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1.
Biosensors (Basel) ; 13(6)2023 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-37366954

RESUMO

In 2019, over 21% of an estimated 10 million new tuberculosis (TB) patients were either not diagnosed at all or diagnosed without being reported to public health authorities. It is therefore critical to develop newer and more rapid and effective point-of-care diagnostic tools to combat the global TB epidemic. PCR-based diagnostic methods such as Xpert MTB/RIF are quicker than conventional techniques, but their applicability is restricted by the need for specialized laboratory equipment and the substantial cost of scaling-up in low- and middle-income countries where the burden of TB is high. Meanwhile, loop-mediated isothermal amplification (LAMP) amplifies nucleic acids under isothermal conditions with a high efficiency, helps in the early detection and identification of infectious diseases, and can be performed without the need for sophisticated thermocycling equipment. In the present study, the LAMP assay was integrated with screen-printed carbon electrodes and a commercial potentiostat for real time cyclic voltammetry analysis (named as the LAMP-Electrochemical (EC) assay). The LAMP-EC assay was found to be highly specific to TB-causing bacteria and capable of detecting even a single copy of the Mycobacterium tuberculosis (Mtb) IS6110 DNA sequence. Overall, the LAMP-EC test developed and evaluated in the present study shows promise to become a cost-effective tool for rapid and effective diagnosis of TB.


Assuntos
Técnicas Biossensoriais , Microeletrodos , Tuberculose , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/isolamento & purificação , Tuberculose/diagnóstico , Tuberculose/microbiologia , Técnicas Biossensoriais/economia , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Técnicas Biossensoriais/normas , Carbono/química , Microeletrodos/normas , Sensibilidade e Especificidade , Microscopia Eletrônica de Varredura , Reprodutibilidade dos Testes , DNA Bacteriano/análise
2.
Nat Nanotechnol ; 17(1): 5-16, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-35046571

RESUMO

Nanophotonic devices, which control light in subwavelength volumes and enhance light-matter interactions, have opened up exciting prospects for biosensing. Numerous nanophotonic biosensors have emerged to address the limitations of the current bioanalytical methods in terms of sensitivity, throughput, ease-of-use and miniaturization. In this Review, we provide an overview of the recent developments of label-free nanophotonic biosensors using evanescent-field-based sensing with plasmon resonances in metals and Mie resonances in dielectrics. We highlight the prospects of achieving an improved sensor performance and added functionalities by leveraging nanostructures and on-chip and optoelectronic integration, as well as microfluidics, biochemistry and data science toolkits. We also discuss open challenges in nanophotonic biosensing, such as reducing the overall cost and handling of complex biological samples, and provide an outlook for future opportunities to improve these technologies and thereby increase their impact in terms of improving health and safety.


Assuntos
Técnicas Biossensoriais , Nanoestruturas/química , Fótons , Técnicas Biossensoriais/economia , Análise Custo-Benefício , Campos Eletromagnéticos , Análise Espectral
3.
PLoS One ; 17(1): e0262312, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34995319

RESUMO

Yellow fever is endemic in Ghana and outbreaks occur periodically. The prodromal signs due to Yellow Fever Virus (YFV) infection are non-specific, making clinical signs unreliable as the sole criteria for diagnosis. Accurate laboratory confirmation of suspected yellow fever cases is therefore vital in surveillance programs. Reporting of ELISA IgM testing results by laboratories can delay due to late arrival of samples from the collection sites as well as limited availability of ELISA kits. In this study, the diagnostic performance characteristics of a rapid immunochromatographic Standard Q Yellow Fever IgM test kit (SD Biosensor) was evaluated for the rapid diagnosis of Yellow Fever infection in Ghana. A panel of 275 sera, comprising 81 confirmed YFV positives and 194 negatives were re-tested in this study using the Standard Q Yellow Fever IgM test kit. Using the CDC/WHO Yellow Fever IgM capture ELISA as a benchmark, the sensitivity, specificity and accuracy of the Standard Q Yellow Fever test kit were 96.3%, 97.9% and 97.5%, respectively. The false positivity rate was 5.1% and there was no cross-reactivity when the Standard Q Yellow Fever test kit was tested against dengue, malaria and hepatitis B and C positive samples. In addition, inter-reader variability and invalid rate were both zero. The results indicate that the diagnostic performance of the Standard Q Yellow Fever IgM test kit on serum or plasma is comparable to the serum IgM detection by ELISA and can be used as a point of care rapid diagnostic test kit for YFV infection in endemic areas.


