Detection Assays and Techniques Against COVID-19
Hanadi Talal Ahmedah, Muhammad Riaz, Sagheer Ahmed, Marius Alexandru Moga in The Covid-19 Pandemic, 2023
A technique known as microfluidics is employed to get exact control and a perfect way to handle the microscale fluids. The basic units under operation for transferring through analysis on the microchip are preparation, extraction, reaction, and detection. By employing the micromachining method, small to moderate type routes having fluid, detectors, pumps, valves, checkpoints with various stages are possible for construction to a silicon surface, polymers, metals, and other substances. Till now, microfluidic media have been employed by various techniques analytically involving fluorescence analysis, MS, chemiluminescence, and electrochemical analysis. Platforms of microfluidic might be divided into pressure-driven, capillary, acoustic, centrifugal, and electro-kinetic methods regarding their liquid propulsion laws. During the ancient times, these bio-sensors were manufactured to diagnose different diseases. Such ailments have been commonly detected through bacteria (such as E. coli, S. agal), pathogens that are foodborne (like listeria, cholera toxin, salmonella), and the viruses (like dengue virus, influenza, hepatitis C). For instance, an extreme horizontal shaped surface wave of acoustic biosensors was manufactured to diagnose anti-gp41 and anti-p24 antibodies of HIV [122].
Emerging Nanotechnology-Enabled Approaches to Mitigate COVID-19 Pandemic
Devarajan Thangadurai, Saher Islam, Charles Oluwaseun Adetunji in Viral and Antiviral Nanomaterials, 2022
Microfluidic devices are another PoC testing-based approach (Syedmoradi et al. 2017). Microfluidic devices are tiny chips containing small channels and reaction cavities, such as poly-dimethyl sulfoxide, paper, or glass. They require only a small amount of sample and detection time (Gupta et al. 2020). These microfluidic devices or chips work on the principal of electrokinetic and capillary action to segregate liquid samples (Bhalla et al. 2020). In a recent study, the microfluidic devices were modified by employing the smartphone application, resulting in much faster diagnosis of various sexually transmitted viral infections with sensitivity and specificity of 100%, and 87%, respectively (Zhang and Liu 2016). In another study, a highly throughput microfluidic device was developed that was able to access the level of IgG and IgM antibodies against four different antigenic proteins of SARS-CoV-2 with 95% sensitivity and 91% specificity. It was further demonstrated that both of the parameters were enhanced up to 100% when the human sera was collected from the 3rd week of symptom onset. Further research is needed to develop new microfluidic devices to diagnose COVID-19.
Diagnosis: Nanosensors in Diagnosis and Medical Monitoring
Harry F. Tibbals in Medical Nanotechnology and Nanomedicine, 2017
The contact angle of a droplet of solution on a surface is a measure of the surface tension of the liquid and the affinity between the molecules of the liquid and the surface. This affinity can be biased by the application of an electric potential difference between a surface and a droplet, a phenomenon known as electrowetting. When a droplet of electrolyte is in contact with a hydrophobic polarizable material, applying an electronic potential can switch the surface from hydrophobic to hydrophilic and back [242-244]. This phenomenon can be used to manipulate droplets and control fluid flow electronically or optically on surfaces, giving a way to design microfluidic devices with electrodes beneath a layer of hydrophobic conducting material to define channels and holding areas for droplets. With suitable droplet formation devices, no material confinement of the fluid is necessary—the entire fluid flow is controlled on the surface by electronics. This opens the way for greatly simplified and cheaper reusable or disposable microfludic devices. All of the electrokinetic dielectrophoretic and electroosmotic mixing techniques are applicable to surface-suspended droplet microfluidics.
