Electrochemical immunosensor for tumor necrosis factor-alpha detection in undiluted serum

An immunosensor for the sensitive detection and estimation of tumor necrosis factor-alpha (TNF-α) in undiluted serum has been developed via an electrochemical enzyme-linked immunosorbent assay (ELISA) process. Electrochemical sensing was performed using a TNF-α specific monoclonal antibody modified self-assembled monolayer of dithiobis(succinimidyl propionate) on a comb-shaped gold electrode microarray. After anti-TNF-α antibody binding, unreacted active groups of DTSP were blocked using ethanol amine (EA) and nonspecific binding was prevented using phosphate buffer based starting block T20 (SB). Sensitive and disposable SB–EA–anti-TNF-α/DTSP/Au electrodes were exposed to solutions with different TNF-α concentrations for 20 min in undiluted serum. Conversion of 4-aminophenyl phosphate to 4-aminophenol and its electrochemical oxidation was utilized for indirect estimation of TNF-α. Results for SB–anti-TNF-α/DTSP/Au electrodes indicate that the sensors can be used for the sensitive estimation of TNF-α in undiluted serum in the range 500 pg/ml to 100 ng/ml with a detection limit of 60 pg/ml and sensitivity of 0.46 (ng/ml)−1. Negligible interference from serum and other biomarker proteins was observed. The described electrochemical ELISA is much faster than conventional ELISA and can be applied for sensing of a range of analytes in real patient samples

Electrochemical ELISA Protein Biosensing in Undiluted Serum Using a Polypyrrole-Based Platform

An electrochemical enzyme-linked immunosorbent assay (ELISA) biosensor platform using electrochemically prepared ~11 nm thick carboxylic functionalized popypyrrole film has been developed for bio-analyte measurement in undiluted serum. Carboxyl polypyrrole (PPy-COOH) film using 3-carboxy-pyrrol monomer onto comb-shaped gold electrode microarray (Au) was prepared via cyclic voltammetry (CV). The prepared Au/PPy-COOH was then utilized for electrochemical ELISA platform development by immobilizing analyte-specific antibodies. Tumor necrosis factor-alpha (TNF-α) was selected as a model analyte and detected in undiluted serum. For enhanced performance, the use of a polymeric alkaline phosphatase tag was investigated for the electrochemical ELISA. The developed platform was characterized at each step of fabrication using CV, electrochemical impedance spectroscopy and atomic force microscopy. The bioelectrodes exhibited linearity for TNF-α in the 100 pg/mL–100 ng/mL range when measured in spiked serum, with limit of detection of 78 pg/mL. The sensor showed insignificant signal disturbance from serum proteins and other biologically important proteins. The developed platform was found to be fast and specific and can be applicable for testing and measuring various biologically important protein markers in real samples

Developing and validating process-aware GUIs in an industrial setting

With classic cars being worth hundreds of thousands to even millions of euros, it is a deal of great importance that any restoration processes that these vehicles go through are following national and international regulations. Certification of the authenticity of restored cars plays a major role in this context. There is also a need to keep their owners informed about the process remotely, especially since these cars are often sent overseas to be repaired. This research is about assessing how monitoring the progress of classic cars’ restora- tion processes can be helpful for involved stakeholders: plant shop managers, certifica- tion bodies, and classic car owners. For that purpose, we developed a process monitoring platform that combines data gathered from plant shop sensors with input provided by a plant shop manager using a process-aware graphical user interface (GUI). The under- lying process is compliant with the best practices expressed in FIVA’s Charter of Turin and any evidence generated can be attached to its tasks to facilitate certification. After the process ends, an automatically generated PDF file that contains a summary of the process and the evidence attached to it can be downloaded. Last, but not least, a plat- form was developed where video-conference sessions with remotely controlled cameras can be performed to allow car owners to witness and record important milestones in the restoration/preservation process. This work allows for workshops using the developed system to show their quality and that the best practices identified by FIVA are followed. For this reason, it has gathered a lot of interest from several parties invested in the industry, including several national classic car workshops. If our system becomes widespread, it could not only distinguish the best workshops but also differentiate the country’s industry from others worldwide. It can also become a fundamental tool for the analysis performed by classic car certification companies in their tasks.Com carros clássicos a serem avaliados em centenas de milhares, ou em alguns casos mi- lhões, de euros, é muito importante que os seus processos de restauro estejam de acordo com as normas nacionais e internacionais. A certificação da autenticidade de carros res- taurados desempenha um papel importante neste contexto. Também é necessário manter os seus proprietários informados sobre o processo remotamente, especialmente visto que estes carros são frequentemente enviados para o estrangeiro para serem reparados. Esta pesquisa trata de avaliar como o monitoramento do progresso dos processos de restauração de carros clássicos pode ser útil para as partes envolvidas: gerentes de oficinas, órgãos de certificação e proprietários de carros clássicos. Para isso, desenvolvemos uma plataforma de monitoramento de processos que combina dados recolhidos por sensores com dados fornecidos pelos gerentes da oficina através duma GUI consciente dos pro- cessos. O processo subjacente está em conformidade com as práticas expressas na Carta de Turim da FIVA e as evidencias generadas podem ser anexadas às suas tarefas, para facilitar a certificação. No fim do processo, um ficheiro PDF gerado automaticamente que contém um resumo do processo e as suas evidências pode ser transferido. Por último, mas não menos importante, uma plataforma foi desenvolvida onde sessões de videoconferên- cia com câmaras remotamente controladas podem ser realizadas para permitir que os proprietários dos carros testemunhem e registem marcos importantes durante o processo de restauro/preservação. Este trabalho permite às oficinas que utilizem o nosso sistema mostrarem a sua qua- lidade e que as boas práticas identificadas pela FIVA são seguidas. Por este motivo, tem suscitado grande interesse pelas diversas partes envolvidas, incluindo diversas oficinas de automóveis clássicos nacionais. Se o nosso sistema ganhar popularidade, poderá não apenas distinguir as melhores oficinas, mas também diferenciar a indústria nacional das restantes mundialmente. Também pode se tornar uma ferramenta fundamental para a análise realizada pelas empresas de certificação de carros clássicos nas suas tarefas

