scholarly journals Digital immunoassay for biomarker concentration quantification using solid-state nanopores

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Liqun He ◽  
Daniel R. Tessier ◽  
Kyle Briggs ◽  
Matthaios Tsangaris ◽  
Martin Charron ◽  
...  
Keyword(s):  
Solid State ◽  
Single Molecule ◽  
Dynamic Range ◽  
Point Of Care ◽  
Magnetic Bead ◽  
Thyroid Stimulating Hormone ◽  
Target Protein ◽  
Diagnostic Tools ◽  
Dna Nanostructures ◽  
Serum Samples

ABSTRACTSingle-molecule counting is the most accurate and precise method for determining the concentration of a biomarker in solution and is leading to the emergence of digital diagnostic platforms enabling precision medicine. In principle, solid-state nanopores—fully electronic sensors with single-molecule sensitivity—are well suited to the task. Here we present a digital immunoassay scheme capable of reliably quantifying the concentration of a target protein in complex biofluids that overcomes specificity, sensitivity, and consistency challenges associated with the use of solid-state nanopores for protein sensing. This is achieved by employing easily-identifiable DNA nanostructures as proxies for the presence (“1”) or absence (“0”) of the target protein captured via a magnetic bead-based sandwich immunoassay. As a proof-of-concept, we demonstrate quantification of the concentration of thyroid-stimulating hormone from human serum samples down to the high femtomolar range. Further optimization to the method will push sensitivity and dynamic range, allowing for development of precision diagnostic tools compatible with point-of-care format.

Ultrasensitive SERS-Based Immunoassay of Tumor Marker in Serum Using Au–Ag Alloy Nanoparticles and Ag/AgBr Hybrid Nanostructure

NANO ◽  
2018 ◽  
Vol 13 (01) ◽  
pp. 1850001 ◽  
Author(s):  
Yongfeng Gao ◽  
Yuanhui Feng ◽  
Lu Zhou ◽  
Lucia Petti ◽  
Zhe Wang ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Healthy Person ◽  
Detection Sensitivity ◽  
Hybrid Nanostructure ◽  
Serum Samples ◽  
Broad Dynamic Range ◽  
Surface Enhanced Raman ◽  
Relative Errors

Ultrasensitive detection of alpha-fetoprotein (AFP) is critical for the early diagnosis of liver cancer. In this work, a novel surface-enhanced Raman scattering (SERS)-based immunoassay complex has been successfully developed for the detection of AFP by using the Au-Ag alloy nanoparticals and the Ag/AgBr hybrid nanostructure. As the typical bimetal or metal/semiconductor plasmonic materials, besides the strong SERS enhancement characteristics, the Au-Ag alloy nanoparticals exhibit excellent monodispersity and the Ag/AgBr hybrid nanostructure demonstrates good stability. The experimental results show that the SERS-based immunoassay of AFP presents a low limit of detection of 1.86[Formula: see text]fg/mL and a broad dynamic range from 2[Formula: see text]fg/mL to 0.8[Formula: see text][Formula: see text]g/mL. Furthermore, the clinical applicability of the proposed SERS-based immunoassay has been assessed by the detection of AFP in the human serum samples of cancer patient and healthy person. The test data are consistent well with that of chemiluminescence immunoassay (CLIA) in the relative errors of [Formula: see text]8.82–8.06% and show better detection sensitivity. It reveals that the proposed immunoassay protocol is significant for giving insight into the design of ultrasensitive biosensor and the point-of-care testing of cancers.

scholarly journals Comparison of Diagnostic Tools for the Detection of Dirofilaria immitis Infection in Dogs

Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 499
Author(s):  
Rossella Panarese ◽  
Roberta Iatta ◽  
Jairo Alfonso Mendoza-Roldan ◽  
Donald Szlosek ◽  
Jennifer Braff ◽  
...  
Keyword(s):  
Dirofilaria Immitis ◽  
Point Of Care ◽  
Microtiter Plate ◽  
Diagnostic Tools ◽  
Diagnostic Strategy ◽  
Serum Samples ◽  
Risk Area ◽  
Large Variability ◽  
High Risk Area ◽  
Knott’S Test

