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Date Added: Jan 27, 2022
Date Added: Jan 27, 2022
We introduce a practically generic approach for the generation of epitope-imprinted polymer-based microarrays for protein recognition on surface plasmon resonance imaging (SPRi) chips. The SPRi platform allows the subsequent rapid screening of target binding kinetics in a multiplexed and label-free manner. The versatility of such microarrays, both as synthetic and screening platform, is demonstrated through developing highly affine molecularly imprinted polymers (MIPs) for the recognition of the receptor binding domain (RBD) of SARS-CoV-2 spike protein. A characteristic nonapeptide GFNCYFPLQ from the RBD and other control peptides were microspotted onto gold SPRi chips followed by the electrosynthesis of a polyscopoletin nanofilm to generate in one step MIP arrays. A single chip screening of essential synthesis parameters, including the surface density of the template peptide and its sequence led to MIPs with dissociation constants (KD) in the lower nanomolar range for RBD, which exceeds the affinity of RBD for its natural target, angiotensin-convertase 2 enzyme. Remarkably, the same MIPs bound SARS-CoV-2 virus like particles with even higher affinity along with excellent discrimination of influenza A (H3N2) virus. While MIPs prepared with a truncated heptapeptide template GFNCYFP showed only a slightly decreased affinity for RBD, a single mismatch in the amino acid sequence of the template, i.e. the substitution of the central cysteine with a serine, fully suppressed the RBD binding.
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2
Date Added: Jan 2, 2022
Date Added: Jan 2, 2022
Saliva is increasingly recognised as an attractive diagnostic fluid. The presence of various disease signalling salivary biomarkers that accurately reflect normal and disease states in humans and the sampling benefits compared to blood sampling are some of the reasons for this recognition. This explains the burgeoning research field in assay developments and technological advancements for the detection of various salivary biomarkers to improve clinical diagnosis, management, and treatment. This paper reviews the significance of salivary biomarkers for clinical diagnosis and therapeutic applications, with focus on the technologies and biosensing platforms that have been reported for screening these biomarkers.
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4
Date Added: Jan 19, 2022
Date Added: Jan 19, 2022
Rapid diagnosis and screening of diseases have become increasingly important in predictive and preventive medicine as they improve patient treatment strategies and reduce cost as well as burden on our healthcare system. In this regard, wearable devices are emerging as effective and reliable point-of-care diagnostics that can allow users to monitor their health at home. These wrist-worn, head-mounted, smart-textile, or smart-patches devices can offer valuable information on the conditions of patients as a non-invasive form of monitoring. However, they are significantly limited in monitoring physiological signals and biomechanics, and, mostly, rely on the physical attributes. Recently, developed wearable devices utilize body fluids, such as sweat, saliva, or skin interstitial fluid, and electrochemical interactions to allow continuous physiological condition and disease monitoring for users. Among them, tear fluid has been widely utilized in the investigation of ocular diseases, diabetes, and even cancers, because of its easy accessibility, lower complexity, and minimal invasiveness. By determining the concentration change of analytes within the tear fluid, it would be possible to identify disease progression and allow patient-oriented therapies. Considering the emerging trend of tear-based biosensing technology, this review article aims to focus on an overview of the tear fluid as a detection medium for certain diseases, such as ocular disorders, diabetes, and cancer. In addition, the rise and application of minimally invasive detection and monitoring via integrated contact lens biosensors will also be addressed, in regards to their practicality and current developmental progress.
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3
Date Added: Jan 8, 2022
Date Added: Jan 8, 2022
Wound management involves repeated clinical trips and procedures of lab tests over days. To eliminate this time lag and provide real-time monitoring of a wound’s progress, we have designed an enzymatic biosensor for determining uric acid (UA) in wound fluid. Uric Acid is a biomarker, having an established correlation with wounds and their healing. This electrochemical biosensor comprises enzyme urate oxidase (uricase, UOx) entrapped in a polyvinyl alcohol based cationic polymer for enhanced stability. Results show that the use of a redox electron shuttle, ferrocene carboxylic acid (FCA), enabled electron transfer between the enzyme and the transducer. The immobilized uricase in the polymer matrix provided stable continuous measurements at body temperature for a week with minimal deviation. Detection of uric acid in wound fluid has been determined from volumes as low as 0.5–50μL. Studies from different wound samples have shown an average recovery of 107%. The sensor has been interfaced with LMP91000 potentiostat and controlled by CC2650 microcontroller on a Kapton tape-based miniaturized flexible platform.
3
Date Added: Jan 10, 2022
Date Added: Jan 10, 2022
This review aims to summarize the rapidly emerging field of real-time stress monitoring by focusing on early breakthroughs and critical developments in portable and wearable cortisol sensors. Here, brief, albeit comprehensive, information on technological advances and current state-of-the-art concepts on real-time cortisol sensing are provided. Specific examples where materials include up-to-date information related to complex sensing conditions, and methodologies, are pieced together. Examples of electrochemical cortisol sensing are categorized by sample types, focusing on sensing from body fluids in vitro and wearable sensors, which have attracted significant interest due to their integration with everyday life activity. The overall progress made to date in building such conceptualized efforts for real-time, continuous monitoring of cortisol and the future of the field is discussed.
