Miniaturized, high-performance trace gas sensors are critical for environmental, industrial, and medical applications. This paper provides a comprehensive overview of recent achievements in miniaturizing infrared laser spectroscopy gas sensors employing the silicon-based platform and critically compares two converging paths: on-chip waveguide sensing and MEMS-enhanced sensing. We consider device physics, fabrication approaches, and performance metrics to enable comparison across systems. The detection limits of on-chip waveguides, based on evanescent field absorption or refractive index change, have advanced from roughly 102 parts per million (ppm) in early demonstrations to below 1 ppm in sub-cm2 layouts. In comparison, MEMS-enhanced micro-transducers achieve parts per billion (ppb) to parts per trillion (ppt) in millimetre-scale cells. Based on this, we propose future goals that emphasize stability-focused materials, nanoscale lasers, and system-level integration to balance sensitivity, robustness, and manufacturability in next-generation miniaturized gas sensors.

Fluorescent visualization detection has emerged as a powerful strategy for rapid on-site monitoring of environmental pollutants, owing to its simplicity, low cost, and easily distinguishable naked-eye signal output. Among various fluorescent nanomaterials, metal nanoclusters (MNCs) have recently attracted considerable attention as promising candidates for developing naked-eye-visible probes, owing to their structural diversity and tunable properties. In particular, copper nanoclusters (CuNCs) not only exhibit adjustable structural and photophysical characteristics but also offer advantages such as lower cost and higher environmental compatibility compared with precious metal nanoclusters. In this review, we summarize recent advances in the synthesis, structural design, and performance optimization of CuNCs-based fluorescent probes. Particular emphasis is placed on their visualization sensing mechanisms, detection strategies, and practical applications in environmental pollutant monitoring, with a focus on studies reported in the past 5 years. Overall, this review provides both theoretical insights and practical guidance for developing CuNCs-based visualization detection methods, strategies, and applications, with significant implications for enhancing the efficiency and convenience of pollutant monitoring and promoting pollution prevention and control.

Cyclodextrins (CDs) are oligosaccharide macromolecules that occur in native and modified forms. CDs’ nontoxicity, ubiquitous availability, relatively low cost, unique conical structural and physical architecture, and chemical characteristics enable CD host-guest inclusion complexations with diverse guest molecules of analytical, environmental, pharmaceutical, medical, and biomedical interest. In recent years, advances in nanotechnology, optical imaging, and microscopy instrumentation have also facilitated robust CD application in biomedical research and clinical diagnosis. This review highlights and discusses the current trend of applications of CD-sensors for the environmental remediation of forever chemicals and emerging pollutants of public health interest with emphasis on per- and poly-fluoroalkyl substances, heavy metals and metal ions, pharmaceuticals, antibiotics, estrogens, and phenols. The review also highlights the applications of CD-fluorescence sensors in biomedical research, biological sample analysis, drug administration, drug cellular bioavailability, and molecular recognition. Additionally, the review discusses the applications of CD-based fluorescence imaging and microscopy in in vivo tissue analysis, antimicrobial detection, cancer research, and clinical diagnostics. The challenges associated with CD host–guest systems are examined, and the review outlines future prospects, emerging trajectories, and growth opportunities in CD host–guest chemistry.

Near-infrared (NIR) spectroscopy is gaining attention as a rapid, non-invasive diagnostic tool for infectious diseases in both humans and animals. By analyzing how NIR light interacts with biological samples, this technique reveals valuable information about molecular composition and structure. Recent advancements, including the integration of chemometrics and artificial intelligence (AI), have significantly enhanced spectral data interpretation and diagnostic accuracy. The development of portable NIR devices further supports its use in resource-limited settings. Compared to conventional diagnostic methods, NIR offers faster results and the ability to assess multiple biological components simultaneously. However, challenges remain, such as limited sensitivity to trace biomarkers, sample complexity, instrument calibration, environmental influences, and the lack of standardized protocols. Despite these issues, NIR spectroscopy holds strong potential for improving infectious disease diagnosis and monitoring. This review discusses the principles of NIR spectroscopy, its current applications, benefits, technological developments, limitations, and its future role as a practical, low-preparation diagnostic method.

Nuclear resonant vibrational spectroscopy (NRVS) is a synchrotron based modern vibrational spectroscopy starting in mid 1990s. This review article focuses on a series of practical issues presented in NRVS for measuring biological samples. The main sections (Sec. 2 to Sec. 6) discuss the special problems facing bio-NRVS and the solutions to these problems. The example tasks include obtaining extra incident beam flux, calibrating energies for sectional scans, increasing signal versus reducing background, manipulating and monitoring samples, reducing real sample temperatures, as well as judging the best spectral simulation(s). All these are critical for successful measurement and understand of a bio-NRVS spectrum, especially of the one with extremely weak feature(s), e.g. the iron-hydride vibrational mode(s) inside various hydrogenases. This article will especially be useful as an overall guide for NRVS users, beamline scientists, and biochemists to work together on the entangled multiple discipline problems facing bio-NRVS. It will also provide general enlightenment for other spectroscopists to fight entangled issues in their measurements. In addition, Sec. 7 provides the readers with information about the latest developments and enlightenments about the future research while Sec. 1 provides a simple but still explanatory introduction for NRVS beginners.

