Field-deployable Device Research Articles

Flow-S: A Field-Deployable Device with Minimal Hands-On Effort to Concentrate and Quantify Schistosoma Circulating Anodic Antigen (CAA) from Large Urine Volumes.

A laboratory-based lateral flow (LF) test that utilizes up-converting reporter particles (UCP) for ultrasensitive quantification of Schistosoma circulating anodic antigen (CAA) in urine is a well-accepted test to identify active infection. However, this UCP-LF CAA test requires sample pre-treatment steps not compatible with field applications. Flow, a new low-cost disposable, allows integration of large-volume pre-concentration of urine analytes and LF detection into a single field-deployable device. We assessed a prototype Flow-Schistosoma (Flow-S) device with an integrated UCP-LF CAA test strip, omitting all laboratory-based steps, to enable diagnosis of active Schistosoma infection in the field using urine. Flow-S is designed for large-volume (5-20 mL) urine, applying passive paper-based filtration and antibody-based CAA concentration. Samples tested for schistosome infection were collected from women of reproductive age living in a Tanzania region where S. haematobium infection is endemic. Fifteen negative and fifteen positive urine samples, selected based on CAA levels quantified in paired serum, were analyzed with the prototype Flow-S. The current Flow-S prototype, with an analytical lower detection limit of 1 pg CAA/mL, produced results correlated with the laboratory-based UCP-LF CAA test. Urine precipitates occurred in frozen banked samples and affected accurate quantification; however, this should not occur in fresh urine. Based on the findings of this study, Flow-S appears suitable to replace the urine pre-treatment required for the laboratory-based UCP-LF CAA test, thus allowing true field-based applications with fresh urine samples. The urine precipitates observed with frozen samples, though less important given the goal of testing fresh urines, warrant additional investigation to evaluate methods for mitigation. Flow-S devices permit testing of pooled urine samples with applications for population stratified testing. A field test with fresh urine samples, a further optimized Flow-S device, and larger statistical power has been scheduled.

What’s in Your Fruit Juice?—Rapid Quality Screening Based on Infrared (FT-IR) Spectroscopy

Fruit juices (FJ) have gained widespread global consumption, driven by their perceived health benefits. The accuracy of nutrition information is essential for consumers assessing FJ quality, especially with increasing concerns about added sugars and obesity risk. Conversely, ascorbic acid (Vitamin C), found in nature in many fruits and vegetables, is often lost due to its susceptibility to light, air, and heat, and it undergoes fortification during FJ production. Current analytical methods for determining FJ components are time-consuming and labor-intensive, prompting the need for rapid analytical tools. This study employed a field-deployable portable FT-IR device, requiring no sample preparation, to simultaneously predict multiple quality traits in 68 FJ samples from US markets. Using partial least square regression (PLSR) models, a strong correlation (RCV ≥ 0.93) between FT-IR predictions and reference values was obtained, with a low standard error of prediction. Remarkably, 21% and 37% of FJs deviated from nutrition label values for sugars and ascorbic acid, respectively. Portable FT-IR devices offer non-destructive, simultaneous, simple, and high-throughput approaches for chemical profiling and real-time prediction of sugars and acid levels in FJs. Their handiness and ruggedness can provide food processors with a valuable “out-of-the-laboratory” analytical tool.

Smartphone-assisted colorimetric and near-infrared ratiometric fluorescent sensor for on-spot detection of H2O2 in food samples

Hydrogen peroxide (H2O2) is closely involved in the fields of food industry. Excessive residual H2O2 in food samples will exert adverse effects on the nutritional value of foods and pose great threat to the health of consumer. Development of a reliable analytical method for on-spot quantitative detection of H2O2 levels in food is of urgent necessity. Here, we presented a colorimetric and near-infrared (NIR) ratiometric fluorescent sensor for on-spot quantitative detection of H2O2 in various food samples. The sensor displayed colorimetric and NIR ratiometric fluorescence dual-signal response to H2O2 with high selectivity and sensitivity. The limits of detection (LOD) was measured to be 23.08 nM (S / N = 3). The sensor has been applied for detecting exogenous and endogenous H2O2 in living cells by fluorescence imaging. Also, the changes of H2O2 level in potato tissue infected by phytophthora infestans has been monitored. Particularly, to achieve on-spot quantitative detection of H2O2 in food samples, a portable and field deployable detection device was rationally developed. The sensor, together with portable detection devices and smartphones, performed on-spot quantitative detection of H2O2 in chicken wings and milk through dual signal outputs of colorimetry and fluorescence. We anticipate that the analytical method developed here could be served as convenient tool for on-spot quantitative detection of H2O2 in different foods in near future.

