Showing papers in "ACS Sensors in 2017"
TL;DR: In this review, the newly emerged aggregation-induced emission fluorogens (AIEgens) are featured with high emission efficiency in the aggregated state, which provide unique opportunities for various sensing applications with advantages of high signal-to-noise ratio, strong photostability, and large Stokes' shift.
Abstract: Fluorescent sensors with advantages of excellent sensitivity, rapid response, and easy operation are emerging as powerful tools in environmental monitoring, biological research, and disease diagnosis. However, conventional fluorophores featured with π-planar structures usually suffer from serious self-quenching in the aggregated state, poor photostability, and small Stokes’ shift. In contrast to conventional aggregation-caused quenching (ACQ) fluorophores, the newly emerged aggregation-induced emission fluorogens (AIEgens) are featured with high emission efficiency in the aggregated state, which provide unique opportunities for various sensing applications with advantages of high signal-to-noise ratio, strong photostability, and large Stokes’ shift. In this review, we will first briefly give an introduction of the AIE concept and the turn-on sensing principles. Then, we will discuss the recent examples of AIE sensors according to types of analytes. Finally, we will give a perspective on the future develop...
482 citations
TL;DR: This Perspective reviews the current status of the field, showcasing a series of early successes in the application of SPR for clinical analysis and detailing aseries of considerations regarding sensing schemes, exposing issues with analysis in biofluids, and comparing SPR with ELISA, while providing an outlook of the challenges currently associated with plasmonic materials, instrumentation, microfluidics, bioreceptor selection, selection of aclinical market, and validation of a clinical assay.
Abstract: The design and application of sensors for monitoring biomolecules in clinical samples is a common goal of the sensing research community. Surface plasmon resonance (SPR) and other plasmonic techniques such as localized surface plasmon resonance (LSPR) and imaging SPR are reaching a maturity level sufficient for their application in monitoring biomolecules in clinical samples. In recent years, the first examples for monitoring antibodies, proteins, enzymes, drugs, small molecules, peptides, and nucleic acids in biofluids collected from patients afflicted with a series of medical conditions (Alzheimer’s, hepatitis, diabetes, leukemia, and cancers such as prostate and breast cancers, among others) demonstrate the progress of SPR sensing in clinical chemistry. This Perspective reviews the current status of the field, showcasing a series of early successes in the application of SPR for clinical analysis and detailing a series of considerations regarding sensing schemes, exposing issues with analysis in bioflui...
448 citations
TL;DR: The demonstrated ultrafast detection and reversible MoS2 gas sensor at room temperature shows reliable selectivity toward NO2 against various other gases and reveals the potential of 2D MoS 2 to develop a low power portable gas sensor.
Abstract: Two-dimensional materials have gained considerable attention in chemical sensing owing to their naturally high surface-to-volume ratio. However, the poor response time and incomplete recovery at room temperature restrict their application in high-performance practical gas sensors. Herein, we demonstrate ultrafast detection and reversible MoS2 gas sensor at room temperature. The sensor’s performance is investigated to NO2 at room temperature, under thermal and photo energy. Incomplete recovery and high response time of ∼249 s of sensor are observed at room temperature. Thermal energy is enough to complete recovery, but it is at the expense of sensitivity. Further, under photo excitation, MoS2 exhibits an enhancement in sensitivity with ultrafast response time of ∼29 s and excellent recovery to NO2 (100 ppm) at room temperature. This significant improvement in sensitivity (∼30%) and response time (∼88%) is attributed to the charge perturbation on the surface of the sensing layer in the context of NO2/MoS2 i...
314 citations
TL;DR: A flexible epidermal microfluidic detection platform fabricated through hybridization of lithographic and screen-printed technologies, for efficient and fast sweat sampling and continuous, real-time electrochemical monitoring of glucose and lactate levels is described.