Arsenic (As) is a significant contaminant in water. Natural processes such as weathering and geological activities potentially result in As contamination. Mining, industrial, and agricultural activities have been the leading anthropogenic causes of As in water. To comprehend the toxicity of As, speciation studies are essential, which facilitate identifying species responsible for debilitating humans’ health. Detection methods for As and its species have evolved from colorimetric techniques to contemporary spectroscopic methods such as atomic absorption spectroscopy, inductively coupled plasma–mass spectroscopy (ICP–MS), hydride generation atomic absorption spectroscopy (HG–AAS), atomic fluorescence spectroscopy (AFS), X-ray photoelectron spectroscopy, and even electrospray ionization mass spectroscopy (ESI–MS). Hyphenating methods with high performance liquid chromatography (HPLC) has drastically improved As speciation. The ICP–MS has emerged as the best method, boasting exceptional sensitivity, and overcoming interference. The present review has elucidated different spectroscopic methods for As detection and speciation in water samples with focus on increasing sensitivity. Researchers should therefore improve on the common interferences when integrating spectroscopic methods with chromatography to enhance accuracy. Additionally, innovative in-situ and remote-sensing techniques for continuous As speciation should be investigated further to maintain sample integrity and reduction in labor and time needed to generate data.

Laser ablation (LA) combined with inductively coupled plasma mass spectrometry has become a widely applied technique for spatially resolved elemental and isotopic analysis of solid materials. The reliability of this approach strongly depends on the properties of the ablation-generated aerosol, including its particle size distribution (PSD), morphology, and chemical composition. These factors affect aerosol transport, ionization efficiency, signal stability, and the extent of elemental fractionation. While numerous reviews have addressed the mechanisms of laser-matter interaction, no comprehensive publication has systematically evaluated the methodologies available for characterizing the aerosol itself. This review fills this gap by summarizing current understanding of aerosol formation and by discussing how experimental conditions – such as laser pulse duration, wavelength, fluence, ablation mode, spot size, sample matrix, surface treatment, and carrier gas – influence particle generation. A comparative overview of experimental studies is provided, along with a critical evaluation of the analytical techniques used for aerosol characterization. Both online approaches, which can provide real-time information, and offline approaches, which allow for detailed morphological and compositional analysis, are explored. By integrating these perspectives, the review offers unique guidance for selecting appropriate strategies to study aerosol properties and for optimizing LA protocols toward improved accuracy, reproducibility, and interpretation of analytical results.

Lung cancer has one of the highest mortality rates in oncological patients worldwide, despite the fact that various possible therapeutic approaches, including molecularly targeted therapies and immunotherapies, have been used in clinical practice. Therefore, efforts continue to be made to improve lung cancer screening, qualification for therapy, and estimation of treatment efficacy. The implementation of new noninvasive tools, either for lung cancer detection or for making treatment decisions, seems crucial to achieving this purpose. Despite many studies focusing on monitoring the molecular landscape using sequencing techniques, more cost-effective and high-throughput methods are also being sought. This review summarizes the possibilities of implementing vibrational spectroscopic methods in clinical practice. We have highlighted the key aspects of Fourier transform infrared (FTIR) and Raman spectroscopy in clinical applications, including their advantages, limitations, and notable differences between these techniques. We also discussed the potential applicability of biofluids, such as blood, serum, and sputum, and explained key pre-analytical factors in preparing these materials for spectroscopic analysis. Moreover, we highlight crucial vibrational frequencies for lung cancer screening, staging, subtyping, differentiation among other solid tumors, and prediction of the treatment outcomes, summarizing their proposed biochemical interpretation.

Urine provides a noninvasive window into the renal and lymphatic systems, providing molecules (potential markers) from around the body that are detectable using mid-range Fourier transform infrared spectroscopy (MR-FTIR). The benefit of MR-FTIR for urine analysis is the simultaneous sampling of many of the 3000+ urine constituents. The highly condensed spectral information in a single drop of urine potentially provides simpler, faster, and cheaper tests for multiple pathologies in a single test, providing hope for simultaneous testing of different pathologies. The shortage of pathologists in the UK and medical experts worldwide motivates research to improve medical diagnostic technologies, increasing interest in techniques like MR-FTIR urine analysis. Clinical MR-FTIR urine analysis is ideally positioned for review, niche enough for an exhaustive progress report, whilst developed enough to highlight challenges and suitable comparison to current approaches. Before clinical spectroscopy can help patients, clinical validation must be demonstrated. The review highlights milestones toward this goal, like replicated or blinded studies. A section is then dedicated to the experimental considerations already investigated, providing a resource for future FTIR urine analysis study design. The paper concludes by testing a critical variable for transmission MR-FTIR spectroscopy, identified by assessment of reviewed references, discussed in only one, urea hydrogen bonding with H2O, emphasizing the importance of robust dehydration protocols for urine MR-FTIR analysis. Academic and industrial collaborators separately duplicated the experiments, increasing confidence in the analysis repeatability and corresponding clinical value of the findings.