A smartphone-integrated imaging device for measuring nitrate and phosphate in soil and water samples

This research presents a smartphone-integrated imaging device to detect nitrate (NO3–) and phosphate (PO43-) in soil and water samples for agricultural input management and environmental pollution monitoring. This low-cost and field-deployable device uses a smartphone with a digital camera to take a color photograph of the extracted solution under test. The sensing principle is based on the standard colorimetric phenoldisulfonic acid and ascorbic acid methods for NO3– and PO43- in soil and water samples, respectively. A 3D printed device that houses the sensor's optical source and other optical components is coupled to the phone's built-in rear camera and turned into a compact handheld system. An android application, 'SMART NP,' is also developed to quantify the concentrations of NO3– and PO43- in soil and water samples using the Value (V) component of the Hue Saturation and Value (HSV) color space model. The results obtained with the proposed device were comparable to laboratory-grade spectrophotometer data. The limit of detection of the device for NO3– in soil, NO3– in water, PO43- in soil, and PO43- in water were calculated as 0.1 mg L-1, 0.07 mg L-1, 0.001 mg L-1, and 0.02 mg L-1, respectively, with good accuracy (≤1% bias) and precision (∼2% residual standard deviation). The device exhibited a sensitivity of 0.17 mg L-1, 0.12 mg L-1, 0.026 mg L-1, and 0.49 mg L-1 for NO3– in soil, NO3– in water, PO43- in soil, and PO43- in water, respectively. Overall, this sensing device has the potential to assist farmers or scientists in easily measuring NO3– and PO43- concentrations in soil and water media, without the need for laboratory equipment.

Rapid and Onsite Detection of Fuel Adulteration.

In numerous developing countries, the lower cost of subsidized liquid fuels such as kerosene compared to market-rate fuels often results in fuel adulteration. Such misuse of kerosene is hard to detect with conventional detection technologies because they are either time consuming, expensive, not sensitive enough or require well-equipped analytical laboratories. In this work, we developed an inexpensive and easy-to-use device for rapid and onsite detection of fuel adulteration. The working principle of our fuel adulteration detection is sensing changes in the mobility of fuel droplets on non-textured (i.e., smooth) and non-polar solid surfaces. Using our device, we demonstrated rapid detection of diesel (market-rate fuel) adulterated with kerosene (subsidized fuel) at concentrations an order of magnitude below typical adulteration concentrations. We envision that our inexpensive, easy-to-use, and field-deployable device as well as the design strategy will pave the way for novel fuel quality sensors.

Programmable magnetic robot (ProMagBot) for automated nucleic acid extraction at the point of need.

Upstream sample preparation remains the bottleneck for point-of-need nucleic acid testing due to its complexity and time-consuming nature. Sample preparation involves extracting, purifying, and concentrating nucleic acids from various matrices. These processes are critical for ensuring the accuracy and sensitivity of downstream nucleic acid amplification and detection. However, current sample preparation methods are often laboratory-based, requiring specialized equipment, trained personnel, and several hours of processing time. As a result, sample preparation often limits the speed, portability, and cost-effectiveness of point-of-need nucleic acid testing. A universal, field-deployable sample preparation device is highly desirable for this critical need and unmet challenge. Here we reported a handheld, battery-powered, reconfigurable, and field-deployable nucleic acid sample preparation device. A programmable electromagnetic actuator was developed to drive a magnetic robot (ProMagBot) in X/Y 2D space, such that various magnetic bead-based sample preparations can be readily translated from the laboratory to point-of-need settings. The control of the electromagnetic actuator requires only a 3-phase unipolar voltage in X and Y directions, and therefore, the motion space is highly scalable. We validated the ProMagBot device with a model application by extracting HIV viral RNAs from plasma samples using two widely used magnetic bead kits: ChargeSwitch and MagMAX beads. In both cases, the ProMagBot could successfully extract viral RNAs from 50 μL plasma samples containing as low as 102 copies of viral RNAs in 20 minutes. Our results demonstrated the ability of ProMagBot to prepare samples from complex mediums at the point of need. We believe such a device would enable rapid and robust sample preparation in various settings, including resource-limited or remote environments, and accelerate the development of next-generation point-of-need nucleic acid testing.