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2
Date Added: Jan 10, 2022
Date Added: Jan 10, 2022
Direct interfacing of nanosensors onto biomaterials could impact health quality monitoring and adaptive threat detection. Graphene is capable of highly sensitive analyte detection due to its nanoscale nature. Here we show that graphene can be printed onto water-soluble silk. This in turn permits intimate biotransfer of graphene nanosensors onto biomaterials, including tooth enamel. The result is a fully biointerfaced sensing platform, which can be tuned to detect target analytes. For example, via self-assembly of antimicrobial peptides onto graphene, we show bioselective detection of bacteria at single-cell levels. Incorporation of a resonant coil eliminates the need for onboard power and external connections. Combining these elements yields two-tiered interfacing of peptide–graphene nanosensors with biomaterials. In particular, we demonstrate integration onto a tooth for remote monitoring of respiration and bacteria detection in saliva. Overall, this strategy of interfacing graphene nanosensors with biomaterials represents a versatile approach for ubiquitous detection of biochemical targets.
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3
Date Added: Jan 9, 2022
Date Added: Jan 9, 2022
Jargon-minized Summary: A room-temperature biosensor based on the quantum mechanical property of Nitrogen-Vacancy(NV) centers in diamond was used to detect the action potential(AP) signal from mice' hind limb muscles. Specifically, ion flows associated AP signal generates weak current and produces magnetic field, which were detected by the NV centers. Since the experiment was carried out in an unshielded environment, the authors further explored de-noise solutions that could remove background and obtained AP magnetic signal that correlates well with simultaneous probe electrophysiology measurement. Optimistically, the authors believe that this is a step towards non-invasive mapping of the brain neuron signal using diamond quantum sensor. Original Summary: The ability to perform noninvasive and non-contact measurements of electric signals produced by action potentials is essential in biomedicine. A key method to do this is to remotely sense signals by the magnetic field they induce. Existing methods for magnetic field sensing of mammalian tissue, used in techniques such as magnetoencephalography of the brain, require cryogenically cooled superconducting detectors. These have many disadvantages in terms of high cost, flexibility and limited portability as well as poor spatial and temporal resolution. In this work we demonstrate an alternative technique for detecting magnetic fields generated by the current from action potentials in living tissue using nitrogen vacancy centres in diamond. With 50 pT/$$\sqrt{\text {Hz}}$$sensitivity, we show the first measurements of magnetic sensing from mammalian tissue with a diamond sensor using mouse muscle optogenetically activated with blue light. We show these proof of principle measurements can be performed in an ordinary, unshielded lab environment and that the signal can be easily recovered by digital signal processing techniques. Although as yet uncompetitive with probe electrophysiology in terms of sensitivity, we demonstrate the feasibility of sensing action potentials via magnetic field in mammals using a diamond quantum sensor, as a step towards microscopic imaging of electrical activity in a biological sample using nitrogen vacancy centres in diamond.
4
Date Added: Jan 19, 2022
Date Added: Jan 19, 2022
An accurate extraction of physiological and physical signals from human skin is crucial for health monitoring, disease prevention, and treatment. Recent advances in wearable bioelectronics directly embedded to the epidermal surface are a promising solution for future epidermal sensing. However, the existing wearable bioelectronics are susceptible to motion artifacts as they lack proper adhesion and conformal interfacing with the skin during motion. Here, we present ultra-conformal, customizable, and deformable drawn-on-skin electronics, which is robust to motion due to strong adhesion and ultra-conformality of the electronic inks drawn directly on skin. Electronic inks, including conductors, semiconductors, and dielectrics, are drawn on-demand in a freeform manner to develop devices, such as transistors, strain sensors, temperature sensors, heaters, skin hydration sensors, and electrophysiological sensors. Electrophysiological signal monitoring during motion shows drawn-on-skin electronics’ immunity to motion artifacts. Additionally, electrical stimulation based on drawn-on-skin electronics demonstrates accelerated healing of skin wounds.
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3
Date Added: Jan 19, 2022
Date Added: Jan 19, 2022
Efficient and rapid detection of viruses plays an extremely important role in disease prevention, diagnosis, and environmental monitoring. Early screening of viral infection among the population has the potential to combat the spread of infection. However, the traditional methods of virus detection being used currently, such as plate culturing and quantitative RT-PCR, give promising results, but they are time-consuming and require expert analysis and costly equipment and reagents; therefore, they are not affordable by people in low socio-economic groups in developing countries. Further, mass or bulk testing chosen by many governments to tackle the pandemic situation has led to severe shortages of testing kits and reagents and hence are affecting the demand and supply chain drastically. We tried to include all the reported current scenario-based biosensors such as electrochemical, optical, and microfluidics, which have the potential to replace mainstream diagnostic methods and therefore could pave the way to combat COVID-19. Apart from this, we have also provided information on commercially available biosensors for detection of SARS-CoV-2 along with the challenges in development of better diagnostic approaches. It is therefore expected that the content of this review will help researchers to design and develop more sensitive advanced commercial biosensor devices for early diagnosis of viral infection, which can open up avenues for better and more specific therapeutic outcomes.
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