Handheld Reader Research Articles

Modular Point-of-Need Tropane Alkaloid Detection at Regulatory Levels: Combining Solid-Liquid Extraction from Buckwheat with a Paper-Immobilized Liquid-Phase Microextraction and Immuno-Detection in Interconnectable 3D-Printed Devices.

Contamination with tropane alkaloids in cereals is expected to increase globally. However, current identification tools (e.g., liquid chromatography-mass spectrometry) for tropane alkaloids are time-consuming and expensive. Furthermore, their miniaturized alternatives lack sensitivity and robustness. Therefore, there is a pressing need for inexpensive and effective screening methods. Here, an on-site applicable modular workflow for tropane alkaloid detection in buckwheat is presented. The modular workflow combines paper microfluidics and interconnectable 3D-printed sample preparation tools and was evaluated for different tropane alkaloids, including atropine and scopolamine. Furthermore, integration with an indirect competitive lateral flow immunoassay (icLFIA) for atropine detection at relevant levels was demonstrated. In the modular workflow, to minimize matrix coextraction, tropane alkaloids were extracted from the milled buckwheat cereals by a mixture of alkaline aqueous and immiscible organic solvents (extraction recoveries: 66-79%). The tropane alkaloids were subsequently concentrated with a newly developed paper-immobilized liquid-phase microextraction (PI-LPME, extraction recoveries: 34-60%, concentration factor to immobilized solution in paper: 60-108×). After the PI-LPME, with an integrated 3D-printed setup, the tropane alkaloids were directly eluted (elution recoveries: 83-93%) and detected with the icLFIA. Digital read-out of the icLFIA, by employing a hand-held reader, enabled semiquantification of atropine (IC50 = 0.56 ng mL-1 in standard solutions). The modular workflow was validated by analyzing 24 blank and spiked buckwheat cereal samples with 5 and 10 μg kg-1 atropine. A cutoff value was established with an estimated false negative rate of 1% and estimated false positive rate of 0.68%. Therefore, the modular workflow can aid in fast, inexpensive, and on-site atropine detection by nonexperts, and when integrated with a scopolamine-specific icLFIA expanded toward scopolamine detection. Moreover, the developed sample extraction and concentration method (PI-LPME) is suitable for the analysis of many other compounds with pH-dependent polarity.

A-348 Portable aptamer-based home monitoring system for blood phenylalanine measurement

Abstract Background Aptatek BioSciences, Inc. has developed a home monitoring tool for blood phenylalanine (phe) levels. The Aptatek system integrates a proprietary aptamer assay approach with a user-friendly handheld, smartphone-enabled test platform. PKU (phenylketonuria), is an inborn error of phenylalanine (Phe) metabolism If undiagnosed or untreated, phe accumulates in all body tissues, including the blood and brain, where it is especially neurotoxic and when untreated it can cause significant cognitive impairment and neurological defects. PKU management targets maintaining blood Phe concentration within the therapeutic range (120-360uM) to avoid severe neurological sequelae, mainly through nutritional therapy. Methods PheCheck™ includes a portable hand-held reader, software accessible as a mobile phone application, and a disposable single-use lateral flow cassette, blood collection, cap, and buffer chamber. PheCheck™ detects phe by binding of the phe in a small blood sample using small molecule-specific DNA aptamers. A patient (or caregiver) collects 5μl of capillary blood using a lancet to lance the fingertip and use the collection cap to collect the specimen. Once collected, the specimen is placed into the buffer chamber where the blood is diluted and processed in preparation for a lateral flow assay. The buffer chamber is placed on top of a lateral flow cassette to release the solution into the cassette. The lateral flow cassette is inserted into a small electronic reader after specimen incubation. The reader will detect a fluorescent signal from the strip and report the quantitative Phe concentration present in the specimen to the integrated mobile phone application. The reader has a simple design with a single operating push button, USB data connection port, and replaceable battery compartment. The reader reads the output of the lateral flow cassette and reports the result to a Smartphone app. The app is designed to either display the quantitative results or store the results without displaying the quantitative value. Results Twelve patients were trained on the PheCheck system and observed using the system for self-testing. Patients also prepared dried blood spot cards for comparative testing using LC-mass spectrometry. Patients were asked to return to the clinic within two weeks to retest. The blood phenylalanine levels measured by the PheCheck system were within targeted standard deviation of the dried blood spots demonstrating the feasibility of portable home-based testing for routine monitoring of blood phenylalanine levels in phenylketonuria patients. Such a portable system would enable real time monitoring and adjustment of diet or therapy for chronic diseases such as PKU. Conclusions Aptatek has developed a DNA aptamer based portable monitor for measuring blood phenylalanine levels. The system quantitatively measures phenylalanine from a 5-microliter finger stick blood sampler. Aptamer-based detection of phenylalanine provides reliable quantitation across a wide clinical concentration range and encouraging performance relative to gold standard testing of venous blood draw or dried blood spots. Analysis of samples from patients on Palynziq indicate that the PheCheck system could provide more reliable testing than venous blood draws. The system shows strong promise for routine home monitoring of blood phe levels by patients.

