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1.
Anal Chem ; 93(28): 9933-9938, 2021 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-34227801

RESUMO

Sensitive detection of the SARS-CoV-2 protein remains a great research interest in clinical screening and diagnosis owing to the coronavirus epidemic. Here, an ultrasensitive chemiluminescence (CL) imaging strategy was developed through proximity hybridization to trigger the formation of a rolling circle-amplified G-quadruplex/hemin DNAzyme for the detection of the SARS-CoV-2 protein. The target protein was first recognized by a pair of DNA-antibody conjugates, Ab-1 and Ab-2, to form a proximity-ligated complex, Ab-1/SARS-CoV-2/Ab-2, which contained a DNA sequence complemental to block DNA and thus induced a strand displacement reaction to release the primer from a block/primer complex. The released primer then triggered a rolling circle amplification to form abundant DNAzyme units in the presence of hemin, which produced a strong chemiluminescent signal for the detection of the target protein by catalyzing the oxidation of luminol by hydrogen peroxide. The proposed assay showed a detectable concentration range over 5 orders of magnitude with the detection limit down to 6.46 fg/mL. The excellent selectivity, simple procedure, acceptable accuracy, and intrinsic high throughput of the imaging technique for analysis of serum samples demonstrated the potential applicability of the proposed detection method in clinical screening and diagnosis.


Assuntos
Técnicas Biossensoriais , COVID-19 , DNA Catalítico , Quadruplex G , DNA Catalítico/metabolismo , Hemina , Humanos , Imunoensaio , Limite de Detecção , Luminescência , SARS-CoV-2
3.
Mikrochim Acta ; 188(8): 262, 2021 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-34282508

RESUMO

COVID-19 is now a severe threat to global health. Facing this pandemic, we developed a space-encoding microfluidic biochip for high-throughput, rapid, sensitive, simultaneous quantitative detection of SARS-CoV-2 antigen proteins and IgG/IgM antibodies in serum. The proposed immunoassay biochip integrates the advantages of graphene oxide quantum dots (GOQDs) and microfluidic chip and is capable of conducting multiple SARS-CoV-2 antigens or IgG/IgM antibodies of 60 serum samples simultaneously with only 2 µL sample volume of each patient. Fluorescence intensity of antigens and IgG antibody detection at emission wavelength of ~680 nm was used to quantify the target concentration at excitation wavelength of 632 nm, and emission wavelength of ~519 nm was used during the detection of IgM antibodies at excitation wavelength of 488 nm. The method developed has a large linear quantification detection regime of 5 orders of magnitude, an ultralow detection limit of ~0.3 pg/mL under optimized conditions, and less than 10-min qualitative detection time. The proposed biosensing platform will not only greatly facilitate the rapid diagnosis of COVID-19 patients, but also provide a valuable screening approach for infected patients, medical therapy, and vaccine recipients.


Assuntos
Antígenos Virais/sangue , Imunoensaio , Imunoglobulina G/sangue , Imunoglobulina M/sangue , SARS-CoV-2/isolamento & purificação , Reações Antígeno-Anticorpo , Antígenos Virais/imunologia , Humanos , Imunoglobulina G/imunologia , Imunoglobulina M/imunologia , Nanopartículas/química , Tamanho da Partícula , SARS-CoV-2/imunologia , Sensibilidade e Especificidade
4.
Sensors (Basel) ; 21(13)2021 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-34202483

RESUMO

Since the introduction of paper-based analytical devices as potential diagnostic platforms a few decades ago, huge efforts have been made in this field to develop systems suitable for meeting the requirements for the point-of-care (POC) approach. Considerable progress has been achieved in the adaptation of existing analysis methods to a paper-based format, especially considering the chemiluminescent (CL)-immunoassays-based techniques. The implementation of biospecific assays with CL detection and paper-based technology represents an ideal solution for the development of portable analytical devices for on-site applications, since the peculiarities of these features create a unique combination for fitting the POC purposes. Despite this, the scientific production is not paralleled by the diffusion of such devices into everyday life. This review aims to highlight the open issues that are responsible for this discrepancy and to find the aspects that require a focused and targeted research to make these methods really applicable in routine analysis.


