Rapid Detection Of Analytes Research Articles

A core–shell AuNRs@BUT-16 nanocomposite for enhancement SERS detection and efficient removal of deoxynivalenol

IntroductionDeoxynivalenol (DON) is widely found in grains and poses a serious threat to human health, so there is an urgent need to develop methods for its simultaneous removal and detection. The novel metal organic framework (MOF) material BUT-16 has a high adsorption capacity (79.8%) for DON. Meanwhile, surface-enhanced Raman spectroscopy (SERS) has been widely used for rapid detection of analytes. ObjectivesThe aim of this work is to prepare a material that can be used for enhancement SERS detection and efficient removal of DON. MethodsAuNRs@BUT-16 was prepared by in-situ solvothermal method and characterized using a series of characterization tools. AuNRs@BUT-16 was used as an adsorbent and SERS substrate for the removal and detection of DON, and some factors affecting the adsorption and SERS detection were investigated. The adsorption mechanism between DON and AuNRs@BUT-16 was investigated using molecular docking. The proposed SERS method was used to detect DON contamination in real samples. ResultsThe prepared core–shell AuNRs@BUT-16 showed a synergistic effect in improving DON adsorption and SERS response. 97.6 % of DON was removed by AuNRs@BUT-16 in aqueous solution, and 70 % in 80 % methanol. The pre-enrichment effect of BUT-16 could trap more DON molecules in the “hot spots” of AuNRs, thus the proposed SERS sensor based on AuNRs@BUT-16 substrate displayed outstanding SERS response and the limit of detection of DON was 3.87 × 10−3 μg/mL. Molecular docking revealed that hydrogen bond and π-alkyl interaction were the main reasons for high affinity between BUT-16 and DON, and Au-O bonds facilitated the adsorption of DON on AuNRs. ConclusionsAuNRs@BUT-16 with superior enrichment and SERS detection capabilities has been used for simultaneous removal and SERS detection of DON, and it also has great potential to realize sensitive and selective detection and removal of DON in multiple disciplines.

Paper-based sensors: affordable, versatile, and emerging analyte detection platforms.

Paper-based sensors, often referred to as paper-based analytical devices (PADs), stand as a transformative technology in the field of analytical chemistry. They offer an affordable, versatile, and accessible solution for diverse analyte detection. These sensors harness the unique properties of paper substrates to provide a cost-effective and adaptable platform for rapid analyte detection, spanning chemical species, biomolecules, and pathogens. This review highlights the key attributes that make paper-based sensors an attractive choice for analyte detection. PADs demonstrate their versatility by accommodating a wide range of analytes, from ions and gases to proteins, nucleic acids, and more, with customizable designs for specific applications. Their user-friendly operation and minimal infrastructure requirements suit point-of-care diagnostics, environmental monitoring, food safety, and more. This review also explores various fabrication methods such as inkjet printing, wax printing, screen printing, dip coating, and photolithography. Incorporating nanomaterials and biorecognition elements promises even more sophisticated and sensitive applications.

Screen Printed Electrodes: A Boon for Forensic Chemistry Analysis for Detection of Narcotics and Explosives

Abstract: Screen printing technology is a method of ink-based printing that utilizes a stencil mesh screen to create a visual pattern on a flat surface, such as plastic or silk. This process finds application in the production of screen-printed electrodes, which are utilized in electrochemical cells as part of voltammetric techniques. These electrodes offer advantages in terms of simplicity, portability, and ease of use compared to more intricate techniques. Various voltammetric methods are employed to analyze materials present in trace quantities, including drugs and explosives. By employing screen-printed electrodes in these electro-analytical techniques, it becomes possible to achieve straightforward, cost-effective, sensitive, and rapid detection of analytes with forensic significance. This highlights the significance of screen-printed electrodes in both onsite and laboratory forensic examinations.

