uso terapêutico , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Cirrose Hepática/prevenção & controle , Camundongos , Microscopia Eletrônica de Transmissão , Células NIH 3T3 , Espectroscopia de Infravermelho com Transformada de Fourier
13.
Anal Chim Acta ; 1068: 18-27, 2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31072474

RESUMO

In this work, water-soluble pillar[6]arene functionalized PdPt porous core-shell octahedral nanodendrites (WP6@PdPt PCONs) were simply synthesized and used for the fabrication of NSE immunosensor. The newest generation of macrocyclic host and biomimetic nano-enzymes have been effectively integrated to achieve the robust immobilization of signal molecules by host-guest molecular recognition and sensitively catalytic amplification of electrochemical signals. The addition of Pd and the formation of WP6@PdPt PCONs unique bimetallic nanostructure are beneficial to changing Pt-based catalyst electronic structure, accelerating the electron transport, promoting the generation of synergistic catalysis effect. Compared with enzyme-based methods, the fabricated sandwich-type immunosensor demonstrates more advantages in robustness owing to the introduction of host-guest chemistry and biomimetic nano-enzymes. In the wide range from 0.0003 to 100.00 ng mL-1, a good linear relationship (R2 = 0.998) and a low LOD (0.095 pg mL-1, S/N = 3) can be obtained. The proposed immunosensor shows remarkable analytical performances in the measurements of selectivity, stability, reproducibility, and real sample analysis, which provided a promising approach for clinical detection of NSE in human serum. Besides, the successful synthesis of WP6@PdPt PCONs provides a new idea for the preparation of biosensors based on bionic materials, nanotechnology and host-guest molecule recognition.


Assuntos
Imunoensaio , Nanocompostos/química , Fosfopiruvato Hidratase/sangue , Compostos de Amônio Quaternário/química , Biocatálise , Técnicas Biossensoriais , Técnicas Eletroquímicas , Humanos , Paládio/química , Tamanho da Partícula , Fosfopiruvato Hidratase/metabolismo , Platina/química , Porosidade , Solubilidade , Propriedades de Superfície , Água/química
14.
Analyst ; 144(10): 3314-3322, 2019 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-30968883

RESUMO

Lateral flow assay (LFA) is a well-established platform for point-of-care (POC) testing due to its low cost and user friendliness. Conventional LFAs provide qualitative or semi-quantitative results and require dedicated instruments for quantitative detection. Here, we developed an "LFA ruler" for quantitative and rapid readout of LFA results, using a 3D printed strip cassette and a simple, inexpensive microfluidic chip. Platinum nanoparticles are used as signal amplification reporters, which catalyze the generation of oxygen to push ink advancement in the microfluidic channel. The concentration of the target is linearly correlated with the ink advancement distance. The entire assay can be completed within 30 minutes without external instruments and complicated operations. We demonstrated quantitative prostate specific antigen testing using the LFA ruler, with a limit of detection of 0.54 ng mL-1, linear range of 0-12 ng mL-1, and high correlation with a clinical gold standard assay. The LFA ruler achieves low cost, quantitative, sensitive and rapid detection, which has great potential in POC testing and can be extended to quantify other disease biomarkers.


Assuntos
Dispositivos Lab-On-A-Chip , Técnicas Analíticas Microfluídicas/métodos , Antígeno Prostático Específico/sangue , Desenho de Equipamento , Humanos , Peróxido de Hidrogênio/química , Limite de Detecção , Masculino , Nanopartículas Metálicas/química , Técnicas Analíticas Microfluídicas/instrumentação , Oxirredução , Oxigênio/química , Platina/química , Testes Imediatos , Impressão Tridimensional
15.
Magn Reson Imaging ; 60: 68-75, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30959177