Enhanced Detection of Klebsiella Pneumoniae Using Electric-Double-Layer FET Sensor: Rapid, Temperature-Boosted Probe-Target Binding Analysis

Klebsiella pneumoniae demonstrates versatility in its pathogenicity, leading to diverse infections in humans such as pneumonia, urinary tract infections, bacteremia, wound infections, meningitis, endocarditis, and sepsis. The severity of these infections is contingent upon the patient's immune status, the site of infection, and the existence of underlying medical comorbidities. A sputum or urine culture, on the other hand, typically takes between 24 and 72 hours to produce results. Over recent years, various innovative methodologies have emerged, including optical and electrochemical techniques and molecular detection via PCR. Despite the diversity of available techniques, concerns persist regarding their sensitivity and specificity. Moreover, fluorescence-based methodologies and Surface Plasmon Resonance (SPR)-based sensors have been explored for bacterial detection. However, these existing methods have drawbacks such as elevated costs, prolonged turnaround times, the need for sophisticated instrumentation, and a demand for skilled personnel. Field-effect transistor (FET) sensors have garnered considerable scientific attention since their inception due to their remarkable sensitivity, facile signal readout, and the capability for label-free assays. The aim of this research is to detect the detect Klebsiella pneumoniae bacteria in blood serum by double electric layer (EDL) extended-gate field-effect transistor (FET) sensor. In this study, a preliminary investigation employed a single-step surface functionalization approach to immobilize receptor probes, specifically single-stranded DNA (ssDNA). This strategy aimed to enable the rapid detection of complementary DNA (cDNA) across varying concentrations, leveraging differential gate voltages to modulate the sensitivity of this analytical platform. The designed probes were successfully immobilized onto a disposable chip housing a pair of gold electrodes. A handheld reader, integrating enhancement-mode N-channel MOSFETs, established connectivity with a laptop via a USB port to facilitate the measurement of sensor signals. By applying pulsed gate voltage to the input electrode, which modulates the channel conductivity which behaves as a function of the charge distribution within the EDL structure, consequently influencing the drain current of the MOSFET. The immobilized probe, positioned on the gate electrode, underwent testing using varying concentrations of cDNA introduced into TE buffer. Detection of probe-target binding occurred through fluorescence alterations and electrically by assessing changes in drain current. In order to improve the response time, we elevated the temperature near the Tm enhances sensitivity and binding rates, in shorter time period of 1 minutes. Figure 1

Spicy Recipe for At-Home Diagnostics: Smart Salivary Sensors for Point-of-Care Diagnosis of Jaundice.

