scholarly journals Suppressing Non-Specific Binding of Proteins onto Electrode Surfaces in the Development of Electrochemical Immunosensors

Biosensors ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 15 ◽  
Author(s):  
Jesús Contreras-Naranjo ◽  
Oscar Aguilar
Keyword(s):  
Solid Phase ◽  
Specific Binding ◽  
Point Of Care ◽  
Low Cost ◽  
Electrochemical Techniques ◽  
High Specificity ◽  
Electrode Surfaces ◽  
Solid Phase Immunoassay ◽  
Electrochemical Immunosensors ◽  
Complex Phenomena

Electrochemical immunosensors, EIs, are systems that combine the analytical power of electrochemical techniques and the high selectivity and specificity of antibodies in a solid phase immunoassay for target analyte. In EIs, the most used transducer platforms are screen printed electrodes, SPEs. Some characteristics of EIs are their low cost, portability for point of care testing (POCT) applications, high specificity and selectivity to the target molecule, low sample and reagent consumption and easy to use. Despite all these attractive features, still exist one to cover and it is the enhancement of the sensitivity of the EIs. In this review, an approach to understand how this can be achieved is presented. First, it is necessary to comprise thoroughly all the complex phenomena that happen simultaneously in the protein-surface interface when adsorption of the protein occurs. Physicochemical properties of the protein and the surface as well as the adsorption phenomena influence the sensitivity of the EIs. From this point, some strategies to suppress non-specific binding, NSB, of proteins onto electrode surfaces in order to improve the sensitivity of EIs are mentioned.

scholarly journals Electroanalytical Biosensors for Circulating Tumor DNA Detection—A Brief Review

2021 ◽  
Author(s):  
Zhijia Peng ◽  
Xiaogang Lin ◽  
Weiqi Nian ◽  
Xiaodong Zheng ◽  
Jayne Wu
Keyword(s):  
Real Time ◽  
Point Of Care ◽  
Low Cost ◽  
High Sensitivity ◽  
High Specificity ◽  
Circulating Tumor Dna ◽  
Minimal Invasive ◽  
Diagnosis And Treatment ◽  
Detection Technology ◽  
Tumor Dna

Early diagnosis and treatment have always been highly desired in the fight against cancer, and detection of circulating tumor DNA (ctDNA) has recently been touted as highly promising for early cancer screening. Consequently, the detection of ctDNA in liquid biopsy gains much attention in the field of tumor diagnosis and treatment, which has also attracted research interest from the industry. However, traditional gene detection technology is difficult to achieve low cost, real-time and portable measurement of ctDNA. Electroanalytical biosensors have many unique advantages such as high sensitivity, high specificity, low cost and good portability. Therefore, this review aims to discuss the latest development of biosensors for minimal-invasive, rapid, and real-time ctDNA detection. Various ctDNA sensors are reviewed with respect to their choices of receptor probes, detection strategies and figures of merit. Aiming at the portable, real-time and non-destructive characteristics of biosensors, we analyze their development in the Internet of Things, point-of-care testing, big data and big health.

scholarly journals Loop-Mediated Isothermal Amplification as Point-of-Care Diagnosis for Neglected Parasitic Infections

2020 ◽  
Vol 21 (21) ◽  
pp. 7981
Author(s):  
Catalina Avendaño ◽  
Manuel Alfonso Patarroyo
Keyword(s):  
Neglected Tropical Diseases ◽  
Point Of Care ◽  
Low Cost ◽  
High Specificity ◽  
World Health Organisation ◽  
Isothermal Amplification ◽  
World Health ◽  
Parasitic Infections ◽  
River Blindness ◽  
Loop Mediated Isothermal Amplification

The World Health Organisation (WHO) has placed twenty diseases into a group known as neglected tropical diseases (NTDs), twelve of them being parasitic diseases: Chagas’ disease, cysticercosis/taeniasis, echinococcosis, food-borne trematodiasis, human African trypanosomiasis (sleeping sickness), leishmaniasis, lymphatic filariasis, onchocerciasis (river blindness), schistosomiasis, soil-transmitted helminthiasis (ascariasis, hookworm, trichuriasis), guinea-worm and scabies. Such diseases affect millions of people in developing countries where one of the main problems concerning the control of these diseases is diagnosis-based due to the most affected areas usually being far from laboratories having suitable infrastructure and/or being equipped with sophisticated equipment. Advances have been made during the last two decades regarding standardising and introducing techniques enabling diagnoses to be made in remote places, i.e., the loop-mediated isothermal amplification (LAMP) technique. This technique’s advantages include being able to perform it using simple equipment, diagnosis made directly in the field, low cost of each test and the technique’s high specificity. Using this technique could thus contribute toward neglected parasite infection (NPI) control and eradication programmes. This review describes the advances made to date regarding LAMP tests, as it has been found that even though several studies have been conducted concerning most NPI, information is scarce for others.