Design and Testing of an Electrochemical Trace Pesticide Assessment System in Soil Run-Off

Despite recent efforts and breakthroughs in the development of environmental biosensors, one particular vital component of the environment has been probed comparatively much more sparsely-namely, the soil ecosystem that directly and indirectly affects the agricultural health and throughput as well as ecosystem balance. One specific problem that is understudied is the application of pesticides in crops and other plants often finds its way seeping into soil in a large manner and there exists a leaching effect at the soil and ground water sources. This causes long-term effects that is deteriorating for environmental as well as human health- due to soil and ground water contamination that further causes dampening of food production and safety as well as causing acute and chronic diseases in the human body. The potential for a sensor system that detects in-field: the levels of pesticide residue in soil run-off is immense and would be beneficial to understand its negative effect on food security and food safety by inhibiting soil microbial activity and therefore impacting crop throughput and food quality. This field deployable sensor probe would help promote responsible agricultural practices and curb overapplication of harmful agents to the soil. Electrochemistry proves to be a viable choice of application for such a sensor to track pesticides in soil samples due to its feasibility for in-situ analysis used as well as solving for the ASSURED criteria as given by the World Health Organization (WHO), wherein it denotes- Affordable, Sensitive, Specific, User-friendly, Rapid, and robust, Equipment-free and Deliverable to end-users. The proposed system would have to utilize minimally complex sensor modification/functionalization and no pre-processing of samples. Hence citing all these factors and requirements, in this work- we present a highly intuitive electroanalytical sensor approach towards rapid, on-demand screening of 2 commonly used pesticides in this proof-of-feasibility study- Glyphosate and Atrazine in soil run-off which have a half-life of 47 days and 60-75 days respectively. By studying the levels of soil contaminant residues at the field site-the sensor acts as a screening instrument for soil pollution levels. The proposed sensor functions based on affinity biosensing mechanism driven via thiol-crosslinker and antibody receptors that holistically behaves as a recognition immunoassay stack that is specific and sensitive to track test pesticide analytes with a detection limit of 0.19 ng/mL or parts per billion (ppb) range for glyphosate and 0.15 pg/mL or parts per trillion (ppt) range for atrazine. Then, this developed sensor is integrated further to create a pesticide sensing ecosystem by means of a front-end field-deployable smart device with post-hoc Machine Learning (ML) assisted classification (LOW-MID-HIGH levels of pesticide) and thereby, a universal pesticide screening analytical device is designed and fabricated for pesticide assessment in real soil run-off samples. Figure 1