Even though significant advances have been made, there is still a lack of reliable sensors capable of noninvasively monitoring bilirubin and diagnosing jaundice as the most common neonatal disease, particularly at the point-of-care (POC) where blood sampling from infants is accompanied by serious challenges and concerns. Herein, for the first time, using an easy-to-fabricate/use assay, we demonstrate the capability of curcumin embedded within paper for noninvasive optical monitoring of bilirubin in saliva. The highly selective sensing of the developed sensor toward bilirubin is attributed to bilirubin photoisomerization under blue light exposure, which can selectively restore the bilirubin-induced quenched fluorescence of curcumin. We also fabricated an IoT-enabled hand-held optoelectronic reader to measure and quantify the fluorescence and color signals of our sensor. Clinical analysis on the saliva of 18 jaundiced infants by using our developed smart salivary sensor proved that it is amenable to be widely exploited in POC applications for bilirubin monitoring as there are good correlations between its results with those of reference methods in saliva and blood. Meeting all WHO's REASSURED criteria by our developed sensor makes it a highly promising sensor for smart noninvasive diagnosis and therapeutic monitoring of jaundice, hepatitis, and other bilirubin-induced neurologic diseases at the POC.

Scanning efficacy of p-Chips implanted in the wing and leg of the Big Brown Bat (Eptesicus fuscus).

Individual marking techniques are critical for studying animals, especially in the wild. Current marking methods for bats (Order Chiroptera) have practical limitations and some can cause morbidity. We tested the p-Chip (p-Chip Corp.)-a miniaturized, laser light-activated microtransponder-as a prospective marking technique in a captive research colony of Big Brown Bats (Eptesicus fuscus). We assessed long-term readability and postimplantation effects of p-Chips injected subcutaneously above the second metacarpal (wing; n = 30) and the tibia (leg; n = 13 in both locations). Following implantation (Day 0), p-Chips were scanned with a hand-held ID reader (wand) on postimplantation days (PIDs) 1, 8, 15, 22, 32, 60, 74, 81, 88, 95, and over 1 year later (PID 464). For each trial, we recorded: (1) animal handling time; (2) scan time; (3) number of wand flashes; (4) p-Chip visibility; and (5) overall condition of the bat. Average scan times for p-Chips implanted in both the wing and leg increased over the duration of the study; however, the number of wand flashes decreased, suggesting that efficacy of p-Chip recording increased with user experience. Importantly, over 464 days both the visibility and readability of p-Chips in the wing remained high and superior to tags in the leg, establishing the second metacarpal as the preferred implantation site. Observed morbidity and mortality in captive bats with p-Chips was similar to baseline values for bats without these tags. Because scan efficiency on PID 464 was comparable with earlier days, this indicates that p-Chips implanted in the wing may be suitable as a long-term marking method. Our provisional results suggest that p-Chips are viable for extended field testing to see if they are suitable as an effective alternative to traditional methods to mark bats.

A digital image colorimetry system based on smart devices for immediate and simultaneous determination of enzyme-linked immunosorbent assays

Standard enzyme-linked immunosorbent assays based on microplates are frequently utilized for various molecular sensing, disease screening, and nanomedicine applications. Comparing this multi-well plate batched analysis to non-batched or non-standard testing, the diagnosis expenses per patient are drastically reduced. However, the requirement for rather big and pricey readout instruments prevents their application in environments with limited resources, especially in the field. In this work, a handheld cellphone-based colorimetric microplate reader for quick, credible, and novel analysis of digital images of human cancer cell lines at a reasonable price was developed. Using our in-house-developed app, images of the plates are captured and sent to our servers, where they are processed using a machine learning algorithm to produce diagnostic results. Using FDA-approved human epididymis protein of ovary IgG (HE4), prostate cancer cell line (PC3), and bladder cancer cell line (5637) ELISA tests, we successfully examined this mobile platform. The accuracies for the HE4, PC3, and 5637 tests were 93%, 97.5%, and 97.2%, respectively. By contrasting the findings with the measurements made using optical absorption EPOCH microplate readers and optical absorption Tecan microplate readers, this approach was found to be accurate and effective. As a result, digital image colorimetry on smart devices offered a practical, user-friendly, affordable, precise, and effective method for quickly identifying human cancer cell lines. Thus, healthcare providers might use this portable device to carry out high-throughput illness screening, epidemiological investigations or monitor vaccination campaigns.