Assuntos
Técnicas Biossensoriais/instrumentação , Cromatografia de Afinidade/instrumentação , Imunoglobulina M/imunologia , Kit de Reagentes para Diagnóstico , Febre Amarela/diagnóstico , Vírus da Febre Amarela/imunologia , Técnicas Biossensoriais/economia , Cromatografia de Afinidade/economia , Desenho de Equipamento , Humanos , Imunoglobulina M/sangue , Limite de Detecção , Kit de Reagentes para Diagnóstico/economia , Fatores de Tempo , Febre Amarela/sangue , Febre Amarela/imunologia , Vírus da Febre Amarela/isolamento & purificação
5.
Biosens Bioelectron ; 179: 113099, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33640656

RESUMO

The SARS-CoV-2 pandemic, an ongoing global health crisis, has revealed the need for new technologies that integrate the sensitivity and specificity of RT-PCR tests with a faster time-to-detection. Here, an emulsion loop-mediated isothermal amplification (eLAMP) platform was developed to allow for the compartmentalization of LAMP reactions, leading to faster changes in emulsion characteristics, and thus lowering time-to-detection. Within these droplets, ongoing LAMP reactions lead to adsorption of amplicons to the water-oil interface, causing a decrease in interfacial tension, resulting in smaller emulsion diameters. Changes in emulsion diameter allow for the monitoring of the reaction by use of angle-dependent light scatter (based off Mie scatter theory). Mie scatter simulations confirmed that light scatter intensity is diameter-dependent and smaller colloids have lower intensity values compared to larger colloids. Via spectrophotometers and fiber optic cables placed at 30° and 60°, light scatter intensity was monitored. Scatter intensities collected at 5 min, 30° could statistically differentiate 10, 103, and 105 copies/µL initial concentrations compared to NTC. Similarly, 5 min scatter intensities collected at 60° could statistically differentiate 105 copies/µL initial concentrations in comparison to NTC. The use of both angles during the eLAMP assay allows for distinction between high and low initial target concentrations. The efficacy of a smartphone-based platform was also tested and had a similar limit of detection and assay time of less than 10 min. Furthermore, fluorescence-labeled primers were used to validate target nucleic acid amplification. Compared to existing LAMP assays for SARS-CoV-2 detection, these times-to-detections are very rapid.


Assuntos
Teste de Ácido Nucleico para COVID-19/instrumentação , COVID-19/diagnóstico , Difusão Dinâmica da Luz/instrumentação , Emulsões/química , Técnicas de Diagnóstico Molecular/instrumentação , Técnicas de Amplificação de Ácido Nucleico/instrumentação , SARS-CoV-2/isolamento & purificação , Técnicas Biossensoriais/economia , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Teste de Ácido Nucleico para COVID-19/economia , Teste de Ácido Nucleico para COVID-19/métodos , Difusão Dinâmica da Luz/economia , Difusão Dinâmica da Luz/métodos , Desenho de Equipamento , Humanos , Limite de Detecção , Técnicas de Diagnóstico Molecular/economia , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificação de Ácido Nucleico/economia , Técnicas de Amplificação de Ácido Nucleico/métodos , Smartphone , Fatores de Tempo
6.
Biosens Bioelectron ; 177: 113005, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33486135

RESUMO

The coronavirus disease 2019 (COVID-19) pandemic has been a major public health challenge in 2020. Early diagnosis of COVID-19 is the most effective method to control disease spread and prevent further mortality. As such, a high-precision and rapid yet economic assay method is urgently required. Herein, we propose an innovative method to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using isothermal amplification of nucleic acids on a mesh containing multiple microfluidic pores. Hybridization of pathogen DNA and immobilized probes forms a DNA hydrogel by rolling circle amplification and, consequently, blocks the pores to prevent fluid movement, as observed. Following optimization of several factors, including pore size, mesh location, and precision microfluidics, the limit of detection (LOD) for SARS-CoV-2 was determined to be 0.7 aM at 15-min incubation. These results indicate rapid, easy, and effective detection with a moderate-sized LOD of the target pathogen by remote point-of-care testing and without the requirement of any sophisticated device.


