Search

In this study, a novel paper biosensor based on Fe3O4@SiO2–NH2 magnetic polymer microspheres and multi walled carbon nanotubes (MWCNTs) for rapid detection of pseudorabies virus (PRV) was first developed. Fe3O4@SiO2–NH2 were functionalized with PRV antibody and doped in cellulose nitrate paper to fabricate the magnetic paper biosensor with good magnetic response and biocompatibility. Using MWCNTs to build conductive network of sensors, PRV antigen binds specifically to the immunomagnetic microspheres on the sensor, and the resulting immune complex changes the magnetic domain structure of the sensor and the structural gap of MWCNTs, causing the magnetic property and impedance change. TEM and EDS characterization proved that the biosensor was successfully doped with Fe3O4@SiO2–NH2 and effectively recognized PRV. Under optimized conditions, the impedance variation was found to be linearly related to the logarithm value of PRV concentrations in the range of 10–1 mg ml−1, with the detection limit of 10 ng ml−1. This paper biosensor demonstrated advantages of portability, high sensitivity and specificity, providing a valuable method for early control of PRV. [ABSTRACT FROM AUTHOR]

In this study, indium modified carbon paper electrode is investigated as the positive electrode for all-vanadium redox flow battery (VRFB). The electrochemical performance is studied using cyclic voltammetry, electrochemical impedance spectroscopy and stability test toward V (IV)/V (V) redox reaction. The results show that the modified carbon paper exhibits excellent electrocatalytic activity and stability after repetitive 100-cycle test in an electrolyte containing 0.5MVOSO4, while degradation is observed in pristine carbon paper. Such improvement is due to the indium particles deposited on the carbon fibers acting as stable active sites promoting the vanadium redox reactions and reducing charge transfer resistance as indicated by impedance measurement. Full cell performance is assessed via polarization curve analysis at different states of charge. A simple cell set-up (without flow field) employing the modified electrode exhibited limiting current of 125 mA cm², which is 73% higher than the cell employing pristine carbon paper (72 mA cm²) at SOC of 96%. Overall, the results demonstrate that indium deposition on carbon paper promotes the electrochemical performance and provides an opportunity for further investigation in the exploration of metal modification of carbon materials for VRFB. [ABSTRACT FROM AUTHOR]

To enlarge the areal capacity of Si-O-C composites as an anode for high energy Li secondary batteries, 3D-structured carbon paper is used as a current collector for electrodeposition of Si-O-C composites. For higher surface affinity between organic solventswith carbon paper, surface treatment of carbon paper is carried out using a sulfuric acid-hydrogen peroxide mixture (SPM) solution. The higher deposited Si amounts and areal capacity are obtained by SPM treatment of carbon paper due to its enhanced surface affinity between carbon paper and electrolytes during Si-O-C electrodeposition. In addition, two kinds of organic solvents, propylene carbonate (PC) and ethylene carbonate/diethyl carbonate (EC/DEC), are employed to investigate their suitability for the electrodeposition of Si-O-C composites. As a result, it is confirmed that the Si-O-C composites synthesized by EC/DEC solvents show more stable cycle abilities than in the case of using PC solvents at a high charge current density of 1.0 mA cm-2. This is due to the exfoliation of carbon paper by PC, resulting in fast capacity fading during charge/discharge cycle. Nevertheless, it is confirmed that the use of carbon paper as a substrate for Si-O-C electrodeposition is an effective way to increase deposited Si amounts and discharge areal capacity. [ABSTRACT FROM AUTHOR]

This paper describes the design, fabrication, and validation of a paper-based diagnostic device for the rapid diagnosis of hypocalcemia in dairy cattle at the point-of-care (POC). The device incorporates a 3D printed calcium ion-selective membrane (ISM) as the sensing element for free—unbound—calcium in real bovine whole blood samples. With a linear response range of 100 mM to 97.7 μ M, the sensor covers the clinically relevant concentrations of Ca ^2+ associated with both healthy cattle as well as those suffering from hypocalcemia. The components of the Ca ^2+ ion-selective electrodes were successfully translated to a paper-based device to provide a sensing platform that is simple to use, disposable, and low-cost, and is therefore well-situated for applications at the POC. The paper-based calcium sensor showed a Nernstian response between 10 mM and 100 μ M and required only 12 μ l of sample to perform a measurement, which can be accomplished in less than two minutes without the need for time-consuming separation steps. The performance of the paper-based Ca ^2+ sensor was validated using the commercially available epoc ^® Blood Analysis System, which provided results within 5% of the data obtained with 3D printed Ca ^2+ -ISM integrated paper-based device.

Tungsten disulfide quantum dots (WS2 QDs) embedded lab on genochip based analytical device (PAD) was developed for the specific DNA detection of Meningitis, a life threatening disease. This paper-based lab on genochip was designed by grafting the two electrodes onto the surface of paper using conductive ink. The WS2 QDs were characterized by X-ray diffraction technique, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Following this, specific oligonucleotide sequence of DNA (capture probe) was immobilized over the surface of WS2 QDs/PAD electrode. The ssDNA/WS2QDs/PAD device was characterized electrochemically by cyclic voltammetry. The device was employed for detection of target DNA (by hybridization) by employing methylene blue (MB) as an indicator. The biosensor exhibited a wide linear response in the range 1 nM-100 µM towards the target DNA. The limit of detection (LOD) of target DNA of the proposed device is 1 nM. The advantageous features of this device than the existing biosensors include cheaper analysis cost, tiny sample requirements and stability. [ABSTRACT FROM AUTHOR]

Paper-based biosensors offer low-cost platforms for fast and easy detection of a biomarker in clinical diagnostics and other fields such as food and environmental monitoring. Since paper is a versatile substrate that enables passive solution flow and is biocompatible, it is suitable to use as a biosensing platform. This perspective article discusses current trends of paper-based biosensors in terms of fabrication and detection techniques in clinical diagnostics. Recently, low performance and manufacturing limitations on large scale are factors limiting microfluidics biosensors commercialization. Key aspects and methods to enhance performance and increase commercialization are proposed in this perspective. [ABSTRACT FROM AUTHOR]

In my previous article (Temiz B K 2020 Phys. Educ. 55 027002), I demonstrated that images on a screen covered with paper are seen clearly when the paper is close to the screen but become blurry when the paper is moved away. I wanted you, the readers, to find the reason behind this phenomenon. In this study, I aim to give the answer to this question. [ABSTRACT FROM AUTHOR]

A square spiral incision was introduced into a 15 × 15 cm regular quadrilateral conductive film to study the modulation of electrothermal distribution by kirigami structure. Based on the simulation of finite element method, the transition from thermal focusing to thermal defocusing could be achieved by increasing the length of connection between adjacent modules. The effective electrothermal area can be increased by nearly two times through increasing the length increment of the notch length between adjacent modules. The maximum temperature was decreased from 254 °C to 44 °C, and the temperature difference was adjusted from 76 °C to 4 °C by increasing the number of kirigami module. Through the contact temperature measurement experiment on graphite paper kirigami structure, the trends could be verified. By creating an equivalent circuit model and considering the influence of heat conduction, the peak temperature at the center of the structure and the decrease of the overall temperature could be explained. By deriving the relationship between the temperature of conductive film of kirigami structure with time and position, the electrothermal characteristics of previously reported graphene kirigami structure could be predicted. [ABSTRACT FROM AUTHOR]