Immunological strip sensor for the rapid determination of niacin in dietary supplements and foods.

Herein, four haptens of niacin (Vitamin B3, VB3) were designed, and after a series of experiments, it was concluded that hapten D had the best immune effect. To avoid false positives in the detection of real samples, a monoclonal antibody (mAb) against VB3 was prepared by a matrix effect-enhanced mAb screening method. The concentration of the inhibition rate reaching 50% (IC50) was 603.41 ng mL-1 and the limit of detection (LOD) using an indirect enzyme-linked immunosorbent assay (ic-ELISA) was 54.89 ng mL-1. A lateral flow immunochromatographic assay (LFIA) based on gold nanoparticles was established to detect the concentration of VB3 in compound vitamin B tablets and infant formulas, with a visual LOD of 5 μg mL-1. Using a handheld reader, the quantitative LOD was calculated to be 0.60 μg mL-1. The contents of the compound vitamin B tablets and infant formulas were also verified by liquid chromatography. Therefore, the LFIA developed in this study can be applied to the specific identification and rapid detection of niacin in nutritional dietary supplements, thus meeting the market's demand for efficient niacin detection methods.

A Wireless System for Monitoring Termite Activity Using Electromagnetic Induction with Non-Looping Method

Termites can cause severe economic damage in households, reservoirs, agriculture, and forests. Monitoring termite activity plays an important role in integrated termite management. A device for the automatic monitoring of termites with high accuracy and reliability is highly demanded. Here, we introduce Dekan electromagnetic induction with non-looping (DEMINL) method and a novel wireless system for the monitoring of termite activities. The system comprises of a termite bait station and a handheld reader. While the wood pieces in the bait station were consumed by termites, the device could generate alarm signals, which are sent to a signal reader (receiver) through radio frequency identification (RFID) and displayed on the handheld reader’s screen. Field tests at three locations over a two-year period showed an accurate detection rate of 97.5–98.5%. The DEMINL-based device demonstrated high accuracy and durability in detecting termites, making it suitable for termite monitoring in households, crop fields, forests, and reservoirs.

Rapid and Sensitive Pathogen Detection in Serum for Early Sepsis Diagnostics Using an Electrical-Double-Layer Gated Field-Effect Transistor-Based Sensor Array

Sepsis is a major medical inflammatory response to bloodstream infection caused bypathogens. Over 30 million infections occur due to sepsis in a year throughout the globe.With over 6 million deaths, sepsis treatment demands timely diagnosis and medicalinterventions to prevent large outspread of the infection. Rapid and sensitive detection ofinfectious bacteria plays an important role in disease control. However, fast and accuratediagnosis remains highly challenging for many hospitalized patients. Among variousbacterial diseases, Escherichia coli, (E. coli) a gram-negative bacterium, is the mostfrequently and extensively researched and has become a global concern of food safetyproblems. Traditional cell culture methods are considered as most accurate method forbacterial diagnosis. But some microorganisms like Bartonella spp, Treponema pallidum, etc.are difficult to grow on a culture plate, while some other virus species are unculturable, soeventually the traditional cell culture may take several days to a week for the diagnosticresults. Hence, over several years, different novel methods have been developed, such asoptical methods, electrochemical methods, molecular detection by PCR etc. Even thoughseveral techniques exist, concerns have been raised regarding their sensitivity, specificity etc.In addition, various fluorescence-based methods, and Surface Plasmon resonance (SPR)-based sensors have also been reported for bacterial detection. However, high cost, largeturnaround time, expensive instrumentation, and requirement of skilled personnel are some ofthe disadvantages of these existing techniques.FET biosensors have previously been used in different diagnosis areas. Nowadays, severalFET-based biosensors have been developed, which primarily concentrate on improving theoverall sensitivity of FET devices. However, the charge screening effect observed in aphysiological environment, and additional sample processing increase the complexity of thesensor platform. To overcome this hurdle, an electrical double layer (EDL) gated FETbiosensor has been proposed and explored in the detection of a variety of biological entities.Here, we proposed an EDL-FET sensor platform for the detection of Escherichia coliO157:H7 strain in blood serum. A single-step surface functionalization strategy was used forimmobilizing receptor probes as ssDNA. The probes were designed and immobilized over adisposable chip containing a pair of gold electrodes. A handheld reader which consists of anenhancement mode N-channel MOSFETs was connected to the laptop through a USB port tomeasure the sensor signals. Pulsed gate voltage was applied to the input electrode and whichmodulated the EDL capacitance and potential change eventually resulting in the drain currentof the MOSFET. The probe was immobilized on the gate electrode and tested with differentconcentrations of cDNA spiked in TE buffer. The probe-target binding was observed throughfluorescence change and electrically by measuring the change in drain current. In addition,surface potential change was also examined by performing KPFM test. Similarly, the BioFETdetections were validated for E. coli O157 variants by spiking with short and long DNAtarget sequences simultaneously in serum. The test results confirm selectivity by testingvarious non-complementary sequences, which ensures the potential of this BioFET as apoint-of-care sensing device. Figure 1

