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Salt marshes provide many important ecosystem services, key among them being carbon sequestration. However, a large degree of uncertainty remains in salt marsh carbon budgets, particularly during colder months of the year when salt marsh microbial and vegetative activity is assumed to dormant. We also lack data on urban systems. In this study, we used an easily portable carbon dioxide sensor package to directly measure net carbon dioxide (CO2) fluxes throughout the winter in a temperate, urban salt marsh. We sampled across the dormant season both on normal (cold) temperature days and on days that were anomalously warm (defined here as air temperatures 2.8°C above the long-term average). We demonstrated that median (±mad) daytime CO2 fluxes doubled on the warm days, compared to cold days (1.7 ± 2 mmol m-2 h-1, 0.7 ± 1.3 mmol m-2 h-1, respectively). We also show that net CO2 emissions scaled with soil temperature. The high day-to-day variability, however, implies that infrequent or sparse measurements cannot sufficiently capture the temporal dynamics of dormant season salt marsh net CO2 fluxes. The magnitude of the net CO2 source from our sampling during the dormant season leads us to hypothesize that, as mean annual temperatures continue to increase, dormant season CO2 emissions from salt marshes will increasingly offset growing season carbon dioxide uptake. This change compromises the carbon sequestration capacity, and therefore the climate mitigation potential of these ecosystems. Future studies should focus on quantifying the impact of dormant season CO2, and other greenhouse gases on salt marsh carbon budgets. [ABSTRACT FROM AUTHOR]

Here, the implementation of a smartphone‐based portable molecularly imprinted photonic crystal hydrogel (MIPCH) colorimetric sensor for the visual and label‐free detection of bisphenol A (BPA) in water samples is reported. The sensor is prepared by photopolymerizing BPA‐added hydrogel precursor solution within the voids of a photonic crystal opal film, followed by the extraction of BPA molecules. Rebinding of the BPA analyte to the MIPCH causes the hydrogel to swell, leading to a significant redshift in the diffracting spectrum. The MIPCH sensor exhibits a low limit of detection of 0.96 × 10−15m. The sensor also shows linear response in the femtomolar range, rapid responsiveness (≤6 min), selective detection of BPA in complex matrices, long‐term stability, and reproducibility. Images of the sensor responses are used to train a deep‐learning‐based regression model on a smartphone to predict the BPA concentration quantitatively. Integration of the regression model with the developed sensor provides an accurate and portable smart sensor platform well‐suited for real‐time and on‐field monitoring of BPA. [ABSTRACT FROM AUTHOR]

The detection of mycotoxins is a worldwide issue given their significant effects on both food safety and human health. The European Union (EU) has implemented various measures to address mycotoxin contamination and regulate their levels in food and feed. Given the high toxicity of mycotoxins, it is essential to develop a sensor that is sensitive, selective, and practical for their detection. The electrochemical sensing platforms emerge as a feasible analytical instrument for tackling specificity and sensitivity concerns, owing to its cost-effectiveness, efficiency, and user-friendly nature. The present review outlines a variety of electrochemical sensing platforms that have been developed in recent years for the detection of mycotoxins. Initially, it provides an overview of electrochemical sensors, both nonenzymatic and enzymatic featuring diverse bioreceptors such as immunosensors, aptasensors, and enzymatic sensors, all geared towards detecting mycotoxins. The subsequent section provides further details on electrochemical sensors that are portable, wireless, and compatible with smartphones. In summary, the review sought to offer valuable perspectives on the existing challenges and prospective advancements in electrochemical sensor technology.

Salt marshes provide many important ecosystem services, key among them being carbon sequestration. However, a large degree of uncertainty remains in salt marsh carbon budgets, particularly during colder months of the year when salt marsh microbial and vegetative activity is assumed to dormant. We also lack data on urban systems. In this study, we used an easily portable carbon dioxide sensor package to directly measure net carbon dioxide (CO2) fluxes throughout the winter in a temperate, urban salt marsh. We sampled across the dormant season both on normal (cold) temperature days and on days that were anomalously warm (defined here as air temperatures 2.8°C above the long-term average). We demonstrated that median (±mad) daytime CO2 fluxes doubled on the warm days, compared to cold days (1.7 ± 2 mmol m−2 h−1, 0.7 ± 1.3 mmol m−2 h−1, respectively). We also show that net CO2 emissions scaled with soil temperature. The high day-to-day variability, however, implies that infrequent or sparse measurements cannot sufficiently capture the temporal dynamics of dormant season salt marsh net CO2 fluxes. The magnitude of the net CO2 source from our sampling during the dormant season leads us to hypothesize that, as mean annual temperatures continue to increase, dormant season CO2 emissions from salt marshes will increasingly offset growing season carbon dioxide uptake. This change compromises the carbon sequestration capacity, and therefore the climate mitigation potential of these ecosystems. Future studies should focus on quantifying the impact of dormant season CO2, and other greenhouse gases on salt marsh carbon budgets.