RESUMO

PURPOSE: To develop an off-resonant frequency filtered method to selectively differentiate between implanted gold fiducial markers and platinum coated brachytherapy seeds. MATERIALS AND METHODS: The magnetic susceptibilities for gold fiducial markers and brachytherapy seeds differ in magnitude and also in their signs, resulting in B0-field inhomogeneity patterns with opposite main lobes. A pulse sequence used to localize brachytherapy seeds with positive contrast, centre-out radial sampling with off-resonance reception (co-RASOR), was used to reconstruct images with a range of off-resonant frequency offsets. The proposed method utilizes two frequency filters to selectively reconstruct maximum intensity projections through band-pass regions where each seed has its maximal localized hyperintensity. Seeds were simulated and then placed in gel and tissue phantoms to validate the technique using orthogonal 2D slices with seeds both parallel and perpendicular to the B0-field. RESULTS: Dual-plane 2D co-RASOR sequences were reconstructed off-resonance with applied frequency filters to create two projections displaying each seed, which were then colour-coded to negative and positive frequencies. Phantom validation showed that each seed contains its maximal CNR in opposing frequency regions as predicted. Local maxima can also appear in both negative and positive frequency regions. The relative difference between the signal of each seed and these local maxima ranged from 1.19 to 3.73, and an image threshold was determined in all cases. Tissue validation showed the technique differentiates seeds correctly and is limited by the hyperintensity patterns observed in the co-RASOR method. CONCLUSIONS: Dual-plane co-RASOR offers sub-millimetre positive contrast from implanted seeds that contain unique off-resonant frequency maxima, which frequency filters can selectively differentiate.


Assuntos
Braquiterapia/instrumentação , Braquiterapia/métodos , Marcadores Fiduciais , Ouro/química , Imagens de Fantasmas , Platina/química , Neoplasias da Próstata/diagnóstico por imagem , Ágar , Cor , Simulação por Computador , Meios de Contraste , Humanos , Imagem por Ressonância Magnética , Masculino , Modelos Teóricos , Próteses e Implantes , Reprodutibilidade dos Testes , Tomografia Computadorizada por Raios X
16.
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
17.
Top Curr Chem (Cham) ; 377(3): 11, 2019 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-30949779

RESUMO

Despite its attractive features as a power source for direct alcohol fuel cells, utilization of ethanol is still hampered by both fundamental and technical challenges. The rationale behind the slow and incomplete ethanol oxidation reaction (EOR) with low selectivity towards CO2 on most Pt-based catalysts is still far from being understood, and a number of practical problems need to be addressed before an efficient and low-cost catalyst is designed. Some recent achievements towards solving these problems are presented. Pt film electrodes and Pt monolayer (PtML) electrodes on various single crystal substrates showed that EOR follows the partial oxidation pathway without C-C bond cleavage, with acetic acid and acetaldehyde as the final products. The role of the substrate lattice on the catalytic properties of PtML was proven by the choice of appropriate M(111) structure (M = Pd, Ir, Rh, Ru and Au) showing enhanced kinetics when PtML is under tensile strain on Au(111) electrode. Nanostructured electrocatalysts containing Pt-Rh solid solution on SnO2 and Pt monolayer on non-noble metals are shown, optimized, and characterized by in situ methods. Electrochemical, in situ Fourier transform infrared (FTIR) and X-ray absorption spectroscopy (XAS) techniques highlighted the effect of Rh in facilitating C-C bond splitting in the ternary PtRh/SnO2 catalyst. In situ FTIR proved quantitatively the enhancement in the total oxidation pathway to CO2, and in situ XAS confirmed that Pt and Rh form a solid solution that remains in metallic form through a wide range of potentials due to the presence of SnO2. Combination of these findings with density functional theory calculations revealed the EOR reaction pathway and the role of each constituent of the ternary PtRh/SnO2 catalyst. The optimal Pt:Rh:Sn atomic ratio was found by the two in situ techniques. Attempts to replace Rh with cost-effective alternatives for commercially viable catalysts has shown that Ir can also split the C-C bond in ethanol, but the performance of optimized Pt-Rh-SnO2 is still higher than that of the Pt-Ir-SnO2 catalyst.


Assuntos
Técnicas Eletroquímicas , Etanol/química , Platina/química , Acetaldeído/síntese química , Acetaldeído/química , Ácido Acético/síntese química , Ácido Acético/química , Catálise , Oxirredução
18.
Bioelectrochemistry ; 128: 165-174, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31004910