Application and Development of Molecularly Imprinted Polymer to Solid Phase Extraction

2013 ◽  
Vol 781-784 ◽  
pp. 1359-1365 ◽  
Author(s):  
Yin Zhe Jin ◽  
Yun Zhe Jin ◽  
Ji Yu Piao ◽  
Ying Shan Jin ◽  
Yong Hao Xuan
Keyword(s):  
Solid Phase Extraction ◽  
Solid Phase ◽  
Specific Binding ◽  
Low Cost ◽  
Enzyme Mechanism ◽  
Phase Extraction ◽  
Imprinted Polymer ◽  
Reliable Technique ◽  
Molecularly Imprinted ◽  
Natural Substances

Recently, molecularly imprinted solid phase extraction (MISPE) has been used more frequently separate drugs and natural substances. This modern separation methodologies require reliable tools that perform on a high level in terms of efficiency and reproducibility. The molecular imprinting technique is a reliable technique for the preparation of materials of predetermined selectivity. It is highly significant in research of the structure of enzyme, mechanism of receptor-antibody and analytical chemistry. Solid phase extraction can be used to isolate and pre-concentrate the analytes in complex samples. This technique is more rapid, simple, economical and environment-friendly than the traditional liquid-liquid extraction. The materials used in SPE are usually based on the non-specific binding of the targets, which often suffers some shortcomings, such as low specificity and selectivity. In recent years, solid phase extraction involving molecular imprinted polymer have been proved to be successful applications for its features of high selectivity, ease of synthesis, low cost for preparation and workability under different conditions especially that of harsh pH and organic solvents. In this work, the principles, application and development tends of MISPE will be reviewed and the disadvantages and limitation of the MISPE and future development direction are also briefly discussed.

scholarly journals Smartphone-Based NFC Potentiostat for Wireless Electrochemical Sensing

2021 ◽  
Vol 11 (1) ◽  
pp. 392
Author(s):  
Karnpimon Krorakai ◽  
Supannika Klangphukhiew ◽  
Sirinan Kulchat ◽  
Rina Patramanon
Keyword(s):  
Cyclic Voltammetry ◽  
Point Of Care ◽  
Low Cost ◽  
Near Field ◽  
Electrochemical Techniques ◽  
Electrochemical Sensing ◽  
Voltage Range ◽  
Resource Limited ◽  
Electrochemical Devices ◽  
User Friendly

Most electrochemical sensing requires affordable, portable and easy-to-use electrochemical devices for use in point-of-care testing and resource-limited settings. This work presents the design and evaluates the analytical performance of a near-field communication (NFC) potentiostat, a flat card-sized electrochemical device containing a microchip for electrical analysis and an NFC antenna for smartphone connection. The NFC interface is a wireless connection between the microchip and smartphone to simplify measuring units and make the potentiostat into a passive operated device, running without a battery. The proposed potentiostat can perform the common electrochemical techniques including cyclic voltammetry and chronoamperometry with a current range and voltage range of ±20 µA and ±0.8 V. The performance of the NFC potentiostat is compared to a commercial benchtop potentiostat using ferricyanide as a standard solution. The results show that the NFC potentiostat is comparable to a commercial benchtop potentiostat for both cyclic voltammetry and chronoamperometry measurements. The application of the proposed potentiostat is demonstrated by measuring ascorbic acid concentration. As described, the NFC potentiostat, which is compatible with a smartphone, is low-cost, small in size and user-friendly. Thus, the device can be developed for on-site measurement to apply in various fields.

scholarly journals Multiplex Solid-Phase RPA Coupled CRISPR-Based Visual Detection of SARS-CoV-2

2021 ◽  
Author(s):  
Xiaochen Qin ◽  
Yuyuan Zhou ◽  
Ratul Paul ◽  
Yue Wu ◽  
Yaling Liu
Keyword(s):  
Solid Phase ◽  
Dna Detection ◽  
Point Of Care ◽  
Low Cost ◽  
Control Sample ◽  
Virus Detection ◽  
Cost Effective ◽  
Analytical Sensitivity ◽  
One Pot ◽  
Hpv Dna