The technological advancements in sensory systems and robotics over the past decade have facilitated the innovation of centralized systems for optimizing resource utilization and monitoring efficiency in inspection applications. This paper presents a novel system designed for gas concentration sensing in environments by implementing a modular artificial nose (emulating the inhalation and exhalation process) equipped with a strategically designed air capture centralization system based on computational fluid dynamics analysis (CFD). The system incorporates three gas identification sensors distributed within the artificial nose, and their information is processed in real-time through embedded systems. The artificial nose is hardware–software integrated with a quadruped robot capable of traversing the environment to collect samples, maximizing coverage area through its mobility and locomotion capabilities. This integration provides a comprehensive perspective on gas distribution in a specific area, enabling the efficient detection of substances in the surrounding environment. The robotic platform employs a graphical interface for real-time gas concentration data map visualization. System integration is achieved using the Robot Operating System (ROS), leveraging its modularity and flexibility advantages. This innovative robotic approach offers a promising solution for enhanced environmental inspection and monitoring applications. [ABSTRACT FROM AUTHOR]

It is a significant challenge to develop acidity probes suitable for use in extremely acidic conditions, especially to achieve real‐time on‐site detection. In this work, carbon dots (CDs) are synthesized on a gram‐scale under mild conditions using 3‐phenylpropionaldehyde as precursors. The CDs have excellent robustness, showing distinguished anti‐photobleaching and ionic stability. Dramatically, a visual transition of the fluorescent color of CDs from cyan to orange is observed when the concentration of H+ ([H+]) increased under high acidity conditions, owing to the generation of another emission peak in the red‐light region. Taking advantage of the optical properties, CDs are designed as a ratiometric sensing platform for the detection of extreme acidity. Furthermore, the platform for [H+] possesses high selectivity and excellent anti‐interference capability. In extremely acidic wastewater, I595 nm/I480 nm and [H+] maintain a very good linear relationship (R2 = 0.996). Moreover, a smartphone is employed to obtain the red‐green‐blue (RGB) values of the samples to realize hand‐held detection. By measuring the R/G, the platform exhibits ultrasensitive recognition of [H+] in the range of 1–9 mol L−1 with R2 of 0.992. This work paves an avenue for the design of rapid and on‐site CDs based sensors for critical environmental applications. [ABSTRACT FROM AUTHOR]

Efficient and accurate diagnostic methods are important for human health monitoring and prevention of major diseases, so the establishment of efficient and convenient testing methods for clinical diagnosis is urgent. Photoelectrochemical (PEC) biosensors have attracted much attention because of their high sensitivity, low detection background, and especially the advantages of combining photoexcitation and electrochemical detection. With the rapid development of integrated circuit technology many wireless transmissions of highly aggregated portable micro devices are manufactured, its small size, easy to carry, and the ability to visualize the results of the test is shown to be the potential for the application of such devices. This review aims to cover recent advances in PEC biosensing within the field of portable detection, including the principles of PEC biosensors, common photovoltaic materials, and scalable fabrication techniques for portable PEC biosensing. Future prospects in the field are also discussed. [ABSTRACT FROM AUTHOR]

Objective: this study proposes the development of a wireless graphical interface with a monitoring system that allows for extensive integration with a variety of non-invasive devices. Method: an evaluation framework was created using ISO/IEC25012 parameters to evaluate each of the physiological parameters. Using an ISO standard as a framework to evaluate the quality of the results and analysis parameters such as consistency, accessibility, compressibility, and others, the Cayenne myDevices platform is used to develop a variety of IoT projects. Results: the successful prototype shows that the temperature sensor's technical capabilities were found to be insufficient for accurately measuring a human's body temperature, requiring a calibration algorithm. The Cayenne myDevices platform provides a web dashboard for continuous tracking and storage of physiological data. Blynk, an IoT-based application with a graphical user interface, enables real-time visualization and tracking of data from the server and the electronic prototype. Conclusion: findings concluded that free software tools such as Cayenne myDevices, the Blynk App, and Arduino enable integration and reduce the need for expensive applications. Electronic prototypes monitor parameters (e.g., temperature, heart rate, oxygen saturation) were used to monitor COVID-19, cardiovascular, and diabetic patients during exercise. Successful prototypes used Max30100, Mlx90614 sensors, and Esp8266 microcontroller. To avoid giving the patient inaccurate results, the instruments must be carefully selected, so they were assessed to ensure a 95% effectiveness level. [ABSTRACT FROM AUTHOR]

To perform on-site bacterial testing at food and pharmaceutical manufacturing sites, it is desired to develop a new method that can quickly measure the number of viable bacterial cells. We have succeeded in measuring the number of viable bacteria using small and inexpensive disposable electrode chips focusing on electrochemical methods that realize quick detection and device miniaturization. The oxidized form of the tetrazolium salt, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), is soluble and highly permeable through cell membranes. MTT is a useful indicator for evaluating cell activity that not only turns color as a result of structural changes related to intracellular metabolism but also causes a clear current response. The carbon-screen-printed electrode chip provides a distinct current response related to the MTT redox reaction in a small volume of bacterial suspension (50 µL). Based on the fact that the current reaction of MTT was strongly dependent on intracellular metabolism, the number of viable cells in a bacterial suspension could be measured electrochemically. Current changes for live cells occurred within 10 min and increased with the incubation time. After only 60 min of incubation, we successfully estimated the number of viable cells in a bacterial suspension of 103 CFU mL−1. This technology eliminates the need for complicated testing, expensive equipment, and lengthy culture testing times, thereby enabling the confirmation of food safety before shipping to prevent food poisoning.

