Sensors & diagnostics最新文献

Spermine is a vital biomarker for clinical diagnosis of cancer and estimating food spoilage. Here, supramolecular assemblies of two donor–π–acceptor dipods R-SPM (λ_em 640 nm) and NIR-SPM (λ_em 720 nm) with SDS have been discovered for the detection of spermine and spermidine under physiological conditions at nanomolar levels. The addition of SDS to R-SPM and NIR-SPM results in the formation of self-assemblies (DLS, zeta-potential and UV-vis studies) with no significant change in their fluorescence but further addition of spermine/spermidine to the R-SPM∩SDS and NIR-SPM∩SDS assemblies results in a 30–80 fold increase in fluorescence intensity, respectively at 640 nm and 720 nm. The LOD for spermine and spermidine detection is 22 nM (4.4 ppb) and 67 nM (9.7 ppb). The ensembles show nominal interference from other biogenic amines, amino acids, metal ions, and anions. Both R-SPM∩SDS and NIR-SPM∩SDS ensembles can be stored in the dark for >3 months without affecting their performance. The potential of these ensembles for real world applications like analysis of spermine in urine, human serum and food spoilage in the case of cheese, mushrooms, chicken and mutton has been demonstrated. The smartphone relied RGB analysis facilitates the on-site determination of spermine in food samples.

The electrochemical aptamer-based (EAB) sensor platform is the only molecular monitoring approach yet reported that is (1) real time and effectively continuous, (2) selective enough to deploy in situ in the living body, and (3) independent of the chemical or enzymatic reactivity of its target, rendering it adaptable to a wide range of analytes. These attributes suggest the EAB platform will prove to be an important tool in both biomedical research and clinical practice. To advance this possibility, here we have explored the stability of EAB sensors upon storage, using retention of the target recognizing aptamer, the sensor's signal gain, and the affinity of the aptamer as our performance metrics. Doing so we find that low-temperature (−20 °C) storage is sufficient to preserve sensor functionality for at least six months without the need for exogenous preservatives.

Correction for ‘Highly sensitive solid-state nanopore aptasensor based on target-induced strand displacement for okadaic acid detection from shellfish samples’ by Mohamed Amin Elaguech et al., Sens. Diagn., 2023, 2, 1612–1622, https://doi.org/10.1039/D3SD00199G.

In this report, ion current rectification, an electrochemical phenomenon observed in asymmetric nanopipettes, is used for the label-free detection of SARS-CoV-2 viral fragments in nasopharyngeal samples. Quartz nanopipettes are functionalized with aptamers targeting the spike protein S1 domain, wherein changes to the surface charge magnitude, distribution, and ion transport behavior modulate the current–voltage response upon binding. The aptamer-modified nanopipette provides a selective and sensitive method for detecting SARS-CoV-2, with a limit of detection in the laboratory of 0.05 pg mL⁻¹. The effectiveness of this low-cost platform was demonstrated by sensing SARS-CoV-2 in nasopharyngeal samples, successfully discriminating between positive and negative cases with minimal template preparation, highlighting the platform's potential as a versatile sensing strategy for infectious disease detection in clinical diagnosis.

Breathomics involves the use of non-invasive methods for diagnosing asthma by analyzing exhaled breath. While significant progress has been made in applying this approach to adult asthma, extending its application to pediatric asthma is crucial due to the increasing concern in this population. This review delineates five potential clinical applications: asthma diagnosis, differential diagnosis of asthma, assessment of asthma control levels, prediction of asthma exacerbation, and asthma phenotyping. Additionally, it highlights the moderate to reasonable predictive accuracy of exhaled breath volatile organic compounds (VOCs) breathomics in childhood asthma. However, it acknowledges that this field is still in its nascent stage of development, with particularly limited data available for Asian populations. Moreover, the identification of VOC biomarkers in pediatric asthma patients remains inconclusive, with varying reports. Therefore, large-scale data collection and standardization are imperative. Refinement and methodological improvements are necessary before integrating breathomics into clinical practice. This article provides clear directions for future research to optimize the clinical applicability of breathomics in evaluating asthma in children.

