Disposable Sensor Research Articles

Cesium–lead–halide perovskite triggered visual platform: a disposable paper-based nano-temperature sensor for cold chain transport

Novel application of a cesium–lead–halide perovskite in a triggered disposable paper-based nano-temperature sensor for efficient temperature monitoring.

First-principles insights into the C6N7 monolayer as a highly efficient sensor and scavenger for the detection of selective volatile organic compounds.

The design of new gas sensors and scavengers of volatile organic compounds (VOCs) is desirable for VOC enriching, separation and utilization. Herein, first-principles methods were performed to investigate the potential of C6N7 monolayers as highly efficient sensors and scavengers for selective VOCs (toluene, benzene, vinyl chloride, ethane, methanal, acetone, ethanol, and acetaldehyde). The physisorption of toluene, benzene, acetone, ethanol, acetaldehyde, and methanal has relatively high adsorption strength and can significantly tune the electronic properties and work function (Φ) of the C6N7, indicating that the C6N7 monolayer is highly sensitive and selective to these VOC gases. In addition, the desorption time of benzene, acetone, ethanol, acetaldehyde, and methanal is about 3, 0.4, 2.0 × 10-2, 3.0 × 10-2, and 3.6 × 10-5 s at 300 K, respectively, indicating that the C6N7-based sensor has high reusability at room temperature. The recovery time of toluene was about 7.8 × 102 s at 300 K, showing disposable toluene gas sensing of the monolayer. Our work confirms that the C6N7 monolayer as a resistance-type and Φ-type gas sensor and scavenger is highly sensitive, selective and reusable for VOCs (benzene, acetone, ethanol, acetaldehyde, and methanol), but is a disposable toluene gas sensor and scavenger at room temperature.

A 3D carbon black disposable electrochemical sensor modified with reduced graphene oxide used for the sensitive determination of levofloxacin

In this work, a simple method for the fabrication of an electrochemical sensor using a conductive carbon black and polylactic acid-based filament (3D-CB/PLA) printed with a 3D-pen is presented.

Electrochemical quantification of Vanillin using hydrazine derivative modified pencil graphite electrode

Herein this report, a disposable electrochemical sensor was developed by modifying pencil graphite electrode by Poly 2,4-dinitrophenylhydrazine (PDNPH) using electropolymerizing technique for the detection of Vanillin (Van) or 4-Hydroxy-3-methoxybenzaldehyde. Electrochemical estimation of Vanillin was done with the help of Cyclic Voltammetry and Differential pulse voltametric techniques. The morphological characteristics were studied using SEM analysis. A single oxidation peak was obtained for Vanillin at the potential of + 0.5214 V. The adapted electrode exhibits a linear range of 1 µM −900 µM with LOD of 0.34 µM. The PDNPH/PG electrode was then used for real sample quantification and it manifested RSD value less than 5 % which revealed that the developed sensor is a favorable tool for quantification of Van. This is the first-time reporting Vanillin determination by using a modified pencil graphite electrode as working electrode in supporting electrolyte PBS 7.

A Rapid Label-Free Disposable Electrochemical Salivary Point-of-Care Sensor for SARS-CoV-2 Detection and Quantification.

The coronavirus disease 2019 (COVID-19) pandemic has created an urgent need for accurate early diagnosis and monitoring. A label-free rapid electrochemical point-of-care (POC) biosensor for SARS-CoV-2 detection in human saliva is reported here to help address the shortcomings of traditional nucleic acid amplification methods and give a quantitative assessment of the viral load to track infection status anywhere, using disposable electrochemical sensor chips. A new chemical construct of gold nanoparticles (GNp) and thionine (Th) are immobilized on carboxylic acid functionalized carbon nanotubes (SWCNT-COOH) for high-performance biosensing. The sensor uses saliva with a one-step pretreatment and simple testing procedure as an analytical medium due to the user-friendly and non-invasive nature of its procurement from patients. The sensor has a response time of 5 min with a limit of detection (LOD) reaching 200 and 500 pM for the freely suspended spike (S) protein in phosphate buffer saline (PBS) and human saliva, respectively. The sensor's performance was also proven for detecting a COVID-19 pseudovirus in an electrolyte solution with a LOD of 106 copies/mL. The results demonstrate that the optimized POC sensor developed in this work is a promising device for the label-free electrochemical biosensing detection of SARS-CoV-2 and different species of viruses.