The technological advancements in sensory systems and robotics over the past decade have facilitated the innovation of centralized systems for optimizing resource utilization and monitoring efficiency in inspection applications. This paper presents a novel system designed for gas concentration sensing in environments by implementing a modular artificial nose (emulating the inhalation and exhalation process) equipped with a strategically designed air capture centralization system based on computational fluid dynamics analysis (CFD). The system incorporates three gas identification sensors distributed within the artificial nose, and their information is processed in real-time through embedded systems. The artificial nose is hardware–software integrated with a quadruped robot capable of traversing the environment to collect samples, maximizing coverage area through its mobility and locomotion capabilities. This integration provides a comprehensive perspective on gas distribution in a specific area, enabling the efficient detection of substances in the surrounding environment. The robotic platform employs a graphical interface for real-time gas concentration data map visualization. System integration is achieved using the Robot Operating System (ROS), leveraging its modularity and flexibility advantages. This innovative robotic approach offers a promising solution for enhanced environmental inspection and monitoring applications.

Useful information about the oxidative stability of a virgin olive oil in terms of oxidation products and antioxidant compounds can be obtained by analyzing the peroxide index (PI) and total phenolic content (TPC), respectively. These quality parameters are usually determined in a chemical laboratory using expensive equipment, toxic solvents, and well-trained personnel. This paper presents a novel portable sensor system for in the field and rapid determination of PI and TPC that is particularly suited in the case of small production environments that cannot afford an internal laboratory for quality control analysis. The system is small, can be powered by both USB ports and batteries, is easy to operate, and integrates a Bluetooth module for wireless data transmission. It estimates the PI and TPC in olive oil from the measurement of the optical attenuation of an emulsion between a reagent and the sample under test. The system has been tested on a set of 12 olive oil samples (eight for calibration and four for validation), and the results have shown how the considered parameters can be estimated with good accuracy. The maximum deviation from the results obtained with the reference analytical techniques is 4.7 meq O2/kg in the case of PI and 45.3 ppm in the case of TPC for the calibration set, while it is 14.8 meq O2/kg in the case of PI and 55 ppm in the case of TPC for the validation set. [ABSTRACT FROM AUTHOR]

Augmented Reality Geographic Information System (ARGIS) applications can only provide users accurate content services with a highly precise geo-registration. However, the absolute 6DOF (Degree of Freedom) pose provided by the portable sensors is usually inaccurate in urban outdoors, resulting in poorly geo-registration accuracy for ARGIS applications. Aiming at this issue, an automatic vision-aided localization method based on the 2D map is proposed to improve the initial localization accuracy of the portable sensors, and an overall geo-registration optimization framework for outdoor ARGIS is proposed. Based on the initial pose provided by the sensors, the basic principles of the vision-aided localization method are expounded in detail. The experimental results show that the proposed method can effectively correct the initial pose obtained by the pose sensors, and improve the geo-registration accuracy of outdoor ARGIS applications ultimately.

The Polluscope project aims to better understand the personal exposure to air pollutants in the Paris region. This article is based on one campaign from the project, which was conducted in the autumn of 2019 and involved 63 participants equipped with portable sensors (i.e., NO2, BC and PM) for one week. After a phase of data curation, analyses were performed on the results from all participants, as well as on individual participants' data for case studies. A machine learning algorithm was used to allocate the data to different environments (e.g., transportation, indoor, home, office, and outdoor). The results of the campaign showed that the participants' exposure to air pollutants depended very much on their lifestyle and the sources of pollution that may be present in the vicinity. Individuals' use of transportation was found to be associated with higher levels of pollutants, even when the time spent on transport was relatively short. In contrast, homes and offices were environments with the lowest concentrations of pollutants. However, some activities performed in indoor air (e.g., cooking) also showed a high levels of pollution over a relatively short period. [ABSTRACT FROM AUTHOR]

In this contribution we report the synthesis and full characterization, via a combination of different spectroscopies (e.g., 1H NMR, UV-vis, fluorescence, MALDI), of a new family of fluorescent zinc complexes with extended π-conjugated systems, with the final aim of setting up higher performance H2S sensing devices. Immobilization of the systems into a polymeric matrix for use in a solid-state portable device was also explored. The results provided proof-of-principle that the title complexes could be successfully implemented in a fast, simple and cost-effective H2S sensing device. [ABSTRACT FROM AUTHOR]

Phenolic compounds are widespread water contaminants with high toxicity and chronic carcinogenicity, whose concentration is restricted by a variety of water quality regulations. In the present study, we developed a tyrosinase biosensor based on a nanocomposite of carbon nanotubes, nanodiamonds, and soluble starch to enhance sensing performance during practical application. Doping nanodiamonds in soluble starch considerably improved the electrode's biocompatibility and electroactive sites, while carbon nanotubes improved the loading capacity and electron transfer efficiency of tyrosinase. The as‐prepared biosensor exhibited a broad detection range from 0.01 μM to 50 μM for phenol, which covered the concentration thresholds of the water standard requirement between drinking water to industrial effluents, and the limit of detection (LOD) is down to 2.9 nM. Furthermore, a portable instrument with an integrated probe and self‐calibrated algorithm software was developed to automatically detect and readout the phenol concentration. The as‐prepared instrument demonstrated good agreement to the ISO 4‐Aminoantipyrine spectrometric method in the phenol detection of wastewaters that was collected from a coal factory, chemical and biological manufacturing plants, and biological fermentation factory. The application of this novel biosensor and instrument are paving the way to a wider application of amperometric biosensors for in‐field phenol monitoring. [ABSTRACT FROM AUTHOR]

