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Paper-based electronics offer a simple and cost-effective means to fabricate reconfigurable devices. In response to the problem of fixed shape and single function of most antennas, which limits their applications, a reconfigurable paper-based metamaterial antenna with 2D and 3D forms is presented for tunable operating frequency. The proposed antenna consists of two square split resonant rings fed by a coplanar waveguide. The working frequency of the 2D antenna is adjusted by the length, width, and opening size of the internal open resonant ring. While the folding angle of the antenna turns from 0° to 90°, the operating frequency of the paper-based metamaterial antenna changes from 2.759 to 4.223 GHz. In terms of 3D form, an additional resonant peak is generated by bending the paper-based metamaterial antenna, thus further realizing dual-band antenna design. After a simple process flow, a series of proposed antennas are fabricated and evaluated. The simulated and measured results both demonstrate that the proposed antenna has a good performance in turning the working band. The environment-friendly nature and pliability of paper, as well as simple fabrication procedures, make paper-based metamaterial promising candidates for future green electronics. [ABSTRACT FROM AUTHOR]

Vibration sensors are widely used in many fields like industry, agriculture, military, medicine, environment, etc. However, due to the speedy upgrading, most sensors composed of rigid or even toxic materials cause pollution to the environment and give rise to an increased amount of electronic waste. To meet the requirement of green electronics, biodegradable materials are advocated to be used to develop vibration sensors. Herein, a vibration sensor is reported based on a strategy of pencil-drawing graphite on paper. Specifically, a repeated pencil-drawing process is carried out on paper with a zigzag-shaped framework and parallel microgrooves, to form a graphite coating, thus serving as a functional conductive layer for electromechanical signal conversion. To enhance the sensor's sensitivity to vibration, a mass is loaded in the center of the paper, so that higher oscillation amplitude could happen under vibrational excitation. In so doing, the paper-based sensor can respond to vibrations with a wide frequency range from 5 Hz to 1 kHz, and vibrations with a maximum acceleration of 10 g. The results demonstrate that the sensor can not only be utilized for monitoring vibrations generated by the knuckle-knocking of plastic plates or objects falling down but also can be used to detect vibration in areas such as the shield cut head to assess the working conditions of machinery. The paper-based MEMS vibration sensor exhibits merits like easy fabrication, low cost, and being environmentally friendly, which indicates its great application potential in vibration monitoring fields. [ABSTRACT FROM AUTHOR]

In the era of liquid biopsy, microRNAs emerge as promising candidates for the early diagnosis and prognosis of cancer, offering valuable insights into the disease's development. Among all the existing analytical approaches, even if traditional approaches such as the nucleic acid amplification ones have the advantages to be highly sensitive, they cannot be used at the point-of-care, while sensors might be poorly sensitive despite their portability. In order to improve the analytical performance of existing electroanalytical systems, we demonstrate how a simple chromatographic paper-based disk might be useful to rationally improve the sensitivity, depending on the number of preconcentration cycles. A paper-based electrochemical platform for miRNA detection has been developed by modifying a paper-based electrode with a methylene blue (MB)-modified single-stranded sequence (ssDNA) complementary to the chosen miRNA, namely miR-224 that is associated with lung cancer. A detection limit of ca. 0.6 nM has been obtained in spiked human serum samples. To further enhance the sensitivity, an external chromatographic wax-patterned paper-based disk has been adopted to preconcentrate the sample, and this has been demonstrated both in standard and in serum solutions. For each solution, three miR-224 levels have been preconcentrated, obtaining a satisfactory lowering detection limit of ca. 50 pM using a simple and sustainable procedure. This approach opens wide possibilities in the field of analytical and bioanalytical chemistry, being useful not only for electrochemistry but also for other architectures of detection and transduction. [ABSTRACT FROM AUTHOR]

The growth of liquid biopsy, i. e., the possibility of obtaining health information by analysing circulating species (nucleic acids, cells, proteins, and vesicles) in peripheric biofluids, is pushing the field of sensors and biosensors beyond the limit to provide decentralised solutions for nonspecialists. In particular, among all the circulating species that can be adopted in managing cancer evolution, both for diagnostic and prognostic applications, microRNAs have been highly studied and detected. The development of electrochemical devices is particularly relevant for liquid biopsy purposes, and the screen‐printed electrodes (SPEs) represent one of the building blocks for producing novel portable devices. In this work, we have taken miR‐2115‐3p as model target (it is related to lung cancer), and we have developed a biosensor by exploiting the use of a complementary DNA probe modified with methylene blue as redox mediator. In particular, the chosen sensing architecture was applied to serum measurements of the selected miRNA, obtaining a detection limit within the low nanomolar range; in addition, various platforms were interrogated, namely commercial and hand‐made SPEs, with the aim of providing the reader with some insights about the optimal platform to be used by considering both the cost and the analytical performance. [ABSTRACT FROM AUTHOR]

Lumpy Skin Disease (LSD) is a notifiable viral disease caused by Lumpy Skin Disease virus (LSDV). It is usually associated with high economic losses, including a loss of productivity, infertility, and death. LSDV shares genetic and antigenic similarities with Sheep pox virus (SPV) and Goat pox (GPV) virus. Hence, the LSDV traditional diagnostic tools faced many limitations regarding sensitivity, specificity, and cross-reactivity. Herein, we fabricated a paper-based turn-on fluorescent Molecularly Imprinted Polymer (MIP) sensor for the rapid detection of LSDV. The LSDV-MIPs sensor showed strong fluorescent intensity signal enhancement in response to the presence of the virus within minutes. Our sensor showed a limit of detection of 101 log10 TCID50/mL. Moreover, it showed significantly higher specificity to LSDV relative to other viruses, especially SPV. To our knowledge, this is the first record of a paper-based rapid detection test for LSDV depending on fluorescent turn-on behavior. [ABSTRACT FROM AUTHOR]

Abstract The growth of liquid biopsy, i. e., the possibility of obtaining health information by analysing circulating species (nucleic acids, cells, proteins, and vesicles) in peripheric biofluids, is pushing the field of sensors and biosensors beyond the limit to provide decentralised solutions for nonspecialists. In particular, among all the circulating species that can be adopted in managing cancer evolution, both for diagnostic and prognostic applications, microRNAs have been highly studied and detected. The development of electrochemical devices is particularly relevant for liquid biopsy purposes, and the screen‐printed electrodes (SPEs) represent one of the building blocks for producing novel portable devices. In this work, we have taken miR‐2115‐3p as model target (it is related to lung cancer), and we have developed a biosensor by exploiting the use of a complementary DNA probe modified with methylene blue as redox mediator. In particular, the chosen sensing architecture was applied to serum measurements of the selected miRNA, obtaining a detection limit within the low nanomolar range; in addition, various platforms were interrogated, namely commercial and hand‐made SPEs, with the aim of providing the reader with some insights about the optimal platform to be used by considering both the cost and the analytical performance.