In the last two decades, reports of canine heartworm (HW) infection have increased even in non-endemic areas, with a large variability in prevalence data due to the diagnostic strategy employed. This study evaluated the relative performance of two microtiter plate ELISA methods for the detection of HW antigen in determining the occurrence of Dirofilaria immitis in a dog population previously tested by the modified Knott’s test and SNAP 4Dx Plus test. The prevalence of this infection in the sheltered dog population (n = 363) from a high-risk area for HW infection was 44.4% according to the modified Knott’s test and 58.1% according to a point-of-care antigen ELISA. All serum samples were then evaluated by a microtiter plate ELISA test performed with and without immune complex dissociation (ICD). The prevalence increased from 56.5% to 79.6% following ICD, indicating a high proportion of samples with immune complexing. Comparing these results to that of the modified Knott’s test, the samples negative for microfilariae (mfs) and those positive only for D. repens mfs demonstrated the greatest increase in the proportion of positive results for D. immitis by ELISA following ICD. While the ICD method is not recommended for routine screening, it may be a valuable secondary strategy for identifying HW infections in dogs.

scholarly journals Effectiveness of Strongyloides Recombinant IgG Immunoreactive Antigen in Detecting IgG and IgG4 Subclass Antibodies for Diagnosis of Human Strongyloidiasis Using Rapid Immunochromatographic Tests

Diagnostics ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 615
Author(s):  
Patcharaporn Boonroumkaew ◽  
Lakkhana Sadaow ◽  
Oranuch Sanpool ◽  
Rutchanee Rodpai ◽  
Tongjit Thanchomnang ◽  
...  
Keyword(s):  
Predictive Value ◽  
Large Scale ◽  
Point Of Care ◽  
Strongyloides Stercoralis ◽  
Diagnostic Tools ◽  
Stool Examination ◽  
Serum Samples ◽  
Diagnostic Efficacy ◽  
Tropical Regions ◽  
Immunosuppressed Patients

Human strongyloidiasis is an important soil-transmitted helminthiasis that affects millions worldwide and can develop into fatal systemic strongyloidiasis in immunosuppressed patients. We have developed two new rapid and simple-to-use immunochromatographic test (ICT) kits for rapid serodiagnosis that support stool examination for clinical diagnosis. Strongyloides stercoralis recombinant IgG immunoreactive antigen (GenBank: AAB97359.1; rSsIR-based ICT kit) was used for detection of IgG and IgG4 antibodies. The diagnostic efficacy of both kits was evaluated using human serum samples from strongyloidiasis patients, healthy individuals, and those with other parasitosis. At a prevalence of infection of 36.4%, the diagnostic sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the rSsIR-based IgG ICT kit were 91.7%, 83.8%, 76.4%, 94.6%, and 86.7%, respectively, and those of the rSsIR-based IgG4 ICT kit were 78.3%, 84.8%, 74.6%, 87.3%, and 82.4% respectively. The concordance between the two kits was 89.7%. The recombinant antigen can be produced to an unlimited extent and the kits can be used as point-of-care diagnostic tools and in large-scale surveys in endemic areas throughout tropical regions without necessitating additional facilities or ancillary supplies.

Comparison of in-clinic point-of-care and reference laboratory total thyroxine immunoassays for diagnosis and post-treatment monitoring of hyperthyroid cats

2017 ◽  
Vol 20 (4) ◽  
pp. 319-324 ◽  
Author(s):  
Mark E Peterson ◽  
Mark Rishniw ◽  
Graham E Bilbrough ◽  
Kate B Cote
Keyword(s):  
Point Of Care ◽  
Method Comparison ◽  
Reference Interval ◽  
Thyroid Stimulating Hormone ◽  
Reference Laboratory ◽  
Good Precision ◽  
Serum Samples ◽  
Free T4 ◽  
Total Thyroxine ◽  
Assay Precision

Objectives The Catalyst One Chemistry Analyzer (IDEXX Laboratories) is a point-of-care instrument that can measure total thyroxine (TT4) by immunoassay. The aims of this study were to evaluate the analytic performance of the Catalyst TT4 assay in feline sera and to examine agreement of the Catalyst TT4 results with those measured by immunoassay at a veterinary reference laboratory. Methods Assay precision, reproducibility and linearity were evaluated for the Catalyst TT4 assay. For method comparison, TT4 concentrations in serum samples from 157 cats (127 hyperthyroid, 30 radioiodine-treated cats) were analyzed by both in-clinic and reference laboratory methods. Results The Catalyst TT4 demonstrated good precision and reproducibility (coefficients of variation ⩽8.5%) and excellent linearity in the diagnostic range of 6–150 nmol/l. Differences between the two TT4 methods showed no proportional or fixed bias (Bland–Altman plots) but did demonstrate greater spread of values at higher TT4 concentrations. Statistical analysis of percent differences between methods indicated 95% limits of agreement of ± 30%. When serum TT4 concentrations were classified as low, high or within the reference interval (12–50 nmol/l) for each assay, there was strong agreement (96.8%) in classification between methods. Conclusions and relevance The Catalyst TT4 assay provided precise serum TT4 concentrations in the 157 samples analyzed, which agreed well with results provided by a reference laboratory. Cats with Catalyst TT4 concentrations near decision thresholds (eg, normal vs high) should either have TT4 concentration repeated a few weeks later and/or undergo further testing (eg, free T4, serum thyroid-stimulating hormone, thyroid scintigraphy) to determine thyroid status.