[Display omitted] • Physiological significance of Glutathione and Cysteamine is highlighted. • Calls for need for accessible, rapid, and cost-effective tests for clinical diagnosis. • Review focus various methods employed for the detection of both the analytes. • Emerging nanotechnology-based approaches for their detection are highlighted. The physiological and clinical importance of Glutathione and Cysteamine is emphasized by their participation in a range of conditions, such as diabetes, cancer, renal failure, Parkinson's disease, and hypothyroidism. This necessitates the requirement for accessible, expedited, and cost-efficient testing that can facilitate clinical diagnosis and treatment options. This article examines numerous techniques used to detect both glutathione and cysteamine. The discussed methods include electroanalytical techniques such as voltammetry and amperometry, which are examined for their sensitivity and ability to provide real-time analysis. Furthermore, this study investigates the accuracy of gas chromatography-mass spectrometry (GC–MS) and high-performance liquid chromatography (HPLC) in measuring the concentrations of glutathione and cysteamine. Additionally, the potential of new nanotechnology-based methods, such as plasmonic nanoparticles and quantum dots, to improve the sensitivity of detecting glutathione and cysteamine is emphasized. [ABSTRACT FROM AUTHOR]

Faced with the increasing prevalence of chronic kidney disease (CKD), portable monitoring of CKD-related biomarkers such as potassium ion (K+), creatinine (Cre), and lactic acid (Lac) levels in sweat has shown tremendous potential for early diagnosis. However, a rapidly manufacturable portable device integrating multiple CKD-related biomarker sensors for ease of sweat testing use has yet to be reported. Here, a portable electrochemical sensor integrated with multifunctional laser-induced graphene (LIG) circuits and laser-printed nanomaterials based working electrodes fabricated by fully automatic laser manufacturing is proposed for non-invasive human kidney function monitoring. The sensor comprises a two-electrode LIG circuit for K+ sensing, a three-electrode LIG circuit with a Kelvin compensating connection for Cre and Lac sensing, and a printed circuit board based portable electrochemical workstation. The working electrodes containing Cu and Cu 2 O nanoparticles fabricated by two-step laser printing show good sensitivity and selectivity toward Cre and Lac sensing. The sensor circuits are fabricated by generating a hydrophilic-hydrophobic interface on a patterned LIG through laser. This sensor recruited rapid laser manufacturing and integrated with multifunctional LIG circuits and laser-printed nanomaterials based working electrodes, which is a potential kidney function monitoring solution for healthy people and kidney disease patients. [ABSTRACT FROM AUTHOR]

Objective: this study proposes the development of a wireless graphical interface with a monitoring system that allows for extensive integration with a variety of non-invasive devices. Method: an evaluation framework was created using ISO/IEC25012 parameters to evaluate each of the physiological parameters. Using an ISO standard as a framework to evaluate the quality of the results and analysis parameters such as consistency, accessibility, compressibility, and others, the Cayenne myDevices platform is used to develop a variety of IoT projects. Results: the successful prototype shows that the temperature sensor’s technical capabilities were found to be insufficient for accurately measuring a human’s body temperature, requiring a calibration algorithm. The Cayenne myDevices platform provides a web dashboard for continuous tracking and storage of physiological data. Blynk, an IoT-based application with a graphical user interface, enables real-time visualization and tracking of data from the server and the electronic prototype. Conclusion: findings concluded that free software tools such as Cayenne myDevices, the Blynk App, and Arduino enable integration and reduce the need for expensive applications. Electronic prototypes monitor parameters (e.g., temperature, heart rate, oxygen saturation) were used to monitor COVID-19, cardiovascular, and diabetic patients during exercise. Successful prototypes used Max30100, Mlx90614 sensors, and Esp8266 microcontroller. To avoid giving the patient inaccurate results, the instruments must be carefully selected, so they were assessed to ensure a 95% effectiveness level.

Urbanisation development affects urban vegetation both directly and indirectly. Since this process usually involves a dramatic change in land use, it is seen as likely to cause ecological pressure on local ecosystems. All forms of human activity, including urbanisation of areas close to residential buildings, significantly impact air quality. This study aims to identify and characterise different measurement solutions of VOCs, allowing the quantification of total and selective compounds in a direct at source (in situ) manner. Portable devices for direct testing can generally be divided into detectors, chromatographs, and electronic noses. They differ in parameters such as operating principle, sensitivity, measurement range, response time, and selectivity. Direct research allows us to obtain measurement results in a short time, which is essential from the point of view of immediate reaction in the case of high concentrations of tested compounds and the possibility of ensuring the well-being of people. The paper also attempts to compare solutions and devices available on the market and assess their application. [ABSTRACT FROM AUTHOR]

Useful information about the oxidative stability of a virgin olive oil in terms of oxidation products and antioxidant compounds can be obtained by analyzing the peroxide index (PI) and total phenolic content (TPC), respectively. These quality parameters are usually determined in a chemical laboratory using expensive equipment, toxic solvents, and well-trained personnel. This paper presents a novel portable sensor system for in the field and rapid determination of PI and TPC that is particularly suited in the case of small production environments that cannot afford an internal laboratory for quality control analysis. The system is small, can be powered by both USB ports and batteries, is easy to operate, and integrates a Bluetooth module for wireless data transmission. It estimates the PI and TPC in olive oil from the measurement of the optical attenuation of an emulsion between a reagent and the sample under test. The system has been tested on a set of 12 olive oil samples (eight for calibration and four for validation), and the results have shown how the considered parameters can be estimated with good accuracy. The maximum deviation from the results obtained with the reference analytical techniques is 4.7 meq O2/kg in the case of PI and 45.3 ppm in the case of TPC for the calibration set, while it is 14.8 meq O2/kg in the case of PI and 55 ppm in the case of TPC for the validation set.