Assuntos
Teste de Ácido Nucleico para COVID-19/métodos , COVID-19/diagnóstico , Hidrogéis/química , Ácidos Nucleicos Imobilizados/química , Testes Imediatos , SARS-CoV-2/isolamento & purificação , Técnicas Biossensoriais/economia , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , COVID-19/virologia , Teste de Ácido Nucleico para COVID-19/economia , Teste de Ácido Nucleico para COVID-19/instrumentação , Sondas de DNA/química , Sondas de DNA/genética , Desenho de Equipamento , Humanos , Ácidos Nucleicos Imobilizados/genética , Dispositivos Lab-On-A-Chip , Limite de Detecção , Técnicas de Diagnóstico Molecular/economia , Técnicas de Diagnóstico Molecular/instrumentação , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificação de Ácido Nucleico/economia , Técnicas de Amplificação de Ácido Nucleico/instrumentação , Técnicas de Amplificação de Ácido Nucleico/métodos , SARS-CoV-2/genética
7.
Biosens Bioelectron ; 171: 112709, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33075724

RESUMO

Coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was classified as a pandemic by the World Health Organization and has caused over 550,000 deaths worldwide as of July 2020. Accurate and scalable point-of-care devices would increase screening, diagnosis, and monitoring of COVID-19 patients. Here, we demonstrate rapid label-free electrochemical detection of SARS-CoV-2 antibodies using a commercially available impedance sensing platform. A 16-well plate containing sensing electrodes was pre-coated with receptor binding domain (RBD) of SARS-CoV-2 spike protein, and subsequently tested with samples of anti-SARS-CoV-2 monoclonal antibody CR3022 (0.1 µg/ml, 1.0 µg/ml, 10 µg/ml). Subsequent blinded testing was performed on six serum specimens taken from COVID-19 and non-COVID-19 patients (1:100 dilution factor). The platform was able to differentiate spikes in impedance measurements from a negative control (1% milk solution) for all CR3022 samples. Further, successful differentiation and detection of all positive clinical samples from negative control was achieved. Measured impedance values were consistent when compared to standard ELISA test results showing a strong correlation between them (R2=0.9). Detection occurs in less than five minutes and the well-based platform provides a simplified and familiar testing interface that can be readily adaptable for use in clinical settings.


Assuntos
Anticorpos Antivirais/sangue , Betacoronavirus/imunologia , Técnicas Biossensoriais/instrumentação , Técnicas de Laboratório Clínico , Infecções por Coronavirus/sangue , Espectroscopia Dielétrica/instrumentação , Pneumonia Viral/sangue , Anticorpos Antivirais/imunologia , Técnicas Biossensoriais/economia , COVID-19 , Teste para COVID-19 , Técnicas de Laboratório Clínico/economia , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/economia , Infecções por Coronavirus/imunologia , Espectroscopia Dielétrica/economia , Impedância Elétrica , Desenho de Equipamento , Humanos , Proteínas Imobilizadas/imunologia , Pandemias , Pneumonia Viral/diagnóstico , Pneumonia Viral/imunologia , SARS-CoV-2 , Sensibilidade e Especificidade , Glicoproteína da Espícula de Coronavírus/imunologia , Fatores de Tempo
8.
Biosens Bioelectron ; 171: 112715, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33099241

RESUMO

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19), a newly emerging human infectious disease. Because no specific antiviral drugs or vaccines are available to treat COVID-19, early diagnostics, isolation, and prevention are crucial for containing the outbreak. Molecular diagnostics using reverse transcription polymerase chain reaction (RT-PCR) are the current gold standard for detection. However, viral RNAs are much less stable during transport and storage than proteins such as antigens and antibodies. Consequently, false-negative RT-PCR results can occur due to inadequate collection of clinical specimens or poor handling of a specimen during testing. Although antigen immunoassays are stable diagnostics for detection of past infection, infection progress, and transmission dynamics, no matched antibody pair for immunoassay of SARS-CoV-2 antigens has yet been reported. In this study, we designed and developed a novel rapid detection method for SARS-CoV-2 spike 1 (S1) protein using the SARS-CoV-2 receptor ACE2, which can form matched pairs with commercially available antibodies. ACE2 and S1-mAb were paired with each other for capture and detection in a lateral flow immunoassay (LFIA) that did not cross-react with SARS-CoV Spike 1 or MERS-CoV Spike 1 protein. The SARS-CoV-2 S1 (<5 ng of recombinant proteins/reaction) was detected by the ACE2-based LFIA. The limit of detection of our ACE2-LFIA was 1.86 × 105 copies/mL in the clinical specimen of COVID-19 Patients without no cross-reactivity for nasal swabs from healthy subjects. This is the first study to detect SARS-CoV-2 S1 antigen using an LFIA with matched pair consisting of ACE2 and antibody. Our findings will be helpful to detect the S1 antigen of SARS-CoV-2 from COVID-19 patients.