Assuntos
Técnicas Biossensoriais , Luminescência , Imunoensaio , Sistemas Automatizados de Assistência Junto ao Leito
5.
Int J Mol Sci ; 22(13)2021 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-34206462

RESUMO

Human fetal gonads acquire endocrine steroidogenic capabilities early during their differentiation. Genetic studies show that this endocrine function plays a central role in the sexually dimorphic development of the external genitalia during fetal development. When this endocrine function is dysregulated, congenital malformations and pathologies are the result. In this review, we explain how the current knowledge of steroidogenesis in human fetal gonads has benefited from both the technological advances in steroid measurements and the assembly of detailed knowledge of steroidogenesis machinery and its expression in human fetal gonads. We summarise how the conversion of radiolabelled steroid precursors, antibody-based assays, mass spectrometry, ultrastructural studies, and the in situ labelling of proteins and mRNA have all provided complementary information. In this review, our discussion goes beyond the debate on recommendations concerning the best choice between the different available technologies, and their degrees of reproducibility and sensitivity. The available technologies and techniques can be used for different purposes and, as long as all quality controls are rigorously employed, the question is how to maximise the generation of robust, reproducible data on steroid hormones and their crucial roles in human fetal development and subsequent functions.


Assuntos
Feto/metabolismo , Hormônios Esteroides Gonadais/metabolismo , Gônadas/metabolismo , Pesquisa , Feminino , Humanos , Imunoensaio , Masculino , Espectrometria de Massas , Ovário/metabolismo , Ovário/ultraestrutura , Pesquisa/tendências , Desenvolvimento Sexual/genética , Testículo/metabolismo , Testículo/ultraestrutura
6.
Artigo em Inglês | MEDLINE | ID: mdl-34208607

RESUMO

BACKGROUND: The aim of our study was to examine the performance of two assays in detecting SARS-CoV-2 antibodies. METHODS: A total of 127 COVID-19 disease contacts from the Infectious Diseases Department were included. Two serological tests were used: SARS-CoV-2 IgG CMIA on the Alinity system (Abbott) and LIAISON® SARS-CoV-2 S1/S2 IgG CLIA (DiaSorin). RESULTS: The assays exhibited a 96.85% (123/127 patients) test result agreement. In two cases, the positive results obtained by SARS-CoV-2 IgG CMIA on the Alinity system (Abbott) were negative based on the LIAISON® SARS-CoV-2 S1/S2 IgG CLIA (DiaSorin) test, and in two cases, negative results from the LIAISON® SARS-CoV-2 S1/S2 IgG CLIA (DiaSorin) test were positive with the SARS-CoV-2 IgG CMIA on the Alinity system (Abbott). CONCLUSIONS: Based on the results of our study, we conclude that in population medicine, the assessments of anti-SARS-CoV-2 antibodies after exposure to SARS-CoV-2 virus based on spike protein or nucleocapsid protein show comparable effectiveness.


Assuntos
COVID-19 , Anticorpos Antivirais , Humanos , Imunoensaio , SARS-CoV-2 , Sensibilidade e Especificidade
7.
Biosensors (Basel) ; 11(6)2021 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-34202953

RESUMO

Aflatoxin B1 (AFB1), a mycotoxin, is hepatotoxic, carcinogenic, and nephrotoxic in humans and animals, and contaminate a wide range of maize. In this study, an immunochromatographic assay (ICA) based on polystyrene microspheres (PMs) was developed for sensitive and quantitative detection of AFB1 in maize. The amounts of PMs, the condition for activating carboxyl groups of PMs, the amount of monoclonal antibody (mAb), and the volume of the immune probe were optimized to enhance the performance PMs-ICA for point-of-care testing of AFB1 in maize. The PMs-ICA showed the cut-off value of 1 ng/mL in phosphate buffer (PB) and 6 µg/kg in maize samples, respectively. The quantitative limit of detection (qLOD) was 0.27 and 1.43 µg/kg in PB and maize samples, respectively. The accuracy and precision of the PMs-ICA were evaluated by analysis of spiked maize samples with recoveries of 96.0% to 107.6% with coefficients of variation below 10%. In addition, the reliability of PMs-ICA was confirmed by the liquid chromatography-tandem mass spectrometry method. The results indicated that the PMs-ICA could be used as a sensitive, simple, rapid point-of-care testing of AFB1 in maize.