Executive Order 14008, signed on 27 January 2021, established environmental justice (EJ) as a core priority of the Biden Administration. There is a need for state and federal regulators, as well as industry, to enhance risk assessment methods and exposure monitoring approaches to be more inclusive of EJ community involvement and more representative of EJ community exposures. Cumulative risk assessment models are critical for understanding the unique interaction between chemical exposures and nonchemical stressors that EJ communities encounter daily. Enhanced environmental monitoring with personal and portable sensors, especially when deployed using community partnerships, can capture chemical exposures with sufficient resolution to characterize exposures down to the neighborhood level. Use of internet‐linked sensors will also require thoughtful advances in management of big data to inform meaningful and time‐sensitive decisions. Integr Environ Assess Manag 2022;18:858–862. © 2021 SETAC Key Points: There is a need for regulators and industry to enhance risk assessment methods and exposure monitoring approaches to be more inclusive of environmental justice community involvement and more representative of EJ community exposures.Cumulative risk assessment models are critical for understanding the unique interaction between chemical exposures and non‐chemical stressors faced by environmental justice communities.Enhanced environmental monitoring with personal and portable sensors, especially when deployed using community partnerships, can capture chemical exposures with sufficient resolution to characterize exposures down to the neighborhood level.Use of internet‐linked sensors will also require thoughtful advances in management of big data to inform meaningful and time‐sensitive decisions. [ABSTRACT FROM AUTHOR]

So far, compliance with ISO 3632 standard specifications for top-quality saffron guarantees good agricultural and post-harvest production practices. Tracking early-stage oxidation remains challenging. Our study aims to address this issue by exploring the visible, fluorescence, and near-infrared spectra of category I saffron. Using a multi-spectral sensor, we tested fresh and artificially aged saffron in powder form. High autofluorescence intensities at 600–700 nm allowed calibration for the 'content of aged saffron'. Samples with minimum coloring strength (200–220 units) were classified as 70% aged, while those exceeding maximum aroma strength (50 units) as 100% aged. Consistent patterns across origin, age, and processing history indicated potential for objectively assessing early-oxidation markers. Further analyses uncovered multiple contributing fluorophores, including cis -apocarotenoids, correlated with FTIR-based aging markers. Our findings underscore that sensing autofluorescence of traded saffron presents an innovative quality diagnostic approach, paving new research pathways for assessing the remaining shelf-life along its supply chain. [Display omitted] • A sensor-based approach to tracing early oxidation of traded saffron. • Increasing autofluorescence as a novel quality indicator. • Strong diagnostic potential based on 'content of aged saffron'. • Multiple contributing fluorophores including cis- apocarotenoids. • Prospects for objective assessment of saffron shelf-life. [ABSTRACT FROM AUTHOR]

• A comprehensive review of on-site portable detection methods for food safety based on the "on–off-on" fluorescence mechanism has been presented. • Detailed explanation was provided on the "on–off-on" fluorescence response process. • An overview of the fluorescent materials commonly employed in fluorescence analysis methods has been outlined. • The underlying design principles of fluorescent probes were discussed. • An in-depth analysis was conducted on the challenges and future development directions of the smartphone based sensing systems. As technology continues to advance and new application scenarios emerge, accurate and rapid on-site detection sensors are essential for monitoring and control the quality and safety of food. The excellent photography and image processing capabilities of smartphone has greatly facilitated the miniaturization, integration, and visual monitoring of sensors, making them essential tools for portable real-time determination. The "on–off-on" fluorescence sensor has garnered significant attention due to its remarkable features, including high sensitivity, excellent selectivity, strong anti-interference ability, and customizable probe structure. In this context, portable sensors with intelligent analysis and sensing systems have been extensively reported according to the "on–off-on" fluorescent signals, and highlight their immense potential and value in various fields. However, to date, a comprehensive review of smartphone-based on-site detection platforms driven by the "on–off-on" fluorescence mechanism remains absent. This review aims to fill this gap by providing an elaborate explanation of the "on–off-on" fluorescence response process, along with a detailed introduction to commonly used fluorescent materials and their underlying design principles. Furthermore, the latest applications of portable sensors based on the "on–off-on" fluorescence approach in detection of food safety are thoroughly reviewed. Finally, an in-depth analysis was conducted on the challenges and future development directions of the smartphone based sensing systems. This review aims to provide a valuable theoretical basis for comprehending and designing portable sensors, ultimately contributing to more effective and accurate real-time detection of pollutants. [ABSTRACT FROM AUTHOR]