Abstract: Despite tremendous recent efforts, noninvasive sweat monitoring is still far from delivering its early analytical promise. Here, we describe a flexible epidermal microfluidic detection platform fabricated through hybridization of lithographic and screen-printed technologies, for efficient and fast sweat sampling and continuous, real-time electrochemical monitoring of glucose and lactate levels. This soft, skin-mounted device judiciously merges lab-on-a-chip and electrochemical detection technologies, integrated with a miniaturized flexible electronic board for real-time wireless data transmission to a mobile device. Modeling of the device design and sweat flow conditions allowed optimization of the sampling process and the microchannel layout for achieving attractive fluid dynamics and rapid filling of the detection reservoir (within 8 min from starting exercise). The wearable microdevice thus enabled efficient natural sweat pumping to the electrochemical detection chamber containing the enzyme-modified e...
288 citations
TL;DR: A wearable, flexible sweat chemical sensor sheet for pH measurement, consisting of an ion-sensitive field-effect transistor (ISFET) integrated with a flexible temperature sensor, which has the potential to be developed into a chemical sensor for sweat for applications in healthcare and sports.
Abstract: Real-time daily healthcare monitoring may increase the chances of predicting and diagnosing diseases in their early stages which, currently, occurs most frequently during medical check-ups. Next-generation noninvasive healthcare devices, such as flexible multifunctional sensor sheets designed to be worn on skin, are considered to be highly suitable candidates for continuous real-time health monitoring. For healthcare applications, acquiring data on the chemical state of the body, alongside physical characteristics such as body temperature and activity, are extremely important for predicting and identifying potential health conditions. To record these data, in this study, we developed a wearable, flexible sweat chemical sensor sheet for pH measurement, consisting of an ion-sensitive field-effect transistor (ISFET) integrated with a flexible temperature sensor: we intend to use this device as the foundation of a fully integrated, wearable healthcare patch in the future. After characterizing the performance,...
269 citations
TL;DR: This review focuses on recent advances in single molecule detection using plasmonic metal nanostructures as a sensing platform, particularly using a single particle–single molecule approach.
Abstract: Single-molecule detection has long relied on fluorescent labeling with high quantum-yield fluorophores. Plasmon-enhanced detection circumvents the need for labeling by allowing direct optical detection of weakly emitting and completely nonfluorescent species. This review focuses on recent advances in single molecule detection using plasmonic metal nanostructures as a sensing platform, particularly using a single particle–single molecule approach. In the past decade two mechanisms for plasmon-enhanced single-molecule detection have been demonstrated: (1) by plasmonically enhancing the emission of weakly fluorescent biomolecules, or (2) by monitoring shifts of the plasmon resonance induced by single-molecule interactions. We begin with a motivation regarding the importance of single molecule detection, and advantages plasmonic detection offers. We describe both detection mechanisms and discuss challenges and potential solutions. We finalize by highlighting the exciting possibilities in analytical chemistry ...
260 citations
TL;DR: Compared with the existing bulky and nonportable clinical instruments, this highly sensitive and soft sensing patch not only provides primary sensor interface to human skin, but also can objectively and accurately detect the subtle pulse signal variations in a real-time fashion, thus presenting a promising solution to home-based pulse monitoring.
Abstract: Profuse medical information about cardiovascular properties can be gathered from pulse waveforms. Therefore, it is desirable to design a smart pulse monitoring device to achieve noninvasive and real-time acquisition of cardiovascular parameters. The majority of current pulse sensors are usually bulky or insufficient in sensitivity. In this work, a graphene-based skin-like sensor is explored for pulse wave sensing with features of easy use and wearing comfort. Moreover, the adjustment of the substrate stiffness and interfacial bonding accomplish the optimal balance between sensor linearity and signal sensitivity, as well as measurement of the beat-to-beat radial arterial pulse. Compared with the existing bulky and nonportable clinical instruments, this highly sensitive and soft sensing patch not only provides primary sensor interface to human skin, but also can objectively and accurately detect the subtle pulse signal variations in a real-time fashion, such as pulse waveforms with different ages, pre- and ...
