scholarly journals Trimodal Waveguide Demonstration and Its Implementation as a High Order Mode Interferometer for Sensing Application

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2821 ◽  
Author(s):  
Jhonattan C. Ramirez ◽  
Lucas H. Gabrielli ◽  
Laura M. Lechuga ◽  
Hugo E. Hernandez-Figueroa
Keyword(s):  
Free Spectral Range ◽  
Point Of Care ◽  
Low Cost ◽  
High Order Mode ◽  
Sio2 Substrate ◽  
Polymer Waveguide ◽  
Sensing Applications ◽  
Highly Sensitive ◽  
Different Types ◽  
Mode Order

This work implements and demonstrates an interferometric transducer based on a trimodal optical waveguide concept. The readout signal is generated from the interference between the fundamental and second-order modes propagating on a straight polymer waveguide. Intuitively, the higher the mode order, the larger the fraction of power (evanescent field) propagating outside the waveguide core, hence the higher the sensitivity that can be achieved when interfering against the strongly confined fundamental mode. The device is fabricated using the polymer SU-8 over a SiO2 substrate and shows a free spectral range of 20.2 nm and signal visibility of 5.7 dB, reaching a sensitivity to temperature variations of 0.0586 dB/ ∘ C. The results indicate that the proposed interferometer is a promising candidate for highly sensitive, compact and low-cost photonic transducer for implementation in different types of sensing applications, among these, point-of-care.

scholarly journals Sensing of Oxygen Partial Pressure in Air with ZnO Nanoparticles

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 562
Author(s):  
Xin Chang ◽  
Shunpu Li ◽  
Daping Chu
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Low Cost ◽  
Electrical Conductance ◽  
Zno Nanoparticle ◽  
Sensing Applications ◽  
Highly Sensitive ◽  
Sensitive Sensor ◽  
Micrometer Scale ◽  
Higher Sensitivity

The demand for sensors in response to oxygen partial pressure in air is increasingly high in recent years and small-size sensors on a micrometer scale and even a nanometer scale are particularly desirable. In this paper, the sensing of oxygen partial pressure in air was realized by a solution-processed ZnO nanoparticle (NP). Thin-film ZnO NP was prepared by spin-coating and a highly sensitive sensor was then fabricated. The oxygen sensing performance was characterized in air and compared with that in nitrogen, which showed an increase in electrical conductance by more than 100 times as a result of decreasing oxygen partial pressure from 103 mBar to 10−5 mBar. Moreover, higher sensitivity was achieved by increasing the annealing temperature and the effect of thermal annealing was also investigated. Furthermore, ZnO NP lines with 7 μm in width were successfully patterned with low cost by a mould-guided drying technique from ZnO NP dispersion, which makes ZnO NP extremely promising for miniaturized and integrated sensing applications.

scholarly journals A low-cost smartphone-based platform for highly sensitive point-of-care testing with persistent luminescent phosphors

Lab on a Chip ◽  
2017 ◽  
Vol 17 (6) ◽  
pp. 1051-1059 ◽  
Author(s):  
Andrew S. Paterson ◽  
Balakrishnan Raja ◽  
Vinay Mandadi ◽  
Blane Townsend ◽  
Miles Lee ◽  
...  
Keyword(s):  
Point Of Care ◽  
Low Cost ◽  
Test Strip ◽  
Lateral Flow ◽  
Point Of Care Testing ◽  
Flow Test ◽  
Highly Sensitive ◽  
Lateral Flow Test ◽  
Gated Imaging

Time-gated imaging on a smartphone of a lateral flow test strip run with persistent luminescent nanophosphors.

scholarly journals Minimally instrumented SHERLOCK (miSHERLOCK) for CRISPR-based point-of-care diagnosis of SARS-CoV-2 and emerging variants

2021 ◽  
Vol 7 (32) ◽  
pp. eabh2944
Author(s):  
Helena de Puig ◽  
Rose A. Lee ◽  
Devora Najjar ◽  
Xiao Tan ◽  
Luis R. Soekensen ◽  
...  
Keyword(s):  
Point Of Care ◽  
Low Cost ◽  
Smartphone Application ◽  
Modular System ◽  
User Needs ◽  
Multiplexed Detection ◽  
Highly Sensitive ◽  
Current Point ◽  
Automated Interpretation ◽  
User Actions