scholarly journals A Paper-Based Analytical Device for Analysis of Paraquat in Urine and Its Validation with Optical-Based Approaches

Diagnostics ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 6
Author(s):  
Tse-Yao Wang ◽  
Yi-Tzu Lee ◽  
Hsien-Yi Chen ◽  
Cheng-Hao Ko ◽  
Chi-Tsung Hong ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Diagnostic Tools ◽  
Point Of Care Testing ◽  
Timely Initiation ◽  
Standard Curve ◽  
Colorimetric Measurements ◽  
Concentration Measurements ◽  
Analytical Device

Paraquat is a highly toxic herbicide. Paraquat poisoning is often fatal and is an important public health threat in many places. The quick identification and timely initiation of treatment based on timely analysis of the paraquat concentration in urine/serum could improve the prognosis for patients. However, current paraquat concentration measurements are time-consuming and difficult to implement due to the expensive and bulky equipment required. To address these practical challenges, paper-based devices have emerged as alternative diagnostic tools for improving point-of-care testing. In this study, we demonstrate the successful use of a paper-based analytical device for the accurate detection of urine paraquat concentration. The developed paper-based analytical device employs colorimetric paraquat concentration measurements. The R2 value for the urine paraquat standard curve was 0.9989, with a dynamic range of 0–100 ppm. The limit of detection was 3.01 ppm. Two other optical-based approaches, Spectrochip and NanoDrop, were used for comparison. The results suggest that the developed paper-based analytical device is comparable to other colorimetric measurements, as determined by Bland–Altman analysis. The device was clinically validated using urine from six paraquat-poisoned patients. The results prove that the developed paper-based analytical device is accurate, easy-to-use, and efficient for urine paraquat concentration measurement, and may enable physicians to improve clinical management.

Single Molecule Solid State Light Emitting Electrochemical Cells with Lifetimes Superior to 3000 Hours

2008 ◽  
Author(s):  
Henk Bolink ◽  
Rubén D. Costa ◽  
Enrique Orti ◽  
Michele Sessolo ◽  
Stefan Graber ◽  
...  
Keyword(s):  
Solid State ◽  
Single Molecule ◽  
Electrochemical Cells ◽  
Light Emitting

Ferromagnetic Resonance Biosensor for Homogeneous and Volumetric Detection of DNA

2017 ◽  
Author(s):  
Bo Tian ◽  
Peter Svedlindh ◽  
Mattias Strömberg ◽  
Erik Wetterskog
Keyword(s):  
Magnetic Nanoparticles ◽  
Ferromagnetic Resonance ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Rolling Circle Amplification ◽  
Resonance Field ◽  
Isothermal Amplification ◽  
Detection Sensitivity ◽  
Serum Samples ◽  
Rolling Circle

In this work, we demonstrate for the first time, a ferromagnetic resonance (FMR) based homogeneous and volumetric biosensor for magnetic label detection. Two different isothermal amplification methods, <i>i.e.</i>, rolling circle amplification (RCA) and loop-mediated isothermal amplification (LAMP) are adopted and combined with a standard electron paramagnetic resonance (EPR) spectrometer for FMR biosensing. For RCA-based FMR biosensor, binding of RCA products of a synthetic Vibrio cholerae target DNA sequence gives rise to the formation of aggregates of magnetic nanoparticles. Immobilization of nanoparticles within the aggregates leads to a decrease of the net anisotropy of the system and a concomitant increase of the resonance field. A limit of detection of 1 pM is obtained with an average coefficient of variation of 0.16%, which is superior to the performance of other reported RCA-based magnetic biosensors. For LAMP-based sensing, a synthetic Zika virus target oligonucleotide is amplified and detected in 20% serum samples. Immobilization of magnetic nanoparticles is induced by their co-precipitation with Mg<sub>2</sub>P<sub>2</sub>O<sub>7</sub> (a by-product of LAMP) and provides a detection sensitivity of 100 aM. The fast measurement, high sensitivity and miniaturization potential of the proposed FMR biosensing technology makes it a promising candidate for designing future point-of-care devices.<br>

scholarly journals Solid‐State Near‐Infrared Circularly Polarized Luminescence from Chiral YbIII‐Single‐Molecule Magnet