Assuntos
Betacoronavirus/isolamento & purificação , Técnicas Biossensoriais/instrumentação , Técnicas de Laboratório Clínico , Infecções por Coronavirus/diagnóstico , Peptidil Dipeptidase A/química , Pneumonia Viral/diagnóstico , Glicoproteína da Espícula de Coronavírus/análise , Enzima de Conversão de Angiotensina 2 , Anticorpos Monoclonais/química , Técnicas Biossensoriais/economia , COVID-19 , Teste para COVID-19 , Técnicas de Laboratório Clínico/economia , Técnicas de Laboratório Clínico/instrumentação , Infecções por Coronavirus/economia , Desenho de Equipamento , Humanos , Imunoensaio/economia , Imunoensaio/instrumentação , Imunoconjugados/química , Pandemias , SARS-CoV-2 , Sensibilidade e Especificidade , Fatores de Tempo
9.
Biosens Bioelectron ; 171: 112685, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33113383

RESUMO

The spread of SARS-CoV-2 virus in the ongoing global pandemic has led to infections of millions of people and losses of many lives. The rapid, accurate and convenient SARS-CoV-2 virus detection is crucial for controlling and stopping the pandemic. Diagnosis of patients in the early stage infection are so far limited to viral nucleic acid or antigen detection in human nasopharyngeal swab or saliva samples. Here we developed a method for rapid and direct optical measurement of SARS-CoV-2 virus particles in one step nearly without any sample preparation using a spike protein specific nanoplasmonic resonance sensor. As low as 370 vp/mL were detected in one step within 15 min and the virus concentration can be quantified linearly in the range of 0 to 107 vp/mL. Measurements shown on both generic microplate reader and a handheld smartphone connected device suggest that our low-cost and rapid detection method may be adopted quickly under both regular clinical environment and resource-limited settings.


Assuntos
Betacoronavirus/isolamento & purificação , Técnicas Biossensoriais/instrumentação , Técnicas de Laboratório Clínico , Infecções por Coronavirus/diagnóstico , Pneumonia Viral/diagnóstico , Testes Imediatos , Vírion/isolamento & purificação , Anticorpos Imobilizados/química , Técnicas Biossensoriais/economia , COVID-19 , Teste para COVID-19 , Técnicas de Laboratório Clínico/economia , Infecções por Coronavirus/economia , Desenho de Equipamento , Humanos , Limite de Detecção , Modelos Moleculares , Pandemias , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus/análise , Fatores de Tempo
10.
Biosensors (Basel) ; 11(1)2020 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-33374119

RESUMO

An optical cavity-based biosensor (OCB) has been developed for point-of-care (POC) applications. This label-free biosensor employs low-cost components and simple fabrication processes to lower the overall cost while achieving high sensitivity using a differential detection method. To experimentally demonstrate its limit of detection (LOD), we conducted biosensing experiments with streptavidin and C-reactive protein (CRP). The optical cavity structure was optimized further for better sensitivity and easier fluid control. We utilized the polymer swelling property to fine-tune the optical cavity width, which significantly improved the success rate to produce measurable samples. Four different concentrations of streptavidin were tested in triplicate, and the LOD of the OCB was determined to be 1.35 nM. The OCB also successfully detected three different concentrations of human CRP using biotinylated CRP antibody. The LOD for CRP detection was 377 pM. All measurements were done using a small sample volume of 15 µL within 30 min. By reducing the sensing area, improving the functionalization and passivation processes, and increasing the sample volume, the LOD of the OCB are estimated to be reduced further to the femto-molar range. Overall, the demonstrated capability of the OCB in the present work shows great potential to be used as a promising POC biosensor.


Assuntos
Técnicas Biossensoriais , Proteína C-Reativa , Estreptavidina , Anticorpos , Técnicas Biossensoriais/economia , Humanos
11.
Anal Chem ; 92(24): 15982-15988, 2020 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-33225684

RESUMO

As a single-chain glycoprotein with endopeptidase activity, the prostate-specific antigen (PSA) is valuable as an informative serum marker in diagnosing, staging, and prognosis of prostate cancer. In this report, an electrochemical biosensor based on the target-induced cleavage of a specific peptide substrate (PSA peptide) is designed for the highly selective detection of PSA at the femtomolar level, using electrochemically controlled atom transfer radical polymerization (eATRP) as a method for signal amplification. The PSA peptides, without free carboxyl sites, are attached to the gold surface via the N-terminal cysteine residue. The target-induced cleavage of PSA peptides results in the generation of carboxyl sites, to which the alkyl halide initiator α-bromophenylacetic acid (BPAA) is linked via the Zr(IV) linkers. Subsequently, the potentiostatic eATRP of ferrocenylmethyl methacrylate (FcMMA, as the monomer) leads to the surface-initiated grafting of high-density ferrocenyl polymers. As a result, a large amount of Fc redox tags can be recruited for signal amplification, through which the limit of detection (LOD) for PSA can be down to 3.2 fM. As the recognition element, the PSA peptide is easy to synthesize, chemically and thermally stable, and low-cost. Without the necessity of enzyme or nanoparticle labels, the eATRP-based amplification method is easy to operate and low-cost. Results also show that the cleavage-based electrochemical PSA biosensor is highly selective and applicable to PSA detection in complex biological samples. In view of these merits, the integration of the eATRP-based amplification method into cleavage-based recognition is believed to hold great promise for the electrochemical detection of PSA in clinical applications.