Facile electrochemical surface-alloying and etching of Au wires to enable high-performance substrates for surface enhanced Raman scattering

Surface-enhanced Raman Spectroscopy (SERS) is a nondestructive technique for rapid detection of analytes even at the single-molecule level. However, highly sensitive and reliable SERS substrates are mostly fabricated with complex nanofabrication techniques, greatly restricting their practical applications. A convenient electrochemical method for transforming the surface of commercial gold wires/foils into silver-alloyed nanostructures is demonstrated in this report. Au substrates are treated with repetitive anodic and cathodic bias in an electrolyte of thiourea, in a one-pot one-step manner. X-rays absorption fine structure (XAFS) spectroscopy confirms that the AuAg alloy is induced at the surface. The unique AuAg alloyed surface nanostructures are particularly advantageous when served as SERS substrates, enabling a remarkably sensitive detection of Rhodamine B (a detection limit of 10−14 ​M, and uniform strong response throughout the substrates at 10−12 ​M).

Microfluidics-Based Nanobiosensors for Healthcare Monitoring.

Efficient healthcare management demands prompt decision-making based on fast diagnostics tools, astute data analysis, and informatics analysis. The rapid detection of analytes at the point of care is ensured using microfluidics in synergy with nanotechnology and biotechnology. The nanobiosensors use nanotechnology for testing, rapid disease diagnosis, monitoring, and management. In essence, nanobiosensors detect biomolecules through bioreceptors by modulating the physicochemical signals generating an optical and electrical signal as an outcome of the binding of a biomolecule with the help of a transducer. The nanobiosensors are sensitive and selective and play a significant role in the early identification of diseases. This article reviews the detection method used with the microfluidics platform for nanobiosensors and illustrates the benefits of combining microfluidics and nanobiosensing techniques by various examples. The fundamental aspects, and their application are discussed to illustrate the advancement in the development of microfluidics-based nanobiosensors and the current trends of these nano-sized sensors for point-of-care diagnosis of various diseases and their function in healthcare monitoring.

Tactile Sensors: Hydroxyl Decorated Silver Metal–Organic Frameworks for Detecting Cr2O72–, MnO4–, Humic Acid, and Fe3+ Ions

Anionic, acidic, and metal ions are common contaminants in water and cause serious concerns for human and aquatic life. With the goal of rapid detection of analytes, we herein design a new array of ligand 5-(4H-1,2,4-triazol-4-yl)pyridin-3-ol-linked silver coordinated metal-organic frameworks Ag-MOFs as a promising sensor for Cr2O72-, MnO4-, humic acid (HA), and Fe3+ ions down to the micro level. Furthermore, as evidenced by luminescence, excitation-emission matrix (EEM) spectroscopic, and PXRD measurements, designed metal-organic frameworks (MOFs) can be fast, stable, and reusable for analyte detection in water.

Unfolding of β-hairpin and α-helical peptides through a biological nanopore.

Nanopore sensing is a useful tool for the rapid detection of analytes at the single-molecule level. Since this technology allows high sensitivity detection based on the ion currents, it is expected to be applied to protein sequencing and folding analysis of proteins. In particular, biological nanopores are 1-4 nm in the size, and proteins pass through the nanopore with unfolding its inside. Therefore, the ion currents will provide insight into the folding process of each secondary structure of proteins, and these analyses may be able to detect specific structures of proteins. Here, we synthesized β-hairpin and α-helix peptides, and analyzed the ion current of the translocation with unfolding. β-hairpin peptides were synthesized using cell-free synthesis, and mass spectrometry characterized each peptide and confirmed secondary structures by fluorescence measurement and circular dichroism spectrum. Channel current measurements identified the behavior of β-hairpin peptides passing through αHL nanopores. As result, signals with three current blocking rates were observed, reflecting the stepwise unfolding of β-hairpin peptides within αHL nanopores. Therefore, we estimated the unfolding behavior of peptides from each blocking state of the ion currents. The estimated results for each level are shown below. Level 1: β-hairpin structure hooked with the upper of nanopore. Level 2: in the pores, the pulling force caused partial unfolding allowing β-hairpin structure to traverse the pore. Level 3: remainder structures unfolded completely and left through the trans entrance. Our experiments with protein denaturants supported our estimations. We are trying to observe the translocation of α-helix peptides, and research the difference in unfolding process of β-hairpin peptides and that of α-helix peptides.

