Dual Functional Sensor Research Articles

A stable Cu-MOF as a dual-functional sensor with high selectivity for fluorescence enhancement and quenching

A stable Cu-MOF as a dual-functional sensor [Cu2(3-bpah) (1,4-NDC)2]·(1,4-H2NDC)·3H2O (1, 3-bpah = N,N′-bis(3-pyridylformamide)-1,2-cyclohexane, 1,4-H2NDC = 1,4-naphthalenedicarboxylic acid) has been synthesized by hydrothermal method. The fluorescence sensing performance and sensing mechanism have been discussed in detail. Complex 1 shows outstanding stability for acid or base solution and organic solution in a wide range. It is worth mentioning that 1 can not only fluorescence quench Fe3+, Cr2O72−, MnO4− and nitrobenzene (NB), but it can also be employed as an effective and sensitive multifunctional sensor for Al3+, Bi3+, and La3+. In addition, the anti-interference ability and recovery rate recovery trials validated the stability and practicality of the real sample. The sensor developed in this work provides a one-of-a-kind capability for real-time monitoring of contaminants.

Solvent-regulated fluorimetric differentiation of Al3+ and Zn2+ using a dual functional sensor based on the photo-induced electron transfer and intramolecular proton transfer mechanism

Solvent-regulated fluorimetric differentiation of Al3+ and Zn2+ using a dual functional sensor based on the photo-induced electron transfer and intramolecular proton transfer mechanism

An Ultra-stable Eu3+ Doped Yttrium Coordination Polymer with Dual-function Sensing for Cr(VI) and Fe(III) Ions in Aqueous Solution

The exploration of a dual-functional sensor is the key to effectively detect the Cr(VI) and Fe(III) cations in water, which is important to human health and environmental sustainability. Because of the phase stability and excellent luminescence, the rare-earth coordination polymers have great potential as dual-functional sensors. Here, we develop a Y0.91Eu0.09(H2O)2{C6H3(CO2)3}(MIL-92(Y):9%Eu3+)-based dual-function luminescent sensor on Cr(VI) and Fe(III), which exhibits excellent phase stability and dispersibility in water. The luminescence of MIL-92(Y):9%Eu3+ aqueous suspension quenches on Fe3+ with Stern-Volmer constant Ksv of 1.79 × 103 M-1 and limit of detection of 17 μM. The MIL-92(Y):9%Eu3+ aqueous suspension also has turn-off sensing ability towards Cr2O72- and CrO42- with Ksv values of 3.5 × 103 and 6.14 × 103 M-1, respectively. It has detection limitations of 10 and 5 μM on Cr2O72- and Cr2O72- ions, respectively.

MOF-Fabric Composites Based on a Multi-Functional MOF as Luminescent Sensors for a Neurotransmitter and an Anti-Cancer Drug.

A biocompatible, reliable, fast, and nanomolar-level dual-functional sensor for a neurotransmitter (e.g., adrenaline) and an anti-cancer drug (e.g., 6-mercaptopurine (6-MP)) is still far away from the hand of modern-day researchers. To address this issue, we synthesized an aqua-stable, bio-friendly, thiourea-functionalized Zr(IV) metal-organic framework (MOF) for selective, rapid sensing of adrenaline and 6-MP with ultra-low limit of detection (LOD for adrenaline = 1.9 nM and LOD for 6-MP = 28 pM). This is the first MOF-based fluorescent sensor of both the targeted analytes. The sensor not only can detect adrenaline in HEPES buffer medium but also in different bio-fluids (e.g., human urine and blood serum) and pH media. It also exhibited 6-MP sensing ability in aqueous medium and in various wastewater specimens and pH solutions. For the quick and on-site detection of this neuro-messenger (adrenaline) and the drug (6-MP), cost-effective sensor-coated cotton fabric composites were fabricated. The MOF@cotton fabric composite is capable of detecting both the analytes up to the nanomolar level by the naked eye under UV light. The sensor can be recycled up to five times without significantly losing its efficiency. The Förster resonance energy transfer in the presence of adrenaline and inner-filter effect in the presence of 6-MP are the most likely reasons behind the quenching of the MOF's fluorescence intensity, which were proved with the help of appropriate instrumental techniques.