Rapid detection of bacterial load in food samples using disposable respirometric sensor sachets

We describe a new sensor platform for simple on-site analysis of total aerobic viable counts (TVCs) in food samples, which uses disposable sealable plastic sachets with phosphorescent oxygen sensor inserts and liquid growth media. Food samples are collected, placed directly in the sachets, which are then sealed and incubated at 30 °C while monitoring (hourly or endpoint) sensor signals non-invasively with a commercial handheld reader FirestingO2. The growth of microbiota produces characteristic respiration profiles, from which sample initial TVC load is quantified: the Threshold Time (TT, in hours), when the sensor signal reaches the set signal threshold, is determined and calibration equation is applied to it to calculate sample TVC load. The initial calibration equation, which provides the conversion of measured TT values (hours) into TVC, was generated with pure Escherichia coli culture: log(CFU/g) = 8.30–0.60 *TT25 ° for signal threshold of 25 degrees phase. Another calibration equation, which provides a better representation of whole food microbiota, was generated with a panel of 90 different food samples: log(CFU/g) = 8.53–0.60 *TT25°. This simple sensor system shows good correlation with traditional plate counting TVC method (ISO 4833) and suitability for autonomous on-site or in-field operation. Time to result of 1–6 h provided by the sensor sachet system is more than seven time faster than for the standard method.

Point-of-care testing: a disposable label-free electrochemical CA125 and HE4 immunosensors for early detection of ovarian cancer.

Cancer antigen 125 (CA125) and human epididymal secretory protein 4 (HE4) are critical biomarkers for ovarian cancer diagnosis and progression monitoring; therefore, sensitive determination of their levels in body fluids is crucial. In recent study, label-free CA125 and HE4 immunosensors were prepared using disposable screen-printed carbon electrodes modified with reduced graphene oxide, polythionine, and gold nanoparticles for the sensitive, fast, and practical determination of CA125 and HE4. Differential pulse voltammetry, square wave voltammetry, and electrochemical impedance spectroscopy methods were used for the electrochemical determination of antigens in four different linear ranges (1-100 pg mL- 1, 0.01-10 ng mL- 1, 10-50 ng mL- 1, and 50-500 ng mL- 1). High sensitivity, low limit of detection, and limit of quantification were obtained for each linear range with a correlation coefficient above 0.99. The application stability of CA125 and HE4 immunosensors was determined as 60 days, and the storage stability was determined as 16 weeks. Immunosensors showed high selectivity in nine different antigen mixtures. The reusability of the immunosensors has been tested up to 9 cycles. The Risk of Ovarian Malignancy Algorithm score% values were calculated using the concentration of CA125 and HE4 in the blood serum and evaluated in terms of ovarian cancer risk. For the point-of-care testing, CA125 and HE4 levels at pg mL- 1 concentration were measured in blood serum samples using the developed immunosensors and a hand-held electrochemical reader in approximately 20-30s, and high recoveries were obtained. These disposable label-free immunosensors are user-friendly and can be used in point-of-care tests for rapid and practical detection of CA125 and HE4 with high selectivity, sensitivity, and repeatability.