Sensitized Lanthanide Photoluminescence Based Sensors–a Review

AbstractPhotoluminescent supramolecular systems such as hydrogels and metal‐organic frameworks (MOFs) can be useful for applications in many areas. In aqueous media, lanthanides exhibit luminescence by sensitization through covalently linked chromophores (antenna effect), making them valuable for sensing and imaging applications. Fluorescent sensing by sensitized lanthanide emission in gels and MOFs provides a simple and rapid detection of analytes with high sensitivity and selectivity. This review presents the gradual evolution and the intriguing conceptualization of sensitized luminescence of lanthanides spanning the sensing of biomolecules, drugs, small organic molecules and enzymes employing hydrogels or MOFs as the sensing platform.

Facile Fabrication of Stable Enzyme-Based Colorimetric Glucose Biosensor on Cotton Using Polymer Entrapment

Easy and rapid analyte detection can be democratised using fabric-based colorimetric sensor, which can be readily incorporated into everyday clothing or accessories, and digitally imaged by non-expert users using pervasive smartphones. However, fabricating colorimetric arrays, particularly enzyme-based sensors, on fabrics is nontrivial because enzyme activity cannot be guaranteed upon solid-state immobilisation on textiles, and because textiles present a highly-textured surface that could cause interference during digital imaging and reduce the limit of detection of known sensing formulations. Here, an enzyme-based multilayer sensor is fabricated on selected fabrics via physical adsorption and drop-casting, and utilised for proof-of-concept colorimetric detection of glucose on textiles. Substrates like cotton, cotton lycra, and filter paper are compared for colour uniformity and potential interference during digital imaging. Colour development on cotton achieved optimal homogeneity and reproducibility. The entrapment of enzymes with polyvinyl alcohol is demonstrated to enhance linear dynamic range, water fastness, and storage stability under different conditions. An image-processing algorithm is developed in OpenCV to automatically detect the colour spot and aid in quantitative analysis of glucose concentration. The present study suggests a facile strategy to fabricate a robust biosensor on textile that can achieve noninvasive monitoring of glucose in human biological fluid.

Ultrasensitive On-Field Luminescence Detection Using a Low-Cost Silicon Photomultiplier Device.

The availability of portable analytical devices for on-site monitoring and rapid detection of analytes of forensic, environmental, and clinical interest is vital. We report the development of a portable device for the detection of biochemiluminescence relying on silicon photomultiplier (SiPM) technology, called LuminoSiPM, which includes a 3D printed sample holder that can be adapted for both liquid samples and paper-based biosensing. We performed a comparison of analytical performance in terms of detectability with a benchtop luminometer, a portable cooled charge-coupled device (CCD sensor), and smartphone-integrated complementary metal oxide semiconductor (CMOS) sensors. As model systems, we used two luciferase/luciferin systems emitting at different wavelengths using purified protein solutions: the green-emitting P. pyralis mutant Ppy-GR-TS (λmax 550 nm) and the blue-emitting NanoLuc (λmax 460 nm). A limit of detection of 9 femtomoles was obtained for NanoLuc luciferase, about 2 and 3 orders of magnitude lower than that obtained with the portable CCD camera and with the smartphone, respectively. A proof-of-principle forensic application of LuminoSiPM is provided, exploiting an origami chemiluminescent paper-based sensor for acetylcholinesterase inhibitors, showing high potential for this portable low-cost device for on-site applications with adequate sensitivity for detecting low light intensities in critical fields.