236 citations
TL;DR: A flexible glove-based electrochemical biosensor with highly stretchable printed electrode system has been developed as a wearable point-of-use screening tool for defense and food security applications and opens the area of flexible wearable sensors to future on-the-hand multiplexed chemical detection in diverse fields.
Abstract: A flexible glove-based electrochemical biosensor with highly stretchable printed electrode system has been developed as a wearable point-of-use screening tool for defense and food security applications. This disposable-mechanically robust “lab-on-a-glove” integrates a stretchable printable enzyme-based biosensing system and active surface for swipe sampling on different fingers, and is coupled with a compact electronic interface for electrochemical detection and real-time wireless data transmission to a smartphone device. Stress-enduring inks are used to print the electrode system and the long serpentine connections to the wireless electronic interface. Dynamic mechanical deformation, bending, and stretching studies illustrate the resilience and compliance of the printed traces against extreme mechanical deformations expected for such on-glove sampling/sensing operation. An organophosphorus hydrolase (OPH)-based biosensor system on the index finger enables rapid on-site detection of organophosphate (OP) n...
232 citations
TL;DR: The recent progress on plasmonic nanoparticles-based colorimetric nanosensors for ultrasensitive molecular diagnostics is reviewed and the challenge is discussed, as well as the future perspective in this emerging field.
Abstract: Colorimetric detection of target analytes with high specificity and sensitivity is of fundamental importance to clinical and personalized point-of-care diagnostics. Because of their extraordinary optical properties, plasmonic nanomaterials have been introduced into colorimetric sensing systems, which provide significantly improved sensitivity in various biosensing applications. Here we review the recent progress on these plasmonic nanoparticles-based colorimetric nanosensors for ultrasensitive molecular diagnostics. According to their different colorimetric signal generation mechanisms, these plasmonic nanosensors are classified into two categories: (1) interparticle distance-dependent colorimetric assay based on target-induced forming cross-linking assembly/aggregate of plasmonic nanoparticles; and (2) size/morphology-dependent colorimetric assay by target-controlled growth/etching of the plasmonic nanoparticles. The sensing fundamentals and cutting-edge applications will be provided for each of them, pa...
226 citations
TL;DR: The hollow SnO2 microfiber using sustainable biomass as a template is a significant strategy for a unique TEA gas sensor and shows a quick response/recovery toward triethylamine.
Abstract: Triethylamine (TEA) gas sensors having excellent response and selectivity are in great demand to monitor the real environment. In this work, we have successfully prepared a hollow SnO2 microfiber by a unique sustainable biomass conversion strategy and shown that the microfiber can be used in a high-performance gas sensor. The sensor based on the hollow SnO2 microfiber shows a quick response/recovery toward triethylamine. The response of the hollow SnO2 microfiber is up to 49.5 when the concentration of TEA gas is 100 ppm. The limit of detection is as low as 2 ppm. Furthermore, the sensor has a relatively low optimal operation temperature of 270 °C, which is lower than those of many other reported sensors. The excellent sensing properties are largely attributed to the high sensitivity provided by SnO2 and the good permeability and conductivity of the one-dimensional hollow structure. Thus, the hollow SnO2 microfiber using sustainable biomass as a template is a significant strategy for a unique TEA gas sensor.
212 citations
TL;DR: A fast-response and flexible nanocrystal-based humidity sensor for real-time monitoring of human activity: respiration and water evaporation on skin in real time and is promising for application in personal health monitoring as well as environmental monitoring.
Abstract: We develop a fast-response and flexible nanocrystal-based humidity sensor for real-time monitoring of human activity: respiration and water evaporation on skin A silicon-nanocrystal film is formed on a polyimide film by spin-coating the colloidal solution and is used as a flexible and humidity-sensitive material in a humidity sensor The flexible nanocrystal-based humidity sensor shows a high sensitivity; current through the nanocrystal film changes by 5 orders of magnitude in the relative humidity range of 8–83% The response/recovery time of the sensor is 40 ms Thanks to the fast response and recovery time, the sensor can monitor human respiration and water evaporation on skin in real time Due to the flexibility and the fast response/recovery time, the sensor is promising for application in personal health monitoring as well as environmental monitoring
TL;DR: The fabricated MOF-based sensor showed a notable detection sensitivity for NH3 at concentrations down to 1 ppm, with a detection limit appraised to be around 100 ppb (at room temperature) even in the presence of humidity and/or CO2.