Assuntos
Aflatoxina B1/análise , Zea mays/microbiologia , Animais , Anticorpos Monoclonais , Cromatografia de Afinidade , Humanos , Imunoensaio , Limite de Detecção , Microesferas , Micotoxinas , Poliestirenos/química , Reprodutibilidade dos Testes
8.
Biosensors (Basel) ; 11(7)2021 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-34203515

RESUMO

The development of quantitative lateral flow immunoassay test strips involves a lot of research from kit manufacturers' standpoint. Kit providers need to evaluate multiple parameters, including the location of test regions, sample flow speed, required sample volumes, reaction stability time, etc. A practical visualization tool assisting manufacturers in this process is very much required for the design of more sensitive and reliable quantitative LFIA test strips. In this paper, we present an image-based quantitative evaluation tool determining the practical functionality of fluorescence-labelled LFIA test cartridges. Image processing-based algorithms developed and presented in this paper provide a practical analysis of sample flow rates, reaction stability times of samples under test, and detect any abnormalities in test strips. Evaluation of the algorithm is done with Glycated Hemoglobin (HbA1C) and Vitamin D test cartridges. Practical sample flow progress for HbA1C test cartridges is demonstrated. The reaction stability time of HbA1C test samples is measured to be 12 min, while that of Vitamin D test samples is 24 min. Experimental evaluation of the abnormality detection algorithm is carried out, and sample flow abnormalities are detected with 100% accuracy while membrane irregularities are detected with 96% accuracy.


Assuntos
Processamento de Imagem Assistida por Computador , Imunoensaio , Humanos , Sistemas Automatizados de Assistência Junto ao Leito
9.
Biosensors (Basel) ; 11(6)2021 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-34205541

RESUMO

A magnetic beads (MB)-involved amperometric immunosensor for the determination of ST2, a member of the IL1 receptor family, is reported in this work. The method utilizes a sandwich immunoassay and disposable screen-printed carbon electrodes (SPCEs). Magnetic immunoconjugates built on the surface of carboxylic acid-microsized magnetic particles (HOOC-MBs) were used to selectively capture ST2. A biotinylated secondary antibody further conjugated with a streptavidin peroxidase conjugate (Strep-HRP) was used to accomplish the sandwiching of the target protein. The immune platform exhibits great selectivity and a low limit of detection (39.6 pg mL-1) for ST2, allowing the determination of soluble ST2 (sST2) in plasma samples from healthy individuals and patients diagnosed with pancreatic ductal adenocarcinoma (PDAC) in only 45 min once the immunoconjugates have been prepared. The good correlation of the obtained results with those provided by an ELISA kit performed using the same immunoreagents demonstrates the potential of the developed strategy for early diagnosis and/or prognosis of the fatal PDAC disease.


Assuntos
Técnicas Biossensoriais , Imunoensaio , Neoplasias/diagnóstico , Anticorpos , Carbono , Técnicas Eletroquímicas , Eletrodos , Ensaio de Imunoadsorção Enzimática , Humanos , Peróxido de Hidrogênio , Limite de Detecção , Magnetismo
10.
Biosensors (Basel) ; 11(6)2021 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-34200643

RESUMO

In this study, we developed the portable chemiluminescence (CL)-based lateral flow assay (LFA) platform for the detection of cortisol in human serum. Cortisol is well-known as a stress hormone due to its high relevancy for human mental and physical health, such as hypertension or depression. To date, a number of optical devices have provided the sensitive determination of levels of analytes. However, this modality type still requires costly optical modules. The developed CL platform is simply composed of two detection modules along with a loading part for the LFA strip. The LFA membrane contains gold nanoparticle probes conjugated with antibodies against cortisol and horseradish peroxidase (HRP), which can also efficiently increase the luminescent signal by providing many areas for anti-cortisol antibody and HRP. The measured voltage signals coming from the photodiode in a CL reader were compared with a standard microplate reader for the evaluation of accuracy. The linear range observed for cortisol was measured to be 0.78-12.5 µg/dL (R2 = 0.99) with a limit of detection (LOD) of 0.342 µg/dL. In addition, the CL-LFA reader showed a high correlation (R2 = 0.96) with the standard cortisol console (COBAS 8000, Roche), suggesting that our developed CL-based LFA platform can be usable in situ.