0006 An At-Home Evaluation of a Light Intervention to Mitigate Sleep Inertia Symptoms

Abstract Introduction Sleep inertia symptoms typically occur after waking from nocturnal sleep. Under laboratory settings, light exposure upon waking has been shown to improve alertness, mood, and vigilant attention. We investigated whether a field-deployable light-emitting device would help to improve alertness and working memory in a real-world setting. Methods Thirty-five participants (18 female; 26.4 ± 6.0 y) completed an at-home, within-subject, randomized crossover study. Participants wore actiwatches during their normal sleep-wake schedule for five nights ahead of the adaptation and experimental nights. On the experimental night, participants performed baseline testing before their self-selected bedtime. Forty-five minutes after bedtime, participants received a phone call and were instructed to perform test bouts while wearing light-emitting glasses with the light either on (light condition) or off (control). A 3-minute descending subtraction task (DST) and the Karolinska Sleepiness Scale (KSS) were performed at +7, +17, +27, and +37 minutes after the call. Participants were then instructed to go back to sleep and were called 45 minutes after lights out to repeat the test bouts in the opposite condition. A series of mixed-effects models were performed with fixed effects of condition, test bout, and their interaction, and a random effect of participant. Condition order, sex, and baseline were included as covariates. Results There was a significant effect of test bout for DST total responses (χ2 [3] = 17.42; p < .001) and total correct (χ2 [3] = 21.29; p < .001) with improved performance at +27 and +37 minutes compared to +7 minutes. Sex was a significant predictor for KSS (F1,30 = 10.26; p = .003), with females (8.20 ± 0.23) rating higher sleepiness than males (7.10 ± 0.25). There were no other significant effects for DST or KSS outcomes (p > .05). Conclusion These results suggest that the intervention was not able to improve working memory or alertness under naturalistic at-home settings. Further analysis is needed to determine whether these results are applicable to other cognitive performance domains. Support (If Any) Funded by the Naval Postgraduate School, via the Naval Medical Research Center's Naval Advanced Medical Development Department (MIPR N3239820WXHN007), with support from the NASA Airspace Operations and Safety Program, System-Wide Safety.

Targeted On-Demand Screening of Pesticide Panel in Soil Runoff.

Using pesticides is a common agricultural and horticultural practice to serve as a control against weeds, fungi, and insects in plant systems. The application of these chemical agents is usually by spraying them on the crop or plant. However, this methodology is not highly directional, and so only a fraction of the pesticide actually adsorbs onto the plant, and the rest seeps through into the soil base contaminating its composition and eventually leaching into groundwater sources. Electrochemical sensors which are more practical for in situ analysis used for pesticide detection in soil runoff systems are still in dearth, while the ones published in the literature are attributed with complex sensor modification/functionalization and preprocessing of samples. Hence, in this work, we present a highly intuitive electroanalytical sensor approach toward rapid (10 min), on-demand screening of commonly used pesticides—glyphosate and atrazine—in soil runoff. The proposed sensor functions based on the affinity biosensing mechanism driven via thiol cross-linker and antibody receptors that holistically behaves as a recognition immunoassay stack that is specific and sensitive to track test pesticide analytes. Then, this developed sensor is integrated further to create a pesticide-sensing ecosystem using a front-end field-deployable smart device. The method put forward in this work is compared and validated against a standard laboratory potentiostat instrument to determine efficacy, feasibility, and robustness for a point-of-use (PoU) setting yielding LoD levels of 0.001 ng/ml for atrazine and 1 ng/ml for glyphosate. Also, the ML model integration resulted in an accurate prediction rate of ≈80% in real soil samples. Therefore, a universal pesticide screening analytical device is designed, fabricated, and tested for pesticide assessment in real soil runoff samples.

Molecular Detection of Infectious Laryngotracheitis Virus in Chickens with a Microfluidic Chip.

Simple SummaryInfectious laryngotracheitis (ILT) presents a major risk to the chicken industry. Rapid, specific, simple, and point-of-need molecular detection of the virus is crucial to enable chicken farms to take timely action and contain the spread of infection. The current study describes an isothermal amplification assay for infectious laryngotracheitis virus (ILTV) infection and the implementation of this assay in a microfluidic chip suitable for molecular detection and quasi-quantification of ILTV in diagnostic veterinary laboratories with low resources and poultry farms. Our assay performance was compared and favorably agreed with quantitative PCR (qPCR). Clinical tests of our assay and chip with samples from diseased chickens demonstrated good concordance with the gold-standard benchtop qPCR assay.Infectious laryngotracheitis (ILT) is a viral disease of chickens’ respiratory system that imposes considerable financial burdens on the chicken industry. Rapid, simple, and specific detection of this virus is crucial to enable proper control measures. Polymerase chain reaction (PCR)-based molecular tests require relatively expensive instruments and skilled personnel, confining their application to centralized laboratories. To enable chicken farms to take timely action and contain the spread of infection, we describe a rapid, simple, semi-quantitative benchtop isothermal amplification (LAMP) assay, and a field-deployable microfluidic device for the diagnosis of ILTV infection in chickens. Our assay performance was compared and favorably agreed with quantitative PCR (qPCR). The sensitivity of our real-time LAMP test is 250 genomic copies/reaction. Clinical performance of our microfluidic device using samples from diseased chickens showed 100% specificity and 100% sensitivity in comparison with benchtop LAMP assay and the gold-standard qPCR. Our method facilitates simple, specific, and rapid molecular ILTV detection in low-resource veterinary diagnostic laboratories and can be used for field molecular diagnosis of suspected ILT cases.