Smart Portable Device Based on the Utilization of a 2D Disposable Paper Stochastic Sensor for Fast Ultrasensitive Screening of Food Samples for Bisphenols.

Since the determination of the high toxicity of bisphenol A, alternative structures for bisphenols have been synthesized, resulting in bisphenols C, E, F, S, and Z. These bisphenols have replaced bisphenol A in plastic bottles, toys, and cans used for preserving food. Later, the toxicity and negative effects of all of these bisphenols on people's health were proven. Therefore, there is a need for a fast ultrasensitive screening method that is able to detect the presence of these bisphenols in any condition directly from food samples. This paper presented a disposable device based on the utilization of a 2D disposable paper stochastic sensor for the fast ultrasensitive screening of food samples for bisphenols A, C, E, F, S, and Z. The 2D disposable sensor was obtained by the deposition of graphene and silver nanolayers on paper using cold plasma. Furthermore, the active side of the sensor was modified using 2,3,7,8,12,13,17,18-octaethyl-21H,23H Mn porphyrin. The limits of quantification of these bisphenols were 1 fmol L-1 for bisphenols C and E, 10 fmol L-1 for bisphenols A and F, 10 pmol L-1 for bisphenol S, and 1 pmol L-1 for bisphenol Z. The recoveries of these bisphenols in milk, canned fruits, vegetables, and fish were higher than 99.00% with RSD (%) values lower than 1.50%.

Disposable Wearable Sensors Based on Nanocellulose for Biomedical Applications

Monitoring of human motor and muscle activity is used in many areas, from prosthetics during rehabilitation to training monitoring of athletes. Sensors for these tasks are usually made of flexible polymers and require recycling after the expiration date. Nanocellulose (NC) can be used as a biodegradable base for this type of sensor. The development of low-cost disposable sensors that do not require disinfection and cleaning is relevant. NC is a composite nanoscale structure of cellulose fibers (fibrils) with a high aspect ratio. The paper aim is to develop disposable wearable biodegradable bend sensors based on nanocellulose using vacuum synthesis methods and the study of their characteristics. Nanocellulose was synthesized by the TEMPO method. The sensors were created by means of magnetron sputtering of Ti/Ni or Cr/Ni thin films at the surface of nanocellulose. Measuring stand was developed to determine the change in resistance due to the bending of the sensor. It’s mechanical part consists of an elastic deformation plate made of high-alloy steel, which can be bent using a micrometric screw. The change in resistance is linearly related to the elongation of the measured sample. A Wheatstone bridge and a 24-Bit ADC HX711 were used to measure the change in resistance. During testing of the sensor for analysis of muscle activity, the sensor element was attached to the human skin with the help of medical glue BF-6. The obtained sensors were tested for biodegradability. The samples were placed in the ground at a depth of 20-30 mm. The mass of nanocellulose samples was measured using a high-precision digital balance EDIS 50 (50/0.001 g) with a built-in level. The optimal ratio of the value of sensitivity and reversibility is observed in the range of the nominal resistance of the nickel film from 10 to 100 Ohms. This is due to an increase in the surface area of ​​the Ni film, which leads to an increase in sensitivity, but at the same time there is a decrease in the repeatability of the characteristics due to a greater influence of the heterogeneous structure of nanofibrillated cellulose. In addition, sensors with different buffer layer materials - Ti and Cr - were selected for testing. For titanium-based sensors, the maximum sensitivity coefficient is 0.312%, while the deviation of the sensor signal after one bending-unfolding cycle (reversibility) is less than 0.001%. Chromium-based sensors have significantly higher sensitivity (0.9753%), but worse reversibility (7.14%). Sensors based on the Cr buffer layer showed poorly reproducible results in the cyclic mode of operation, namely: there are significant fluctuations in the signal amplitude (up to 50-60%) already after the second bending-unfolding cycle. Therefore, despite the high sensitivity of such sensors, they are unsuitable for analyzing human motor and muscle activity/ The sensors based on the Ti buffer layer showed good response (2.5-3%) and good repeatability and resistance to cyclic bending (30 times). It can be seen that the obtained dependencies are approximated by a linear law. Some deviation from linearity is obviously related to the inhomogeneity of the Ni thin film. Also, the sensors showed a good loss of mass (40% in 9 weeks) during the biodegradability test, which confirms their ability to decompose under the influence of atmospheric phenomena. So, in this work, disposable wearable sensors on a nanocellulose substrate were synthesized for the evaluation of motor and muscle activity of a person. It was found that such sensors can be used to test of finger and biceps movement during at least 10-30 full flexion-extension cycles. For test of elbow movement, it is planned to synthesize a high-elastic composite material based on nanocellulose and bioelastic material (for example, polyvinyl alcohol). Thus, the proposed sensor manufacturing technology makes it possible to obtain cheap, light, flexible disposable wearable sensors that do not require further disposal after the end of operation.