Assuntos
Técnicas Biossensoriais/métodos , Limite de Detecção , Polimerização , Antígeno Prostático Específico/análise , Técnicas Biossensoriais/economia , Custos e Análise de Custo , Eletroquímica , Ouro/química , Humanos , Metacrilatos/química , Antígeno Prostático Específico/química , Fatores de Tempo
12.
J Mater Chem B ; 8(44): 10182-10189, 2020 11 18.
Artigo em Inglês | MEDLINE | ID: mdl-33103693

RESUMO

The monitoring of respiratory disorders requires breath sensors that are fast, robust, and convenient to use and can function under real time conditions. A MOF based flexible sensor is reported for the first time for breath sensing applications. The properties of a highly porous HKUST-1 MOF and a conducting MoS2 material have been combined to fabricate an electronic sensor on a flexible paper support for studying sleep apnea problems. Extensive breath sensing experiments have been performed and interestingly the fabricated sensor is efficient in detecting various kinds of breaths such as deep, fast, slow and hydrated breath. The MOF breath sensor shows a fast response time of just ∼0.38 s and excellent stability with no decline in its performance even after a month. A plausible mechanism has been proposed and a smartphone based prototype has been prepared to demonstrate the real time applications of the hybrid device. This work demonstrates great potential for the application of MOFs in healthcare with a special focus on breath sensing and sleep apnea diagnosis.


Assuntos
Técnicas Biossensoriais/métodos , Análise Custo-Benefício/métodos , Estruturas Metalorgânicas/química , Mecânica Respiratória/fisiologia , Síndromes da Apneia do Sono/diagnóstico , Dispositivos Eletrônicos Vestíveis , Técnicas Biossensoriais/economia , Humanos , Máscaras/economia , Estruturas Metalorgânicas/economia , Estruturas Metalorgânicas/metabolismo , Síndromes da Apneia do Sono/economia , Síndromes da Apneia do Sono/metabolismo , Termogravimetria/métodos , Dispositivos Eletrônicos Vestíveis/economia
13.
Opt Express ; 28(22): 32239-32248, 2020 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-33114915

RESUMO

Resonant biosensors are attractive for diagnostics because they can detect clinically relevant biomarkers with high sensitivity and in a label-free fashion. Most of the current solutions determine their detection limits in a highly stabilised laboratory environment, which does, however, not apply to real point-of-care applications. Here, we consider the more realistic scenario of low-cost components and an unstabilised environment and consider the related design implications. We find that sensors with lower quality-factor resonances are more fault tolerant, that a filtered LED lightsource is advantageous compared to a diode laser, and that a CMOS camera is preferable to a CCD camera for detection. We exemplify these findings with a guided mode resonance sensor and experimentally determine a limit of detection of 5.8 ± 1.7×10-5 refractive index units (RIU), which is backed up by a model identifying the various noise sources. Our findings will inform the design of high performance, low cost biosensors capable of operating in a real-world environment.


Assuntos
Técnicas Biossensoriais/economia , Refratometria/economia , Ressonância de Plasmônio de Superfície/instrumentação , Técnicas Biossensoriais/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento , Limite de Detecção , Refratometria/instrumentação , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Transdutores
14.
Molecules ; 25(21)2020 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-33126549