The usage of RFID robots in logistics process management

The aim of this post is to point out the use of RFID robots in the management of logistics processes. RFID technology is defined first. RFID technology represents identification using radio frequency waves. The principle is to store the necessary data in radio frequency memory chips and then repeatedly read or write the data using a reader. We divide RFID chips into active and passive. Active RFID chips use energy from a battery, while passive RFID chips are a technology without an internal power source. Passive RFID is the most common form of RFID in warehouses, using which inventory is taken using RFID robots or hand-held RFID readers. Nowadays, many RFID robots from different manufacturers are available on the market. When choosing, I must consider where we want to use the RFID robot and choose the one that suits us based on its specific characteristics. The RFID robot is a mobile and autonomous RFID system that performs an inventory of the given space based on our initial setup. The RFID robot locates each item in 2 dimensions (x and y). Most robots can move in all directions because they can rotate without shifting. The accuracy of the inventory using the RFID robot ranges from 95-99%, while the accuracy of the inventory performed by employees using handheld RFID readers ranges from 85-95%. As for speed, it is on average 10 times faster compared to manual RFID readers.

CoVSense: Ultrasensitive Nucleocapsid Antigen Immunosensor for Rapid Clinical Detection of Wildtype and Variant SARS-CoV-2.

The widespread accessibility of commercial/clinically-viable electrochemical diagnostic systems for rapid quantification of viral proteins demands translational/preclinical investigations. Here, Covid-Sense (CoVSense) antigen testing platform; an all-in-one electrochemical nano-immunosensor for sample-to-result, self-validated, and accurate quantification of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid (N)-proteins in clinical examinations is developed. The platform's sensing strips benefit from a highly-sensitive, nanostructured surface, created through the incorporation of carboxyl-functionalized graphene nanosheets, and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) conductive polymers, enhancing the overall conductivity of the system. The nanoengineered surface chemistry allows for compatible direct assembly of bioreceptor molecules. CoVSense offers an inexpensive (<$2 kit) and fast/digital response (<10min), measured using a customized hand-held reader (<$25), enabling data-driven outbreak management. The sensor shows 95% clinical sensitivity and 100% specificity (Ct<25), and overall sensitivity of 91% for combined symptomatic/asymptomatic cohort with wildtype SARS-CoV-2 or B.1.1.7 variant (N = 105, nasal/throat samples). The sensor correlates the N-protein levels to viral load, detecting high Ct values of ≈35, with no sample preparation steps, while outperforming the commercial rapid antigen tests. The current translational technology fills the gap in the workflow of rapid, point-of-care, and accurate diagnosis of COVID-19.

Validation of a novel point-of-care test for alanine aminotransferase measurement: A pilot cohort study.

Alanine aminotransferase (ALT) measurement is essential for evaluation of liver disease. We validated a novel rapid point-of-care (POC) test for ALT1 against laboratory ALT. Stored plasma samples from adults with chronic liver disease (Test cohort n=240; Validation cohort n=491) were analysed using the BioPoint® antigen immunoassay POC ALT1 lateral flow test, which provides quantitative ALT results (Axxin handheld reader) or semi-quantitative results (visual read, cut off 40 IU/ml). The accuracy of POC ALT1 to detect ALT > 40 IU/L was determined by ROC analysis. In patients with chronic hepatitis B, treatment eligibility (EASL criteria) was determined using POC ALT1 and compared to laboratory ALT. POC ALT1 test had good accuracy for laboratory ALT > 40 IU/L: AUROC 0.93 (95% CI: 0.89-0.96) in the Test cohort and AUROC 0.92 (95% CI: 0.88-0.95) in the Validation cohort. POC ALT1 cut off of 0.8 for ALT > 40 IU/L maximised sensitivity (97%) and specificity (71%) in the Test cohort (42% laboratory ALT > 40 IU/L) and yielded PPV 84% and NPV 91% in the Validation cohort (19% laboratory ALT > 40 IU/L). Semi-quantitative POC ALT1 had good accuracy for laboratory ALT in the Validation cohort (AUROC 0.85, 95% CI: 0.81-0.99; sensitivity 77% and specificity 93%). Combined with HBV DNA and transient elastography, both quantitative and semi-quantitative POC ALT1 tests had good accuracy for excluding hepatitis B treatment needs (sensitivity 96%, specificity 78% and NPV 99%). The POC ALT1 test had good accuracy for elevated ALT levels and for determining treatment eligibility among people with chronic hepatitis B.