Ultra-stable strain/ humidity dual-functional flexible wearable sensor based on brush-like AgNPs@CNTs@TPU heterogeneous structure

Wearable flexible sensors have a broad applications prospect in human motion and health monitoring. However, designing and manufacturing ultra-stable sensors with wide operating ranges and extremely low detection limits remain a challenging task. In this paper, a heterogeneous-structured fibrous membrane was constructed using the electrospinning process and subsequent ultrasonic homogenizer treatment. The fibrous membrane is composed of brush-like thermoplastic polyurethane (TPU) fibers, which are embedded with carbon nanotubes decorated with silver nanoparticles (AgNPs@CNTs). A dual-function sensor for strain and humidity based on the fiber membrane was designed. As a strain sensor, it has an ultra-low detection limit (0.05 %), an ultra-wide sensing range of 600 %, and excellent stability (100,000 cycles of stretch/release operation at 50 % strain). As a humidity sensor, it can achieve fast response as low as 1 s. With excellent sensing capabilities in terms of strain and humidity, the fiber membrane can be used to monitor breathing, pulse, and limb movement, as well as non-contact sensing, such as sensing the vibration of guitar strings or monitoring footsteps. The versatility and manufacturability of fiber membranes provide a new way for the application of wearable sensors in health monitoring and motion tracking.

High-performance flexible dual-function networks based on MXene hybrid film for human–machine interaction

Flexible multifunctional devices can be used in many fields, but it needs to solve the limitations of their integration and mutual interference, which limits their practical applications. Therefore, it is urgent to develop a flexible sensor that can sense multiple signals at the same time and apply it to human physiological monitoring in real-time. Herein, we developed a flexible dual function sensor which used Ti3C2T x MXene/Ag nanowires (Ag NWs)/tissue hybrid film as the sensing materials. The flexible devices exhibit two types of sensing, including high-performance pressure sensing with a high sensitivity and fast response speed, and high-performance humidity sensing with wide detection range of relative humidity. These new functions enable the device to monitor human motion information and human–machine interaction in a personalized way like an electronic skin. The synthesis of Ti3C2T x MXene/Ag NWs/tissue hybrid film provides a material suitable for large-scale preparation for the development of wearable electronic devices with high performance and high integration.

The phosphomolybdate hybrids based on nanoscale heteropoly blue and metal-organic chain for supercapacitor and dual-functional electrochemical biosensor

The metal-organic complexes/chains were implanted into the basket-shaped heteropoly blue to yield two organic-inorganic hybrids, (H2bpy)5[{Co(H2O)2}{Co(H2O)3(bpy)}2{SrP6MoV2MoVI16O73}2]·8H2O (1) and (H2imi)(H2pz)(pz)2[{Zn(H2O)2(pz)}{Zn(H2O)3(pz)}{SrP6MoV2MoVI16O73}]·4H2O (2), (bpy = 4,4′-bipyridine; imi = imidazole; pz = pyrazines). Compound 1 is a 3D supramolecular hybrid net based on single-supported basket-shaped dimer. The basic unit of 2 is a unique dimeric chain built by metal-organic chains {Zn(H2O)2(pz)}n alternately anchoring two kinds of spatially oriented bi-arm basket dimers, which are extended into a staggered 3D hybrid network with 1-D regular tunnels inside the molecule. Compound 2 possess more prominent redox ability than 1 and most reported POM-based materials due to its structural advantages. 2-CPE presents excellent pseudocapacitive properties with high specific capacity and rate capability. A supercapacitor equipment (2-CPE//AC-CPE) shows superhigh energy density (40.2 Wh kg−1), power density (580.3 W kg−1), capacitance retention (91.89 %) and coulomb efficiency (98.05 %) after 10,000 cycles of GCD. In addition, 2-AB-GCE can be used as a dual-function sensor for hydrogen peroxide (H2O2) and dopamine (DA), which is outstanding in including linear range, detection line and feasibility evaluation. The recoveries of the two substrates were tested using human urine samples as background to evaluate their utility.

Development of Eco-Friendly TiO2 Doped ZnO Nanorods Based Dual Functional Sensor for the Sewage System Monitoring

Pertaining to the drainage of urban runoff and the expulsion of sewage, sewer systems are a vital component of urban engineering. Owing to this, a dual functional sensor to detect the toxic gases and pipeline leakages was developed with TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> doped (1, 3 and 5Wt. %) ZnO nanorods using a wet chemical approach. The morphological and structural analysis depicts the formation of nanorods morphology and characteristic ZnO hexagonal wurtzite structure (dominant (002) peak plane) despite doping. A decrease in bandgap (optical analysis −3.03 eV) and internal resistance (Nyquist plot–74 Ω) was observed when doped with 5Wt.% of TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> . A distinguishing p-n junction curve was observed in all the doped samples during the photoconductivity (J-V) study. A systematic experimental exploratory of the developed sensors at room temperature unfolds the improved dual functional property of the developed sensors when exposed to target gases (10 ppm) (CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> –0.60 and CO–0.64) and acceleration (2.45 V at 1 g).

