Sensors & diagnostics最新文献

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.

The introduction of surface-enhanced Raman scattering (SERS) in lateral flow assays (LFA) has been recently exploited to increase the sensitivity and quantification capabilities of these rapid tests. Herein, we took advantage of a SERS–LFA combination to improve LFAs designed to test for P. gingivalis, a biomarker for oral health. We have demonstrated a limit of detection (LOD) < 10 ng mL⁻¹, which is within the range of concentration needed to monitor oral health. By comparison, conventional colorimetric LFAs achieve an LOD ≈ 100 ng mL⁻¹, generating a lower diagnostic sensitivity. To achieve this enhanced sensitivity, we optimized the materials used in the SERS–LFA, investigating nanostars (NS) differing in size and material composition and comparing them to commercial gold nanoparticles, as a benchmark. We found that large (56 nm) NSs with a silver coating were the most sensitive nanomaterials for SERS–LFA. To prove the applicability of this SERS–LFA to point-of-care (POC) settings, we tested the optimized LFA with a portable Raman system prototype designed to work on LFAs with 3D-printed cartridges and a line-shaped laser illumination. Using this prototype, we achieved the same LOD observed with the traditional benchtop Raman system. The use of a portable Raman system has brought the SERS–LFA technology closer to the POC use.

Phosgene (carbonyl dichloride, COCl₂) is an extremely toxic and hazardous chemical warfare agent (CWA; schedule 3 substance) that poses significant threats to public safety and human well-being. Simultaneously, it is a commonly employed reagent in chemical synthesis in laboratories and industrial settings. Therefore, monitoring phosgene concentration levels is essential for handling them within the workplace and for safeguarding public security. Activity-based fluorescent probes are the most effective real-time detection methods currently used for the detection of CWAs. Reaction-based sensing offers excellent temporal and spatial resolution, minimal side effects, and quick response times. Recently, a plethora of reaction-based fluorescent probes have been designed for the detection of phosgene. This review provides an overview of the latest developments using amino-1,8-naphthalimide-based small-molecule fluorescent probes designed for phosgene detection/sensing. Additionally, we investigate the existing challenges and prospects in the field of reaction-based fluorescent probes for phosgene detection. Herein, various fluorescence sensors are categorized based on their reactions with phosgene, and each section highlights the reaction sites, sensing mechanisms, structure–function relationships, photophysical performances, and practical applications of these sensors. It is our aspiration that this review will provide valuable insights into the advancement of cutting-edge fluorescent probes tailored for phosgene detection and sensing.