Tetracycline is a broad-spectrum antibiotic for human, poultry and livestock that may cause health damage when enriched in humans. Therefore, it is essential to create a rapid tetracycline assay with high sensitivity, specificity and portability. In this study, a miniaturized tetracycline biosensor based on aptamer-modified graphene field-effect transistor (Apt-SGGT) was fabricated and two detection strategies using transfer characteristic curves and real-time channel current were established for different circumstances. The detection limits of the two strategies were 2.073 pM and 100 pM, respectively. The biosensor also demonstrated outstanding stability, anti-interference and specificity ability. Finally, the biosensor was employed to detect the content of tetracycline in Skim Milk with outstanding recovery rate. We believe that the miniaturized Apt-SGGT biosensor with appropriate detection strategies will provide an ideal portable sensing platform for many important analytes in food with superior selectivity and sensitivity. [Display omitted] • A miniaturized tetracycline biosensor was developed based on aptamer-modified SGGT. • The sensing mechanism was attributed to the conformational change of aptamers. • Two detection strategies were established for different circumstances. • The biosensor showed high selectivity, portability and stability for use in milk. [ABSTRACT FROM AUTHOR]

The Polluscope project aims to better understand the personal exposure to air pollutants in the Paris region. This article is based on one campaign from the project, which was conducted in the autumn of 2019 and involved 63 participants equipped with portable sensors (i.e., NO2, BC and PM) for one week. After a phase of data curation, analyses were performed on the results from all participants, as well as on individual participants’ data for case studies. A machine learning algorithm was used to allocate the data to different environments (e.g., transportation, indoor, home, office, and outdoor). The results of the campaign showed that the participants’ exposure to air pollutants depended very much on their lifestyle and the sources of pollution that may be present in the vicinity. Individuals’ use of transportation was found to be associated with higher levels of pollutants, even when the time spent on transport was relatively short. In contrast, homes and offices were environments with the lowest concentrations of pollutants. However, some activities performed in indoor air (e.g., cooking) also showed a high levels of pollution over a relatively short period.

In this contribution we report the synthesis and full characterization, via a combination of different spectroscopies (e.g., 1H NMR, UV-vis, fluorescence, MALDI), of a new family of fluorescent zinc complexes with extended π-conjugated systems, with the final aim of setting up higher performance H2S sensing devices. Immobilization of the systems into a polymeric matrix for use in a solid-state portable device was also explored. The results provided proof-of-principle that the title complexes could be successfully implemented in a fast, simple and cost-effective H2S sensing device.

The spatiotemporal heterogeneity of the air pollutants complicates appropriate monitoring. The collective measures or crowdsensing is a promising approach to achieve a better air pollution assessment because it includes the local concentration of pollutants, as well as the position and mobility of people. Thus, compared to traditional static monitoring, the participatory sensing data by low-cost sensors can avoid the misclassification of exposition to air pollutants, enabling a comprehensive understanding of their health effects. This systematic review integrates each core part of what is required to achieve crowdsensing for air pollution: sensors, portable devices, and data models. Despite the limitations of sensors in terms of sensitivity and selectivity, it has been possible to use portable air monitors to determine pollution hotspots around the world. However, limited models for data processing, performance issues when using low-cost devices, in addition to lack of community engagement, are the challenges to overcome for the feasibility of air pollution assessment with portable monitors. [ABSTRACT FROM AUTHOR]

Although the research on nanozymes has attracted widespread attention in recent years, the development of highly active and multifunctional nanozymes remains a challenge. Here, a bifunctional AMP-Cu nanozyme with laccase- and catecholase-like activities was successfully prepared at room temperature with Cu2+ as the metal ion and adenosine-5′-monophosphate (AMP) as the ligand molecule. Based on the excellent catalytic performance of AMP-Cu, a three-channel colorimetric sensor array was constructed using reaction kinetics as the sensing unit to achieve high-throughput detection and identification of six common phenolic compounds at low concentrations. This strategy simplifies the construction of sensor array and demonstrates the capacity to obtain multidimensional data from a single material. Finally, with the assistance of smartphones and homemade dark boxes, a portable on-site detection method for phenolic compounds was developed. This work would contribute to the development of portable sensors and the highly efficient identification of phenolic compounds in complex samples. [Display omitted] • A bifunctional AMP-Cu nanozyme with high laccase- and catecholase-like activity was successfully prepared at room temperature. • A colorimetric sensor array was established based on reaction kinetics. • A portable on-site detection method for phenolic compounds was developed. [ABSTRACT FROM AUTHOR]

In chronic neurological conditions, wearable/portable devices have potential as innovative tools to detect subtle early disease manifestations and disease fluctuations for the purpose of clinical diagnosis, care and therapeutic development. Huntington's disease (HD) has a unique combination of motor and non-motor features which, combined with recent and anticipated therapeutic progress, gives great potential for such devices to prove useful. The present work aims to provide a comprehensive account of the use of wearable/portable devices in HD and of what they have contributed so far. We conducted a systematic review searching MEDLINE, Embase, and IEEE Xplore. Thirty references were identified. Our results revealed large variability in the types of sensors used, study design, and the measured outcomes. Digital technologies show considerable promise for therapeutic research and clinical management of HD. However, more studies with standardized devices and harmonized protocols are needed to optimize the potential applicability of wearable/portable devices in HD. [ABSTRACT FROM AUTHOR]

The effects of environmental exposure on human health have been widely explored by scholars in health geography for decades. However, recent advances in geospatial technologies, especially the development of mobile approaches to collecting real-time and high-resolution individual data, have enabled sophisticated methods for assessing people’s environmental exposure. This study proposes an individual environmental exposure assessment system (IEEAS) that integrates objective real-time monitoring devices and subjective sensing tools to provide a composite way for individual-based environmental exposure data collection. With field test data collected in Chicago and Beijing, we illustrate and discuss the advantages of the proposed IEEAS and the composite analysis that could be applied. Data collected with the proposed IEEAS yield relatively accurate measurements of individual exposure in a composite way, and offer new opportunities for developing more sophisticated ways to measure individual environmental exposure. With the capability to consider both the variations in environmental risks and human mobility in high spatial and temporal resolutions, the IEEAS also helps mitigate some uncertainties in environmental exposure assessment and thus enables a better understanding of the relationship between individual environmental exposure and health outcomes.