Theoretical Study of Dual-Function Sensor for Analysis of Blood Composition and Glucose Concentration Based on Nonreciprocal Analog of the Electromagnetically Induced Absorption

Theoretical Study of Dual-Function Sensor for Analysis of Blood Composition and Glucose Concentration Based on Nonreciprocal Analog of the Electromagnetically Induced Absorption

A self-powered dual-functional hybrid Cu2O/SiNWs heterojunction with applications in broadband photodetectors and ozone gas sensors

Dual-functional sensors can replace two or more individual sensors in a platform so they decrease the system area. However, these devices have a major limitation in that they feature high power consumption. A self-powered dual-functional device that detects broadband light detecting and senses ozone (O 3 ) is reported. The device architecture features a solution-processed Cu 2 O thin film that covers silicon nanowire (SiNW) arrays to form a heterojunction. The hybrid Cu 2 O/SiNWs heterojunction structure allows light trapping and gas adsorption because it has a large specific interface area. The proposed device generates an open-circuit voltage of 0.36 V when illuminated using visible-light and can be used to detect various concentrations of O 3 with excellent selectivity and long-term stability. This Cu 2 O/SiNW heterojunction structure shows that capability to develop self-powered dual-functional sensors in the future. • A self-powered dual-functional device with a hybrid Cu 2 O/SiNWs heterojunction is fabricated to detect broadband light and sense O 3 gas. • Upon exposure to 5 ppm O 3 , V oc increases from 0.36 V to 0.53 V, so it can be used to measure different O 3 concentrations. • The device acting as a photodetector exhibits a relatively high responsivity (0.13 A/W) with fast response speed (< 50 ms). • The device serving as a gas sensor exhibits a relatively high gas response (47%) at zero bias.

Stretchable and Self-Powered Temperature-Pressure Dual Sensing Ionic Skins Based on Thermogalvanic Hydrogels.

Tactile sensors with both temperature- and pressure-responsive capabilities are critical to enabling future smart artificial intelligence. These sensors can mimic haptic functions of human skin and inevitably suffer from tensile deformation during operation. However, almost all actual multifunctional tactile sensors are either nonstretchable or the sensing signals interfere with each other when stretched. Herein, we propose a stretchable and self-powered temperature-pressure dual functional sensor based on thermogalvanic hydrogels. The sensor operates properly under stretching, which relies on the thermogalvanic effect and constant elastic modulus of hydrogels. The thermogalvanic hydrogel elastomer exhibits an equivalent Seebeck coefficient of -1.21 mV K-1 and a pressure sensitivity of 0.056 kPa-1. Combined with unit array integration, the multifunctional sensor can be used for accurately recording tactile information on human skin and spatial perception. This work provides a conceptual framework and systematic design for stretchable artificial skin, interactive wearables, and smart robots.

A Dual-Function Sensor for Highly Sensitive Detection of Flame and Humidity.

Early warning sensors rapidly monitor critical temperatures, humidity, and fires, which are crucial to reduce or avoid natural disasters in complex environments, such as fire or water disasters. Here, a highly sensitive, readable, and dual-functional sensor is designed for a fast-response fire alarm and rapid humidity detection based on sustainable biological films (named MSCG films). The MSCG films are composed of grafted sisal nanofibers (MgC), silk nanofibers, graphene, and citric acid (CA). After crosslinking with CA, MSCG films exhibit good wet strength (i.e., 128.8MPa) after soaking in 100 °C water, thus confirming that the films would be applicable to a broad temperature range in humid environments. After flame ignition, the MSCG films are rapidly carbonized to activate an alarm sound and a light in the circuit with a fire response time as short as 1 s. It exhibits ultrafast temperature response/recovery time (i.e., 0.1 s/0.3 s) and rapid humidity response time (i.e., 0.9 s). The dual-functional sensor is further assembled into a versatile sensor system for real-time monitoring of fire accidents and environmental humidity, which can be integrated into consumer electronics, such as portable laptops and mobile phones.

Dual-functional SERRS and fluorescent aptamer sensor for abscisic acid detection via charged gold nanorods.