Abstract: This work reports on the fabrication and deployment of a select metal–organic framework (MOF) thin film as an advanced chemical capacitive sensor for the sensing/detection of ammonia (NH3) at room temperature. Namely, the MOF thin film sensing layer consists of a rare-earth (RE) MOF (RE-fcu-MOF) deposited on a capacitive interdigitated electrode (IDE). Purposely, the chemically stable naphthalene-based RE-fcu-MOF (NDC-Y-fcu-MOF) was elected and prepared/arranged as a thin film on a prefunctionalized capacitive IDE via the solvothermal growth method. Unlike earlier realizations, the fabricated MOF-based sensor showed a notable detection sensitivity for NH3 at concentrations down to 1 ppm, with a detection limit appraised to be around 100 ppb (at room temperature) even in the presence of humidity and/or CO2. Distinctly, the NDC-Y-fcu-MOF based sensor exhibited the required stability to NH3, in contrast to other reported MOFs, and a remarkable detection selectivity toward NH3 vs CH4, NO2, H2, and C7H8. The N...
TL;DR: This review examines the use of amperometric electrochemical gas sensors for monitoring inorganic gases that affect urban air quality and considers the roles of companies, urban infrastructure requirements, and public research in the development of this technology.
Abstract: This review examines the use of amperometric electrochemical gas sensors for monitoring inorganic gases that affect urban air quality. First, we consider amperometric gas sensor technology including its development toward specifically designed air quality sensors. We then review recent academic and research organizations’ studies where this technology has been trialed for air quality monitoring applications: early studies showed the potential of electrochemical gas sensors when colocated with reference Air Quality Monitoring (AQM) stations. Spatially dense networks with fast temporal resolution provide information not available from sparse AQMs with longer recording intervals. We review how this technology is being offered as commercial urban air quality networks and consider the remaining challenges. Sensors must be sensitive, selective, and stable; air quality monitors/nodes must be electronically and mechanically well designed. Data correction is required and models with differing levels of sophisticat...
TL;DR: A ratiometric fluorescence sensor constructed for the selective and sensitive detection of Hg2+, which is based on the inner filter effect of tetraphenylporphyrin tetrasulfonic acid toward black phosphorus quantum dots (BP QDs), reveals a good linear response to H g2+ ranging from 1 to 60 nM with a detection limit of 0.39 nM.
Abstract: In this work, a novel ratiometric fluorescence sensor has been constructed for the selective and sensitive detection of Hg2+, which is based on the inner filter effect (IFE) of tetraphenylporphyrin tetrasulfonic acid (TPPS) toward black phosphorus quantum dots (BP QDs). Highly fluorescent BP QDs were successfully synthesized from bulk BP by sonication-assisted solvothermal method via a top-down route. In the presence of Hg2+, the IFE originating from spectral overlap between the excitation of BP QDs and the absorption of TPPS is inhibited and the fluorescence of BP QDs is restored. At the same time, the red fluorescence of TPPS is quenched due to its coordination with Mn2+. These phenomena result from the rapid coordination between Mn2+ and TPPS in the presence of Hg2+, which leads to the dramatic decrease of the absorption of TPPS. On the basis of these findings, we design a ratiometric fluorescence sensor for the detection of Hg2+. The as-constructed sensor reveals a good linear response to Hg2+ ranging...
TL;DR: Laser-scribed graphene (LSG) electrodes are demonstrated here as highly sensitive and reliable biosensor transducers in blood serum analysis, with extremely low detection limits.