Research Advances in Excited State Intramolecular Proton Transfer Fluorescent Probes Based on Combined Fluorescence Mechanism

Fluorescent probes can achieve rapid detection of analytes, and have become a research hotspot in recent years due to their excellent selectivity, high sensitivity and easy operation. Excited state intramolecular proton transfer (ESIPT) is one of the most basic strategies for designing fluorescence probes. Fluorescent probes based on ESIPT possess large Stokes shift, strong luminescence and high fluorescence quantum yield. However, these are still some disadvantages, such as sensitivity to the environment and short emission wavelength. In recent years, the ESIPT combined with other fluorescence mechanisms, can obtain new fluorescent probes with dual mechanism of fluorescence response. This strategy can not only solve the shortage of ESIPT fluorophore, but also realize multi-fluorescence signal channel, and significantly improve the selectivity and sensitivity of the new probe. In this review, we mainly summarized the detection mechanism and imaging application of fluorescence probes of PET-ESIPT, ICT-ESIPT, FRET-ESIPT, AIE-ESIPT for ions, small molecules, biological macromolecules in recent years.

Refractive index sensing characteristics of electromagnetic metamaterial absorber in terahertz band

<sec>Terahertz metamaterial (THz MM) absorber, as an important type of MM functional device, can not only achieve perfect absorption of incident THz waves, but also act as a refractive index sensor to capture and monitor changes in the information about surrounding environment. Generally, the sensing characteristics of the THz MM absorber can be improved by optimizing the structure of the surface metal resonance unit and changing the material and shape of the dielectric layer. In order to further study the influence of the intermediate dielectric layer on the sensing characteristics of the THz MM absorber, in this paper we implement three THz MM absorbers with continuous dielectric layer, discontinuous dielectric layer and microcavity structure based on the metallic split-ring resonator array, and conduct in-depth study of their sensing characteristics and sensing mechanism. </sec><sec>The THz MM absorber with continuous dielectric layer and metallic split-ring resonator array can be used as a refractive index sensor to realize the sensing detection of analytes coated on its surface with different refractive indexes. However, it can be seen from its corresponding refractive index frequency sensitivity and FOM value that the detection sensitivity of this sensor is limited, and its sensing performance still needs improving. The main reason is that most of the resonant electromagnetic (EM) field of the THz MM absorber is tightly bound in the intermediate dielectric layer, and only the fringe field extending to the surface of the MM absorber resonant unit array can interact with the analyte to be measured, and the intensity of this part of the field directly determines the sensitivity of the sensor. In order to further improve the refractive index frequency sensitivity of the THz MM absorber, reduce the restriction of the intermediate dielectric layer to the resonant EM field, and enhance the interaction between the resonant EM field and the analyte to be measured, a THz MM absorber with discontinuous dielectric layer is proposed and studied. Compared with the THz MM absorber with continuous dielectric layer, the THz MM absorber based on discontinuous dielectric layer can be used as a refractive index sensor to realize higher-sensitivity sensing and detection of the analyte coated on the surface. In order to further enhance the interaction between the resonant EM field and the analyte to be measured, and improve the refractive index frequency sensitivity of the THz MM absorber, a THz MM absorber with a microcavity structure is proposed. For this THz MM absorber, the analyte to be measured filled in the microcavity structure can serve as the intermediate dielectric layer of the THz MM absorber, and when the metallic split-ring resonator array is completely immersed in the analyte to be measured, the resonant EM field originally confined in the intermediate dielectric layer and the analyte to be measured completely overlap in space. Therefore, compared with the first two THz MM absorbers, THz MM absorber with a microcavity structure achieves the tightly and fully contacting the resonant EM field, thereby greatly improving its sensitivity as a sensor. </sec><sec>The results show that in order to improve the sensing characteristics of the THz MM absorber, such as the refractive index sensitivity and the maximum detection range, in addition to using the materials with lower relatively permittivity as the intermediate dielectric layer, the morphology of the intermediate dielectric layer can be changed, thereby reducing the restraint of the intermediate dielectric layer on the resonant field and enhancing the coupling between the resonant field and the analyte to be measured. Compared with the conventional THz MM absorber with continuous dielectric layer, the MM absorber with discontinuous dielectric layer and microcavity structure have many superior sensing characteristics, and can be applied to the high-sensitivity and rapid detection of analytes to be measured, and has a broader application prospect in the future sensing field. </sec>

Lateral flow immunochromatographic assay on a single piece of paper.