Development of a Force Sensor for a Neuroendovascular Intervention Support Robot System

Neuroendovascular catheterization using fluoroscopy poses the problem to operators and staffs of cumulative radiation exposure. To solve this problem, we are developing a remote-controlled master-slave robot. Because a wire-like elongated treatment device is inserted into a blood vessel using a catheter, the robot requires a sensor to detect the insertion force of the wire. The proposed sensor is integrated into a robot installed in an X-ray fluoroscopy room that is remotely controlled from another room. The features of this sensor include measurement of the insertion force with sufficient accuracy, simple wire attachment, and an inexpensive disposable sensor head, rendering it very suitable for practical application. In this paper, we report on these features, as well as the results of a practical test of the sensor using a cerebrovascular model.

Evaluation of dry stored disposable sensor strip on rapid SARS-CoV-2 detection platform

This study investigated a SARS-CoV-2 virus detection mechanism using dry-stored disposable strips. The accuracy of this sensing platform is as good as polymerase chain reaction (PCR) with a detection time of fewer than 30 s. SARS-CoV-2 antibodies were biofunctionalized on disposable strips similar to glucose detection strips to detect the presence and concentrations of SARS-CoV-2 in saliva samples. Eight 1 ms electric pulses were sent through the sensor strip with a saliva sample in its microfluidic chamber. A circuit board embedded with MOSFET was also employed to amplify the detected signals and convert the signal to digital readings displayed on an LCD screen. The COV-antibody functionalized disposable strips were stored in a dry condition for at least one day before analyzing clinical human saliva samples with known cycling threshold (Ct) values confirmed with conventional PCR tests. Results demonstrate our system is capable of showing qualitative positive or negative results within 30 s and providing quantitative SARS-CoV-2 concentrations in terms of Ct values in 5 min.

Highly hydrophobic TEMPO-functionalized conducting copolymers for solid-contact ion-selective electrodes

Solid-contact ion-selective electrodes (SCISEs) emerged as the best electrode embodiment for miniaturized, wearable and disposable sensors for ion/electrolyte measurements in body fluids. The commercialization of inexpensive single-use “calibration-free” electrodes requires large scale manufacturing of electrodes with reproducible calibration parameters, e.g. E0. This is perhaps the most important shortcoming of SCISEs, beside the many advantages over their conventional liquid-contact counterparts. However, adjusting the E0 value for optimal potential stability is challenging for all state-of-the-art solid-contact materials, which may combine several types of transducing mechanism (e.g. capacitive and redox materials or their combination) for enhanced potential stability and analytical performance. Therefore, here we introduce for the first time the galvanostatic intermittent titration technique (GITT) to determine the best preadjusment potential. The proof of concept is shown for a novel type of solid-contact based on the copolymerization of 3,4-ethylenedioxythiophene with perfluorinated alkyl side chain (EDOTF) and (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl modified 3,4-ethylenedioxythiophene (EDOT-TEMPO). Such materials that are compliant with local electrodeposition and provide multiple functionalities, i.e. high hydrophobicity by the perfluorinated alkyl side chain, electron-to-ion transduction by the conducting polymer (EDOT) backbone and the confinement of well-defined redox couple (TEMPO), are expected to prevail as solid-contacts.

