Sensors & diagnostics最新文献

We report the synthesis and characterization of two new molecules based on the N-annulated perylene diimide (PDIN-H) dye, modified with an octyl sulfide or octyl sulfone group. The octyl sulfone group increases electron affinity of the PDI core for higher sensitivity to amine detection in both solution and film, which was validated by using a flexible electronic sensing platform towards n-butylamine detection.

Fluorescence imaging along with a wide range of fluorescence detection methodologies enables the visualization of macromolecular dynamics in clinical diagnostics and fundamental biomedical research. However, multiplexed fluorescence-based detection has hitherto been largely limited by the overlap of the emission spectra of fluorophores, which only with four or five fluorochrome dyes enable simultaneous use. Fluorescent barcodes with high resolution and high throughput have emerged as a versatile biosensor platform for multianalyte analysis via fine control of fluorescence proportional types, spatial geometries, specific fluorescence properties, and time dimensions. Fluorescence imaging of RNA enables the visualization of physiological and pathological processes at the subcellular level, which is highly important for biomedical diagnostics and therapies and has made tremendous progress toward understanding the complexity of biological systems. In this review, we provide the design and development of fluorescence coding techniques for multiplexed bioanalysis detection and then discuss their applications in RNA biosensors. Additionally, associated challenges in the field and potential solutions will be discussed. Overall, we hope this review will inspire researchers and pave the way for the future design of fluorescent biosensors.

In view of the worldwide impact of SARS-CoV-2, developing rapid and accurate ELISA-based methods for detecting SARS-CoV-2 is of great importance for diagnosing and controlling coronavirus disease 2019. Herein, we report highly stable and fluorescently bright Si–rhodamine analogues with obviously improved Stokes shifts for IgG antibody labelling. These new fluorescent dye labels provide a promising fluorescence tool for SARS-Cov-2 detection.

Modified synthetic peptides have emerged as an exciting avenue for enhancing therapeutic efficacy and expanding the scope of applications in various disease contexts. Indeed, the inherent tunability of synthetic peptides has facilitated the creation of highly selective and responsive sensors capable of detecting specific analytes with precision. More recently, their unique structural diversity and chemical versatility has been elegantly adapted for use in supramolecular sensing platforms. This Perspective article highlights the synergistic interplay between modified synthetic peptides, therapeutic applications, and the sensing technologies that underscore the interdisciplinary nature of contemporary chemistry.

Fluoride is a vital trace mineral for healthy bones and teeth, but a higher intake can lead to nephrolithiasis, dental/skeletal fluorosis, etc. Many dry regions worldwide contain higher fluoride than the WHO permissible limit of 1.5 ppm, necessitating a simple fluoride detection protocol. We adopted a fluoride-triggered desilylation strategy, which releases a sensitizer and enhances Tb³⁺ luminescence in a TbCh gel matrix. Under the optimized assaying conditions, the pro-sensitizer exhibited a selective response with a detection limit of 27 ppb, well below the WHO permissible limit. We also immobilized the gels on paper discs to detect fluoride from real-life samples (e.g., toothpaste, groundwater), and the results were validated using the standard ISE method. The promising results suggest nonexpert users adapting the protocol in resource-limited areas to provide quality control analysis.

Tomatoes (Solanum lycopersicum), a high-value crop, exhibit a unique relationship with salt, where increased levels of NaCl can enhance flavor, aroma and nutritional quality but can cause oxidative damage and reduce yields. A drive for larger, better-looking tomatoes has reduced the importance of salt sensitivity, a concern considering that the sodium content of agricultural land is increasing over time. Currently, there are no simple ways of comparing salt tolerance between plants, where a holistic approach looking at [Na⁺] throughout the plant typically involves destructive, single time point measurements or expensive imaging techniques. Finding methods that collect rapid information in real time could improve the understanding of salt resistance in the field. Here we investigate the uptake of NaCl by tomatoes using TETRIS (Time-resolved Electrochemical Technology for plant Root environment In situ chemical Sensing), a platform used to measure chemical signals in the root area of living plants. Low-cost, screen-printed electrochemical sensors were used to measure changes in salt concentration via electrical impedance measurements, facilitating the monitoring of the uptake of ions by roots. We not only demonstrated differences in the rate of uptake of NaCl between tomato seedlings under different growth conditions, but also showed differences in uptake between varieties of tomato with different NaCl sensitivities and the relatively salt-resistant “wild tomato” (Solanum pimpinellifolium) sister species. Our results suggest that TETRIS could be used to ascertain physiological traits of salt resistance found in adult plants but at the seedling stage of growth. This extrapolation, and the possibility to multiplex and change sensor configuration, could enable high-throughput screening of many hundreds or thousands of mutants or varieties.