RESUMO

Most clinical tests for biomarker detection require the support of a laboratory, and the results are usually slow, less sensitive, and lack the possibility for Point-of-Care (PoC) testing. Further, with the increasing demand for sensitive, portable, rapid, and low-cost devices for clinical PoC applications, innovative methods are crucial. Thus, we report on utilizing nanostructured gold-platinum (Au-Pt) hybrid electrodes as a PoC device for highly sensitive and selective PTH detection in human serum samples. The method employs the immobilization of 3-mercaptopropionic acid to Au and subsequent activation of the carboxyl groups to enable anti-PTH antibody immobilization. Serum PTH was detected by monitoring the changes in electrochemical properties (ΔRct and Δi) of the sensor using electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) against a standard hexacyanoferrate (II/III) probe. Changes in relative response percentage (RR%) in electrochemical properties due to increased PTH concentrations in serum were observed with EIS and DPV. The biosensor exhibited a low detection limit of 0.36 pg.mL-1 (EIS) and 0.59 pg.mL-1 (DPV) in serum with a linear range of 1 to 100,000 pg.mL-1. Further, to validate the accuracy of the proposed method, clinical samples (n = 20) were examined using the EIS method and compared to an established commercial test.


Assuntos
Eletrodos , Ouro/química , Nanoestruturas , Hormônio Paratireóideo/sangue , Platina/química , Estudos de Casos e Controles , Espectroscopia Dielétrica , Ensaio de Imunoadsorção Enzimática , Humanos , Hiperparatireoidismo/sangue , Limite de Detecção , Sistemas Automatizados de Assistência Junto ao Leito , Reprodutibilidade dos Testes
19.
Anal Bioanal Chem ; 411(18): 4063-4071, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30972472

RESUMO

It is well known that 3,3',5,5'-tetramethylbenzidine (TMB) can be oxidized into blue or yellow oxidzed TMB (oxTMB) with the catalysis of peroxidase or mimetic enzyme of platinum nanoparticles (Pt NPs). In this work, we found that TMB could be oxidized into very stable black oxTMB with the catalysis of Pt NPs under certain chromogenic reaction conditions. For the first time, the black oxTMB was revealed to consist of nanowires (oxTMB NWs) with lengths of more than 100 µm and diameters of around 100 nm. The black oxTMB NWs showed very strong light absorption ability, thus could be used to greatly amplify the signal of Pt NP-based immunochromatography test strips (ICTSs). The Pt NP-based ICTSs with black oxTMB NW signal amplification have shown much better assay ability (linear response range and limit of detection) than those of gold nanoparticle (Au NP)-based ICTS, Pt NP-based ICTS, and Pt NP-based ICTS with blue or yellow oxTMB signal amplifications. The developed Pt NP-oxTMB NW-based ICTS has been demonstrated to be a new, accurate, sensitive, selective, and rapid immunosensor for quantitative detection of antigens such as human chorionic gonadotropin (HCG).


Assuntos
Benzidinas/química , Imunoensaio/instrumentação , Nanopartículas Metálicas/química , Nanofios/química , Platina/química , Biomarcadores/análise , Humanos , Oxirredução , Proteinúria/urina
20.
J Nanobiotechnology ; 17(1): 38, 2019 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-30866971

RESUMO

BACKGROUND: Rapid and sensitive detection of H2O2 especially endogenous H2O2 is of great importance for series of industries including disease diagnosis and therapy. In this work, uniform FePt nanoparticles are successfully anchored onto Few-layer molybdenum disulfide nanosheets (F-MoS2 NSs). The powder X-ray diffraction, transmission electron microscopy, UV-Vis spectra and atomic force microscopy were employed to confirm the structure of the obtained nanocomposites (F-MoS2-FePt NCs). The prepared nanocomposites show efficient peroxidase-like catalytic activities verified by catalyzing the peroxidation substrate 4,4'-diamino-3,3',5,5'-tetramethylbiphenyl (TMB) with the existence of H2O2. RESULTS: The optimal conditions of the constructed colorimetric sensing platform is proved as 35 °C and pH 4.2. Under optimal catalytic conditions, the detection limit for H2O2 detection reaches 2.24 µM and the linear ranger is 8 µM to 300 µM. Furthermore, the proposed colorimetric sensing platform was successfully utilized to detect the intracellular H2O2 of cancer cells (MCF-7). CONCLUSIONS: These findings indicated that the F-MoS2-FePt-TMB-H2O2 system provides a potential sensing platform for hydrogen peroxide monitoring in living cells.


Assuntos
Colorimetria , Dissulfetos/química , Peróxido de Hidrogênio/análise , Ferro/química , Molibdênio/química , Nanocompostos/química , Platina/química , Ligas/química , Catálise , Humanos , Concentração de Íons de Hidrogênio , Células MCF-7 , Oxirredução , Peroxidases/metabolismo
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