Assuntos
Técnicas Biossensoriais , Hidrocortisona/sangue , Anticorpos , Ouro , Peroxidase do Rábano Silvestre , Humanos , Imunoensaio , Limite de Detecção , Luminescência , Medições Luminescentes , Nanopartículas Metálicas , Aplicativos Móveis , Testes Imediatos
11.
Mikrochim Acta ; 188(8): 261, 2021 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-34278534

RESUMO

The ongoing global pandemic of SARS-CoV-2 has promoted to develop novel serological testing technologies since they can be effectively complementary to RT-PCR. Here, a new all-fiber Fresnel reflection microfluidic biosensor (FRMB) was constructed through combining all-fiber optical system, microfluidic chip, and multimode fiber bio-probe. The transmission of the incident light and the collection and transmission of Fresnel reflection light are achieved using a single-multi-mode fiber optic coupler (SMFC) without any other optical separation elements. This compact design greatly simplifies the whole system structure and improves light transmission efficiency, which makes it suitable for the label-free, sensitive, and easy-to-use point-of-care testing (POCT) of targets in nanoliter samples. Based on Fresnel reflection mechanism and immunoassay principle, both the SARS-CoV-2 IgM and IgG antibodies against the SARS-CoV-2 spike protein could be sensitively quantified in 7 min using the secondary antibodies-modified multimode fiber bio-probe. The FRMB performs in one-step, is accurate, label-free, and sensitive in situ/on-site detection of SARS-CoV-2 IgM or IgG in serum with simple dilution only. The limits of detection of SARS-CoV-2 IgM and SARS-CoV-2 IgG were 0.82 ng/mL and 0.45 ng/mL, respectively. Based on our proposed theory, the affinity constants of SARS-CoV-2 IgM or IgG antibody and their respective secondary antibodies were also determined. The FRMB can be readily extended as a universal platform for the label-free, rapid, and sensitive in situ/on-site measurement of other biomarkers and the investigation of biomolecular interaction.


Assuntos
Anticorpos Antivirais/sangue , Técnicas Biossensoriais/métodos , Teste Sorológico para COVID-19/métodos , COVID-19/diagnóstico , Técnicas Analíticas Microfluídicas/métodos , SARS-CoV-2/imunologia , Anticorpos Antivirais/imunologia , Humanos , Imunoensaio/métodos , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Imunoglobulina M/sangue , Imunoglobulina M/imunologia , Limite de Detecção , SARS-CoV-2/química , Sensibilidade e Especificidade , Glicoproteína da Espícula de Coronavírus/imunologia
12.
Analyst ; 146(14): 4473-4479, 2021 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-34227625

RESUMO

Electrochemical detection is the simplest analytical tool to be integrated into digital microfluidics (DMF). It offers the advantages of small size, with detector electrodes incorporated into the device by patterning, and high compatibility with portable analytical instruments. Indium tin oxide (ITO) coated on glass has been commonly used for the top plate of DMF due to its good conductivity and transparency. However, instability and the low current response of ITO electrodes patterned on glass hindered their application for immunoassays. It has been reported that ITO coated on polyethylene terephthalate (PET) has better conductivity, owing to its higher carrier concentration, faster mobility and lower resistivity. Herein, we investigated the use of ITO electrodes patterned on PET film as the top plate of DMF for a simple and stable electrochemical immunoassay using square wave voltammetry (SWV), with an excellent peak resolution and high sensitivity. A magnetic bead-based immunoassay for H5N1 antigen was performed on a DMF platform with a limit of detection of 0.6 ng mL-1 in buffer and 18 ng mL-1 in human serum. These results showed the good electrochemical performance of ITO coated on a PET film, a lightweight, shock resistant and cost-effective material, which is promising for DMF fabrication and transparent electrodes for various electroanalytical methods.