Abstract While gamified technology integration in vocabulary instruction within a flipped classroom has yielded beneficial teaching outcomes, specific studies have raised concerns about potential adverse effects linked to this approach. As a result, conducting a comparative analysis between gamified technology and conventional paper-based methods within the flipped classroom framework has become essential. This analysis aims to foster the development of a targeted teaching approach that adeptly addresses the unique needs of students. This study employed a sequential explanatory research design to examine the effectiveness of flipped classroom with gamified technology and paper-based method in teaching vocabulary to students with different proficiency levels. Quantitative data was gathered from a pretest and a posttest, whilst qualitative data was collected through teachers’ guided reflection. Using Academic Word List (300 target words), control groups employed a paper-based, while experimental groups applied gamified technology (Quizlet, Kahoot!, Quizizz, Socrative, and Google Form), which lasted 10 weeks. The participants were 144 non-English major students who took a general English course in the 2nd semester of 2023. Quantitative data analysis ran in SPSS 25 using Paired Sample t-Test and One-way ANOVA. The qualitative data were analyzed using thematic progression. The results showed that gamified technology did not affect students’ learning outcomes, while the paper-based method resulted conversely. It revealed that the paper-based method is more effective than gamified technology for students in general, with low proficiency and high-proficiency level. Further, teachers’ beliefs admitted distinctive issues that gamified technology was more effective for high-proficiency learners, whereas paper-based was more effective for low-proficiency learners. The difference analysis of quantitative and qualitative data sheds light on discussing threats while implementing gamified technology and possible solutions.

Nowadays, mycotoxin contamination in cereals and wastewater exposes a safety hazard to consumer health. This work describes the design of a simple, low-cost, and sensitive origami microfluidic paper-based device using electrochemical detection for zearalenone determination. The microfluidic immunosensor was designed on a paper platform by a wax printing process. The graphitized carbon working electrode modified with carbon nanohorns-decorated nanoporous gold showed a higher surface area, sensitivity, and adequate analytical performance. Electrodes were characterized by scanning electron microscopy, energy-dispersive spectroscopy, and cyclic voltammetry. The determination of zearalenone was carried out through a competitive immunoassay using specific antibodies immobilized by a covalent bond on the electrode surface. In the presence of HRP-labeled enzyme conjugate, substrate, and catechol, zearalenone was detected employing the developed immunosensor by applying −0.1 V to the working electrode vs silver as a pseudo-reference electrode. A calibration curve with a linear range between 10 and 1000 µg Kg−1 (R2 = 0.998) was obtained, and the limit of detection and quantification for the electrochemical immunosensor were 4.40 and 14.90 µg Kg−1, respectively. The coefficient of variation for intra- and inter-day assays was less than 5%. The selectivity and specificity of the sensor were evaluated, comparing the response against zearalenone metabolites and other mycotoxins that could affect the corn samples. Therefore, origami is a promising approach for paper-based electrochemical microfluidic sensors coupled to smartphones as a rapid and portable tool for in situ mycotoxins detection in real samples. [ABSTRACT FROM AUTHOR]

While gamified technology integration in vocabulary instruction within a flipped classroom has yielded beneficial teaching outcomes, specific studies have raised concerns about potential adverse effects linked to this approach. As a result, conducting a comparative analysis between gamified technology and conventional paper-based methods within the flipped classroom framework has become essential. This analysis aims to foster the development of a targeted teaching approach that adeptly addresses the unique needs of students. This study employed a sequential explanatory research design to examine the effectiveness of flipped classroom with gamified technology and paper-based method in teaching vocabulary to students with different proficiency levels. Quantitative data was gathered from a pretest and a posttest, whilst qualitative data was collected through teachers' guided reflection. Using Academic Word List (300 target words), control groups employed a paper-based, while experimental groups applied gamified technology (Quizlet, Kahoot!, Quizizz, Socrative, and Google Form), which lasted 10 weeks. The participants were 144 non-English major students who took a general English course in the 2nd semester of 2023. Quantitative data analysis ran in SPSS 25 using Paired Sample t-Test and One-way ANOVA. The qualitative data were analyzed using thematic progression. The results showed that gamified technology did not affect students' learning outcomes, while the paper-based method resulted conversely. It revealed that the paper-based method is more effective than gamified technology for students in general, with low proficiency and high-proficiency level. Further, teachers' beliefs admitted distinctive issues that gamified technology was more effective for high-proficiency learners, whereas paper-based was more effective for low-proficiency learners. The difference analysis of quantitative and qualitative data sheds light on discussing threats while implementing gamified technology and possible solutions. [ABSTRACT FROM AUTHOR]

Vibration sensors are widely used in many fields like industry, agriculture, military, medicine, environment, etc. However, due to the speedy upgrading, most sensors composed of rigid or even toxic materials cause pollution to the environment and give rise to an increased amount of electronic waste. To meet the requirement of green electronics, biodegradable materials are advocated to be used to develop vibration sensors. Herein, a vibration sensor is reported based on a strategy of pencil-drawing graphite on paper. Specifically, a repeated pencil-drawing process is carried out on paper with a zigzag-shaped framework and parallel microgrooves, to form a graphite coating, thus serving as a functional conductive layer for electromechanical signal conversion. To enhance the sensor’s sensitivity to vibration, a mass is loaded in the center of the paper, so that higher oscillation amplitude could happen under vibrational excitation. In so doing, the paper-based sensor can respond to vibrations with a wide frequency range from 5 Hz to 1 kHz, and vibrations with a maximum acceleration of 10 g. The results demonstrate that the sensor can not only be utilized for monitoring vibrations generated by the knuckle-knocking of plastic plates or objects falling down but also can be used to detect vibration in areas such as the shield cut head to assess the working conditions of machinery. The paper-based MEMS vibration sensor exhibits merits like easy fabrication, low cost, and being environmentally friendly, which indicates its great application potential in vibration monitoring fields.

