scholarly journals A Smartphone Camera Colorimetric Assay of Acetylcholinesterase and Butyrylcholinesterase Activity

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1796
Author(s):  
Miroslav Pohanka ◽  
Jitka Zakova
Keyword(s):  
Limit Of Detection ◽  
Colorimetric Assay ◽  
Point Of Care ◽  
Specific Treatment ◽  
Point Of Care Testing ◽  
Analytical Instruments ◽  
Colorimetric Test ◽  
3D Printed ◽  
Butyrylcholinesterase Activity ◽  
Additional Education

Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) can serve as biochemical markers of various pathologies like liver disfunction and poisonings by nerve agents. Ellman’s assay is the standard spectrophotometric method to measure cholinesterase activity in clinical laboratories. The authors present a new colorimetric test to assess AChE and BChE activity in biological samples using chromogenic reagents, treated 3D-printed measuring pads and a smartphone camera as a signal detector. Multiwell pads treated with reagent substrates 2,6-dichlorophenolindophenyl acetate, indoxylacetate, ethoxyresorufin and methoxyresorufin were prepared and tested for AChE and BChE. In the experiments, 3D-printed pads containing indoxylacetate as a chromogenic substrate were optimal for analytical purposes. The best results were achieved using the red (R) channel, where the limit of detection was 4.05 µkat/mL for BChE and 4.38 µkat/mL for AChE using a 40 µL sample and a 60 min assay. The major advantage of this method is its overall simplicity, as samples are applied directly without any specific treatment or added reagents. The assay was also validated to the standard Ellman’s assay using human plasma samples. In conclusion, this smartphone camera-based colorimetric assay appears to have practical applicability and to be a suitable method for point-of-care testing because it does not require specific manipulation, additional education of staff or use of sophisticated analytical instruments.

3D Printed Smart Silk Wearable Sensors

The Analyst ◽  
2021 ◽  
Author(s):  
Tianshu Chu ◽  
Huili Wang ◽  
Yumeng Qiu ◽  
Haoxi Luo ◽  
Bingfang He ◽  
...  
Keyword(s):  
Point Of Care ◽  
Wearable Sensors ◽  
Point Of Care Testing ◽  
Biochemical Sensing ◽  
3D Printed ◽  
Physiological And Biochemical

Wearable sensors play a key role in point-of-care testing (POCT) for its flexible and integration capability on sensitive physiological and biochemical sensing. Here, we present a multifunction wearable silk patch...

scholarly journals Wave-shaped microfluidic chip assisted point-of-care testing for accurate and rapid diagnosis of infections

2021 ◽  
Author(s):  
Binfeng Yin ◽  
Xinhua Wan ◽  
Mingzhu Yang ◽  
Changcheng Qian ◽  
A S M Muhtasim Fuad Sohan
Keyword(s):  
Microfluidic Chip ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Simultaneous Detection ◽  
Accurate Diagnosis ◽  
Point Of Care Testing ◽  
Promising Alternative ◽  
Reactive Protein ◽  
Linear Relationships ◽  
Multiple Biomarkers