COVID-19 has challenged the world's public health and led to over 4.5 million deaths. A rapid, sensitive, and cost-effective point-of-care virus detection device is crucial to the control and surveillance of the contagious severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic. Here we demonstrate a solid phase isothermal recombinase polymerase amplification coupled CRISPR-based (spRPA-CRISPR) assay for on-chip multiplexed, sensitive, and visual COVID-19 DNA detection. By targeting the SARS-CoV-2 structure protein encoded genomes, two specific genes were simultaneously detected with the control sample without cross-interaction with other sequences. The endpoint signal can be directly visualized for rapid detection of COVID-19. The amplified target sequences were immobilized on the one-pot device surface and detected using the mixed Cas12a-crRNA collateral cleavage of reporter released fluorescent signal when specific genes were recognized. The system was tested with samples of a broad range of concentrations (20 to 2x105 copies) and showed analytical sensitivity down to 20 copies per reaction. Furthermore, a low-cost LED UV flashlight (~$12) was used to provide a visible SARS-CoV-2 detection signal of the spRPA-CRISPR assay which could be purchased online easily. Thus, our platform provides a sensitive and easy-to-read multiplexed gene detection method with the capacity to specifically identify low concentration genes. Similar CRISPR biosensor chips can support a broad range of applications such as HPV DNA detection, influenza SARS-CoV-2 multiplex detection, and other infectious disease testing assays.

scholarly journals Bioluminescent Binding Microassay Using Aptamers as Biospecific Elements

2019 ◽  
pp. 244-252 ◽  
Author(s):  
Ludmila A. Frank ◽  
Eugenia E. Bashmakova ◽  
Natalia S. Goncharova ◽  
Vasilisa V. Krasitskaya
Keyword(s):  
Solid Phase ◽  
Specific Binding ◽  
High Specificity ◽  
Base Sequences ◽  
Highly Sensitive ◽  
Target Molecules ◽  
Oligonucleotide Library ◽  
Analytical System ◽  
Solid Phase Assay ◽  
Highly Sensitive Detection

High specificity is an important requirement for an analytical system aimed at identifying a specific molecular target. Traditionally, antibodies, haptens and some other molecules are used for this purpose. Recently, aptamers were proposed as biospecific elements. Aptamers are short single-stranded oligonucleotides with a unique spatial structure that enables them to recognize target molecules and bind to them. Aptamers are obtained from synthetic random DNA(RNA)-libraries, a pool of oligonucleotides of the same length with different base sequences (1014-1015 variants), by selecting the oligonucleotides that are capable of specific binding to a given target. Aptamers are stable molecules with high affinity and specificity; they can be developed for any target, including toxic and nonimmunogenic ones; and they can be easily synthesized chemically. Due to these useful qualities, aptamers are often considered to be an alternative to antibodies. This paper describes the use of aptamer sensors and a highly sensitive bioluminescent reporter, the Ca2+-regulated photoprotein obelin, for the detection of diagnostically important targets in the blood of patients. Additionally, obelin was successfully applied as a reporter in the process of obtaining aptamers. A proposed bioluminescent solid-phase assay enables the enrichment of the oligonucleotide library with target-specific oligonucleotides to be monitored rapidly, the affinity of individual aptamers and their shortened variants to be evaluated and the relative position of the aptamers on the target molecule to be determined. The results of the studies reviewed in this paper open promising avenues for developing analytical systems that include highly specific aptamer sensing, as well as highly sensitive detection based on bioluminescent reporter proteins

scholarly journals Loop-Mediated Isothermal Amplification (LAMP) for the Diagnosis of Zika Virus: A Review

Viruses ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 19 ◽  
Author(s):  
Severino Jefferson Ribeiro da Silva ◽  
Keith Pardee ◽  
Lindomar Pena
Keyword(s):  
Zika Virus ◽  
Molecular System ◽  
Point Of Care ◽  
Low Cost ◽  
Quantitative Polymerase Chain Reaction ◽  
High Specificity ◽  
Isothermal Amplification ◽  
Loop Mediated Isothermal Amplification ◽  
Freeze Dried ◽  
Polymerase Chain

The recent outbreak of Zika virus (ZIKV) in the Americas and its devastating developmental and neurological manifestations has prompted the development of field-based diagnostics that are rapid, reliable, handheld, specific, sensitive, and inexpensive. The gold standard molecular method for lab-based diagnosis of ZIKV, from either patient samples or insect vectors, is reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The method, however, is costly and requires lab-based equipment and expertise, which severely limits its use as a point-of-care (POC) tool in resource-poor settings. Moreover, given the lack of antivirals or approved vaccines for ZIKV infection, a POC diagnostic test is urgently needed for the early detection of new outbreaks and to adequately manage patients. Loop-mediated isothermal amplification (LAMP) is a compelling alternative to RT-qPCR for ZIKV and other arboviruses. This low-cost molecular system can be freeze-dried for distribution and exhibits high specificity, sensitivity, and efficiency. A growing body of evidence suggests that LAMP assays can provide greater accessibility to much-needed diagnostics for ZIKV infections, especially in developing countries where the ZIKV is now endemic. This review summarizes the different LAMP methods that have been developed for the virus and summarizes their features, advantages, and limitations.