Assuntos
Virus da Influenza A Subtipo H5N1 , Polietilenotereftalatos , Eletrodos , Humanos , Imunoensaio , Microfluídica , Compostos de Estanho
13.
Sci Rep ; 11(1): 14026, 2021 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-34234188

RESUMO

Lateral flow immunoassays are low cost, rapid and highly efficacious point-of-care devices, which have been used for SARS-CoV-2 antibody testing by professionals. However, there is a lack of understanding about how self-administered tests are used by the general public for mass testing in different environmental settings. The purpose of this study was to assess the user experience (UX) (including usability) of a self-testing kit to identify COVID-19 antibodies used by a representative sample of the public in their cars, which included 1544 participants in Northern Ireland. The results based on 5-point Likert ratings from a post-test questionnaire achieved an average UX score of 96.03% [95% confidence interval (CI) 95.05-97.01%], suggesting a good degree of user experience. The results of the Wilcoxon rank sum tests suggest that UX scores were independent of the user's age and education level although the confidence in this conclusion could be strengthened by including more participants aged younger than 18 and those with only primary or secondary education. The agreement between the test result as interpreted by the participant and the researcher was 95.85% [95% CI 94.85-96.85%], Kappa score 0.75 [95% CI 0.69-0.81] (indicating substantial agreement). Text analysis via the latent Dirichlet allocation model for the free text responses in the survey suggest that the user experience could be improved for blood-sample collection, by modifying the method of sample transfer to the test device and giving clearer instructions on how to interpret the test results. The overall findings provide an insight into the opportunities for improving the design of SARS-CoV-2 antibody testing kits to be used by the general public and therefore inform protocols for future user experience studies of point-of-care tests.


Assuntos
Anticorpos Antivirais/análise , Teste para COVID-19/estatística & dados numéricos , Imunoensaio/estatística & dados numéricos , Adolescente , Adulto , Anticorpos Antivirais/imunologia , Criança , Escolaridade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Satisfação do Paciente , Sistemas Automatizados de Assistência Junto ao Leito , Autoadministração , Sensibilidade e Especificidade , Adulto Jovem
14.
Biosensors (Basel) ; 11(7)2021 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-34206922

RESUMO

Cardiac troponin I (cTnI) plays an important role in the assessment of various cardiac diseases. However, accurate detection of cTnI at the point-of-care (POC) remains unfeasible. In this study, we report the development of an electrochemical immunosensor designed for rapid and accurate cTnI detection in pre-hospital settings. Rapid cTnI analysis of whole blood samples was then performed. cTnI measurements were highly correlated with the results of the standard clinical laboratory method for cTnI detection. The results of this study suggest that the proposed POC immunosensor can deliver fast and accurate cTnI analysis in pre-hospital settings to achieve rapid diagnosis and guide patient management.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Troponina I/análise , Eletrodos , Humanos , Imunoensaio , Limite de Detecção , Sistemas Automatizados de Assistência Junto ao Leito
15.
Talanta ; 233: 122540, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34215043

RESUMO

While lateral flow immunoassay (LFIA) is a simple technique that offers a rapid, robust, user friendly, and point-of-care test, its capacity for multiplex detection is rather limited. This study therefore combined the multiplexity of microarray technique and the simple and rapid characteristics of LFIA to enable simultaneous and quantitative detection of five mycotoxins, namely aflatoxin B1 (AFB1), deoxynivalenol (DON), fumonisin B1 (FUMB1), T-2 toxin (T-2), and zearalenone (ZON). In addition, we have synthesized a novel extra-large Stokes shift and strong fluorescence organic compound to be used as a reporter molecule which can be detected under UV light without light filter requirement. Many parameters including microarray spotting buffer, blocking buffer, and concentrations of mycotoxin antibodies were optimized for the microarray LFIA (µLFIA) construction. With the optimal conditions, the µLFIA could accurately and quantitatively detect multiple mycotoxins at the same time. The limits of detection of AFB1, DON, FUMB1, T-2, and ZON were 1.3, 0.5, 0.4, 0.4, and 0.9 ppb, respectively. The recoveries of these five mycotoxins were 70.7%-119.5% and 80.4%-124.8% for intra-assay and inter-assay, respectively. Combining the advantages of the novel reporter molecule and the multiplex capability of µLFIA test, this system could simultaneously detect multiple mycotoxins in one sample with high specificity and high sensitivity. Moreover, this system presents a promising affordable point-of-care platform to detect other analytes as well.