Anti-Biofouling Electrochemical Sensor Based on the Binary Nanocomposite of Silica Nanochannel Array and Graphene for Doxorubicin Detection in Human Serum and Urine Samples.

A disposable and portable electrochemical sensor was fabricated by integrating vertically-ordered silica mesoporous films (VMSF) and electrochemically reduced graphene (ErGO) on a screen-printed carbon electrode (SPCE). Such VMSF/ErGO/SPCEs could be prepared by a simple and controllable electrochemical method. Stable growth of VMSF on SPCE could be accomplished by the introduction of an adhesive ErGO nanolayer owing to its oxygen-containing groups and two-dimensional (2D) planar structure. An outer VMSF layer acting as a protective coating is able to prevent the leakage of the inner ErGO layer from the SPCE surface. Thanks to the electrostatic permselectivity and anti-fouling capacity of VMSF and to the good electroactive activity of ErGO, binary nanocomposites of VMSF and ErGO endow the SPCE with excellent analytical performance, which could be used to quantitatively detect doxorubicin (DOX) in biological samples (human serum and urine) with high sensitivity, good long-term stability, and low sample amounts.

A DFT studies on absorbing and sensing possibilities of glucose on graphene surface doped with Ag, Au, Cu, Ni & Pt atoms

The adsorption of glucose is theoretically examined using the Density Functional Theory method (DFT) over pure graphene and graphene surface doped with transition metal atoms (silver, gold, copper, nickel, and platinum). The graphene sheets are altered by substitutional doping of silver, gold, copper, nickel, and platinum atoms remarks in altering the electronic properties and actively reassuring glucose absorption. The outcomes revealed that metal atoms doped with graphene sheets improve the reactivity. Our study found that the interaction of glucose with pure graphene is weak when compared to metal-doped graphene flakes. Our studies concluded that due to strong adsorption energies, high bandgap variation, and excellent work function values of metal-doped graphene sheets make them beneficial for glucose sensing devices. The sensitivity and conductivity variations are high for the metal doped graphene sheets except nickel, however the recovery time value is high, suggesting that these sheets can be used as a disposable sensor.

First‐principles Study of SO2 and NO Gas Sensors Based on SnTe Monolayer

AbstractThe structural and electronic properties of SnTe monolayer after the adsorption of gas molecules (CH4, CO2, NH3, CO, H2S, NO, SO2, NO2 and Cl2) were investigated by first‐principles calculations based on density functional theory (DFT). The results showed that SO2, NO, NO2 and Cl2 were chemisorbed on SnTe monolayer with strong adsorption energies. In addition, because of the high sensitivity of the adsorption of SO2 and NO gases on SnTe monolayer, the bandgap of the developed system changed significantly, with a reduction of 22.88 % and 71.65 %, respectively. The results indicate that SnTe monolayer has highly sensitive SO2 and NO gas detection capability, especially for NO. And it can act as a disposable gas sensor or metal‐free catalyst for the detection and catalysis of pollution gases, such as NO2 and Cl2.