Detecting sputum pyocyanin (PYO) with a competitive immunoassay is a promising approach for diagnosing Pseudomonas aeruginosa respiratory infections. However, it is not possible to perform a negative control to evaluate matrix-effects in competitive immunoassays, and the highly complex sputum matrix often interferes with target detection. Here, we show that these issues are alleviated by performing competitive immunoassays with a paper biosensor. The biosensing platform consists of a paper reservoir, which contains antibody-coated gold nanoparticles, and a substrate containing a competing recognition element, which is a piece of paper modified with an albumin-antigen conjugate. Detection of PYO with a limit of detection of 4.7·10−3 µM and a dynamic range between 4.7·10−1 µM and 47.6 µM is accomplished by adding the sample to the substrate with the competing element and pressing the reservoir against it for 5 min. When tested with patient samples, the biosensor was able to qualitatively differentiate spiked from non-spiked samples, whereas ELISA did not show a clear cut-off between them. Furthermore, the relative standard deviation was lower when determining sputum with the paper-based biosensor. These features, along with a mild liquefaction step that circumvents the use of harsh chemicals or instruments, make our biosensor a good candidate for diagnosing Pseudomonas infections at the bedside through the detection of sputum PYO. [ABSTRACT FROM AUTHOR]

As a result of its excellent analytical performance and high economic efficiency, the lateral flow immunoassay (LFIA) has proved to be a robust bioanalytical method. To achieve the application of LFIA in health care, several issues still need to be addressed, including a dramatic increase in sensitivity and reliability which is vital to enable early disease diagnosis and to avoid false-negative results. Electrokinetics in paper-based biosensors allows an integrated solution that simultaneously enables separation, preconcentration, and detection of different target analytes. Miniaturized electrokinetic biosensing platforms that incorporate all necessary electronics and use portable batteries for power sources enable their practical use at the point of care (PoC). The potential of electrokinetic phenomena in biosensing is still in its infancy, and there is still work to be done to boost the analytical sensitivity. In order to decentralize health care, the development of point-of-care (PoC) assays has gained significant attention in recent decades. The lateral flow immunoassay (LFIA) has emerged as a promising bioanalytical method due to its low cost and single-step detection process. However, its limited sensitivity and inability to detect disease biomarkers at clinically relevant levels have hindered its application for early diagnosis. This review explores the potential of merging different electrokinetic phenomena into paper-based assays to enhance their analytical performance, offering a versatile and affordable approach for PoC testing. The review exposes the challenges faced in integrating electrokinetic phenomena with paper-based biosensing and concludes by discussing the issues that need to be improved to maximize the potential of this technology for early diagnosis. [ABSTRACT FROM AUTHOR]

Lumpy Skin Disease (LSD) is a notifiable viral disease caused by Lumpy Skin Disease virus (LSDV). It is usually associated with high economic losses, including a loss of productivity, infertility, and death. LSDV shares genetic and antigenic similarities with Sheep pox virus (SPV) and Goat pox (GPV) virus. Hence, the LSDV traditional diagnostic tools faced many limitations regarding sensitivity, specificity, and cross-reactivity. Herein, we fabricated a paper-based turn-on fluorescent Molecularly Imprinted Polymer (MIP) sensor for the rapid detection of LSDV. The LSDV-MIPs sensor showed strong fluorescent intensity signal enhancement in response to the presence of the virus within minutes. Our sensor showed a limit of detection of 101 log10 TCID50/mL. Moreover, it showed significantly higher specificity to LSDV relative to other viruses, especially SPV. To our knowledge, this is the first record of a paper-based rapid detection test for LSDV depending on fluorescent turn-on behavior.

Gas, ion, and biological sensors have been widely utilized to detect analytes of great significance to the environment, food, and health. Paper-based sensors, which can be constructed on a low-cost paper substrate through a simple and cost-effective fabrication process, have attracted much interests for development. Moreover, many materials can be employed in designing sensors, such as metal oxides and/or inorganic materials, carbon-based nanomaterials, conductive polymers, and composite materials. Most of these provide a large surface area and pitted structure, along with extraordinary electrical and thermal conductivities, which are capable of improving sensor performance regarding sensitivity and limit of detection. In this review, we surveyed recent advances in different types of paper-based gas, ion, and biological sensors, focusing on how these materials' physical and chemical properties influence the sensor's response. Challenges and future perspectives for paper-based sensors are also discussed below. [ABSTRACT FROM AUTHOR]

Nowadays, mycotoxin contamination in cereals and wastewater exposes a safety hazard to consumer health. This work describes the design of a simple, low-cost, and sensitive origami microfluidic paper-based device using electrochemical detection for zearalenone determination. The microfluidic immunosensor was designed on a paper platform by a wax printing process. The graphitized carbon working electrode modified with carbon nanohorns-decorated nanoporous gold showed a higher surface area, sensitivity, and adequate analytical performance. Electrodes were characterized by scanning electron microscopy, energy-dispersive spectroscopy, and cyclic voltammetry. The determination of zearalenone was carried out through a competitive immunoassay using specific antibodies immobilized by a covalent bond on the electrode surface. In the presence of HRP-labeled enzyme conjugate, substrate, and catechol, zearalenone was detected employing the developed immunosensor by applying −0.1 V to the working electrode vs silver as a pseudo-reference electrode. A calibration curve with a linear range between 10 and 1000 µg Kg−1 (R2 = 0.998) was obtained, and the limit of detection and quantification for the electrochemical immunosensor were 4.40 and 14.90 µg Kg−1, respectively. The coefficient of variation for intra- and inter-day assays was less than 5%. The selectivity and specificity of the sensor were evaluated, comparing the response against zearalenone metabolites and other mycotoxins that could affect the corn samples. Therefore, origami is a promising approach for paper-based electrochemical microfluidic sensors coupled to smartphones as a rapid and portable tool for in situ mycotoxins detection in real samples.