2021 ◽  
Author(s):  
Fabrice Pointillart ◽  
Bertrand Lefeuvre ◽  
Carlo Andrea Mattei ◽  
Jessica Flores Gonzalez ◽  
Frédéric Gendron ◽  
...  
Keyword(s):  
Solid State ◽  
Single Molecule ◽  
Near Infrared ◽  
Circularly Polarized ◽  
Single Molecule Magnet ◽  
Circularly Polarized Luminescence ◽  
Polarized Luminescence

scholarly journals A Label and Probe-Free Zika Virus Immunosensor Prussian Blue@carbon Nanotube-Based for Amperometric Detection of the NS2B Protein

Biosensors ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 157
Author(s):  
Bárbara V. M. Silva ◽  
Marli T. Cordeiro ◽  
Marco A. B. Rodrigues ◽  
Ernesto T. A. Marques ◽  
Rosa F. Dutra
Keyword(s):  
Carbon Nanotube ◽  
Prussian Blue ◽  
Zika Virus ◽  
Point Of Care ◽  
Amperometric Detection ◽  
Cross Reactivity ◽  
Structural Protein ◽  
Serum Samples ◽  
Polypyrrole Composite ◽  
Congenital Disabilities

Zika virus (ZIKV) is a mosquito-borne infection, predominant in tropical and subtropical regions causing international concern due to the ZIKV disease having been associated with congenital disabilities, especially microcephaly and other congenital abnormalities in the fetus and newborns. Development of strategies that minimize the devastating impact by monitoring and preventing ZIKV transmission through sexual intercourse, especially in pregnant women, since no vaccine is yet available for the prevention or treatment, is critically important. ZIKV infection is generally asymptomatic and cross-reactivity with dengue virus (DENV) is a global concern. An innovative screen-printed electrode (SPE) was developed for amperometric detection of the non-structural protein (NS2B) of ZIKV by exploring the intrinsic redox catalytic activity of Prussian blue (PB), incorporated into a carbon nanotube–polypyrrole composite. Thus, this immunosensor has the advantage of electrochemical detection without adding any redox-probe solution (probe-less detection), allowing a point-of-care diagnosis. It was responsive to serum samples of only ZIKV positive patients and non-responsive to negative ZIKV patients, even if the sample was DENV positive, indicating a possible differential diagnosis between them by NS2B. All samples used here were confirmed by CDC protocols, and immunosensor responses were also checked in the supernatant of C6/36 and in Vero cell cultures infected with ZIKV.

scholarly journals All-Solid-State Potentiometric Ion-Sensors Based on Tailored Imprinted Polymers for Pholcodine Determination

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1192
Author(s):  
Hisham S. M. Abd-Rabboh ◽  
Abd El-Galil E. Amr ◽  
Abdulrahman A. Almehizia ◽  
Ayman H. Kamel
Keyword(s):  
Solid State ◽  
Low Cost ◽  
Cost Effective ◽  
Pharmaceutical Formulations ◽  
Measurement Sensitivity ◽  
Serum Samples ◽  
Multiwalled Carbon ◽  
Imprinted Polymers ◽  
High Measurement ◽  
Liquid Chromatographic

In recent times, the application of the use of ion-selective electrodes has expanded in the field of pharmaceutical analyses due to their distinction from other sensors in their high selectivity and low cost of measurement, in addition to their high measurement sensitivity. Cost-effective, reliable, and robust all-solid-state potentiometric selective electrodes were designed, characterized, and successfully used for pholcodine determination. The design of the sensor device was based on the use of a screen-printed electrode modified with multiwalled carbon nanotubes (MWCNTs) as a solid-contact transducer. Tailored pholcodine (PHO) molecularly imprinted polymers (MIPs) were prepared, characterized, and used as sensory receptors in the presented potentiometric sensing devices. The sensors exhibited a sensitivity of 31.6 ± 0.5 mV/decade (n = 5, R2 = 0.9980) over the linear range of 5.5 × 10−6 M with a detection limit of 2.5 × 10−7 M. Real serum samples in addition to pharmaceutical formulations containing PHO were analyzed, and the results were compared with those obtained by the conventional standard liquid chromatographic approach. The presented analytical device showed an outstanding efficiency for fast, direct, and low-cost assessment of pholcodine levels in different matrices.

Sign in / Sign up

Export Citation Format

Share Document