Abscisic acid (ABA) is a plant hormone, which plays an important role in plant growth, crop cultivation and modern agricultural engineering management. Accordingly, the detection of ABA content combined with new techniques and methods has become a more and more popular problem in the field of agricultural engineering. In this work, a SERRS and fluorescence dual-function sensor based on the fluorescence quenching and Raman enhancement properties of gold nanorods (AuNRs) was developed, and applied to the detection of plant hormone ABA. The dual-function reporter molecule Rhodamine isothiocyanate (RBITC) and complementary DNA (cDNA) were modified on AuNRs (AuNRs@RBITC@cDNA) as signal probes and aptamer modified magnetic nanoparticles (Fe3O4MNPs@Apt) as capture probes. Through the specific recognition of ABA aptamer and its complementary chains, an dual-function aptamer sensor based on SERRS and fluorescence was constructed. When ABA molecules were present in the detection system, the signal probes were detached from the capture probes due to the preferential binding between aptamer and ABA molecules. SERS signal of the reporter molecules appeared in the supernatant after magnetic separation, and it increased with the increase of ABA concentration. If the etching agent that can etch AuNRs was added to the supernatant, the AuNRs was etching disappeared, then the signal molecules fall off from the AuNRs, and the fluorescence signal intensity would recovered. The intensity of fluorescence signal also increased with the increase of ABA concentration. Thus, the quantitative relationship between ABA concentration and SERRS intensity and fluorescence intensity of signal molecules was established. The linear range of SERRS detection was 100 fM–0.1 nM, the detection limit was 38 fM; The linear range of fluorescence detection was 1 pM–100 nM, the detection limit is 0.33 p.m. The constructed dual-effect sensor was used in the recovery laboratory of real ABA samples, the recovery rate was up to 85–108%.

A dual-functional polyaniline film-based flexible electrochemical sensor for the detection of pH and lactate in sweat of the human body.

A flexible dual functional electrochemical sensor based on macroscopic polyaniline (PANI) film is reported. The PANI film is prepared by interfacial synthesis without any additional templates and surfactants, and is easily transferred from the water surface to any substrate. The surface of PANI film is flat and has a certain degree of crystallization. The PANI film exhibits good electrochemical properties, which is attributed to the order structure of PANI. The flexible sensor based on PANI film exhibits good electrochemical performances to pH and lactate. And the flexible PANI sensor has good reproducibility, selectivity and long-term stability. Meanwhile, the PANI sensor is also applied to detect the actual sample (such as food and human sweat), and the results are in accordance with the commercial pH meter, indicating the reliability of the PANI sensor.

Two stable cobalt(II) coordination polymers as dual-functional fluorescent sensors for efficient detection of Zn2+/Cu2+ ions and norfloxacin

The detection of metal cations and antibiotics based optical sensing material in the human body and environment is very vital. Two new ternary Co(II) coordination polymers, namely {Co(L)0.5(BTCA)0.5(H2O)]·3H2O}n (1) and [Co(L)(HIPA)·H2O]n (2) (H4BTCA ​= ​1, 2, 3, 4-butanetetracarboxylic acid, H2HIPA ​= ​5-hydroxyisophthalic acid), were constructed and characterized from the rarely reported semi-rigidity 1,4-bis(thiabendazole-1-yl)-2-butene (L) N-donor linker. 1 displays a 2D 3,4-connected 3,4L13 layer, while 2 features a 1D straight chain, and further extends into a 2D supramolecular network via O–H⋯O interactions. 1 and 2 exhibit superior chemical and thermal stability. 1 and 2 can be used as efficient sensors toward Zn2+ ions via turn-on fluorescent enhancing and Cu2+ ions by a turn-off fluorescent quenching effect, separately. They were also applied as probes to detect norfloxacin with high sensitivity, selectivity, and recyclability by fluorescence quenching. The luminescent sensing mechanisms for these analytes were speculated. 1 and 2 are the first dual-functional sensors for the detection of Zn2+/Cu2+ ions and norfloxacin.

Dual-functional hybrid ZnSnO/Graphene nanocomposites with applications in high-performance UV photodetectors and ozone gas sensors

Dual-functional metal oxide semiconductors that can detect the values of two different physical quantities, such as light intensity and gas concentration, have been the subject of many studies because they are used in the Internet of Things (IoT). However, the opposite sensing mechanisms for photons and gas molecules pose challenges for material design. In this study, we developed a dual-functional sensor that uses hybrid amorphous ZnSnO (a-ZTO)/graphene nanosheet (GNS) composite films. GNSs were incorporated into a-ZTO films so that the recombination process for photo-generated electron/hole pairs was suppressed owing to the favorable band alignment at the ZTO/GNS interface. The a-ZTO/GNS dual-functional sensor had a responsivity of 26.39 A/W at 350 nm and exhibited a fast response speed, with a rise time of 0.71 s and a decay time of 0.95 s. ZTO/GNS nanocomposite film also featured a smaller cluster size so that more electrons were produced for the chemical reaction of gas. Under UV illumination of 10 mW/cm 2 , the dual-functional sensor exhibited a gas response of 12.8, against a 5-ppm concentration of ozone gas. These results demonstrate that this dual-functional device can serve as not only a high-performance UV photodetector but also a highly sensitive gas sensor.