Abstract Background: Simultaneous and timely detection of C-reactive protein (CRP), procalcitonin (PCT), and interleukin-6 (IL-6) provides effective information for the accurate diagnosis of infections. Early diagnosis and classification of infections increase the cure rate while decreasing complications, which is significant for severe infections, especially for war surgery. However, traditional methods rely on laborious operations and bulky devices. On the other hand, point-of-care (POC) methods suffer from limited robustness and accuracy. Therefore, it is of urgent demand to develop POC devices for rapid and accurate diagnosis of infections to fulfill on-site militarized requirements.Methods: We developed a wave-shaped microfluidic chip (WMC) assisted multiplexed detection platform (WMC-MDP). WMC-MDP reduces detection time and improves repeatability through premixing of the samples and reaction of the reagents. We further combined the detection platform with the streptavidin-biotin (SA-B) amplified system to enhance the sensitivity while using chemiluminescence (CL) intensity as signal readout. We realized simultaneous detection of CRP, PCT, and IL-6 on the detection platform and evaluated the sensitivity, linear range, selectivity, and repeatability. Finally, we finished detecting 15 samples from volunteers and compared the results with commercial ELISA kits.Results: Detection of CRP, PCT, and IL-6 exhibited good linear relationships between CL intensities and concentrations in the range of 1.25-40 μg/mL, 0.4-12.8 ng/mL, and 50-1600 pg/mL. The limit of detection (LOD) of CRP, PCT, and IL-6 were 0.54 μg/mL, 0.11 ng/mL, and 16.25 pg/mL, respectively. WMC-MDP is capable of good adequate selectivity and repeatability. The whole detection procedure takes only 22 minutes that meets the requirements of a POC device. Results of 15 samples from volunteers were consistent with the results detected by commercial ELISA kits.Conclusion: WMC-MDP allows simultaneous, rapid, and sensitive detection of CRP, PCT, and IL-6 with satisfactory selectivity and repeatability, requiring minimal manipulation. However, WMC-MDP takes advantage of being a microfluidic device showing the coefficients of variation less than 10% enabling WMC-MDP to be a type of POCT. Therefore, WMC-MDP provides a promising alternative to point-of-care testing (POCT) of multiple biomarkers. We believe the practical application of WMC-MDP in militarized fields will revolutionize infection diagnosis for soldiers.

Colorimetric assay of K-562 cells based on folic acid-conjugated porous bimetallic Pd@Au nanoparticles for point-of-care testing

2014 ◽  
Vol 50 (4) ◽  
pp. 475-477 ◽  
Author(s):  
Shenguang Ge ◽  
Fang Liu ◽  
Weiyan Liu ◽  
Mei Yan ◽  
Xianrang Song ◽  
...  
Keyword(s):  
Folic Acid ◽  
Au Nanoparticles ◽  
Colorimetric Assay ◽  
Point Of Care ◽  
Point Of Care Testing ◽  
K 562 Cells

scholarly journals Performance evaluation of the point-of-care SAMBA II SARS-CoV-2 Test for detection of SARS-CoV-2

2020 ◽  
Author(s):  
Sonny M Assennato ◽  
Allyson V Ritchie ◽  
Cesar Nadala ◽  
Neha Goel ◽  
Hongyi Zhang ◽  
...  
Keyword(s):  
Public Health ◽  
Infection Control ◽  
Sensitivity And Specificity ◽  
Patient Management ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Clinical Samples ◽  
Analytical Sensitivity ◽  
Point Of Care Testing ◽  
Clinical Sensitivity

AbstractNucleic acid amplification for the detection of SARS-CoV-2 RNA in respiratory samples is the standard method for diagnosis. These tests are centralised and therefore turnaround times can be 2-5 days. Point-of-care testing with rapid turnaround times would allow more effective triage in settings where patient management and infection control decisions need to be made rapidly.Inclusivity and specificity of the SAMBA II SARS-CoV-2 assay was determined by in silico analyses of the primers and probes. Analytical and clinical sensitivity and specificity of the SAMBA II SARS-CoV-2 Test was evaluated for analytical sensitivity and specificity. Clinical performance was evaluated in residual clinical samples compared to the Public Health England reference tests.The limit of detection of the SAMBA II SARS-CoV-2 Test is 250 cp/mL and is specific for detection of 2 regions of the SARS-CoV-2 genome. The clinical sensitivity was evaluated in 172 clinical samples provided by the Clinical Microbiology and Public Health Laboratory, Addenbrooke’s Hospital, Cambridge (CMPHL), which showed a sensitivity of 98.9% (95% CI 94.03-99.97%), specificity of 100% (95% CI 95.55-100%), PPV of 100% and NPV of 98.78% (92.02-99.82%) compared to testing by CMPHLSAMBA detected 3 positive samples that were initially negative by PHE Test. The data shows that the SAMBA II SARS-CoV-2 Test performs equivalently to the centralised testing methods with a much quicker turnaround time. Point of care testing, such as SAMBA, should enable rapid patient management and effective implementation of infection control measures.