Wireless devices have become extremely inexpensive and popular in recent years. The two most significant advantages of wireless devices over wired ones are convenience and flexibility. Considering this, a wireless mouse pad prototype for access has been developed in this study. A capacitive sensors-based mouse pad with basic operations and conventional features has been developed using sensing arrays on paper. A facile, do-it-yourself fabrication process was utilized to develop a cost-effective, thin, wearable, and cleanroom-free wireless mouse cursor control (MCC) pad. The ablation process was used to cut the traces of conductive tape and paste them onto the paper to develop the MCC pad. The pad was connected with Espressif Systems (ESP)32 to wirelessly control the cursor of mobile and laptop. The capacitive touch sensor array-based pad is easy to reproduce and recycle. This pad can contribute to future advancements in thin human-machine interfaces, soft robotics, and medical and healthcare applications.

This paper presents a laminated paper-based Planar Inverted F Antenna (PIFA) for wireless body area network (WBAN) applications. The major challenges like providing adequate thickness, uniformity of surface, and water wet ability associated with paper substrate have been transcended in this antenna design by laminating the substrate with a transparent sheet. The simulated and measured reflection coefficients of the fabricated antenna in free space and on human arm are remarkably good, validating the prototype's utility. It can operate effectively in GSM, WMTS, GPS, DCS, ISM, WiMAX, HIPERLAN, WLAN, and UWB frequency bands with S11 less than -10 dB and the gain ranging from 0.94 to 9.53 dB (free space) and 1.03 to 6.07 dB (on-body). The electrical size of the proposed antenna is 0.16 λg x 0.12 λg at 0.7 GHz with a group delay below 2.3 ns over the desired frequency bands. The performance characteristics are also investigated on-body and it encompasses most of the desired frequency bands for the body area network. This paper also analyses the specific absorption rate (SAR) of the designed antenna by placing it on a tissue-layered human arm model, which is 0.64 Watt/kg, complying with the SAR safety guidelines. [ABSTRACT FROM AUTHOR]

Food quality and safety are important to protect consumers from foodborne illnesses. Currently, laboratory scale analysis, which takes several days to complete, is the main way to ensure the absence of pathogenic microorganisms in a wide range of food products. However, new methods such as PCR, ELISA, or even accelerated plate culture tests have been proposed for the rapid detection of pathogens. Lab-on-chip (LOC) devices and microfluidics are miniaturized devices that can enable faster, easier, and at the point of interest analysis. Nowadays, methods such as PCR are often coupled with microfluidics, providing new LOC devices that can replace or complement the standard methods by offering highly sensitive, fast, and on-site analysis. This review's objective is to present an overview of recent advances in LOCs used for the identification of the most prevalent foodborne and waterborne pathogens that put consumer health at risk. In particular, the paper is organized as follows: first, we discuss the main fabrication methods of microfluidics as well as the most popular materials used, and then we present recent literature examples for LOCs used for the detection of pathogenic bacteria found in water and other food samples. In the final section, we summarize our findings and also provide our point of view on the challenges and opportunities in the field. [ABSTRACT FROM AUTHOR]

Electrochemical immunosensors comprise the merging of two different disciplines: molecular biology and electrochemistry. This review explains in depth the main parts of electrochemical immunosensors and how the enzyme‐linked immunosorbent assay (ELISA) has been integrated into sophisticated "lab‐on‐a‐chip" and "point‐of‐care" devices. It also reviews how nanotechnology has been a powerful tool for achieving lower detection limits, more signal amplification, and constructing label‐free devices. It finally explores the new perspectives on electrochemical immunosensors to integrate them in novel paper microfluidic devices called EμPADs. Colleagues introducing themselves to the topic for the first time will find in this review a comprehensive revision of how the basics of the technology have given rise to the emerging topic of EμPADs. [ABSTRACT FROM AUTHOR]

In paper-based microfluidics, the simplest devices are colorimetric, giving qualitative results. However, getting quantitative data can be quite a bit more difficult. Distance-based devices provide a user-friendly means of obtaining quantitative data without the need for any additional equipment, simply by using an included ruler or calibrated markings. This article details the development of a quantitative DNA detection device that utilizes the aggregation of polystyrene microspheres to affect the distance that microspheres wick through filter paper. The microspheres are conjugated to single-stranded DNA (ssDNA) oligomers that are partially complementary to a target strand and, in the presence of the target strand, form a three-strand complex, resulting in the formation of aggregates. The higher the concentration of the target strand, the larger the aggregate, and the shorter the distance wicked by the microspheres. This behavior was investigated across a wide range of target concentrations and under different incubation times to understand aggregate formation. The device was then used to successfully detect a target strand spiked in extracted plant DNA.

Nucleic acid amplification testing (NAAT) is the gold standard for infectious disease diagnostics. Currently NAATs are mainly limited to centralized laboratories, while paper‐based antigen tests are used for rapid home‐based diagnostics. DNA extraction, the initial sample preparation step in NAATs, remains a bottleneck that hinders its development toward home‐based kits. This step requires the use of compounds detrimental to the enzymes in downstream DNA amplification. Here, this work overcomes this bottleneck by immobilizing the enzyme achromopeptidase (ACP) on nitrocellulose, to both store and enable the separation of the enzymes from the other steps. This work provides proof‐of‐concept that immobilized ACP is effective at lysis and release of amplifiable DNA from gram‐positive Staphylococcus epidermidis and enables the use of the lysate directly for DNA amplification, without the need for heat deactivation of the enzyme. This sample preparation method requires only incubation at 37 °C and mild agitation, which allows to implement it with fully disposable and affordable equipment. Consequently, this work enables to combine the paper‐based DNA extraction method with the isothermal recombinase polymerase amplification (RPA) followed by lateral flow detection to demonstrate a sample‐to‐answer NAAT packaged as an instrument free self‐test kit expanding the capabilities of home‐testing beyond antigen tests. [ABSTRACT FROM AUTHOR]

As a human-computer interaction technology for the Internet of Things (IoT), non-contact humidity sensors have been widely explored. However, traditional humidity sensors have become a bottleneck in the development of flexible electronics owing to their complex processes and non-degradability. Here, bacterial cellulose (BC) and MWCNT were sequentially coated on paper to construct a durable and highly sensitive bacterial cellulose/MWCNT humidity sensor (BCNT). The BC endows the paper substrate with dense structure and significantly reduces the consumption of active materials (6.7 times reduction). Further, the well-dispersed CNT coating forms an interlocking structure with the BC nano-network, which results in a high mechanical strength (66.3 MPa). The maximum response of BCNT02 can be up to 94.5% (− ΔI/I0) under 98% RH, and the response and recovery times were 150 and 297 s, respectively. Moreover, the high humidity sensitivity of the BCNT make it an excellent choice for research and development of humidity sensors for respiration detection, non-contact switching and humidity localization. [ABSTRACT FROM AUTHOR]