The use of high-frequency strain waves to perform examinations and note measurements is referred to as ultrasonic testing (UT). UT is commonly used for the detection or evaluation of flaws and characterization of materials, among other applications. A standard ultrasonic inspection system comprises a pulser/receiver, transducer, and display devices. The pulser/receiver produces electrical pulses of high voltage. The transducer generates high-frequency ultrasonic energy after being driven by the pulser. The reflected wave is then converted into an electrical signal by the transducer and is displayed on a screen. The reflected signal strength versus the time plot helps to glean information regarding the features of a defect. In this paper, we discuss the experiments performed in a laboratory setting to determine ultrasound-based biofilm sensor sensitivity in relation to changes in the surrounding environment of temperature, concentration, turbidity, and conductivity of the liquid passing through the system. The effect of the change in frequency of the sensors was also studied. The sensors being developed are small and compact, portable, can be placed on the outer walls of the desired surface, use digital signal processing techniques, and the biofilm presence on the inner walls of the surface can be monitored.

Diabetes is a metabolic disorder that affects more than 400 million people worldwide. Most existing approaches for measuring fasting blood glucose levels (FBGLs) are invasive. This work presents a proof-of-concept study in which saliva is used as a proxy biofluid to estimate FBGL. Saliva collected from 175 volunteers was analysed using portable, handheld sensors to measure its electrochemical properties such as conductivity, redox potential, pH and K^+, Na^+ and Ca^2+ ionic concentrations. These data, along with the person's gender and age, were trained and tested after casewise annotation with their true FBGL values using a set of mathematical algorithms. An accuracy of 87.4 ± 1.7% and a mean relative deviation of 14.1% (R^2 = 0.76) was achieved using a mathematical algorithm. All parameters except the gender were found to play a key role in the FBGL determination process. Finally, the individual electrochemical sensors were integrated into a single platform and interfaced with the authors’ algorithm through a simple graphical user interface. The system was revalidated on 60 new saliva samples and gave an accuracy of 81.67 ± 2.53% (R^2 = 0.71). This study paves the way for rapid, efficient and painless FBGL estimation from saliva.

Supply of safe drinking water is a challenging task requiring not only the availability of suitable devices but also satisfactory monitoring methods to ensure that the contaminants are present well within safe limits. In this context, microfluidic devices have recently emerged as promising technologies for point-of-use screening of water samples. These devices allow for easy interpretation, rapid and cost-effective analysis. The analytical approach employed in these devices for the detection of various water contaminants have different limits of detection that are bound by the nature and stoichiometry of the underlying chemical reaction. These limitations need to be addressed to make these devices more applicable and relevant for field analysis. In this work, we report a simple and novel technique to enhance the limit of detection for determining iron content in contaminated water. We utilize the coffee-ring phenomenon induced by outward capillary flows and differential evaporation rates on paper-based microfluidic devices. On addition of coloring agent, the response is obtained as a brown ring, analogous to the coffee-ring stain. The color intensity and the width of the ring are proportional to the concentration of iron in the water sample. The proposed scheme allowed a five-fold improvement in the limit of detection compared to the unmodified detection tests. The phenomenon can be utilized to enhance the signal from other heavy metal tests as well to enhance the limit of detection and bring these devices into their relevant market for widespread adoption. [ABSTRACT FROM AUTHOR]

Objective: To review published empirical literature on the use of smartphone-based passive sensing for health and wellbeing.Material and Methods: A systematic review of the English language literature was performed following PRISMA guidelines. Papers indexed in computing, technology, and medical databases were included if they were empirical, focused on health and/or wellbeing, involved the collection of data via smartphones, and described the utilized technology as passive or requiring minimal user interaction.Results: Thirty-five papers were included in the review. Studies were performed around the world, with samples of up to 171 (median n = 15) representing individuals with bipolar disorder, schizophrenia, depression, older adults, and the general population. The majority of studies used the Android operating system and an array of smartphone sensors, most frequently capturing accelerometry, location, audio, and usage data. Captured data were usually sent to a remote server for processing but were shared with participants in only 40% of studies. Reported benefits of passive sensing included accurately detecting changes in status, behavior change through feedback, and increased accountability in participants. Studies reported facing technical, methodological, and privacy challenges.Discussion: Studies in the nascent area of smartphone-based passive sensing for health and wellbeing demonstrate promise and invite continued research and investment. Existing studies suffer from weaknesses in research design, lack of feedback and clinical integration, and inadequate attention to privacy issues. Key recommendations relate to developing passive sensing strategies matching the problem at hand, using personalized interventions, and addressing methodological and privacy challenges.Conclusion: As evolving passive sensing technology presents new possibilities for health and wellbeing, additional research must address methodological, clinical integration, and privacy issues. Doing so depends on interdisciplinary collaboration between informatics and clinical experts. [ABSTRACT FROM AUTHOR]