Lateral flow immunochromatographic assays (LFIAs) are analytical devices used to detect the presence of one or more target analytes in a liquid sample. While LFIAs are one of the simplest and inexpensive types of immunoassays, they consist of multiple components (sample pad, conjugate pad, membrane, absorbent pad, backing card) and materials, requiring time-consuming device assembly. Here, we report a unique lateral flow immunochromatographic assay constructed from a single piece of cellulose paper, which is fabricated via laser cutting. Compared with conventional lateral flow immunochromatographic devices, this single-layer immunoassay enables simpler and faster fabrication, while minimizing material consumption and overall device costs. For proof-of-concept, this device was used to detect Plasmodium falciparum histidine-rich protein 2 (PfHRP2), a biomarker for malaria infection, which could be detected at concentrations as low as 4 ng mL-1 by the naked eye with no cross reactivity with other common Plasmodium protein biomarkers. While offering similar speed and ease-of-use as conventional LFIAs with a higher detection sensitivity than existing LFIAs for PfHRP2 detection, this single-layer lateral flow immunoassay has the potential to improve malaria testing, as well as the detection of other important protein biomarkers for point-of-care testing.

Simple Fabrication of Solid-Phase Microextraction with Surface-Coated Aluminum Foil for Enhanced Detection of Analytes in Biological and Clinical Samples by Mass Spectrometry.

Rapid detection of analytes in biological and clinical samples is highly desirable, and significant progress has been made with direct mass spectrometric (MS) analysis. Rapid and sensitive detection, however, remains a major challenge in direct analysis of raw samples. In this study, we described a simple, rapid, and efficient method for enhanced detection of analytes in complex samples, using surface-coated aluminum (Al) foil that was simply made with conductive resin for physical adhesion of functional particles. The surface-coated Al foils were used as a solid-phase microextraction (SPME) tip for rapid sampling of target analytes from raw samples and then applied as an electrospray ionization (ESI) tip to couple MS for sensitive detection. Our results show that surface-coated Al foil is highly effective for enhanced detection of analytes in complex samples with excellent analytical performances, including sensitivity, reproducibility, and linear ranges. Overall, this development enabled an extremely simplified protocol to integrate SPME and ESI that is expected to have a significant impact on rapid screening of raw samples.

Supercritical Fluid-Assisted Fabrication of Manganese (III) Oxide Hollow Nanozymes Mediated by Polymer Nanoreactors for Efficient Glucose Sensing Characteristics.

Despite their inherent efficacy in significantly accelerating the rate of chemical reactions in biological processes, the applicability of natural enzymes is often hindered because of their intrinsic limitations such as high sensitivity, poor operational stability, and relatively high cost for purification as well as preparation. Thus, the fabrication of catalytically active nanomaterials as artificial enzymes (nanozymes) has become a newly burgeoning area of research in bionic chemistry, aiming in designing functional nanomaterials that mimic various inherent properties of natural enzymes. To address these issues, we present the supercritical fluid (SCF)-assisted fabrication of discrete, monodisperse, and uniform-sized manganese (III) oxide (Mn2O3)-based hollow containers as high-efficiency nanozymes for glucose sensing characteristics. Initially, the core-shell nanoreactors based on polyvinylpyrrolidone (PVP)-encapsulated manganese (III) acetylacetonate (Mn(acac)3) as precursors are fabricated using the SCF technology and subsequent calcination resulted in the Mn2O3 hollow nanoparticles (MHNs). This eco-friendly approach has resulted in the PVP-coated Mn(acac)3 nanoreactors with an average diameter of 220 nm and subsequent calcined hollow products are about one-fifth to that of the precursor. Such MHNs conveniently catalyzed 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2) as a prominent peroxidase mimic, resulting in the oxidation products (TMB*+) at a specific absorption (UV-vis) maxima of 652 nm. Following typical Michaelis-Menten theory, this approach is further utilized to develop visual nonenzymatic sensing of glucose in a linear range of 0.1-1 mM at a detection limit of 2.31 μM. Collectively, this reliable as well as a cost-effective system with high precision potentially allows rapid detection of analytes, providing a convenient way for its utilization in diverse fields.