Tuberculosis (TB) poses a serious threat to human health and social development. Accurate diagnosis of mycobacterium tuberculosis infection plays a critical role in the prevention and treatment of tuberculosis. Interferon-γ (INF-γ) release assay (IGRA) is currently the only quantitative tuberculosis infection diagnosis method. An accurate, fast, and easily handled INF-γ detection method is the key to obtaining accurate results. Herein, we report a novel paper-based electrochemiluminescence (ECL) method based on lateral flow immunosensors that combines the easy handling characteristics of immunochromatography and the high sensitivity of electrochemiluminescence to detect IFN-γ. To our knowledge this is the first INF-γ detection method that combines immunochromatography with electrochemiluminescence. The paper-based ECL-LFI test consists of a sample pad, conjugation pad (with binding antibody IFN-γ-Ab1 conjugated with ruthenium tripyridine), detection pad (with capture antibody IFN-γ-Ab2 immobilized on nanospheres), absorbent pad, and electrode for signal activation. The ECL signal is obtained by cyclic voltammetry scanning at a speed of 0.1 V/s in the detection area of the paper-based ECL-LFI test. In our experiments, the paper-based ECL-LFI test exhibited a minimum detection limit of 2.57 pg/mL within 12 min, and a broad detection range of 2.57–5,000 pg/mL, with repeatability of 8.10% and stability of 4.97%. With the advantage of high accuracy and sensitivity, easy handling, and low user training requirements, this ECL-LFI test might be used as point-of-care testing (POCT) in the IGRA for tuberculosis diagnosis.

Abstract Introduction The Ministry of Public Health in Lebanon is in the process of converting the surveillance reporting from a cumbersome paper-based system to a web-based electronic platform (DHIS-2) to have real-time information for early detection of alerts and outbreaks and for initiating a prompt response. Objectives This paper aimed to document the Lebanese experience in implementing DHIS-2 for the disease surveillance system. It also targets to assess the improvement of reporting rates and timeliness of the reported data and to disclose the encountered challenges and opportunities. Methodology This is a retrospective description of processes involved in the implementation of the DHIS-2 tool in Lebanon. Initially, it was piloted for the school-based surveillance in 2014; then its use was extended in May 2017 to cover other specific surveillance systems. This included all surveillance programs collecting aggregate data from hospitals, medical centers, dispensaries, or laboratories at the first stage. As part of the national roll-out process, the online application was developed. The customized aggregated-based datasets, organization units, user accounts, specific and generic dashboards were generated. More than 80 training sessions were conducted throughout the country targeting 1290 end-users including health officers at the national and provincial levels, focal persons who were working in all public and private hospitals, laboratories, and medical centers as well. Completeness and timeliness of reported data were compared before and after the implementation of DHIS-2. The unveiled challenges and the main lessons learned during the roll-out process were discussed. Results For laboratory-based surveillance, completeness of reporting increased from 70.8% in May to 89.6% in October. Timeliness has improved from 25 to 74%. For medical centers, an improvement of 8.1% for completeness and 9.4% in timeliness was recorded before and after training sessions. For zero reporting, completeness remains the same (88%) and timeliness has improved from 74 to 87%. The main challenges faced during the implementation of DHIS-2 were mainly infrastructural and system-related in addition to poor internet connectivity, limited workforce, and frequent changes to DHIS-2 versions. Conclusion Implementation of DHIS-2 improved timeliness and completeness for aggregated data reporting. Continued on-site support, monitoring, and system enhancement are needed to improve the performance of DHIS-2.

Origami biosensors leverage paper foldability to develop total analysis systems integrated in a single piece of paper. This capability can also be utilized to incorporate additional features that would be difficult to achieve with rigid substrates. In this article, we report a new design for 3D origami biosensors called OriPlex, which leverages the foldability of filter paper for the multiplexed detection of bacterial pathogens. OriPlex immunosensors detect pathogens by folding nanoparticle reservoirs containing different types of nanoprobes. This releases antibody-coated nanoparticles in a central channel where targets are captured through physical interactions. The OriPlex concept was demonstrated by detecting the respiratory pathogens Pseudomonas aeruginosa (PA) and Klebsiella pneumoniae (KP) with a limit of detection of 3.4·103 cfu mL−1 and 1.4·102 cfu mL−1, respectively, and with a turn-around time of 25 min. Remarkably, the OriPlex biosensors allowed the multiplexed detection of both pathogens spiked into real bronchial aspirate (BAS) samples at a concentration of 105 cfu mL−1 (clinical infection threshold), thus demonstrating their suitability for diagnosing lower tract respiratory infections. The results shown here pave the way for implementing OriPlex biosensors as a screening test for detecting superbugs requiring personalized antibiotics in suspected cases of nosocomial pneumonia. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, a “green” electrochemical paper-based device (ePAD) for the voltammetric determination of Tl(I) is described. A mini voltammetric cell was patterned on chromatographic paper by using screen printing to deposit three carbon electrodes and plotting with hydrophobic ink to form a circular assay zone. The sample was added to the assay zone (which was pre-loaded with Bi(III)) and Tl(I) was quantified using anodic stripping voltammetry (ASV). The experimental conditions and potential interferences were studied. The limit of detection was at the low μg L−1 level, indicating that these devices can serve successfully as fit-for-purpose disposable voltammetric sensors for Tl(I).