Video‐Rate Imaging with Undetected Photons

AbstractImaging and microscopy are some of the most important tools in modern life science for getting new insights into metabolisms or unravelling bio‐chemical processes. However, in particular low‐light observations outside the visible spectrum are still challenging and a limiting factor. A rugged, label‐free quantum imaging system is presented capable of recording at video rate in the visible regime, while illuminating the sample with undetected light of different wavelength. The results pave the way for a field deployable quantum imaging device allowing live‐cell imaging in extreme spectral ranges with a minimal photo dose.

An amplification-free ultra-sensitive electrochemical CRISPR/Cas biosensor for drug-resistant bacteria detection.

Continued development of high-performance and cost-effective in vitro diagnostic tools is vital for improving infectious disease treatment and transmission control. For nucleic acid diagnostics, moving beyond enzyme-mediated amplification assays will be critical in reducing the time and complexity of diagnostic technologies. Further, an emerging area of threat, in which in vitro diagnostics will play an increasingly important role, is antimicrobial resistance (AMR) in bacterial infections. Herein, we present an amplification-free electrochemical CRISPR/Cas biosensor utilizing silver metallization (termed E-Si-CRISPR) to detect methicillin-resistant Staphylococcus aureus (MRSA). Using a custom-designed guide RNA (gRNA) targeting the mecA gene of MRSA, the Cas12a enzyme allows highly sensitive and specific detection when employed with silver metallization and square wave voltammetry (SWV). Our biosensor exhibits excellent analytical performance, with detection and quantitation limits of 3.5 and 10 fM, respectively, and linearity over five orders of magnitude (from 10 fM to 0.1 nM). Importantly, we observe no degradation in performance when moving from buffer to human serum samples, and achieve excellent selectivity for MRSA in human serum in the presence of other common bacteria. The E-Si-CRISPR method shows significant promise as an ultrasensitive field-deployable device for nucleic acid-based diagnostics, without requiring nucleic acid amplification. Finally, adjustment to a different disease target can be achieved by simple modification of the gRNA protospacer.

Enabling Direct Protein Detection in a Drop of Whole Blood with an "On-Strip" Plasma Separation Unit in a Paper-Based Lateral Flow Strip.

Conventional paper lateral flow assays have low sensitivity and suffer from severe interference from complex human fluid sample matrices, which prevents their practical application in the testing of whole blood samples in the point-of-care settings. To solve this problem, gold nanostar@Raman reporter@silica-sandwiched nanoparticles have been developed as the surface-enhanced Raman scattering (SERS) probes for sensing transduction; and a functionalized filter membrane assembly has been designed and constructed in the paper-based lateral flow strip (PLFS) as a built-in plasma separation unit. In this "on-strip" plasma separation unit, three layers of filter membranes are stacked and surface-modified to maximize the separation efficiency and the plasma yield. As a result, the integrated PLFS has been successfully used for the detection of carcinoembryonic antigen (CEA) in 30 μL of whole blood with the assistance of a portable Raman reader, achieving a limit of detection of 1.0 ng mL-1. In short, this report presents an inexpensive, disposable, portable, and field-deployable paper-based device as a general point-of-care testing tool for protein biomarker detection in a drop of whole blood.

Rapid identification of melioidosis agent by an insulated isothermal PCR on a field-deployable device.