Assuntos
Micotoxinas , Zearalenona , Aflatoxina B1/análise , Contaminação de Alimentos/análise , Imunoensaio , Limite de Detecção , Micotoxinas/análise , Zearalenona/análise
16.
Talanta ; 233: 122552, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34215055

RESUMO

In this work, a fire-new "signal-off" type photoelectrochemical (PEC) immunosensor based on bismuth sulfide/iodine doped bismuth oxychloride (Bi2S3/I:BiOCl) heterostructure as a platform and Au nanoparticles loaded hollow CoSnO3 nanoboxes (Au NPs@CoSnO3) as quenching label was designed, for sensitive detection of CYFRA 21-1. The I:BiOCl with flower-like structure could supply high specific surface area for loading nanometer materials. Then, Bi2S3 was formed in-situ by S2- adsorption on the surface of I:BiOCl by dangling bond of Bi3+, but did not change the flower-like structure of I:BiOCl. Then, n-type Bi2S3 and p-type I:BiOCl heterostructure showed good photoelectric behavior by providing an additional electric field to accelerate electron-hole separation. Furthermore, the production process of the heterostructure was simple, fast, low temperature, and without complex raw materials. The Au NPs@CoSnO3 with good photocatalytic activity could strongly compete with Bi2S3/I:BiOCl for electron donor of ascorbic acid (AA). Meanwhile, the CoSnO3 with hollow structure made the quenching effect more significant by the light-scattering effect that enhanced the light absorption capacity and shorten distance of carrier transport. Under optimal conditions, this proposed strategy displayed the low detection limit of 30 fg/mL, with a high linearity range from 100 fg/mL to 100 ng/mL for tumor markers CYFRA 21-1. Simultaneously, it also exhibited excellent specificity and acceptable stability, which might provide a new perspective for the fabrication of other PEC immunosensors with heterostructure simple synthesis and hollow materials.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Antígenos de Neoplasias , Técnicas Eletroquímicas , Ouro , Imunoensaio , Queratina-19 , Limite de Detecção
17.
Talanta ; 233: 122564, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34215060

RESUMO

Photoelectrochemical (PEC) immunoassay is a burgeoning and promising bioanalytical method. However, the practical application of PEC still exist some challenges such as the inevitable damage of biomolecules caused by the PEC system and the unsatisfactory sensitivity for biomarkers with low abundance in real sample. To solve the problems, we integrated the cosensitized structure of Ag2S/ZnO nanocomposities as photoelectrode with photogenerated hole-induced chemical redox cycling amplification (CRCA) strategy to develop a split-type PEC immunosensor for cardiac troponin I (cTnI) with high sensitivity. Initially, the immunoreaction was carried out on the 96-well plates in which alkaline phosphatase (ALP) could catalyze ascorbic acid 2-phosphate (AAP) to generate the signal-reporting species ascorbic acid (AA). Subsequently, the AA participated and the tris (2-carboxyethyl) phosphine (TCEP) mediated chemical redox cycling reaction took place on the photoelectrode, thus leading to signal amplification. Under the optimized conditions, the immunosensor demonstrated a detection limit (LOD) of 3.0 × 10-15 g mL-1 with a detection range of 1.0 × 10-14 g mL-1 to 1.0 × 10-9 g mL-1 for cTnI. Impressively, the proposed method could determine the cTnI in human serum samples with high sensitivity and satisfactory accuracy. Considering the virtues of the photoelectrode and the chemical redox cycling strategy, the method would hold great potential for highly sensitive biosensing and bioanalysis.