Deposition of Ni/RGO nanocomposite on conductive cotton fabric as non-enzymatic wearable electrode for electrochemical sensing of uric acid in sweat

In this work, the development of a wearable electrochemical sensor for the direct measurement of uric acid in human sweat is reported. The preparation of Ni and reduced graphene oxide composites with stable electrocatalytic responses, as well as their structural characterization, was carried out. The electrochemical properties of the Ni/RGO/CCF modified electrode of conductive cotton fabric were investigated for the purpose of uric acid determination using differential pulse voltammetry. On a scale ranging from 10 μM to 60 μM, the electrode signals (Ni/RGO/CCF) were found to be linearly related to the uric acid concentration. It was possible to attain a low limit of detection (5.083 μM) with good reproducibility. Finally, an interference investigation and real-time sample analysis of the modified electrode demonstrate that it has a great potential for use as disposable sensors in biological systems. • A wearable electrochemical sensor for the direct measurement of uric acid (UA) in human sweat is reported. • The fabricated electrode is investigated for the purpose of UA determination using differential pulse voltammetry. • The fabricated sensing electrode exhibits a great potential for use as disposable sensors in biological systems.

2-D Be2C as Multitime Reversible Environmental Oxygen- and Nitrogen-Containing Gases Sensor Material Under First Principle Investigations

A combined density functional theory and nonequilibrium Green’s function (DFT-NEGF) approach has been conducted to examine the potential of monolayer Be2C nanosheet as a promising sensor for various environmentally toxic/nontoxic nitrogen- and oxygen-containing multigases (NCGs and OCGs). A total of eight gases comprising four OCGs (O2, CO, CO2, and H2O) and four NCGs (NO, NO2, N2O, and NH3) are investigated on the surface of monolayer Be2C to identify its gas sensing potential. The nontoxic O2, CO2, and H2O are also included in the study considering their obvious presence in the environment. Our investigation suggests that at room temperature, larger adsorption energy of NO, NH3, and O2 gas molecules on the surface of Be2C reflects a more significant recovery time as 1016, 105, and 1012 s, respectively. The positive higher adsorption energy of NO2 gas molecules as 0.91 eV adsorbed on the Be2C nanosheet at room temperature results in a very short recovery time of 10−29 s. The adsorption energy of the NO2 gas molecule is positive, making it unsuitable for gas sensors. In all cases, notable variation is observed in electronic and adsorption properties, charge transfer, recovery time, work function, and transport characteristics of OCGs and NCGs on Be2C surface. OCGs and NCGs show electron acceptor nature during interaction with Be2C nanosheet. The electronic transport of Be2C sheet shows its highly selective and sensitive nature toward OCGs and NCGs. Overall, monolayer Be2C reveals as an excellent multitime reversible multigas sensor material for four gases, viz. CO, CO2, H2O, and N2O with their significantly low recovery time, whereas it appears to be one-time disposable sensor material for O2, NO, and NH3 gases with higher adsorption energy and relatively long recovery time.

Disposable luminescent kit based on dithizone-functionalized waste blue-phosphor as field-deployable sensor for environment monitoring

A new disposable sensor based on waste blue-phosphor (BaMgAl10O17:Eu2+, BAM) embedded in polyvinyl alcohol (PVA) support and modified dithizone (Dz) was designed and fabricated for the determination of Pb2+ ions in environmental samples. Dz is used as the modifier to give indirect sensing property through interacting with BAM particles via surface coordinating reactions to form Dz-BAM conjugates resulting in quenching of natural fluorescence of BAM by fluorescence resonance energy transfer (FRET) mechanism. The Box-Behnken response surface factorial design was used to optimize the prepared sensor using two spectrophotometric and spectrofluorimetric approaches. The calibration curve was found to be linear in the range of 500–4500 nmol/L (R2 = 0.9986) with LOD of 150 nmol/L and LOQ of 500 nmol/L. The potential interference ions were studied and the applicability of the sensor was successfully evaluated by determination of the target ion in real tap and river water samples containing potential interferences.