Background Burkholderia pseudomallei causes melioidosis, a serious illness that can be fatal if untreated or misdiagnosed. Culture from clinical specimens remains the gold standard but has low diagnostic sensitivity.MethodIn this study, we developed a rapid, sensitive and specific insulated isothermal Polymerase Chain Reaction (iiPCR) targeting bimA gene (Burkholderia Intracellular Motility A; BPSS1492) for the identification of B. pseudomallei. A pair of novel primers: BimA(F) and BimA(R) together with a probe were designed and 121 clinical B. pseudomallei strains obtained from numerous clinical sources and 10 ATCC non-targeted strains were tested with iiPCR and qPCR in parallel.ResultsAll 121 B. pseudomallei isolates were positive for qPCR while 118 isolates were positive for iiPCR, demonstrating satisfactory agreement (97.71%; 95% CI [93.45–99.53%]; k = 0.87). Sensitivity of the bimA iiPCR/POCKIT assay was 97.52% with the lower detection limit of 14 ng/µL of B. pseudomallei DNA. The developed iiPCR assay did not cross-react with 10 types of non-targeted strains, indicating good specificity.ConclusionThis bimA iiPCR/POCKIT assay will undoubtedly complement other methodologies used in the clinical laboratory for the rapid identification of this pathogen.

A methodology to detect explosive residues using a gelled ionic liquid based field-deployable electrochemical device

A simple and robust, low-cost electrochemical device is proposed for the combined sampling and detection of the trace solid explosive 2,4,6-trinitrotoluene (TNT) from a non-porous surface. Four different substrates were investigated to collect explosive residue – a bare thin-film electrode, glass microfiber filter paper, a gel-polymer electrolyte (GPE), and a GPE-filter paper composite. The GPE contained the hydrophobic room temperature ionic liquid (RTIL) trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide ([P14,6,6,6][NTf2]) and the polymer poly(methyl methacrylate) (PMMA). A simple “swabbing” technique was used to sample explosive residue on all substrates. Square wave voltammetry was performed to determine the effects of oxygen and moisture on the current response. The most robust method for use in the field – a GPE drop-casted on a TFE – was applied in real environments using a hand-held portable potentiostat. The prototype device was able to detect TNT with a 30 min development time in different ambient environmental conditions. The portability, ease of use and low-cost of the sensor device makes this a viable platform for the rapid onsite detection of explosives.

Design and application of a portable luminometer for bioluminescence detection.

The silicon photomultiplier (SiPM) for low light detection has many advantages when compared to existing photon counting detectors, such as high sensitivity, low cost, robustness, and compact hardware. To facilitate the use of SiPM as a portable, field deployable device, an electrical circuit was designed consisting of an amplifier, comparator, and microcontroller. In addition, a 3D printing was used to create a portable cradle for housing the SiPM. To evaluate its detection ability, a laser experiment and bioluminescent experiments, including Pseudomonas fluorescens M3A detection, E. coli O157:H7 PhiV10nluc lysogen detection, and a luminescence-based detection of E. coli O157:H7 in ground meat using the engineered luminescent-based reporter phage PhiV10nluc, were conducted. In the same experimental setting, our previously developed smartphone-based luminometer called the bioluminescent-based analyte quantitation by smartphone and a conventional photomultiplier tube-based benchtop luminometer were used to compare detection levels and applicability for supporting luminescent phage-based pathogen detection. Results showed that the SiPM provides better performance in terms of time to detection and SNR and could be used as the light detection component of the PhiV10nluc phage-based detection format.

A Low-Cost, Passive Release Device for the Surveillance and Control of Mosquitoes.

Mosquitoes continue to be a major threat to global health, and the ability to reliably monitor, catch, and kill mosquitoes via passive traps is of great importance. Global, low-cost, and easy-to-use outdoor devices are needed to augment existing efforts in mosquito control that combat the spread of disease, such as Zika. Thus, we have developed a modular, portable, non-powered (passive), self-contained, and field-deployable device suitable for releasing volatiles with a wide range of applications such as attracting, repelling, and killing mosquitoes. This unique device relies on a novel nested wick and two-reservoir design that achieves a constant release of volatiles over several hundred hours. Devices loaded with one of either two compounds, geraniol or 1-methylpiperazine (MP), were tested in a controlled environment (32 °C and 70% relative humidity), and both compounds achieved a constant release from our devices at a rate of 2.4 mg/h and 47 mg/h, respectively. The liquid payload can be volatile attractants or repellants as well as mosquitocide-containing feeding solutions for capture and surveillance. This low-cost device can be utilized for both civilian and military mosquito control purposes, but it will be particularly important for protecting those in economically repressed environments, such as sub-Saharan Africa and Central and South America.