Technological advancements are revolutionizing diabetic care worldwide, particularly in the realm of glucose monitoring. Traditionally invasive and cumbersome, glucose monitoring is shifting towards less invasive methods, enhancing patient quality of life and reducing risks associated with hypo- and hyperglycemia. Wearable biosensors, focusing on sweat and interstitial fluid, offer novel avenues for early disease detection and personalized point-of-care testing. This review paper provides a comprehensive overview of recent strides in wearable sweat sensors, including historical perspectives, electrochemical sensing mechanisms, material advancements, and the role of nanomaterials in enhancing sensor performance. By examining the evolution of glucose monitoring devices and highlighting commercially available devices, the review underscores the wide-ranging utility of electrochemical sensors in glucose monitoring. Enzymatic and non-enzymatic sensing mechanisms, potentiometric, amperometric/voltammetric sensors, ion-selective electrodes, and biosensors are discussed in detail, alongside various materials employed to optimize sensor performance. The burgeoning interest in nanomaterial-enabled sensor platforms signifies a promising future for sweat-based glucose monitoring, with potential implications for personalized healthcare and disease management.

With the coronavirus pandemic, companies and governments around the world have been investing millions of dollars in the development of contactless sensor technologies that minimize the need for physical interactions between patients and healthcare providers. This has led to rapid progress in healthcare research on innovative contactless technologies, particularly for infants and elderly individuals with chronic diseases that require continuous, real-time monitoring and control. The combination of sensing technology and wireless communication has emerged as a promising research area, as patients often find it unpleasant or anxiety-provoking to wear sensor devices, and physical contact can exacerbate the spread of contagious diseases. To address these issues, research has focused on sensor-less or contactless technology to send and analyse wireless signals to remotely monitor and measure vital signs without requiring physical contact or sensor devices. Herein, we have provided a comprehensive survey and study of non-invasive/contactless vital sign monitoring systems, particularly the heart rate and the respiration rate monitoring systems to achieve accurate and reliable measurements. We have found that there is a lack of a comprehensive comparison and analysis over existing contactless vital sign monitoring systems. Therefore, we first present and classify the existing non-invasive monitoring designs based on their approaches and techniques, and then compare them based on the performance and accuracy.

An electrochemical immunoassay for interleukin-6 (IL-6) was developed based on IL-6 capture using magnetic beads and electrochemical signal production using horseradish peroxidase/tetramethylbenzidine. We achieved IL-6 detection from the 50–1000 pg mL⁻¹ range, which is a physiologically relevant IL-6 range for a variety of biological systems. The sandwich assay performed well in phosphate buffered solution as well as in cellular media and human plasma spiked with IL-6, and decreased time to IL-6 concentration readout to approximately one hour. There is also future potential to apply this assay to real-time point-of-care human disease diagnostics.

Contamination of heavy metals in the environment is a burning and contemporary issue of modern life. Whilst lead contamination is historic, the ongoing extensive use of lead in batteries is likely to continue to cause serious environmental problems. Silver ions also present multiple environmental issues, such as bioaccumulation and toxicity. As a result, these two heavy metal ions have a high impact from an environmental and industrial point of view. Thus, the colorimetric and fluorescence detection of these two metal ions has been the subject of intense research during the last decade and pyrene-based fluorophores have played a crucial role in their detection. This review article summarizes the recent chronological progress on pyrene moiety integrated small molecule chemosensors for the colorimetric and fluorescent detection of silver and lead ions. Herein, the different strategies that have been utilized for the recognition of lead and silver ions are discussed. Throughout, the juxtaposition of structural aspects of the chemosensors and their sensitivity has been scrutinized together with an overview and future vision.

Among the currently developed analytical tools, sensors based on fluorescence detection have received immense recognition owing to their high sensitivity, low cost, fast response, and simplicity. The design and synthesis of fluorescence chemosensors to sense metals that are of environmental and biological relevance are of appreciable interest. The efficacy of fluorescent sensors relies on two crucial features: a metal binding unit and a fluorophore that can absorb and emit light. The electronic structure of the sensor is altered upon complexation, leading to a change in light emission or absorption intensity and wavelength. Hydroxypyridinones, a class of N-heterocyclic metal chelators, are appreciated as magnificent chemical tools in metal chelation with a higher affinity towards hard metals, displaying various medical, biological, and industrial applications. However, such compounds are scarcely used as sensors. This article outlines the recent invention of fluorescence chemosensors related to hydroxypyridinone based chelators for the selective sensing of analytes of biological and environmental importance. This discussion involves the structural parameters, coordination mode, and other approaches that helped develop highly selective fluorescence sensors for the ions. In addition, the luminescence properties of the hydroxypyridinones in the energy transfer process of lanthanide chelates as sensitizers are determined.