RESUMO

Despite the fact that a considerable amount of effort has been invested in the development of biosensors for the detection of pesticides, there is still a lack of a simple and low-cost platform that can reliably and sensitively detect their presence in real samples. Herein, an enzyme-based biosensor for the determination of both carbamate and organophosphorus pesticides is presented that is based on acetylcholinesterase (AChE) immobilized on commercially available screen-printed carbon electrodes (SPEs) modified with carbon black (CB), as a means to enhance their conductivity. Most interestingly, two different methodologies to deposit the enzyme onto the sensor surfaces were followed; strikingly different results were obtained depending on the family of pesticides under investigation. Furthermore, and towards the uniform application of the functionalization layer onto the SPEs' surfaces, the laser induced forward transfer (LIFT) technique was employed in conjunction with CB functionalization, which allowed a considerable improvement of the sensor's performance. Under the optimized conditions, the fabricated sensors can effectively detect carbofuran in a linear range from 1.1 × 10-9 to 2.3 × 10-8 mol/L, with a limit of detection equal to 0.6 × 10-9 mol/L and chlorpyrifos in a linear range from 0.7 × 10-9 up to 1.4 × 10-8 mol/L and a limit of detection 0.4 × 10-9 mol/L in buffer. The developed biosensor was also interrogated with olive oil samples, and was able to detect both pesticides at concentrations below 10 ppb, which is the maximum residue limit permitted by the European Food Safety Authority.


Assuntos
Técnicas Biossensoriais/instrumentação , Carbamatos/análise , Custos e Análise de Custo , Limite de Detecção , Azeite de Oliva/química , Compostos Organofosforados/análise , Resíduos de Praguicidas/análise , Técnicas Biossensoriais/economia , Carbono/química , Eletrodos , Análise de Alimentos/instrumentação , Contaminação de Alimentos/análise , Propriedades de Superfície
15.
Biosens Bioelectron ; 170: 112656, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33010706

RESUMO

Point-of-care risk assessment (PCRA) for airborne viruses requires a system that can enrich low-concentration airborne viruses dispersed in field environments into a small volume of liquid. In this study, airborne virus particles were collected to a degree above the limit of detection (LOD) for a real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). This study employed an electrostatic air sampler to capture aerosolized test viruses (human coronavirus 229E (HCoV-229E), influenza A virus subtype H1N1 (A/H1N1), and influenza A virus subtype H3N2 (A/H3N2)) in a continuously flowing liquid (aerosol-to-hydrosol (ATH) enrichment) and a concanavalin A (ConA)-coated magnetic particles (CMPs)-installed fluidic channel for simultaneous hydrosol-to-hydrosol (HTH) enrichment. The air sampler's ATH enrichment capacity (EC) was evaluated using the aerosol counting method. In contrast, the HTH EC for the ATH-collected sample was evaluated using transmission-electron-microscopy (TEM)-based image analysis and real-time qRT-PCR assay. For example, the ATH EC for HCoV-229E was up to 67,000, resulting in a viral concentration of 0.08 PFU/mL (in a liquid sample) for a viral epidemic scenario of 1.2 PFU/m3 (in air). The real-time qRT-PCR assay result for this liquid sample was "non-detectable" however, subsequent HTH enrichment for 10 min caused the "non-detectable" sample to become "detectable" (cycle threshold (CT) value of 33.8 ± 0.06).


Assuntos
Técnicas Biossensoriais/instrumentação , Coronavirus Humano 229E/isolamento & purificação , Infecções por Coronavirus/virologia , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Influenza Humana/virologia , Aerossóis/análise , Microbiologia do Ar , Técnicas Biossensoriais/economia , Coronavirus Humano 229E/genética , Monitoramento Ambiental/economia , Monitoramento Ambiental/instrumentação , Desenho de Equipamento , Humanos , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H3N2/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa/instrumentação , Fatores de Tempo
16.
Biosens Bioelectron ; 170: 112673, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33038584

RESUMO

Currently the world is being challenged by a public health emergency caused by the coronavirus pandemic (COVID-19). Extensive efforts in testing for coronavirus infection, combined with isolating infected cases and quarantining those in contact, have proven successful in bringing the epidemic under control. Rapid and facile screening of this disease is in high demand. This review summarises recent advances in strategies reported by international researchers and engineers concerning how to tackle COVID-19 via rapid testing, mainly through nucleic acid- and antibody- testing. The roles of biosensors as powerful analytical tools are emphasized for the detection of viral RNAs, surface antigens, whole viral particles, antibodies and other potential biomarkers in human specimen. We critically review in depth newly developed biosensing methods especially for in-field and point-of-care detection of SARS-CoV-2. Additionally, this review describes possible future strategies for virus rapid detection. It helps researchers working on novel sensor technologies to tailor their technologies in a way to address the challenge for effective detection of COVID-19.