Hand-held optical sensor using denatured antibody coated electro-active polymer for ultra-trace detection of copper in blood serum and environmental samples

An optimum copper concentration in environment is highly desired for all forms of life. We have developed an ultrasensitive copper sensor which functions from femto to micro molar concentration accurately (R2 = 0.98). The sensor is based on denatured antibody immunoglobulin G (IgG), immobilized on polyaniline (PAni) which in turn is the coating on the core of an optical fiber. The sensing relies on changes in evanescent wave absorbance in the presence of the analyte. The sensor showed excellent selectivity towards Cu (II) ions over all other metal ions. The sensor was tested with lake and marine water samples to determine unknown concentrations of copper ions and the recovery results were within 90–115%, indicating reasonable accuracy. We further integrated the fiber-optic sensor with a miniaturized hand-held instrumentation platform to develop an accurate and field deployable device which can broadly be applicable to determine Cu (II) concentration in a wide range of systems – natural water bodies, soil as well as blood serum.

Ultrasensitive and Selective Sensing of Selenium Using Nitrogen-Rich Ligand Interfaced Carbon Quantum Dots.

This work reports a label-free, ultrasensitive, and selective optical chemosensory system for trace level detection of selenite (SeO32-), the most toxic form of selenium, in water. The probe, i.e., carbon quantum dots (CQDs), is designed from citric acid by means of pyrolysis and is interfaced with a newly synthesized nitrogen-rich ligand to create a selective sensor platform (functionalized CQDs, fCQDs) for selenite in a water matrix. Spectral (NMR, UV-vis, photoluminescence, Raman, and Fourier transform infrared analyses) and structural (high-resolution transmission electron microscopy) characteristics of the designed new probe were investigated. The developed sensor exhibits high sensitivity (limit of detection = 0.1 ppb), a wide detection range (0.1-1000 ppb range, relative standard deviation: 3.2%), and high selectivity even in the presence of commonly interfering ions reported to date, including Cl-, NO3-, NO2-, Br-, F-, As(V), As(III), Cu2+, Pb2+, Cd2+, Zn2+, Sr2+, Rb2+, Na+, Ca2+, Cs+, K+, Mg2+, Li+, NH4+, Co2+, etc. The observed selectivity is due to designed ligand characteristics in terms of strong Se-N chemistry. Ultrafast spectroscopic analysis of the fCQDs in the absence and presence of selenite was studied to understand the sensing mechanism. The sensor was successfully exemplified for real water samples and exhibits comparative performance to conventional ion channel chromatography as well as flame atomic absorption spectroscopy for selenite analysis. The promising results pave ways for realization of a field deployable device based upon a developed probe for selenite quantification in water.

Rapid and sensitive detection of Mycoplasma synoviae by an insulated isothermal polymerase chain reaction-based assay on a field-deployable device

Mycoplasma synoviae (MS), causing respiratory diseases, arthritis, and eggshell apex abnormalities in avian species, is an important pathogen in the poultry industry. Implementation of a biosecurity plan is important in MS infection management. Working on a field-deployable POCKIT™ device, an insulated isothermal polymerase chain reaction (iiPCR) assay has a potential for timely MS detection on the farm. The MS iiPCR assay had limit of detection 95% of about 9 genome equivalents by testing serial dilutions of a standard DNA. The detection endpoint of the assay for detection of MS genomic DNA was comparable to a reference real-time PCR. The assay did not crossreact with other important avian pathogens, including avian reovirus, Mycoplasma gallisepticum, Staphylococcus aureus, Escherichia coli, Pasteurella multocida, and Salmonella Pullorum. When 92 synovial fluid and respiratory tract swab samples collected from chickens, turkeys, and geese suspected of MS infection were tested, the clinical performance of the MS iiPCR had 97.8% agreement (Cohen's kappa value, 0.95) with that of the reference real-time PCR. In conclusion, the MS iiPCR/POCKIT™ system, working with field-deployable manual or automatic nucleic acid extraction methods, has potential to serve as a rapid and sensitive on-site tool to facilitate timely detection of MS.