In-House monitoring and measurement of respiration rateusing Disposable Paper Sensor

This present work provides an easily disposable paper-based interdigitated sensor embedded inside the mask for the detection of respiration rate continuously without direct contact with the human body. In present COVID scenario, everyone needs to wear mask for preventing the unwanted spreading of the said virus. But in tropical countries like India, People always complain about a suffocating situation while wearing mask. In order to address this, we have designed a non-invasive paper sensor that can be placed inside the mask (beneath nostril) for measuring breathing rate regularly to find out a cost-effective device capable of monitoring breathing rate. In general, we prefer use and throw type mask, thus the proposed paper-based sensor gives a cost-effective solution compared to the Current appliances of breathing sensing as most of them are burdensome, bulky, inconvenient as well as exorbitant than a paper-based respiration sensor. Essentially, these current approaches undergo through a practical limitation of frequency and time span i.e. static measurement. It is known that the humidity level of a paper changes according to the moisture content. Thus, it can easily detect the inhalation and exhalation through this changing. Moreover, variation of moisture level that happens due to breathing cycle changes the ionic conductivity of the sensor. The interdigitated design is the most suited for achieving higher sensitivity and easy to fabricate. First, we have designed it in Finite Element Method (FEM) based platform and finally this design is implemented with graphite-based electrodes on cellulose paper. Microcontroller based electronic circuitry is used in order to monitor and record the real-time respiration rate. It has been observed that the breathing rate as well as pattern gives a significant variation along with physical conditions and obstructive pulmonary diseases.

Electrochemical Sensing of Paracetamol Using 3D Porous Laser Scribed Graphene Platform

AbstractThis work presents a novel disposable electrochemical sensor for paracetamol (PCM). The sensing platform is based on graphene, manufactured via laser‐scribing technology (LSG) to produce a 3D‐porous structure that offers a large surface area. The analytical performances of LSG electrodes were greatly enhanced due to the high catalytic activity of graphene produced by LSG technology compared to conventional carbon electrodes. Moreover, the results showed an outstanding adsorption feature towards PCM, allowing its detection at nanomolar level from 5 nM to 100 nM through pre‐concentration. The proposed sensing strategy was successfully applied for the determination of PCM in human urine samples.

Rapid Measurement of Lactate in the Exhaled Breath Condensate: Biosensor Optimization and In-Human Proof of Concept.

Lactate concentration is of increasing interest as a diagnostic for sepsis, septic shock, and trauma. Compared with the traditional blood sample media, the exhaled breath condensate (EBC) has the advantages of non-invasiveness and higher user acceptance. An amperometric biosensor was developed and its application in EBC lactate detection was investigated in this paper. The sensor was modified with PEDOT:PSS-PB, and two different lactate oxidases (LODs). A rotating disk electrode and Koutecky-Levich analysis were applied for the kinetics analysis and gel optimization. The optimized gel formulation was then tested on disposable screen-printed sensors. The disposable sensors exhibited good performance and presented a high stability for both LOD modifications. Finally, human EBC analysis was conducted from a healthy subject at rest and after 30 min of intense aerobic cycling exercise. The sensor coulometric measurements showed good agreement with fluorometric and triple quadrupole liquid chromatography mass spectrometry reference methods. The EBC lactate concentration increased from 22.5 μM (at rest) to 28.0 μM (after 30 min of cycling) and dropped back to 5.3 μM after 60 min of rest.

Facile Synthesis of Fe-Doped Hydroxyapatite Nanoparticles from Waste Coal Ash: Fabrication of a Portable Sensor for the Sensitive and Selective Colorimetric Detection of Hydrogen Sulfide.

In this work, a new strategy has been reported for the portable detection of H2S based on Fe-doped hydroxyapatite nanoparticles (Fe-HA) using a colorimetric paper test strip integrated with a smartphone platform. Fe-HA NPs were fabricated successfully via recycling waste coal ash. The obtained probe response toward H2S was through a distinct visual color change. The sensing mechanism is based on the displacement reaction, in which PO4 3- is replaced by S2-. The prepared test strip shows high selectivity, and the other compounds containing thiol and sulfur anion have a negligible effect on the detection of H2S. The designed scheme is applied for H2S detection in the concentration range of 0.5-130 ppm with a limit of detection of 70 ppb. Furthermore, such a disposable sensor was used as a practical system for monitoring H2S in actual water samples, suggesting the promising potential of this platform for suitable analysis of H2S in an aqueous environment.