The COVID-19 pandemic highlights the need for diagnostics that can be rapidly adapted and deployed in a variety of settings. Several SARS-CoV-2 variants have shown worrisome effects on vaccine and treatment efficacy, but no current point-of-care (POC) testing modality allows their specific identification. We have developed miSHERLOCK, a low-cost, CRISPR-based POC diagnostic platform that takes unprocessed patient saliva; extracts, purifies, and concentrates viral RNA; performs amplification and detection reactions; and provides fluorescent visual output with only three user actions and 1 hour from sample input to answer out. miSHERLOCK achieves highly sensitive multiplexed detection of SARS-CoV-2 and mutations associated with variants B.1.1.7, B.1.351, and P.1. Our modular system enables easy exchange of assays to address diverse user needs and can be rapidly reconfigured to detect different viruses and variants of concern. An adjunctive smartphone application enables output quantification, automated interpretation, and the possibility of remote, distributed result reporting.

scholarly journals Detection and quantification of Mycobacterium tuberculosis antigen CFP10 in serum and urine for the rapid diagnosis of active tuberculosis disease

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marva Seifert ◽  
Eva Vargas ◽  
Victor Ruiz-Valdepeñas Montiel ◽  
Joseph Wang ◽  
Timothy C. Rodwell ◽  
...  
Keyword(s):  
Point Of Care ◽  
Low Cost ◽  
Specific Antigen ◽  
Active Tuberculosis ◽  
Serum Samples ◽  
Tuberculosis Patients ◽  
Tuberculosis Antigen ◽  
Highly Sensitive ◽  
Tuberculosis Disease ◽  
Serum And Urine

AbstractOutside of the ongoing COVID-19 pandemic, tuberculosis is the leading cause of infectious disease mortality globally. Currently, there is no commercially available point-of-care diagnostic that is rapid, inexpensive, and highly sensitive for the diagnosis of active tuberculosis disease. Here we describe the development and optimization of a novel, highly sensitive prototype bioelectronic tuberculosis antigen (BETA) assay to detect tuberculosis-specific antigen, CFP10, in small-volume serum and urine samples. In this proof-of-concept study we evaluated the performance of the BETA assay using clinical specimens collected from presumptive tuberculosis patients from three independent cohorts. Circulating CFP10 antigen was detected in ALL serum (n = 19) and urine (n = 3) samples from bacteriologically confirmed tuberculosis patients who were untreated or had less than one week of treatment at time of serum collection, successfully identifying all culture positive tuberculosis patients. No CFP10 antigen was detected in serum (n = 7) or urine (n = 6) samples from individuals who were determined to be negative for tuberculosis disease. Additionally, antigen quantification using the BETA assay of paired serum samples collected from tuberculosis patients (n = 8) both before and after treatment initiation, indicate consistently declining within-person levels of CFP10 antigen during treatment. This novel, low-cost assay demonstrates potential as a rapid, non-sputum-based, point-of-care tool for the diagnosis of tuberculosis disease.

scholarly journals Direct diagnostic testing of SARS-CoV-2 without the need for prior RNA extraction

2020 ◽  
Author(s):  
Shan Wei ◽  
Esther Kohl ◽  
Alexandre Djandji ◽  
Stephanie Morgan ◽  
Susan Whittier ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
Low Cost ◽  
Diagnostic Testing ◽  
Rna Extraction ◽  
Nucleic Acid Amplification ◽  
Nasopharyngeal Swab ◽  
Viral Transport ◽  
Extraction Step ◽  
Highly Sensitive

AbstractThe COVID-19 pandemic has resulted in an urgent global need for rapid, point-of-care diagnostic testing. Existing methods for nucleic acid amplification testing (NAAT) require an RNA extraction step prior to amplification of the viral RNA. This step necessitates the use of a centralized laboratory or complex and costly proprietary cartridges and equipment, and thereby prevents low-cost, scalable, point-of-care testing. We report the development of a highly sensitive and robust, easy-to-implement, SARS-CoV-2 test that utilizes isothermal amplification and can be run directly on viral transport media following a nasopharyngeal swab without the need for prior RNA extraction. Our assay provides visual results in 30 min with 85% sensitivity, 100% specificity, and a limit of detection (LoD) of 2.5 copies/μl, and can be run using a simple heat block.