Assuntos
Betacoronavirus/isolamento & purificação , Técnicas Biossensoriais , Técnicas de Laboratório Clínico , Infecções por Coronavirus/diagnóstico , Pneumonia Viral/diagnóstico , Testes Imediatos , Animais , Técnicas Biossensoriais/economia , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , COVID-19 , Teste para COVID-19 , Técnicas de Laboratório Clínico/economia , Técnicas de Laboratório Clínico/instrumentação , Técnicas de Laboratório Clínico/métodos , Infecções por Coronavirus/economia , Desenho de Equipamento , Humanos , Pandemias , Testes Imediatos/economia , SARS-CoV-2 , Fatores de Tempo
17.
Biosens Bioelectron ; 169: 112572, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32916610

RESUMO

Convalescent serum with a high abundance of neutralization IgG is a promising therapeutic agent for rescuing COVID-19 patients in the critical stage. Knowing the concentration of SARS-CoV-2 S1-specific IgG is crucial in selecting appropriate convalescent serum donors. Here, we present a portable microfluidic ELISA technology for rapid (15 min), quantitative, and sensitive detection of anti-SARS-CoV-2 S1 IgG in human serum with only 8 µL sample volume. We first identified a humanized monoclonal IgG that has a high binding affinity and a relatively high specificity towards SARS-CoV-2 S1 protein, which can subsequently serve as the calibration standard of anti-SARS-CoV-2 S1 IgG in serological analyses. We then measured the abundance of anti-SARS-CoV-2 S1 IgG in 16 convalescent COVID-19 patients. Due to the availability of the calibration standard and the large dynamic range of our assay, we were able to identify "qualified donors" for convalescent serum therapy with only one fixed dilution factor (200 ×). Finally, we demonstrated that our technology can sensitively detect SARS-CoV-2 antigens (S1 and N proteins) with pg/mL level sensitivities in 40 min. Overall, our technology can greatly facilitate rapid, sensitive, and quantitative analysis of COVID-19 related markers for therapeutic, diagnostic, epidemiologic, and prognostic purposes.


Assuntos
Anticorpos Antivirais/sangue , Betacoronavirus/imunologia , Infecções por Coronavirus/virologia , Ensaio de Imunoadsorção Enzimática/instrumentação , Imunoglobulina G/sangue , Técnicas Analíticas Microfluídicas/instrumentação , Pneumonia Viral/virologia , Adolescente , Adulto , Anticorpos Antivirais/imunologia , Antígenos Virais/sangue , Antígenos Virais/imunologia , Técnicas Biossensoriais/economia , Técnicas Biossensoriais/instrumentação , COVID-19 , Infecções por Coronavirus/terapia , Ensaio de Imunoadsorção Enzimática/economia , Desenho de Equipamento , Humanos , Imunização Passiva , Imunoglobulina G/imunologia , Limite de Detecção , Medições Luminescentes/economia , Medições Luminescentes/instrumentação , Técnicas Analíticas Microfluídicas/economia , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/terapia , SARS-CoV-2 , Fatores de Tempo , Adulto Jovem , Soroterapia para COVID-19
18.
J Mater Chem B ; 8(41): 9502-9511, 2020 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-32996975

RESUMO

In purine metabolism, the xanthine oxidoreductase enzyme converts hypoxanthine (HXN) to xanthine (XN) and XN to uric acid (UA). This leads to the deposition of UA crystals in several parts of the body and the serum UA level might be associated with various multifunctional disorders. The dietary intake of caffeine (CF) and ascorbic acid (AA) decreases the UA level in the serum, which leads to cellular damage. Hence, it is highly needed to monitor the UA level in the presence of AA, XN, HXN, and CF and vice versa. Considering this sequence of complications, the present paper reports the fabrication of an electrochemical sensor using low-cost N-doped carbon dots (CDs) for the selective and simultaneous determination of UA in the presence of AA, XN, HXN, and CF at the physiological pH. The colloidal solution of CDs was prepared by the pyrolysis of asparagine and fabricated on a GC electrode by cycling the potential from -0.20 to +1.2 V in a solution containing CDs and 0.01 M H2SO4. Here, the surface -NH2 functionalities of CDs were used to make a thin film of CDs on the GC electrode. FT-IR spectroscopy confirmed the involvement of the -NH2 group in the formation of the CD film. HR-TEM analysis depicts that the formed CDs showed spherical particles with a size of 1.67 nm and SEM analysis exhibits the 89 nm CD film on the GC electrode surface. The fabricated CD film was successfully used for the sensitive and selective determination of UA. The determination of UA was achieved selectively in a mixture consisting of AA, XN, HXN, and CF with 50-fold high concentration. The CDs-film fabricated electrode has several benefits over the bare electrode: (i) well-resolved oxidation peaks for five analytes, (ii) boosted sensitivity, (iii) shifted oxidation as well as on-set potentials toward less positive potentials, and (iv) high stability. The practical utility of the present sensor was tested by simultaneously determining the multifactorial disorders-causing agents in human fluids. The electrocatalyst developed in the present study is sustainable and can be used for multiple analyses; besides, the electrochemical method used for the fabrication of the CD film is environmentally benign.