Critical design parameters to develop biomimetic organ-on-a-chip models for the evaluation of the safety and efficacy of nanoparticles
Published in Expert Opinion on Drug Delivery, 2023
Mahmoud Abdelkarim, Luis Perez-Davalos, Yasmin Abdelkader, Amr Abostait, Hagar I. Labouta
Microfluidics is a discipline of science that deals with the flow and manipulation of small volumes of fluid down to picolitres or lower, constrained in dimensions <1000 µm [35]. When the dimensions in a fluidic system are downsized to the microscale, many of the impacts or phenomena observed on the macroscale are no longer valid. For example, gravitational forces become negligible on the microscale as the surface tension dominates the gravity [36]. Fluid flow in microfluidic channels, therefore, behaves differently in which viscous force (the force due to the friction between fluid layers) dominates over inertial force (the resistance to change the motion state; speed, and direction), and a fully laminar flow prevails [37,38]. These characteristics of the microfluidic devices allow the recapitulation of the different micro-cellular systems in the human body [39]. Microfluidics offers many advantages, including the economical use of samples and reagents due to the small volumes of liquids involved, the ability to conduct experiments under highly replicable conditions, and the precise control over the flow. In addition, Microfluidics provides a high surface-to-volume ratio that allows a fast and cost-effective heat and mass transfer, the high Spatio-temporal resolution and high control of variables in the microenvironment such as concentration gradients of nutrients and chemicals, and the ability to integrate different feedback control elements (like sensors and cameras) [39,40].
Unveiling the underpinnings of various non-conventional ELISA variants: a review article
Published in Expert Review of Molecular Diagnostics, 2022
Rajesh Ahirwar, Akanksha Bhattacharya, Saroj Kumar
Microfluidics is a science of designing and fabricating miniaturized devices containing compartments and channels through which fluids can be manipulated and controlled [63]. It presents distinctive advantages, such as faster reaction times, lower sample consumption, greater sensitivity, small dimensions, short diffusion distance, and high surface tension. The need of an automated and miniaturized platform for immunoassays can be met with the microfluidic-based ELISA which may eliminate multiple incubation steps, labor intensive and lengthy procedure, and the inefficient mass transport issue (diffusion of immuno-reagents to the solid surface) of the conventional ELISA [26,27]. Microfluidic systems fabricated by micro electromechanical systems technology, referred to as lab-on-a-chip, biochips, or micro-total-analysis-system can perform the entire protocol of an assay on a small chip, which is otherwise traditionally performed in a laboratory (Table 1) [64]. Many studies have described immunoassays in microfluidic devices using 5–10 µL sample/reagent, achieving assay outcome in few hours to 15–20 min using detection methods based on color, fluorescence, or surface Plasmon resonance [65]. The microfluidic- ELISA can be performed in different assay formats using conventional pair of antigens-antibodies. A variety of materials such as paper, silicon, glass, and polymers are reported for fabricating microfluidic-ELISA devices [64].
A platform-agnostic, function first-based antibody discovery strategy using plasmid-free mammalian expression of antibodies
Published in mAbs, 2021
Ruijun Zhang, Ponraj Prabakaran, Xiaocong Yu, Brian C. Mackness, Ekaterina Boudanova, Joern Hopke, Jose Sancho, Jacqueline Saleh, HyunSuk Cho, Ningning Zhang, Helene Simonds-Mannes, Samuel D. Stimple, Dietmar Hoffmann, Anna Park, Partha S. Chowdhury, Sambasiva P. Rao
For antibody discovery, display methodologies and single B-cell selection approaches are widely used and complement the conventional hybridoma method.1,2 Microfluidics is an evolving technology that is also gaining traction and being developed by investigators both in academia and the biopharmaceutical industries.30 Despite these impressive advancements, a lingering problem that continues to plague the field is the inability to retrieve VH/VL cognate pairs efficiently26,30 and the lack of strategies that enable identification of the desired hits in the final format from the beginning of the discovery process.26,31 More importantly, the expression of the cognate VH and VL chains for activity screening is a bottleneck, requiring time-consuming, and sometimes cost-prohibitive, plasmid construction and high throughput functional screening. In this study, we addressed this important issue and created plasmid-free DNA expression cassettes (LECs) of antigen-specific cognate VH/VL gene fragments isolated by either single B-cell cloning or phage library panning. We expressed the LECs to obtain rmAbs in quantities sufficient to screen for binding and high-throughput functional screening. This entire process was relatively fast and could be completed within 10 days (Figure 2).
Related Knowledge Centers
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