Fabrication of a Low-Coercivity, Large-Magnetoresistance PVA/Fe/Co/Ni Nanofiber Composite Using an Electrospinning Technique and Its Characterization

2020 ◽  
Vol 20 (6) ◽  
pp. 3504-3511 ◽  
Author(s):  
A. Robertsam ◽  
N. Victor Jaya
Keyword(s):  
Low Cost ◽  
Cobalt Nitrate ◽  
Electrospinning Process ◽  
Poly Vinyl Alcohol ◽  
Ferric Nitrate ◽  
Electrospinning Technique ◽  
Nanofiber Composite ◽  
Sensing Applications ◽  
Heat Treated ◽  
Highly Sensitive

A nanofiber composite is a unique engineered material, which can impart new physical, chemical, and electrical properties. Among existing polymer composites, the metallic nanofiber composite has a significant role in biomedical applications. In this study, a metallic nanofiber composite was fabricated using poly vinyl alcohol [PVA-(C2H4O)n] reinforced with ferric nitrate [Fe(NO3)3·9H2O], cobalt nitrate [Co(NO3)2·6H2O], and nickel acetate [C4H6NiO4·4H2O] using a low-cost electrospinning process. The process parameters were optimized for fabricating uniform, bead-free, and substratefree fibers. The morphological features of the composite were evaluated using a scanning electron microscope (SEM). Hysteresis of the heat-treated composite was studied using a vibrating sample magnetometer (VSM). This study showed that the composite behaved as a ferromagnetic (intermediate) material with coercivity in the range 318–671 G for different wt.% of nickel. Pellets (8-mm diameter and 250-μm thickness) of this composite changed the resistance by 18% when dispensed in a magnetic field of 1200 G at an ambient temperature. Based on a thermogravimetric analysis, the thermal stability and magnetoresistance property showed that the fabricated composite was suitable for developing a highly sensitive magnetic sensor, which could be used in bio-sensing applications.

A portable point-of-care testing system to diagnose lung cancer through the detection of exosomal miRNA in urine and saliva

2020 ◽  
Vol 56 (63) ◽  
pp. 8968-8971 ◽  
Author(s):  
Ping Zhou ◽  
Fei Lu ◽  
Jianbo Wang ◽  
Kaiye Wang ◽  
Bo Liu ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Point Of Care ◽  
Low Cost ◽  
Testing System ◽  
Point Of Care Testing ◽  
Lung Cancers ◽  
Non Invasive ◽  
Diagnose Lung Cancer ◽  
Highly Sensitive ◽  
Exosomal Mirna

A low-cost, easy-to-operate, highly sensitive and effective lung cancer diagnostic kit (LCDK) was developed, and can realize non-invasive detection of early-, middle- and late-stage lung cancers using clinical salivary and urine samples.

scholarly journals Graphene FET Sensors for Alzheimer’s Disease Protein Biomarker Clusterin Detection

Proceedings ◽  
2020 ◽  
Vol 60 (1) ◽  
pp. 14
Author(s):  
Theodore Bungon ◽  
Carrie Haslam ◽  
Samar Damiati ◽  
Benjamin O’Driscoll ◽  
Toby Whitley ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Low Cost ◽  
Electrical Measurements ◽  
Protein Biomarker ◽  
Sio2 Substrate ◽  
Lift Off ◽  
Graphene Fet