Acoustofluidic Micromixing Enabled Hybrid Integrated Colorimetric Sensing, for Rapid Point-of-Care Measurement of Salivary Potassium.

The integration of microfluidics with advanced biosensor technologies offers tremendous advantages such as smaller sample volume requirement and precise handling of samples and reagents, for developing affordable point-of-care testing methodologies that could be used in hospitals for monitoring patients. However, the success and popularity of point-of-care diagnosis lies with the generation of instantaneous and reliable results through in situ tests conducted in a painless, non-invasive manner. This work presents the development of a simple, hybrid integrated optical microfluidic biosensor for rapid detection of analytes in test samples. The proposed biosensor works on the principle of colorimetric optical absorption, wherein samples mixed with suitable chromogenic substrates induce a color change dependent upon the analyte concentration that could then be detected by the absorbance of light in its path length. This optical detection scheme has been hybrid integrated with an acoustofluidic micromixing unit to enable uniform mixing of fluids within the device. As a proof-of-concept, we have demonstrated the real-time application of our biosensor format for the detection of potassium in whole saliva samples. The results show that our lab-on-a-chip technology could provide a useful strategy in biomedical diagnoses for rapid analyte detection towards clinical point-of-care testing applications.

Bioconjugates of Microbial Enzyme and Nanoparticles for The Rapid Detection of Analytes

The enormous complexity and diversity of bioconjugates presents a great challenge to researchers attempting to reveal their chemical basis and functional aspects...

Paper-Based Sensors: Emerging Themes and Applications.

Paper is a versatile, flexible, porous, and eco-friendly substrate that is utilized in the fabrication of low-cost devices and biosensors for rapid detection of analytes of interest. Paper-based sensors provide affordable platforms for simple, accurate, and rapid detection of diseases, in addition to monitoring food quality, environmental and sun exposure, and detection of pathogens. Paper-based devices provide an inexpensive technology for fabrication of simple and portable diagnostic systems that can be immensely useful in resource-limited settings, such as in developing countries or austere environments, where fully-equipped facilities and highly trained medical staff are absent. In this work, we present the different types of paper that are currently utilized in fabrication of paper-based sensors, and common fabrication techniques ranging from wax printing to origami- and kirigami-based approaches. In addition, we present different detection techniques that are employed in paper-based sensors such as colorimetric, electrochemical, and fluorescence detection, chemiluminescence, and electrochemiluminescence, as well as their applications including disease diagnostics, cell cultures, monitoring sun exposure, and analysis of environmental reagents including pollutants. Furthermore, main advantages and disadvantages of different types of paper and future trends for paper-based sensors are discussed.

Near Real-time Surveillance of Disease during 2016-17 Influenza Season in the U.S.