Objective To establish a simple and rapid paper-based extraction method for human papilloma virus (HPV) DNA and to evaluate the method. Methods The plasmid containing HPV type 16 gene fragment was employed as the test subjects, and then 6 different paper materials were compared and selected by ultraviolet spectrophotometry and real-time fluorescence quantitative PCR (qPCR). Then, according to the efficiency of nucleic acid extraction and the optimal binding area, a convenient paper strip was designed. Finally, the designed paper strip was applied to extract HPV DNA from 18 clinical cervical exfoliated cell samples (13 positives and 5 negatives), with its performance being evaluated after comparing with the conventional boiling method. Results The qualitative filter paper with a nucleic acid binding zone of 2 mm×10 mm could successfully extract HPV DNA from clinical cervical exfoliated cells. When this test strip was used for DNA extraction, all the 13 high-risk HPV positives were successfully detected out of the 18 clinical samples, which was consistent with the results of the conventional boiling method. In addition, the extraction time of the test strip was less than 1 min for each sample, with a detection limit of 8×102 copies/mL and relative standard deviation of 1.15%. Conclusion Our paper-based rapid extraction for HPV DNA does not require pipetting, heating and centrifugation, and the eluent can be directly used as the PCR template for amplification, which greatly simplifies the extraction process of HPV DNA from clinical cervical exfoliated cell samples.

A novel assay platform consisting of a microfluidic sliding double-track paper-based chip and a hand-held Raspberry Pi detection system is proposed for determining the albumin-to-creatine ratio (ACR) in human urine. It is a clinically important parameter and can be used for the early detection of related diseases, such as renal insufficiency. In the proposed method, the sliding layer of the microchip is applied and the sample diffuses through two parallel filtration channels to the reaction/detection areas of the microchip to complete the detection reaction, which is a simple method well suited for self-diagnosis of ACR index in human urine. The RGB (red, green, and blue) value intensity signals of the reaction complexes in these two reaction zones are analyzed by a Raspberry Pi computer to derive the ACR value (ALB and CRE concentrations). It is shown that the G + B value intensity signal is linearly related to the ALB and CRE concentrations with the correlation coefficients of R2 = 0.9919 and R2 = 0.9923, respectively. It is additionally shown that the ALB and CRE concentration results determined using the proposed method for 23 urine samples were collected from real suffering chronic kidney disease (CKD) patients are in fine agreement with those acquired operating a traditional high-reliability macroscale method. Overall, for point-of-care (POC) CKD diagnosis and monitoring in clinical applications, the results prove that the proposed method offers a convenient, real time, reliable, and low-spending solution for POC CKD diagnosis. [ABSTRACT FROM AUTHOR]

Commercial Chinese ink was employed to disperse pristine vapor-grown carbon nanofibers (VGCNFs) in aqueous suspensions via horizontal ball milling. The obtained suspension was used to fabricate conductive paper-based composites through filtration-deposition onto filter paper. It was found that the carbon black particles from the Chinese ink helped separate VGCNFs and acted as connection points between the VGCNFs, while the glue reinforced the conduction network. Thus, the VGCNF-ink/paper ternary composite showed sufficiently low sheet resistance. With merely 2.5 mg·cm−2 VGCNFs, the sheet resistance could be reduced to 4.5 Ω·sq−1. As a proof of concept, these paper-based composites were directly used as electrodes of solid-state symmetric electronic double-layer capacitors (EDLCs) and the substrate for the electrodeposition of MnO2 to achieve higher electrochemical performances. The EDLCs fabricated with 2.5 mg·cm−2 VGCNFs showed a specific capacitance of 224 mF·cm−2 at a current density of 1 mA·cm−2, which was retained by 86.4% after 10,000 charge-discharge cycles. Moreover, thanks to the high electrical conductivity and the porous structure, the MnO2 decorated paper-based composites exhibited dramatically enhanced specific capacitance. It is believed that our finding offers an idea to directly utilize commercial Chinese ink for the fabrication of electrode materials.

Food quality and safety are important to protect consumers from foodborne illnesses. Currently, laboratory scale analysis, which takes several days to complete, is the main way to ensure the absence of pathogenic microorganisms in a wide range of food products. However, new methods such as PCR, ELISA, or even accelerated plate culture tests have been proposed for the rapid detection of pathogens. Lab-on-chip (LOC) devices and microfluidics are miniaturized devices that can enable faster, easier, and at the point of interest analysis. Nowadays, methods such as PCR are often coupled with microfluidics, providing new LOC devices that can replace or complement the standard methods by offering highly sensitive, fast, and on-site analysis. This review’s objective is to present an overview of recent advances in LOCs used for the identification of the most prevalent foodborne and waterborne pathogens that put consumer health at risk. In particular, the paper is organized as follows: first, we discuss the main fabrication methods of microfluidics as well as the most popular materials used, and then we present recent literature examples for LOCs used for the detection of pathogenic bacteria found in water and other food samples. In the final section, we summarize our findings and also provide our point of view on the challenges and opportunities in the field.

Abnormal glucose level can cause irreversible damage, including diabetes. In this work, a sensor was designed that mimics the peroxidase property of the natural horseradish peroxidase (HRP). The proposed sensor detects the presence of glucose through the reduction of hydrogen peroxide (H2O2) and the oxidation of tetramethylbenzidine (TMB). This sensor shows linear behaviour in the range of 0.001–50 μM with a limit of detection down to 0.8 nM. In addition, a paper‐based format of this sensing platform was performed which enables fast and sensitive detection and further reduces the expenses. In this method the linear behaviour of the sensor is between 0.005–40 μM and the detection limit is as low as 2.4 nM. The glucose detection in human saliva was also performed, showing an acceptable accuracy. Thus the sensor is practically suitable for the non‐invasive detection of glucose. [ABSTRACT FROM AUTHOR]

Since 2020, human pharmaceuticals were included in the list of emerging contaminants from the UNESCO and their detection and elimination were incorporated in the 2030 Agenda for Sustainable Development Goal Targets. Among these, analgesic and antipyretic drugs are the most widely used drugs worldwide and, despite their advantages, unused or expired pharmaceuticals are a potential source of water pollution. Paracetamol is one of the most common drugs used for analgesic and antipyretic purposes and has been found to have a much higher concentration in water streams in many European countries. Considering that, an all-in-one paper-based 2 dimensional (2D) fluidic configuration, able to detect paracetamol, was developed in order to deal with environmental matrices without complex/expensive analytical procedures. An ad-hoc paper-based testing area, coupled with a channel was designed and wax-printed onto a porous filter paper. Successively three electrodes were screen-printed, and the whole system was applied for the detection of paracetamol in wastewaters (prior and after the filtration system) without pretreating the sample. In order to detect paracetamol with the easiest approach, the configuration of the paper-based device was optimized in terms of type of substrate used for printing, microfluidic paper strip length/width and combination of them in an integrated architecture, capable to detect paracetamol in the matrices tested in few seconds with a detection limit down to micromolar range, ca. 1 μM. The integrated device shown great promise for simple, fast, sensitive, and sustainable detection of paracetamol in its role of emerging contaminant, especially in the environmental matrices. [ABSTRACT FROM AUTHOR]