Abstract: Graphene as a transducer material has produced some of the best-performing sensing approaches to date opening the door toward integrated miniaturized all-carbon point-of-care devices. Addressing this opportunity, laser-scribed graphene (LSG) electrodes are demonstrated here as highly sensitive and reliable biosensor transducers in blood serum analysis. These flexible electrodes with large electrochemical surface areas were fabricated using a direct-write laser process on polyimide foils. A universal immobilization approach is established by anchoring 1-pyrenebutyric acid to the graphene and subsequently covalently attaching an aptamer against the coagulation factor thrombin as an exemplary bioreceptor to the carboxyl groups. The resulting biosensor displays extremely low detection limits of 1 pM in buffer and 5 pM in the complex matrix of serum.
TL;DR: This work reports on the observation of magnetic toroidal modes using artificially engineered multimetallic planar plasmonic resonators to detect Zika-virus envelope protein using a specific ZIKV antibody and envision that the proposed toroidal metasurface opens new avenues for developing low-cost, and efficient THz plAsmonic sensors for infection and targeted bioagent detection.
Abstract: Unconventional characteristics of magnetic toroidal multipoles have triggered researchers to study these unique resonant phenomena by using both 3D and planar resonators under intense radiation. Here, going beyond conventional planar unit cells, we report on the observation of magnetic toroidal modes using artificially engineered multimetallic planar plasmonic resonators. The proposed microstructures consist of iron (Fe) and titanium (Ti) components acting as magnetic resonators and torus, respectively. Our numerical studies and following experimental verifications show that the proposed structures allow for excitation of toroidal dipoles in the terahertz (THz) domain with the experimental Q-factor of ∼18. Taking the advantage of high-Q toroidal line shape and its dependence on the environmental perturbations, we demonstrate that room-temperature toroidal metasurface is a reliable platform for immunosensing applications. As a proof of concept, we utilized our plasmonic metasurface to detect Zika-virus (ZI...
TL;DR: In vivo biosensors are emerging as powerful tools in biomedical research and diagnostic medicine and a range of emerging materials likely to lead to significant developments in the field are identified.
Abstract: In vivo biosensors are emerging as powerful tools in biomedical research and diagnostic medicine. Distinct from “labels” or “imaging”, in vivo biosensors are designed for continuous and long-term monitoring of target analytes in real biological systems and should be selective, sensitive, reversible and biocompatible. Due to the challenges associated with meeting all of the analytical requirements, we found relatively few reports of research groups demonstrating devices that meet the strict definition in vivo. However, we identified several case studies and a range of emerging materials likely to lead to significant developments in the field.
TL;DR: A fast method to determine the fish freshness by using a sensing system containing an ultrasensitive amine gas sensor to detect the volatileAmine gas from the raw fish meat is demonstrated.
Abstract: In this work, we successfully demonstrate a fast method to determine the fish freshness by using a sensing system containing an ultrasensitive amine gas sensor to detect the volatile amine gas from the raw fish meat. When traditional titration method takes 4 h and complicated steps to test the total volatile basic nitrogen (TVB-N) as a worldwide standard for fish freshness, our sensor takes 1 min to deliver an electrical sensing response that is highly correlated with the TVB-N value. When detecting a fresh fish with a TVB-N as 18 mg/100 g, the sensor delivers an effective ammonia concentration as 100 ppb. For TVB-N as 28–35 mg/100 g, a well-accepted freshness limit, the effective ammonia concentration is as 200–300 ppb. The ppb-regime sensitivity of the sensor and the humidity control in the sensing system are the keys to realizing fast and accurate detection. It is expected that the results in this report enable the development of on-site freshness detection and real-time monitoring in a fish factory.
TL;DR: Three-dimensional cone-shaped hierarchical SnO2 nanostructures display the highest relative response up to about 175 toward 100 ppm of acetone as an example and exhibit good sensing responses toward other typical volatile organic compounds (VOCs).