Community sewage sensors towards evaluation of drug use trends: detection of cocaine in wastewater with DNA-directed immobilization aptamer sensors

Illicit drug use has a global concern and effective monitoring and interventions are highly required to combat drug abuse. Wastewater-based epidemiology (WBE) is an innovative and cost-effective approach to evaluate community-wide drug use trends, compared to traditional population surveys. Here we report for the first time, a novel quantitative community sewage sensor (namely DNA-directed immobilization of aptamer sensors, DDIAS) for rapid and cost-effective estimation of cocaine use trends via WBE. Thiolated single-stranded DNA (ssDNA) probe was hybridized with aptamer ssDNA in solution, followed by co-immobilization with 6-mercapto-hexane onto the gold electrodes to control the surface density to effectively bind with cocaine. DDIAS was optimized to detect cocaine at as low as 10 nM with a dynamic range from 10 nM to 5 μM, which were further employed for the quantification of cocaine in wastewater samples collected from a wastewater treatment plant in seven consecutive days. The concentration pattern of the sampling week is comparable with that from mass spectrometry. Our results demonstrate that the developed DDIAS can be used as community sewage sensors for rapid and cost-effective evaluation of drug use trends, and potentially implemented as a powerful tool for on-site and real-time monitoring of wastewater by un-skilled personnel

An electrochemical device to control sample pH locally in Lab-on-PCB devices: an investigation into spatial resolution.

During the recent pandemic outbreak, Lab-on-Chip devices did not manage to fully reach their potential in rapid diagnosis of pathogens, mainly due to the lack of cost-effective LoC solutions integrated with all required sample preparation modules. This paper presents such a critical step, aiming to translate electrochemical pH control into practical protein preconcentration modules, easy to integrate with subsequent quantification modules seamlessly via Lab-on-PCB technology. In this work we present a device capable of electrochemically controlling the pH of a solution local to an individually addressed electrode in a PCB array. The electrodes were functionalised with an electropolymerised self-assembled monolayer of 4-Aminothiophenol and were subjected to voltages of 0.2–0.4 V, evaluating for the first time the bias effect both over time and over space. This study enables for the first time the implementation of this technique for electrochemical pH control into practical Lab-on-PCB devices such as isoelectric focusing, via the informed design of such electrode arrays of appropriate size and spacing

Oligonucleotide-based systems:DNA, microRNAs, DNA/RNA aptamers

There is an increasing number of applications that have been developed for oligonucleotide-based biosensing systems in genetics and biomedicine. Oligonucleotide-based biosensors are those where the probe to capture the analyte is a strand of DNA, RNA or a synthetic analogue to naturally occurring nucleic acids. This chapter will draw light upon various types of nucleic acids such as DNA, RNA (particularly microRNAs), their role and their application in biosensing. Also, it will cover DNA/RNA aptamers, which can be used as bioreceptors to a wide range of targets such as proteins, small molecules, bacteria and even cells. It will also highlight how the invention of synthetic oligonucleotides like PNA or LNA has pushed the limits of molecular biology and biosensor development to new perspectives. These technologies are very promising albeit still in need of development in order to bridge the gap between the lab-based status and the reality of biomedical applications

Printable graphene BioFETs for DNA quantification in Lab-on-PCB microsystems

Lab-on-Chip is a technology that aims to transform the Point-of-Care (PoC) diagnostics field; nonetheless a commercial production compatible technology isyet to be established. Lab-on-Printed Circuit Board (Lab-on-PCB) is currentlyconsidered as a promising candidate technology for cost-aware butsimultaneously high specification applications, requiring multi-componentmicrosystem implementations, due to its inherent compatibility with electronicsand the long-standing industrial manufacturing basis. In this work, wedemonstrate the first electrolyte gated field-effect transistor (FET) DNAbiosensor implemented on commercially fabricated PCB in a planar layout.Graphene ink was drop-casted to form the transistor channel and PNA probeswere immobilized on the graphene channel, enabling label-free DNA detection. Itis shown that the sensor can selectively detect the complementary DNAsequence, following a fully inkjet-printing compatible manufacturing process. The results demonstrate the potential for the effortless integration of FET sensorsinto Lab-on-PCB diagnostic platforms, paving the way for even higher sensitivityquantification than the current Lab-on-PCB state-of-the-art of passive electrodeelectrochemical sensing. The substitution of such biosensors with our presentedFET structures, promises further reduction of the time-to-result in microsystemscombining sequential DNA amplification and detection modules to few minutes,since much fewer amplification cycles are required even for low-abundancenucleic acid targets