Triple-negative breast cancer (TNBC) is one of the most aggressive and lethal types of BC, affecting mostly young women and its diagnosis is difficult and requires invasive methods, such as tissue biopsy which is painful and expensive. However, nowadays liquid biopsy is emerging as a great tool for determining blood-circulating species associated to cancer and to its early diagnosis and prognosis. Among the species, the relevance of microRNAs (miRNAs) has been highlighted as promising biomarker, and miRNA-652 has been associated with TNBC as it promotes the growth and migration of cancer cells. In this work we designed and characterized a paper-based electrochemical device capable of recognizing and quantifying miRNA-652, as future tool for liquid biopsy in TNBC. The device consists of an AuNP-modified office paper-based screen-printed electrode customized with an anti-miRNA probe for the selective recognition of miRNA-652. All the experimental parameters have been carefully evaluated, and the platform allowed to detect miRNA-652 in standard solution and human serum down to 0.4 nM, with a satisfactory repeatability of about 6 and 3 % respectively. The selectivity presence of other miRNA sequences was satisfactory demonstrated. In addition, we demonstrated the effectiveness of pre-concentration of miRNA by coupling the office paper-based electrode with an external disk made by chromatographic paper: the detection limit has been improved of 10-fold without the use of complex/expensive procedures. The presented manuscript represents an important step towards the development of a non-invasive, sensitive and TNBC-specific diagnostic platform that could improve patients' prognosis and quality of life, ulteriorly improved with pre-concentering properties of frugal supports as the external chromatographic paper-based ones. [Display omitted] [ABSTRACT FROM AUTHOR]

Introduction: The Ministry of Public Health in Lebanon is in the process of converting the surveillance reporting from a cumbersome paper-based system to a web-based electronic platform (DHIS-2) to have real-time information for early detection of alerts and outbreaks and for initiating a prompt response.Objectives: This paper aimed to document the Lebanese experience in implementing DHIS-2 for the disease surveillance system. It also targets to assess the improvement of reporting rates and timeliness of the reported data and to disclose the encountered challenges and opportunities.Methodology: This is a retrospective description of processes involved in the implementation of the DHIS-2 tool in Lebanon. Initially, it was piloted for the school-based surveillance in 2014; then its use was extended in May 2017 to cover other specific surveillance systems. This included all surveillance programs collecting aggregate data from hospitals, medical centers, dispensaries, or laboratories at the first stage. As part of the national roll-out process, the online application was developed. The customized aggregated-based datasets, organization units, user accounts, specific and generic dashboards were generated. More than 80 training sessions were conducted throughout the country targeting 1290 end-users including health officers at the national and provincial levels, focal persons who were working in all public and private hospitals, laboratories, and medical centers as well. Completeness and timeliness of reported data were compared before and after the implementation of DHIS-2. The unveiled challenges and the main lessons learned during the roll-out process were discussed.Results: For laboratory-based surveillance, completeness of reporting increased from 70.8% in May to 89.6% in October. Timeliness has improved from 25 to 74%. For medical centers, an improvement of 8.1% for completeness and 9.4% in timeliness was recorded before and after training sessions. For zero reporting, completeness remains the same (88%) and timeliness has improved from 74 to 87%. The main challenges faced during the implementation of DHIS-2 were mainly infrastructural and system-related in addition to poor internet connectivity, limited workforce, and frequent changes to DHIS-2 versions.Conclusion: Implementation of DHIS-2 improved timeliness and completeness for aggregated data reporting. Continued on-site support, monitoring, and system enhancement are needed to improve the performance of DHIS-2. [ABSTRACT FROM AUTHOR]

How to monitor the freshness of packaged food, the safety of sealed medicine, or the other substances in sealed space wirelessly and environment‐friendly has become an urgent problem in recent years. After summarizing the theory of the LC sensor, a design of a paper‐based resonator (30 mm × 30 mm × 0.15 mm) consisting of a finger capacitor is proposed in this paper. The sensor is embedded inside the package by adhering it to the package's inner wall. Its response is remotely detected through a readout coil. This paper establishes a circuit simulation model and an electromagnetic simulation model to verify the feasibility of the design. Compared with the real object and the theoretical simulation model, the difference between the results only within 1 MHz, which verifies the correctness of the theory. Additionally, the measured results indicate that the resonant frequency of the resonator shifted from 102.441 MHz to 88.195 MHz, after dropping water on the sensor. Besides, the simple fabrication technology and inexpensive sensor material ensure a low cost, thus making this technology economically viable. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic has resulted in significant global social and economic disruption. The highly transmissive nature of the disease makes rapid and reliable detection critically important. Point-of-care (POC) tests involve performing diagnostic tests outside of a laboratory that produce a rapid and reliable result. It therefore allows the diagnostics of diseases at or near the patient site. Paper-based POC tests have been gaining interest in recent years as they allow rapid, low-cost detection without the need for external instruments. In this review, we focus on the development of paper-based POC devices for the detection of SARS-CoV-2. The review first introduces the principles of detection methods that are available to paper-based devices. It then summarizes the state-of-the-art paper devices and their analytical performances. The advantages and drawbacks among methods are also discussed. Finally, limitations of the existing devices are discussed, and prospects are given with the hope to identify research opportunities and directions in the field. We hope this review will be helpful for researchers to develop a clinically useful and economically efficient paper-based platform that can be used for rapid, accurate on-site diagnosis to aid in identifying acute infections and eventually contain the COVID-19 pandemic.