Abstract: Hierarchical morphology-dependent gas-sensing performances have been demonstrated for three-dimensional SnO2 nanostructures. First, hierarchical SnO2 nanostructures assembled with ultrathin shuttle-shaped nanosheets have been synthesized via a facile and one-step hydrothermal approach. Due to thermal instability of hierarchical nanosheets, they are gradually shrunk into cone-shaped nanostructures and finally deduced into rod-shaped ones under a thermal treatment. Given the intrinsic advantages of three-dimensional hierarchical nanostructures, their gas-sensing properties have been further explored. The results indicate that their sensing behaviors are greatly related with their hierarchical morphologies. Among the achieved hierarchical morphologies, three-dimensional cone-shaped hierarchical SnO2 nanostructures display the highest relative response up to about 175 toward 100 ppm of acetone as an example. Furthermore, they also exhibit good sensing responses toward other typical volatile organic compounds ...
TL;DR: A colorimetric immunosensor was developed for the point-of-care testing of ApoE by layer-by-layer nanoassembly techniques and novel nanobodies (Nbs) and may have potential application in the clinical diagnosis and real-time monitoring for AD.
Abstract: Alzheimer′s disease (AD) biomarkers can reflect the neurochemical indicators which is used to estimate the risk in clinical nephrology. Apolipoprotein E (ApoE) is an early biomarker for AD in clinical diagnosis. In this research, through bactrian camel immunization, lymphocyte isolation, RNA extraction and library construction, ApoE-specific Nbs with high affinity were successfully separated from an immune phage display nanobody library. Herein, a colorimetric immunosensor was developed for the point-of-care testing of ApoE by layer-by-layer nano-assembly techniques and novel nanobodies (Nbs). Using highly oriented Nbs as the capture and detection antibodies, an on-site immunosensor was developed by detecting the mean gray value of fade color due to the glutaraldehyde@3-aminopropyltrimethoxysilane oxidation by H2O2. The detection limit of AopE is 0.42 pg/mL, and the clinical analysis achieves a good performance. The novel easy-operated immunosensor may have potential application in the clinical diagnosis ...
TL;DR: The obtained biosensing interface responded to the target AFP with a strikingly selective and sensitive manner, exhibited excellent protein-resistant performance even in complex human serum solution, and showed promising feasibility for the quantitative analysis of AFP in real human serum samples.
Abstract: A sensitive and low-fouling aptasensor for alpha-fetoprotein (AFP) was developed based on mixed self-assembled aptamers and newly designed zwitterionic peptides, where densely immobilized peptides formed an antifouling layer to resist nonspecific protein adsorption, and sparsely attached aptamers acted as the recognizing layer to achieve target binding. The obtained biosensing interface responded to the target AFP with a strikingly selective and sensitive manner, exhibited excellent protein-resistant performance even in complex human serum solution, and showed promising feasibility for the quantitative analysis of AFP in real human serum samples.
TL;DR: In this review, the recent advances in genetic PoC technologies are discussed, including the extraction and PCR amplification chemistry suitable for PoC use and the new frontiers of research in this field.
Abstract: Since the Human Genome Project completed in 2000, the sequencing of the first genome, massive progress has been made by medical science in the early diagnosis and personalized therapies based on nucleic acids (NA) analysis. To allow the extensive use of these molecular methods in medical practice, scientific research is nowadays strongly focusing on the development of new miniaturized and easy-to-use technologies and devices allowing fast and low cost NA analysis in decentralized environments. It is now the era of so-called genetic “Point-of-Care” (PoC). These systems must integrate and automate all steps necessary for molecular analysis such as sample preparation (extraction and purification of NA) and detection based on PCR (Polymerase Chain Reaction) technology in order to perform, by unskilled personnel, in vitro genetic analysis near the patient (in hospital, in the physician office, clinic, or home), with rapid answers and low cost. In this review, the recent advances in genetic PoC technologies are...
TL;DR: Three sensing categories that combine carbon dots and inner filter effect are demonstrated, including direct, metal nanoparticle-assisted, and enzymatic reaction-supported detection.