A single-step laser scribing process is used to pattern nanostructured electrodes on paper-based devices. The facile and low-cost technique eliminates the need for chemical reagents or controlled conditions. This process involves the use of a CO2 laser to pyrolyze the surface of the paperboard, producing a conductive porous non-graphitizing carbon material composed of graphene sheets and composites with aluminosilicate nanoparticles. The new electrode material was extensively characterized, and it exhibits high conductivity and an enhanced active/geometric area ratio; it is thus well-suited for electrochemical purposes. As a proof-of-concept, the devices were successfully employed for different analytical applications in the clinical, pharmaceutical, food, and forensic fields. The scalable and green fabrication method associated with the features of the new material is highly promising for the development of portable electrochemical devices. [ABSTRACT FROM AUTHOR]

Nanomaterial-based sensing approaches that incorporate different types of nanoparticles (NPs) and nanostructures in conjunction with natural or synthetic receptors as molecular recognition elements provide opportunities for the design of sensitive and selective assays for rapid detection of contaminants. This review summarizes recent advancements over the past ten years in the development of nanotechnology-enabled sensors and systems for capture and detection of pathogens. The most common types of nanostructures and NPs, their modification with receptor molecules and integration to produce viable sensing systems with biorecognition, amplification and signal readout are discussed. Examples of all-in-one systems that combine multifunctional properties for capture, separation, inactivation and detection are also provided. Current trends in the development of low-cost instrumentation for rapid assessment of food contamination are discussed as well as challenges for practical implementation and directions for future research. [ABSTRACT FROM AUTHOR]

The use of portable sensors to measure air quality is a promising approach for the management of urban air quality given its potential to improve public participation in environmental issues and to promote healthy behaviors. However, not all the projects that use air quality mobile sensors consider the potential effects of their use on the attitudes and behaviors of non-expert individuals. This study explores the experiences, perceptions, attitudes, and behavioral intentions of 12 participants who used a real-time NO sensor over a period of 7 days in the metropolitan area of Barcelona and compares them with 16 participants who did not have access to the device but rather to documentary information. The study design is based on recombined focus groups who met at the beginning and end of a 7-day activity. The results suggest that the experience with the sensors, in comparison with the traditional information, generates greater motivation among participants. Also, that the use of the sensor seems to support a more specific awareness of the problem of air pollution. In relation to risk perception, the textual and visual information seems to generate stronger beliefs of severity among participants. In both groups, beliefs of low controllability and self-efficacy are observed. Neither using the sensor nor reading the documentary information seems to contribute positively in this sense. The results of the study aim to contribute to the design of public involvement strategies in urban air pollution. [ABSTRACT FROM AUTHOR]

Nanozymes with enzyme-mimicking catalytic activity and unique functions have stimulated increasing interest in the biosensing field. Herein, we report a magnetic nanozyme (MNE) with integrated superior peroxidase-like activity and efficient mixing ability. This nanozymatic magnetic nanomixer is synthesized by depositing a Fe2+-doped polydopamine coating on the surface of well-aligned magnetic nanoparticles to form a rigid chain-like nanostructure. Polydopamine coating of the nanozymatic MNE allows for efficient immobilization of natural enzymes such as glucose oxidase, cholesterol oxidase or urate oxidase to produce a series of enzymes-immobilized MNE (MNE@enzymes) with intrinsic multienzyme cascade properties. These MNE@enzymes show synchronously rotating capability in spinning magnetic fields, which leads to an 80∼100% improvement in their overall catalytic efficiencies. In the on-chip detection of small molecular metabolites (i.e., glucose, cholesterol, and uric acid), the rotating MNE@enzymes lead to detection sensitivities 2.1∼4.3 times higher than those of the static ones. Importantly, the consistent performance of the rotating MNE@enzymes offers the possibility of integrating the detection of glucose, free cholesterol and uric acid into a single multiplexing microchip assay with smartphone readout, affording an improved sensitivity, good selectivity and reliability. The designed enzymes-loaded MNEs holds great promise in developing rapid and ultrasensitive measurements of diverse targets of healthcare concerns using portable devices. [Display omitted] [ABSTRACT FROM AUTHOR]

Nanomaterial-based sensing approaches that incorporate different types of nanoparticles (NPs) and nanostructures in conjunction with natural or synthetic receptors as molecular recognition elements provide opportunities for the design of sensitive and selective assays for rapid detection of contaminants. This review summarizes recent advancements over the past ten years in the development of nanotechnology-enabled sensors and systems for capture and detection of pathogens. The most common types of nanostructures and NPs, their modification with receptor molecules and integration to produce viable sensing systems with biorecognition, amplification and signal readout are discussed. Examples of all-in-one systems that combine multifunctional properties for capture, separation, inactivation and detection are also provided. Current trends in the development of low-cost instrumentation for rapid assessment of food contamination are discussed as well as challenges for practical implementation and directions for future research.

Agricultural pests are responsible for millions of dollars of crop losses and control costs every year. To reduce these losses and minimize control costs, new methods to detect pests and/or pest damage must be investigated in order to optimize control measures. One such method evaluated in this study was to detect the chemicals released by pests or pest-damaged products. A portable device was developed to draw volatiles from pests or pest-damaged products over carbon black–polymer composite sensors and measure the change in resistance for each sensor. The device successfully sampled pest and plant volatiles and these volatiles were detected using carbon black–polymer composite sensors. These results indicated an electronic nose is a feasible approach to detect pests and/or pest damage. [ABSTRACT FROM AUTHOR]