Chlorpyrifos (CPF) residues in food pose a serious threat to ecosystems and human health. Herein, we propose a three-dimensional folded paper-based microfluidic analysis device (3D-μPAD) based on multifunctional metal-organic frameworks, which can achieve rapid quantitative detection of CPF by fluorescence-colorimetric dual-mode readout. Upconversion nanomaterials were first coupled with a bimetal organic framework possessing peroxidase activity to create a fluorescence-quenched nanoprobe. After that, the 3D-μPAD was finished by loading the nanoprobe onto the paper-based detection zone and spraying it with a color-developing solution. With CPF present, the fluorescence intensity of the detection zone gradually recovers, the color changes from colorless to blue. This showed a good linear relationship with the concentration of CPF, and the limits of detection were 0.028 (fluorescence) and 0.043 (colorimetric) ng/mL, respectively. Moreover, the 3D-μPAD was well applied in detecting real samples with no significant difference compared with the high-performance liquid chromatography method. We believe it has huge potential for application in the on-site detection of food hazardous substance residues.

Bimetallic-metal organic frameworks (BiM-MOFs) or bimetallic organic frameworks represent an innovative and promising class of porous materials, distinguished from traditional monometallic MOFs by their incorporation of two metal ions alongside organic linkers. BiM-MOFs, with their unique crystal structure, physicochemical properties, and composition, demonstrate distinct advantages in the realm of biochemical sensing applications, displaying improvements in optical properties, stability, selectivity, and sensitivity. This comprehensive review explores into recent advancements in leveraging BiM-MOFs for fluorescence-based biochemical sensing, providing insights into their design, synthesis, and practical applications in both chemical and biological sensing. Emphasizing fluorescence emission as a transduction mechanism, the review aims to guide researchers in maximizing the potential of BiM-MOFs across a broader spectrum of investigations. Furthermore, it explores prospective research directions and addresses challenges, offering valuable perspectives on the evolving landscape of fluorescence-based probes rooted in BiM-MOFs.

Commercial Chinese ink was employed to disperse pristine vapor-grown carbon nanofibers (VGCNFs) in aqueous suspensions via horizontal ball milling. The obtained suspension was used to fabricate conductive paper-based composites through filtration-deposition onto filter paper. It was found that the carbon black particles from the Chinese ink helped separate VGCNFs and acted as connection points between the VGCNFs, while the glue reinforced the conduction network. Thus, the VGCNF-ink/paper ternary composite showed sufficiently low sheet resistance. With merely 2.5 mg·cm−2 VGCNFs, the sheet resistance could be reduced to 4.5 Ω·sq−1. As a proof of concept, these paper-based composites were directly used as electrodes of solid-state symmetric electronic double-layer capacitors (EDLCs) and the substrate for the electrodeposition of MnO2 to achieve higher electrochemical performances. The EDLCs fabricated with 2.5 mg·cm−2 VGCNFs showed a specific capacitance of 224 mF·cm−2 at a current density of 1 mA·cm−2, which was retained by 86.4% after 10,000 charge-discharge cycles. Moreover, thanks to the high electrical conductivity and the porous structure, the MnO2 decorated paper-based composites exhibited dramatically enhanced specific capacitance. It is believed that our finding offers an idea to directly utilize commercial Chinese ink for the fabrication of electrode materials. [ABSTRACT FROM AUTHOR]

• Developing electrowetting-on-dielectric device using office inkjet printer. • Mixing thirty-milliliter droplets using surface capillary wave at coalescence spot. • Characterizing enhanced salute diffusivity accelerated by mixing. • Improving chemiluminescence signal intensity reproducibility with mixing device. We use inkjet printing and film adhesion methods to economically develop paper-based electrowetting-on-dielectric (EWOD) mixing device. Because the periodic shrinking and stretching of droplet contact line induces surface capillary wave, the coalesced droplet on EWOD device vibrates to accelerate solute mixing on the merged spot. An office inkjet printer fabricates pads of conducting silver nanoparticles to compose EWOD activation electrodes on a piece of glossy label paper, covered with one oil-coated dielectric film. Using the triggering relays of each pad, two droplets of thirty microliter individually loaded on the electrode ends are driven to coalesce. Alloy nanorod-catalyzed chemiluminescence assay can be performed on this mixing device. When ac voltage of 100 Hz is applied on the electrode flakes, compared with solute transport efficiency in static condition, solute diffusivity is enhanced by 4 times using this mixing device. Linear relation (R2 = 0.99) between luminescence intensity acquired with smartphone camera and luminol concentration of aforementioned chemiluminescence assay is obtained, demonstrating reproducibility improvement for accurate determination. [Display omitted] [ABSTRACT FROM AUTHOR]

A novel assay platform consisting of a microfluidic sliding double-track paper-based chip and a hand-held Raspberry Pi detection system is proposed for determining the albumin-to-creatine ratio (ACR) in human urine. It is a clinically important parameter and can be used for the early detection of related diseases, such as renal insufficiency. In the proposed method, the sliding layer of the microchip is applied and the sample diffuses through two parallel filtration channels to the reaction/detection areas of the microchip to complete the detection reaction, which is a simple method well suited for self-diagnosis of ACR index in human urine. The RGB (red, green, and blue) value intensity signals of the reaction complexes in these two reaction zones are analyzed by a Raspberry Pi computer to derive the ACR value (ALB and CRE concentrations). It is shown that the G + B value intensity signal is linearly related to the ALB and CRE concentrations with the correlation coefficients of R2 = 0.9919 and R2 = 0.9923, respectively. It is additionally shown that the ALB and CRE concentration results determined using the proposed method for 23 urine samples were collected from real suffering chronic kidney disease (CKD) patients are in fine agreement with those acquired operating a traditional high-reliability macroscale method. Overall, for point-of-care (POC) CKD diagnosis and monitoring in clinical applications, the results prove that the proposed method offers a convenient, real time, reliable, and low-spending solution for POC CKD diagnosis.

Paper-based visual analogue scale (VAS) items were developed 100 years ago. Although they gained great popularity in clinical and medical research for assessing pain, they have been scarcely applied in other areas of psychological research for several decades. However, since the beginning of digitization, VAS have attracted growing interest among researchers for carrying out computerized and paper-based data assessments. In the present study, we investigated the research question "Which different design characteristics of paper-based VAS items are preferred by women and men?" Based on a sample of 115 participants (68 female), our results revealed that the respondents preferred a paper-based VAS item with a horizontal, 8-cm long, 3 DTP ("desktop publishing point") wide, black line, with flat line endpoints, and the ascending numerical anchors "0" and "10", both for women and men. Although we did not identify any gender difference in these characteristics, our findings uncovered clear preferences on how to design paper-based VAS items. [ABSTRACT FROM AUTHOR]