Abstract: Carbon dots are admirable fluorescent nanomaterials due to their low cost, high photostability, excellent biocompatibility, and environmental friendliness. Most conventional carbon dot fabrication approaches produce single-colored fluorescent material in the preparation process; different methods are therefore required to synthesize distinct carbon dots for specific optical applications. In this study, carbon dots carrying different emission colors are prepared through a one-step refluxing process. The emission of these materials can be well-tuned by sodium hydroxide content in the precursor solution. The carbon dots produced are used as sensing probes based on the spectrofluorometric inner filter effect for target molecule detection. Three sensing categories that combine carbon dots and inner filter effect are demonstrated, including direct, metal nanoparticle-assisted, and enzymatic reaction-supported detection. Caffeine, melamine, and fenitrothion are selected as targets to demonstrate the strategies, ...
TL;DR: The results demonstrated that the 2D AuNCs@521-MOF-based aptasensor had high sensitivity for detecting cocaine within the broad concentration range of 0.001-1.0 ng·mL-1 and the low limit of detection of 1.29 pM as determined by electrochemical impedance spectroscopy and differential pulse voltammetry.
Abstract: Two-dimensional (2D) zirconium-based metal–organic framework nanosheets embedded with Au nanoclusters (denoted as 2D AuNCs@521-MOF) were prepared via a one-pot method under mild conditions. The optimized 2D AuNCs@521-MOF nanosheets not only possessed high specific surface area, physicochemical stability, and good electrochemical activity but also exhibited strong bioaffinity toward biomolecule-bearing phosphate groups. Consequently, a large amount of cocaine aptamer strands can be immobilized onto the substrate modified by 2D AuNCs@521-MOF nanosheet, further leading to the formation of a constructed biosensitive platform, which can be used to successfully detect cocaine through the specific binding interactions between cocaine and aptamer strands. The results demonstrated that the 2D AuNCs@521-MOF-based aptasensor had high sensitivity for detecting cocaine within the broad concentration range of 0.001–1.0 ng·mL–1 and the low limit of detection of 1.29 pM (0.44 pg·mL–1) and 2.22 pM (0.75 pg·mL–1) as determ...
TL;DR: A novel strategy using fluorescent quantum dots (QDs) combined with molecularly imprinted polymers (MIPs) on three-dimensional (3D) origami paper-based microfluidic devices for specific recognition and sensitive detection of phycocyanin.
Abstract: In this work, we developed a novel strategy using fluorescent quantum dots (QDs) combined with molecularly imprinted polymers (MIPs) on three-dimensional (3D) origami paper-based microfluidic devices for specific recognition and sensitive detection of phycocyanin. This method can realize the liquid phase of QDs@MIPs being transferred to the solid-phase paper base and achieve easy portability for the analysis. Under optimal conditions, we successfully demonstrated the proposed paper@QDs@MIPs 3D microfluidic chip for the sensitive and selective detection of phycocyanin protein target in a simple and robust manner. Our results revealed that the method exhibited a dynamic response to phycocyanin in the range of 10–50 mg/L with a limit of detection of 2 mg/L. Importantly, this device could provide quantitative information very conveniently and show great potential to be further extended to the detection of other proteins or biomarkers for environmental and food safety research.
TL;DR: This label-free oligonucleotide and unmodified gold nanoparticle solution-based technique is extended to a paper-based system that can be measured using a smartphone to obtain rapid parallel colorimetric results with low reagent consumption and without the need for sophisticated analytical equipment.
Abstract: We have developed a colorimetric sensing strategy employing gold nanoparticles and a paper-based analytical platform for the diagnosis of tuberculosis (TB). By utilizing the surface plasmon resonance effect, we were able to monitor changes in the color of a gold nanoparticle colloid based on the effects of single-stranded DNA probe molecules hybridizing with targeted double-stranded TB DNA. The hybridization event changes the surface charge density of the nanoparticles, causing them to aggregate to various degrees, which modifies the color of the solution in a manner that can be readily measured to determine the concentration of the targeted DNA analyte. In order to adapt this TB diagnosis method to resource-limited settings, we extended this label-free oligonucleotide and unmodified gold nanoparticle solution-based technique to a paper-based system that can be measured using a smartphone to obtain rapid parallel colorimetric results with low reagent consumption and without the need for sophisticated anal...