Azines are an important class of compounds that display solvent-dependent fluorescence emission depending upon the substituents in the aromatic scaffolds. They are affordable, easy to synthesize, stable, and well-suited for numerous applications. Unlike most other AIE fluorophores, aromatic units of AIE-active azine derivatives are bridged by rotatable N–N bonds rather than C–C bonds. Their derivatives have been widely used in pharmaceuticals, drug delivery, organometallics, optoelectronics, dyes, etc., and most importantly in several sensing applications. This comprehensive review encapsulates the recent developments in the field of AIE-active azine molecules and their applications as chemosensors in the detection of various analytes. The review discusses the different chemosensing strategies involved in the detection of metal ions (Cu²⁺, Zn²⁺, Al³⁺, Fe³⁺, Cr³⁺, Hg²⁺, UO₂²⁺, etc.), anions (F⁻, CN⁻, ClO⁻, ONOO⁻, HSO₃⁻), small molecules (thiols, hydrazine, hydrogen peroxide), and bio-analytes (protamine/heparin, HSA/BSA, neuraminidase, β-lactamase, β-galactosidase, etc.) with a focus on the development in the last five years. The review also highlights the advancements in azine-based systems for their use in imaging, supramolecular host–guest recognitions, AIE polymers, COFs/MOFs, etc.

Plasmonic sensors are candidates for numerous clinical applications, but few examples demonstrate their performance on large sample cohorts, a necessary step for clinical translation. The COVID-19 pandemic provided an unprecedented opportunity to validate a surface plasmon resonance (SPR) sensor for SARS-CoV-2 inhibition with a cohort of over 1000 clinical samples from the longitudinal study of a food and retail worker population. The SPR sensor provided an in vitro model to assess the level of neutralizing antibodies by measuring the inhibition of the SARS-CoV-2 spike protein interaction with ACE-2 following exposure of the spike protein to naive and immune sera (from vaccination and/or infection). In conjunction with population data on vaccination and infection, and epidemiological data from the local jurisdiction of the study cohort, it is shown that the SPR sensor performed well in assessing the level of “pseudo-neutralization” of participant sera and that the response of the SPR sensor correlates (r = 0.74) with a live virus microneutralization assay as well as with metadata of relevant events (vaccination, waves of infection, etc.) that occurred during the study period. Using these data, the article details the challenges and opportunities of using plasmonic sensors in clinical practice.

While pH determination is a commonplace laboratory practice, conventional commercial pH probes exhibit drawbacks of bulkiness, slow response times, and signal drift. These become particularly limiting in specialized fields like tissue engineering and bio-industrial processing, where unique pH probe specifications surpass the capabilities of standard laboratory equipment. Here, we present the development of compact pH fiber probes by integrating silica optical fiber with a colorimetric pH indicator. Our approach involves cross-linking the pH indicator with a biocompatible synthetic hydrogel matrix, facilitating colorimetric and precise pH measurements. Two distinct designs of optical fiber sensors were devised to cater to a broad spectrum of applications. The first design involved attaching the hydrogel sensor to the fiber tip during the photopolymerization process, while the second design was crafted by folding the hydrogel sensor onto the bare terminal of the fiber using the casting process. The fiber sensor exhibited high sensitivity (17 nm pH⁻¹) within physiological and pathophysiological pH ranges (6–8) when tested in reflection configuration. Validation of the developed fiber sensors was carried out on cancerous tissue phantoms derived from an ovine extracellular matrix. The unique specifications of these fiber sensors position them as promising candidates for applications in tissue engineering, cell growth, and continuous blood pH monitoring.

In the rapidly evolving landscape of the internet of things (IoT) and the burgeoning field of biomedical applications, development in human–machine interfaces and human motion monitoring has accentuated the need for real-time pressure sensing. However, the challenge of developing a sensor that combines high sensitivity in the low pressure range with real-time remote sensing capability has remained a significant obstacle in both fields. Herein, a self-powered triboelectric nanogenerator (TENG) based pressure sensor (STEPs) with real-time remote sensing ability is proposed to meet these critical demands, offering high sensitivity in the range of 0–70 mmHg, catering to the needs of human–machine interface and biomedical applications. The STEPs introduces an innovative composite material, blending polydimethylsiloxane (PDMS), carbon black (CB), and polyvinylpyrrolidone (PVP) for improved sensing performance, then this is subjected to ultrasonication and degassing to ensure homogeneous dispersion. The doping of CB and PVP at optimal percentages into the PDMS matrix of the STEPs, together with a unique three-dimensional structure of the sensor, achieves an optimized surface charge density, leading to a high sensitivity 2.61 ± 0.02 mV mmHg⁻¹, as compared with previous works. A wireless measurement and data transfer system, established between a STEPs array for multidirectional pressure sensing and a remote readout device following the Transmission Control Protocol (TCP), further enables real-time remote display of pressure readings. This research underscores the novelty and broad applicability of this sensor, with the potential to revolutionize self-powered wearable sensors in both human–machine interface and biomedical applications.