scholarly journals SAM Composition and Electrode Roughness Affect Performance of a DNA Biosensor for Antibiotic Resistance

Biosensors ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 22 ◽  
Author(s):  
Adrian Butterworth ◽  
Elizabeth Blues ◽  
Paul Williamson ◽  
Milovan Cardona ◽  
Louise Gray ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Target Gene ◽  
Gene Sequence ◽  
Point Of Care ◽  
Low Cost ◽  
Self Assembled Monolayer ◽  
Electrode Surfaces ◽  
Recognition Elements ◽  
Target Gene Sequence ◽  
Electrode Selection

Antibiotic resistance is a growing concern in the treatment of infectious disease worldwide. Point-of-care (PoC) assays which rapidly identify antibiotic resistance in a sample will allow for immediate targeted therapy which improves patient outcomes and helps maintain the effectiveness of current antibiotic stockpiles. Electrochemical assays offer many benefits, but translation from a benchtop measurement system to low-cost portable electrodes can be challenging. Using electrochemical and physical techniques, this study examines how different electrode surfaces and bio-recognition elements, i.e. the self-assembled monolayer (SAM), affect the performance of a biosensor measuring the hybridisation of a probe for antibiotic resistance to a target gene sequence in solution. We evaluate several commercially available electrodes which could be suitable for PoC testing with different SAM layers and show that electrode selection also plays an important role in overall biosensor performance.

scholarly journals A Complete Protocol for Rapid and Low-Cost Fabrication of Polymer Microfluidic Chips Containing Three-Dimensional Microstructures Used in Point-of-Care Devices

Micromachines ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 624 ◽  
Author(s):  
Trieu Nguyen ◽  
Aaydha Chidambara Vinayaka ◽  
Dang Duong Bang ◽  
Anders Wolff
Keyword(s):  
Salmonella Enteritidis ◽  
Solid Phase ◽  
Point Of Care ◽  
Low Cost ◽  
Three Dimensional ◽  
Diagnostic Methods ◽  
Molecular Diagnostic ◽  
Microfluidic Chips ◽  
Industrial Companies ◽  
Polymerase Chain

This protocol provides insights into the rapid, low-cost, and largescale fabrication of polymer microfluidic chips containing three-dimensional microstructures used in point-of-care devices for applications such as detection of pathogens via molecular diagnostic methods. The details of the fabrication methods are described in this paper. This study offers suggestions for researchers and experimentalists, both at university laboratories and in industrial companies, to prevent doom fabrication issues. For a demonstration of bio-application in point-of-care testing, the 3D microarrays fabricated are then employed in multiplexed detection of Salmonella (Salmonella Typhimurium and Salmonella Enteritidis), based on a molecular detection technique called solid-phase polymerase chain reaction (SP-PCR).

scholarly journals Rapid and Sensitive Point of Care Detection of MRSA Genomic DNA by Nanoelectrokinetic Sensors

Chemosensors ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 97
Author(s):  
Rania Oueslati ◽  
Yu Jiang ◽  
Jiangang Chen ◽  
Jayne Wu
Keyword(s):  
Genomic Dna ◽  
Point Of Care ◽  
Low Cost ◽  
High Sensitivity ◽  
High Specificity ◽  
Hybridization Chain Reaction ◽  
Sensor Surface ◽  
Ac Electrokinetics ◽  
Interdigitated Microelectrodes ◽  
Nanostructured Sensor

Biosensors have shown great potential in realizing rapid, low cost, and portable on-site detection for diseases. This work reports the development of a new bioelectronic sensor called AC electrokinetics-based capacitive (ABC) biosensor, for the detection of genomic DNA (gDNA) of methicillin-resistant Staphylococcus aureus (MRSA). The ABC sensor is based on interdigitated microelectrodes biofunctionalized with oligonucleotide probes. It uses a special AC signal for direct capacitive monitoring of topological change on nanostructured sensor surface, which simultaneously induces dielectrophoretic enrichment of target gDNAs. As a result, rapid and specific detection of gDNA/probe hybridization can be realized with high sensitivity. It requires no signal amplification such as labeling, hybridization chain reaction, or nucleic acid sequence-based amplification. This method involves only simple sample preparation. After optimization of nanostructured sensor surface and signal processing, the ABC sensor demonstrated fast turnaround of results (~10 s detection), excellent sensitivity (a detection limit of 4.7 DNA copies/µL MRSA gDNA), and high specificity, suitable for point of care diagnosis. As a bioelectronic sensor, the developed ABC sensors can be easily adapted for detections of other infectious agents.

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