A new visual and stable fluorescent Cu-MOF as a dual-function sensor for glyphosate and Cr2O72−

A new visual and stable Cu-MOF as a dual-function sensor with high sensitivity for the detection of glyphosate and Cr2O72−.

Integrated Wearable Sensors for Sensing Physiological Pressure Signals and β-Hydroxybutyrate in Physiological Fluids.

Flexible and wearable sensors have attracted much attention for their applications in health monitoring and the human-machine interaction. The most studied wearable sensors have been demonstrated for sensing a limited range of metabolites such as ions, glucose, uric acid, lactate, etc. Both sweat and urine contain numerous other physiologically relevant metabolites indicative of health and wellness. This work demonstrates the use of the wearable sensor for the detection of β-hydroxybutyrate (HB) in sweat. HB is an important biomarker for diabetic ketoacidosis, a condition caused by the accumulation of ketone bodies in hyperglycemia or metabolic acidosis patients. Herein, we fabricated an integrated sensing system coupling an HB detection chamber with a serpentine electrode for sensing physiological signals such as pulse beat, vocal cord vibration, etc. The real-time HB detection was based on a β-hydroxybutyrate dehydrogenase enzymatic reaction. The stability of the enzyme and the cofactor couple was achieved by cross-linking networks and a redox mediator, thereby achieving high selectivity and low detection limits to HB in urine and sweat. The dual-functional sensor was integrated with a signal processing circuitry for signal transduction, conditioning, processing, wireless transmission, and real-time convenient health monitoring display to a smartphone via home-developed software.

A dual-functional chemical sensor for the detection of Cu2+ and Cd2+ based on the photochromic diarylethene

A dual-functional sensor DTF-o with a photochromic diarylethene moiety has been designed and synthesized. Its structure was confirmed and analyzed by NMR and MS. The photochromism and fluorescence photoswitching properties of DTF-o were studied in acetonitrile/water (9:1, v/v) solution. DTF-o could selectively recognize Cu2+ by changing its color from colorless to yellow which was attributed to the metal-to-ligand charge transfer (MLCT) absorption band of metal-ligand cooperation. Meanwhile, DTF-o could also be used to detect Cd2+ through obvious emission intensity enhancement by inhibition of CN isomerization with chelation enhanced fluorescence (CHEF). Finally, DTF-o was successfully used in practical samples and made into test strips to detect Cu2+/Cd2+ with high accuracy.

Luminescent Metal–Organic Framework-Based Fluorescence Turn-On and Red-Shift Sensor toward Al3+ and Ga3+: Experimental Study and DFT Calculation

A dual-functional sensor based on a two-dimensional metal–organic framework (MOF), namely, {[Cd(BBZB)(2,6-NDC)]·CH3OH}n (JXUST-6, BBZB = 4,7-bis(1H-benzimidazole-1-yl)-2,1,3-benzothiadiazole and 2,6-NDC = 2,6-naphthalenedicarboxylate), has been designed and synthesized under solvothermal conditions. JXUST-6 exhibits good stability in aqueous solution, boiling water, and N,N-dimethylformamide (DMF) solution. Luminesecence studies of JXUST-6 reveal the existence of fluorescence red shift toward Al3+ and Ga3+ accompanied by turn-on fluorescence response. After gradually adding Al3+ solution to JXUST-6 suspended solution, the emission peak moved from 505 to 529 nm and triggered the color conversion from yellow to yellow-green under 365 UV light irradiation. Similarly, the addition of Ga3+ to JXUST-6 suspended solution caused the enhancement of fluorescence intensity as well as the red-shift from 505 to 530 nm. The detection limits of JXUST-6 toward Al3+ and Ga3+ ions are 0.081 and 0.047 ppm, respectively. Actually, the test paper can be used to sense Al3+ and Ga3+ ions, thereby expanding the potential application scope of JXUST-6. Importantly, JXUST-6 represents the rare turn-on MOF toward Ga3+. The red-shift effect of JXUST-6 toward Al3+ and Ga3+ could account for the formation of a strong exciplex between JXUST-6 and Al3+ and Ga3+. The theoretical caculation suggests that the occurrence of strong intramolecular charge transfer leads to turn-on effect toward Al3+ and Ga3+ ions.