Development of a simple, rapid, and sensitive molecular diagnostic assay for cholera

Cholera continues to inflict high rates of morbidity and mortality. Prompt identification of cholera cases facilitates rapid outbreak responses in the short term while providing reliable surveillance data to guide long-term policies and interventions. Microbiological stool culture, the current recognized gold standard for diagnosing cholera, has significant limitations. Rapid diagnostic tests (RDTs) represent promising alternatives for diagnosing cholera in areas with limited laboratory infrastructure. However, studies conducted with the current cholera RDTs demonstrated wide variations in sensitivity and specificity. To address this gap in the diagnosis of cholera, we developed a simple, rapid, and sensitive diagnostic assay, "Rapid LAMP based Diagnostic Test (RLDT)." With a novel, simple sample preparation method directly from the fecal samples along with lyophilized reaction strips and using established Loop-mediated Isothermal Amplification (LAMP) platform, cholera toxin gene (ctxA) and O1 (O1rfb) gene could be detected in less than an hour. Cholera RLDT assay is cold chain and electricity-free. To avoid any end-user bias, a battery-operated, handheld reader was used to read the RLDT results. The performance specifications of the cholera RLDT assay, including analytical sensitivity and specificity, were evaluated using direct fecal samples, dried fecal samples on filter paper, and environmental water samples spiked with cholera strain. The limit of detection (LOD) was ~104 CFU/gm of stool for both ctxA and O1 genes, corresponding to about 1 CFU of Vibrio cholerae per reaction within 40 minutes. The LOD was 10 bacteria per ml of environmental water when tested with RLDT directly, without enrichment. Being simple, RLDT has the potential to be applied in resource-poor endemic settings for rapid, sensitive, and reliable diagnosis of cholera.

GuideAndTrack: A Novel Guidance and Localization Method by a Handheld UHF-RFID Reader

In this paper we present GuideAndTrack; a prototype method for guiding a user to any RFID-tagged target. The user is equipped with a handheld RFID reader, which measures the phase of RFID tags placed at known positions in the map. Motion of the user is captured by estimating the Rate Of Change (ROC) of the collected phase measurements along discrete time-slots; i.e. null rate implies zero radial vector with respect to the corresponding tag, while negative/positive rates signify approaching towards or moving away from the corresponding tag respectively. The phase ROC represents an advantageous metric for accurate localization, since it can be easily measured in any given time-slot and does not necessitates knowledge of the prior state of the reader-to-tag link. The proposed method, initially estimates the direction of motion of the user, by sorting the estimated phase-ROCs from the surrounding tags during one’s translational motion, guiding one to the desired target. Then, the position of the user is accurately estimated by feeding the estimated phase-ROCs in a particle filter. The proposed method has been experimentally verified in two cases; one by deploying a robot, in order to acquire the ground truth of the moving “user” and another case, where a human held a portable RFID reader. In all cases, the method performed well, guiding the user to the desired target, while estimating one’s pose accurately. Characteristic results and comparison with prior art are presented herein.