ObjectiveDemonstrate performance of the Virena Global Wireless Surveillance System, an automated platform utilized in conjunction with the Sofia FIA Analyzer, for near real-time transmission of infectious disease test results to public health and other healthcare organizations.IntroductionPublic health agencies worldwide all enjoy the same mission—providing healthcare warnings, guidance, and support to the public and healthcare professionals they represent. A critical element in achieving this mission is accessing timely and comprehensive surveillance information about disease in their regions of responsibility. Advances in diagnostic technologies for infectious disease and in the wireless conveyance of information hold great promise for advancing the quality of surveillance information and in facilitating the delivery of timely, accurate, and impactful public health information. Quidel Corporation has developed a cloud–based, wireless communications system that is fully integrated with its Sofia fluorescence immunoassay (FIA) platform for rapid, point-of-care diagnosis of infectious disease. The system, called the Virena Global Wireless Surveillance System (hereinafter, Virena) provides test results to public health organizations and other appropriate entities in near-real time. Currently, more than 4,000 Sofia instruments are transmitting results automatically by Virena. This presentation describes the use of Virena in surveilling influenza in the U.S. in the 2016-2017 influenza season, when over 700,000 influenza-like-illness (ILI) patient results were transmitted. The methods employed, results, and the promise of this innovative system will be discussed.MethodsThe Sofia Fluorescent Immunoassay Analyzer (FIA) is a small FDA-cleared, CLIA-waived bench top device that uses immunofluorescence-based, lateral-flow technology for rapid analyte detection within 15 minutes for influenza. With Sofia2, a recent upgrade, positive influenza test results can be obtained in as few as 3 minutes, depending on virus levels. The results are encrypted, and automatically transmitted by Virena--often within 5 seconds--to a dual cloud system for further encryption and formatting. The test results (also including location, date, and patient age) are subsequently pushed to participating public health and healthcare organizations for daily collection and analysis. Healthcare providers utilizing the Virena system may also access their own data and facility-de-identified regional and national data, using a password-enabled internet application called MyVirena.com.ResultsBetween August 1, 2016 and October 6, 2017, 706,654 ILI patient results were transmitted by Virena from over 3,000 clinical sites in the United States. The influenza positivity rate (influenza A and B combined) peaked on February 9th at 33% and maintained this level for two weeks (Figure 1). During this period, as many as 7,048 results were transmitted by Virena per day. Influenza A activity peaked on the same day at 26%, and influenza B peaked at 18% nearly 6.5 weeks later. In the six months from December 15th to June 15th, the influenza positivity rate for patients with ILI was 10% or greater in the United States. Data analysis for individual states revealed significant differences in time of onset of influenza and in the peak positivity rates. For example, the state of Arizona experienced peak positivity rates for influenza activity (42%) as late as mid-May, driven largely by influenza B. In California, influenza A peaked at 43% on January 16th and maintained a positivity rate greater than 15% for nearly three months, while influenza B averaged below 4% for the entire period. Age-specific analysis showed that children in the 2 to 18 year old group had the highest positivity rate (44%, n=251,756) and the longest incidence period. Virena data demonstrated similar influenza activity trends on national and regional levels as that depicted by the clinical laboratory and NREVSS data collected by the CDC; however, the Virena data were collected and reported sooner (Figure 2).ConclusionsThe Virena system represents a major stride for disease surveillance, providing clinical testing data in near real-time time, with local, national, and global scope. This first substantial evaluation of the Virena system, with over 4,000 transmitting Sofia Analyzers, demonstrates capabilities for near real-time assessment of disease onset, regionally varying positivity rates, durations of outbreaks, differential assessment of influenza A and B prevalence, and dynamic mapping throughout the year. With expanding regional and metropolitan coverage, the Virena system holds promise as both a powerful surveillance tool, and as a valuable resource for healthcare quality initiatives, epidemiological research, and the development of new mathematical models for influenza forecasting .

Highly sensitive and selective detection of mercury ions using N, S-codoped graphene quantum dots and its paper strip based sensing application in wastewater

The development of robust and low-cost sensing materials with superior selectivity and sensitivity for rapid detection of analytes in a wide variety of samples has attracted much attention. Herein, the N, S-codoped graphene quantum dots (N, S-GQDs) with high quantum yield were fabricated by one-pot hydrothermal method for highly sensitive and selective detection of nanomolar level of mercury ions (Hg2+) in water and wastewater. The as-prepared N, S-GQDs are uniform in size with mean particle size of 3.5±0.5nm. The doping of nitrogen atoms increases the quantum yield to 41.9%, while the introduction of sulfur atoms enhances the selectivity of Hg2+ via strong coordination interaction. The fluorescence intensity of N, S-GQDs is quenched proportionally after adding Hg2+ and a dynamic range of 4 orders of magnitude with limit of detection of 0.14nM is obtained in deionized water. The N, S-GQDs nanosensing probes can be successfully applied to the sewage and dye wastewater samples and a linear range of 0.1–15μM with recovery of 96–116% is obtained. In addition, the coating of N, S-GQDs onto paper strip provides an excellently rapid screening and highly selective technique for Hg2+ detection in real wastewater. Results obtained in this study clearly indicate that the N, S-GQDs are promising nanomaterials which can open an new avenue to design the GQD based sensing probe for highly sensitive and selective detection of metal ions and other analytes in environmental and biological fluid samples.