Assuntos
Técnicas Biossensoriais , Troponina I , Fosfatase Alcalina/metabolismo , Técnicas Eletroquímicas , Humanos , Imunoensaio , Limite de Detecção , Oxirredução
18.
Talanta ; 233: 122407, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34215097

RESUMO

Recent virus outbreaks have revealed a critical need for large scale serological assays. However, many available tests either require a cumbersome, costly apparatus or lack the availability of full automation. In order to address these limitations, we describe a homogeneous assay for antibody detection via measurement of superparamagnetic particles agglutination. Application of a magnetic field permits to overcome the limitations governed by Brownian translational diffusion in conventional assays and results in an important acceleration of the aggregation process as well as an improvement of the limit of detection. Furthermore, the use of protein-concentrated fluid such as 5 times-diluted human plasma does not impair the performances of the method. Screening of human plasma samples shows a strict discrimination between seropositive and seronegative samples in an assay duration as short as 14 s. The sensitivity of this method, combined with its quickness and simplicity, makes it a promising diagnostic tool.


Assuntos
Aglutinação , Bioensaio , Humanos , Imunoensaio , Campos Magnéticos , Programas de Rastreamento , Sensibilidade e Especificidade
19.
Talanta ; 233: 122515, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34215130

RESUMO

In this work, we structured a colorimetric ultrasensitive detection of carcinoembryonic antigen (CEA) based on a proximity hybridization-induced gold nanoparticles (Au NPs) dimers structure. Under the dark-field microscope, this method takes advantage of the distinctive and strong distance-relative localized surface plasmon resonance (LSPR) of Au NPs and their oriented assembly. DNA served as a medium showing wonderful flexibility to label antibody and Au NPs, and tune interparticle spacing as well. Two capture probes were formed by the integration of DNA labeled antibody (DNA1-Ab1 or DNA2-Ab2) and asymmetrically assembled DNA (DNA 3 or DNA 4)- Au NPs via partly hybridization between DNA sequences. In the presence of antigen, the reaction between target protein and capture probes could trigger the generation of immunocomplex which led to the proximity hybridization of the DNA1 and DNA2, and then change the distance of interparticle to form Au NP dimers and thus showed a different color under dark-field microscope. A limit of detection of 14.25 pg/mL was obtained for the detection of CEA, which indicated a promising sensing method in clinical diagnosis of protein biomarkers.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Técnicas Eletroquímicas , Ouro , Imunoensaio , Limite de Detecção
20.
Talanta ; 233: 122520, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34215135

RESUMO

This work describes a novel affinity peptide-antibody sandwich electrochemical strategy for the ultrasensitive detection of prostate-specific antigen (PSA). Herein, polydopamine-coated boron-doped carbon nitride (Au@PDA@BCN) was synthesized and used as a sensing platform to anchor gold nanoparticles and immobilize primary antibody. Meanwhile, AuPt metallic nanoparticle and manganese dioxide (MnO2)-functionalized covalent organic frameworks (AuPt@MnO2@COF) was facilely synthesized to serve as a nanocatalyst and ordered nanopore for the enrichment and amplification of signal molecules (methylene blue, MB). PSA affinity peptide was bound to AuPt@MnO2@COF to form Pep/MB/AuPt@MnO2@COF nanocomposites (probe). The peptide-PSA-antibody sandwich biosensor was constructed, and the redox signal of MB was measured with the existence of PSA. The fabricated sensor exhibited a linear response (0.00005-10 ng mL-1) with a low detection limit of 16.7 fg mL-1 under the optimum condition. Additionally, the sensor showed an excellent selectivity, ideal repeatability, and good stability for PSA detection in real samples. Furthermore, the porous structure of COF can enrich more MB molecules and increase the sensitivity of the biosensor. This study provides an efficient and ultrasensitive strategy for PSA detection and broadens the use of organic/inorganic porous nanocomposite in biosensing.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Estruturas Metalorgânicas , Técnicas Eletroquímicas , Ouro , Humanos , Imunoensaio , Limite de Detecção , Masculino , Compostos de Manganês , Óxidos , Peptídeos , Antígeno Prostático Específico
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