TL;DR: A significant step has been made with this study toward solving the limitations imposed by previous MoS2-based sensors, which mostly produce a single response to various VOC analytes.
Abstract: Controlling the charge concentrations of two-dimensional (2D) materials is a critical requirement for realizing versatility and potential application of these materials in high-performance electronics and sensors. In order to exploit the novel chemical-sensing characteristics of 2D materials for sensitive and selective sensors, various functionalization methods are needed to ensure efficient doping of channels based on 2D materials. In the present study, the gas-sensing performance of MoS2 has been significantly enhanced by controlled Au nanoparticle functionalization. By using the difference in reduction potential between the Au precursor and MoS2 work functions, MoS2 prepared by chemical exfoliation process was decorated with nanoparticles with sizes of tens of nanometers. The n-doping effect of Au nanoparticles was observed, that is, these particles were found to have facilitated in electron charge transfer from Au to MoS2. The controlled n-doping effect enables the tuning of the sensing of hydrocarbon...
TL;DR: A highly selective fluorescent probe constructed through o-phenylenediamine covalently linking to coumarin (o-Pac), which can respond to phosgene in turn-on fluorescence mode, which exhibits good selectivity to phOSgene over triphosgenes and various acyl chlorides.
Abstract: The detection of highly toxic chemicals in a convenient, fast, and reliable manner is essential for coping with serious threats to humankind and public security caused by unexpected terrorist attacks and industrial accidents. In this paper, a highly selective fluorescent probe has been constructed through o-phenylenediamine covalently linking to coumarin (o-Pac), which can respond to phosgene in turn-on fluorescence mode. The response time is less than 0.5 min and the detection limit is as low as 3 nM in solutions. More importantly, the sensor exhibits good selectivity to phosgene over triphosgene and various acyl chlorides. Furthermore, a portable test paper has been fabricated with polystyrene membrane containing o-Pac for real-time selective monitoring of phosgene in gas phase.
TL;DR: The successful application of a sensor platform based on graphene oxide and upconversion nanoparticles (NPs) for the specific detection of mRNA-related oligonucleotide markers in complex biological fluids for Alzheimer's disease as well as prostate cancer in human blood serum is demonstrated.
Abstract: The development of new sensors for the accurate detection of biomarkers in biological fluids is of utmost importance for the early diagnosis of diseases. Next to advanced laboratory techniques, there is a need for relatively simple methods which can significantly broaden the availability of diagnostic capability. Here, we demonstrate the successful application of a sensor platform based on graphene oxide and upconversion nanoparticles (NPs) for the specific detection of mRNA-related oligonucleotide markers in complex biological fluids. The combination of near-infrared light upconversion with low-background photon counting readout enables reliable detection of low quantities of small oligonucleotide sequences in the femtomolar range. We demonstrate the successful detection of analytes relevant to mRNAs present in Alzheimer’s disease as well as prostate cancer in human blood serum. The high performance and relative simplicity of the upconversion NP-graphene sensor platform enables new opportunities in early...
TL;DR: 3D printing as the fabrication method enables the device to be customized for the wearer for more personalized healthcare by enabling real-time monitoring of one of the most important medical parameters, core body temperature, employed in preliminary medical screening tests.
Abstract: Real-time detection of basic physiological parameters such as blood pressure and heart rate is an important target in wearable smart devices for healthcare. Among these, the core body temperature is one of the most important basic medical indicators of fever, insomnia, fatigue, metabolic functionality, and depression. However, traditional wearable temperature sensors are based upon the measurement of skin temperature, which can vary dramatically from the true core body temperature. Here, we demonstrate a three-dimensional (3D) printed wearable “earable” smart device that is designed to be worn on the ear to track core body temperature from the tympanic membrane (i.e., ear drum) based on an infrared sensor. The device is fully integrated with data processing circuits and a wireless module for standalone functionality. Using this smart earable device, we demonstrate that the core body temperature can be accurately monitored regardless of the environment and activity of the user. In addition, a microphone an...