We report on the fabrication and characterisation of Graphene field-effect transistor (GFET) Biosensors for detecting clusterin, a prominent protein biomarker of Alzheimer’s disease (AD). There are approximately 54 million people currently living with dementia worldwide and this is expected to rise to 130 million by 2050. Although there are over 400 different types of dementia, AD is the most common type, affecting between 50–75% of those diagnosed with dementia. Diagnosis of AD can take up to 2 years currently using MRI, PET, CT scans and memory tests. There is, therefore, an urgent need to develop low-cost, accurate, non-invasive and point-of-care (PoC) sensors for early diagnosis of AD. The GFET sensors we are developing to address this challenge were fabricated on Si/SiO2 substrate through processes of photolithographic patterning and metal lift-off techniques with evaporated chromium and sputtered gold contacts. Raman Spectroscopy was performed on the devices to determine the quality of the graphene. The GFETs were annealed to improve their performance before the channels were functionalized by immobilising the graphene surface with a linker molecule and anti-clusterin antibody. The detection was achieved through the binding reaction between the antibody and varying concentrations of clusterin antigen from 1 pg/mL to 1 ng/mL. The GFETs were characterized using 4-probe direct current (DC) electrical measurements which demonstrated a limit of detection of the biosensors to be below 1 pg/mL.

scholarly journals Aerogels for Biomedical, Energy and Sensing Applications

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 264
Author(s):  
Muhammad Tayyab Noman ◽  
Nesrine Amor ◽  
Azam Ali ◽  
Stanislav Petrik ◽  
Radek Coufal ◽  
...  
Keyword(s):  
High Performance ◽  
Structural Characteristics ◽  
Low Cost ◽  
Three Dimensional ◽  
Strain Sensors ◽  
High Porosity ◽  
Energy Materials ◽  
Sensing Applications ◽  
Highly Sensitive ◽  
Solid State Structures

The term aerogel is used for unique solid-state structures composed of three-dimensional (3D) interconnected networks filled with a huge amount of air. These air-filled pores enhance the physicochemical properties and the structural characteristics in macroscale as well as integrate typical characteristics of aerogels, e.g., low density, high porosity and some specific properties of their constituents. These characteristics equip aerogels for highly sensitive and highly selective sensing and energy materials, e.g., biosensors, gas sensors, pressure and strain sensors, supercapacitors, catalysts and ion batteries, etc. In recent years, considerable research efforts are devoted towards the applications of aerogels and promising results have been achieved and reported. In this thematic issue, ground-breaking and recent advances in the field of biomedical, energy and sensing are presented and discussed in detail. In addition, some other perspectives and recent challenges for the synthesis of high performance and low-cost aerogels and their applications are also summarized.

Developing enhanced magnetoimmunosensors based on low-cost screen-printed electrode devices

2016 ◽  
Vol 35 (2) ◽  
pp. 53-85 ◽  
Author(s):  
Zorione Herrasti ◽  
Erica de la Serna ◽  
Gisela Ruiz-Vega ◽  
Eva Baldrich
Keyword(s):  
High Performance ◽  
Magnetic Particles ◽  
Electrochemical Cell ◽  
Point Of Care ◽  
Low Cost ◽  
Screen Printed Electrode ◽  
Spectrophotometric Detection ◽  
Complex Sample ◽  
Different Types ◽  
Screen Printed

AbstractElectrochemical magnetoimmunosensors combine a number of issues that guarantee extremely high performance and also compatibility with the study of complex sample matrices. First, analyte immunocapture exploits the high affinity and specificity of antibodies. Second, magnetic particles (MP) provide faster and more efficient immunocapture than binding on two-dimensional structures, separation from nontarget sample components, and concentration of the target analyte. Finally, electrochemical detection supplies sensitivity and fast signal generation using robust and potentially miniaturized measurement equipment and transducers. On the contrary, MP handling is slightly more complex for end-users and more difficult to integrate in point-of-care devices than the manipulation of a classical biosensor. Attempts have been made to automate immunomagnetic binding, and the first robotized systems and platforms for the fluorescent and spectrophotometric detection of magnetoimmunoassays have already reached the market. Among the different types of electrodes available, screen-printed electrodes (SPE) stand out because of their low production cost and yet acceptable performance and interdevice reproducibility, which make them an excellent choice for analytical applications. In addition, each SPE entails a whole electrochemical cell stamped on a planar physical substrate, which makes it possible detection in small volumes and is especially favorable for the magnetic confinement of MP and the integration of microfluidic structures. In this article, we discuss the advantages obtained by using SPE and MP for the production of electrochemical magnetoimmunosensors and the clues for the successful development of such devices. We then revise some of the most outstanding works published in the literature.

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