Assuntos
Ácido Ascórbico/sangue , Cafeína/sangue , Técnicas Eletroquímicas/instrumentação , Hipoxantina/sangue , Ácido Úrico/sangue , Xantina/sangue , Técnicas Biossensoriais/economia , Técnicas Biossensoriais/instrumentação , Carbono/química , Catálise , Técnicas Eletroquímicas/economia , Eletrodos , Feminino , Humanos , Masculino
19.
Anal Sci ; 36(9): 1119-1124, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32908068

RESUMO

A flow-injection analytical (FIA) system was developed for the determination of cholesterol concentrations based on enzymatic reactions that occurred in a cholesterol oxidase (CHOx)-immobilized, fused-silica capillary followed by electrochemical detection. The production of hydrogen peroxide from cholesterol in an enzymatic reaction catalyzed by CHOx was subsequently oxidized electrochemically at an electrode. Our FlA system demonstrated its cost-effectiveness and utility at an applied potential of 0.6 V (vs. Ag/AgCl), a flow rate of 100 µL/min and, under optimal conditions, the resulting signal demonstrated a linear dynamic range from 50 µM to 1.0 mM with a limit of detection (LOD) of 12.4 µM, limit of quantification (LOQ) of 44.9 µM, and the coefficient of variation of 5.17%. In addition, validation of our proposed system using a reference HDL-cholesterol kit used for clinical diagnosis suggested our FIA system was comparable to commercial kits for the determination of the cholesterol incorporation amount in various aqueous liposomal suspensions. These good analytical features achieved by FIA could make the implementation of this methodology possible for on-line monitoring of cholesterol in various types of samples.


Assuntos
Técnicas Biossensoriais/economia , Técnicas Biossensoriais/métodos , Colesterol Oxidase/metabolismo , Colesterol/análise , Análise Custo-Benefício , Análise de Injeção de Fluxo , Colesterol Oxidase/química , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Limite de Detecção , Lipossomos/química , Dióxido de Silício/química
20.
Int J Mol Sci ; 21(14)2020 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-32708609

RESUMO

Urinary tract infection (UTI) is one of the most common infections, accounting for a substantial portion of outpatient hospital and clinic visits. Standard diagnosis of UTI by culture and sensitivity can take at least 48 h, and improper diagnosis can lead to an increase in antibiotic resistance following therapy. To address these shortcomings, rapid bioluminescence assays were developed and evaluated for the detection of UTI using intact, viable cells of Photobacterium mandapamensis USTCMS 1132 or previously lyophilized cells of Photobacterium leiognathi ATCC 33981™. Two platform technologies-tube bioluminescence extinction technology urine (TuBETUr) and cellphone-based UTI bioluminescence extinction technology (CUBET)-were developed and standardized using artificial urine to detect four commonly isolated UTI pathogens-namely, Escherichia coli, Proteus mirabilis, Staphylococcus aureus, and Candida albicans. Besides detection, these assays could also provide information regarding pathogen concentration/level, helping guide treatment decisions. These technologies were able to detect microbes associated with UTI at less than 105 CFU/mL, which is usually the lower cut-off limit for a positive UTI diagnosis. Among the 29 positive UTI samples yielding 105-106 CFU/mL pathogen concentrations, a total of 29 urine specimens were correctly detected by TuBETUr as UTI-positive based on an 1119 s detection window. Similarly, the rapid CUBET method was able to discriminate UTIs from normal samples with high confidence (p ≤ 0.0001), using single-pot conditions and cell phone-based monitoring. These technologies could potentially address the need for point-of-care UTI detection while reducing the possibility of antibiotic resistance associated with misdiagnosed cases of urinary tract infections, especially in low-resource environments.


Assuntos
Infecções Bacterianas/urina , Técnicas Biossensoriais/métodos , Candidíase/urina , Medições Luminescentes/métodos , Photobacterium , Infecções Urinárias/urina , Infecções Bacterianas/microbiologia , Técnicas Biossensoriais/economia , Candida albicans/isolamento & purificação , Candidíase/microbiologia , Escherichia coli/isolamento & purificação , Humanos , Limite de Detecção , Luminescência , Medições Luminescentes/economia , Photobacterium/citologia , Photobacterium/isolamento & purificação , Proteus mirabilis/isolamento & purificação , Staphylococcus aureus/isolamento & purificação , Fatores de Tempo , Infecções Urinárias/microbiologia
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