Tag Localization by Handheld UHF RFID Reader With Optical and RFID Landmarks

In this paper a prototype method for manual inventorying and real-time 3D localization of RFID tagged products by a low-cost handheld UHF RFID reader is introduced. The device is equipped with a UHF RFID reader and an optical camera. "ArUco" markers with RFID tags are placed at known positions. Those optical and RF landmarks are used for the estimation of the pose of the handheld reader over time, by fusing the corresponding measurements in a Kalman filter. The reader also measures RFID tagged items at unknown locations. The positions of the tags are estimated by unwrapping the collected phase measurements, combined with the estimated antenna trajectory. Experimental results show that increased accuracy can be achieved by increasing the spatial density of the optical and RFID markers. The proposed method is expected to enhance low-cost manual inventorying, delivering 3D localization of the tagged products.

Design and analysis of broadband circularly polarized compact planar antennas for 2.45 GHz RFID handheld reader applications

AbstractIn this article, an innovative design of a broadband circularly polarized compact planar antenna for RFID (radio frequency identification) receivers is presented. The suggested structure used the concept of slots loaded parasitic element printed underneath a coplanar waveguide-fed radiator to achieve the circularly polarized (CP) radiation and size reduction. A parasitic element loaded with F-slot and L-slot, and a window-type slotted ground plane was used to achieve resonance at 2.45 GHz with right-handed circularly polarized radiation for RFID handheld reader application. Experimental results confirmed that the designed antenna of size 16.5 × 14.8 × 1.6 mm3 attained a −10 dB impedance bandwidth of 15.8% (from 2.330 to 2.716 GHz) and 3 dB AR bandwidth of 3.43% (from 2.410 to 2.494 GHz). An axial ratio of 0.43 dB was achieved in the boresight of the antenna at the 2.45 GHz RFID band. The concept of electric field distribution on the antenna was used to elaborate the excitation of CP radiation in the antenna.

RFID Technology Study for Traffic Signage Inventory Management Application

This paper presents the design and analysis of an automated traffic signage inventory management system employing the radio-frequency identification (RFID) technology. Traffic signage inventory management faces the operational challenge of recognizing a large number of traffic signs spread in a large area without obvious identifications on them. Thanks to the remote sensing ability of RFID, the operational efficiency can be significantly improved by scanning traffic signs remotely in motion. The system consists of an in-vehicle RFID reader and a handheld RFID reader, both of which connect to mobile applications with user-friendly interfaces. Additionally, user-friendly control software and a database are developed. In this paper, the adequacy of the RFID technology for the task is assessed. On the theoretical side, this paper investigates the radio-wave propagation model and the antenna radiation range. Additionally, the influences of the vehicle speed and the sign-to-reader distance on the reading performance are studied and empirical tests of the tag positioning are conducted. Finally, a system protocol is validated by a field test.

An integrated RFID–UWB method for indoor localization of materials in construction

A considerable body of literature exists on automated object localization and tracking of construction operations. While GPS-based solutions have been widely investigated in many studies for outdoor tracking of these operations, indoor tracking proved to be more challenging. This paper focuses on indoor material localization and investigates the use of two remote sensing technologies—ultra-wideband and radio frequency identification—and the integrated use of these technologies to leverage the benefits of each for a cost-effective and practical solution for location identification of materials on site. The developed method is based on an experimental study conducted in two phases. In the first phase, experiments are designed and performed to evaluate the accuracy of ultra-wideband for localization, as well as to determine the optimal output power for a hand-held radio frequency identification reader. The optimal power is identified by evaluating the range measurement accuracy and maximum reading range of the hand-held radio frequency identification reader. In the second phase, the integrated use of radio frequency identification device and ultra-wideband for object localization is studied, and an improved trilateration technique is developed. The results of the experiments show an absolute error of 0.52 m and 1.15 m for 2D and 3D localization, respectively. Accordingly, the integration of these two technologies eliminates the need for using a large number of radio frequency identification reference tags on site for indoor material localization. The method is expected to enhance automated material tracking on construction sites by improving the localization accuracy and providing a straightforward data acquisition protocol. The analysis of experimental data captured in a lab setting is also presented, demonstrating the advantages of the proposed method.