scholarly journals Label-Free Colorimetric Detection of Urine Glucose Based on Color Fading Using Smartphone Ambient-Light Sensor

Chemosensors ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 10 ◽  
Author(s):  
Wang ◽  
Guo ◽  
Hu ◽  
Liang ◽  
Li ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Colorimetric Assay ◽  
Point Of Care ◽  
Colorimetric Detection ◽  
Diabetic Patients ◽  
Ambient Light ◽  
Label Free ◽  
Urine Glucose ◽  
Light Sensor

In this work, a label-free colorimetric assay was developed for the determination of urine glucose using smartphone ambient-light sensor (ALS). Using horseradish peroxidase—hydrogen peroxide—3,3′,5,5′-tetramethylbenzidine (HRP-H2O2-TMB) colored system, quantitative H2O2 was added to samples to-be-determined for deepest color. The presence of glucose oxidase in urine led to the formation of H2O2 and the reduction of TMBred. As a result of this, the color of the urine faded and the solution changed from deep blue to light blue. We measured the illuminance of the transmitted light by a smartphone ambient light sensor, and thereby color changes were used to calculate the content of urine glucose. After method validation, this colorimetric assay was practically applied for the determination of urine samples from diabetic patients. Good linearity was obtained in the range of 0.039–10.000 mg/mL (R2 = 0.998), and a limit of detection was 0.005 mg/mL. Our method was had high accuracy, sensitivity, simplicity, rapidity, and visualization, providing a new sensor to be potentially applicable for point-of-care detection of urine glucose.

scholarly journals A Smart Device to Substitute the Neurothesiometer

2017 ◽  
Author(s):  
Neil Vaughan ◽  
Venketesh N. Dubey ◽  
Tamas Hickish ◽  
Jonathan Cole
Keyword(s):  
Gold Standard ◽  
Point Of Care ◽  
Care Center ◽  
Smart Device ◽  
Smartphone App ◽  
Sensitivity Threshold ◽  
Point Of Care Testing ◽  
New Device ◽  
3D Printed ◽  
Sensation Loss

This paper presents a patented smart point-of-care testing (POCT) system for the diagnosis and grading of peripheral neuropathy at the patient’s home or care center. The device aims to detect changes or worsening of a patient’s neuropathy. Our system utilizes the vibration motor within a smartphone, applied through a 3D printed probe attachment to detect sensation loss in vibration sensitivity threshold (VST). A smartphone app displays several neuropathy questionnaires to the user to identify and monitor changes in their condition. This paper presents results from comparison between the new smart device and the gold standard Neurothesiometer. Results suggest that the new device performs closely to the gold standard in terms of the frequency and amplitude of vibration.

scholarly journals Polystyrene Microsphere-Based Immunochromatographic Assay for Detection of Aflatoxin B1 in Maize

Biosensors ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 200
Author(s):  
Jin Wang ◽  
Xiangmei Li ◽  
Xing Shen ◽  
Ang Zhang ◽  
Jinxiu Liu ◽  
...  
Keyword(s):  
Aflatoxin B1 ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Immunochromatographic Assay ◽  
Quantitative Detection ◽  
Point Of Care Testing ◽  
Polystyrene Microsphere ◽  
Accuracy And Precision ◽  
Wide Range ◽  
Liquid Chromatography Tandem Mass

Aflatoxin B1 (AFB1), a mycotoxin, is hepatotoxic, carcinogenic, and nephrotoxic in humans and animals, and contaminate a wide range of maize. In this study, an immunochromatographic assay (ICA) based on polystyrene microspheres (PMs) was developed for sensitive and quantitative detection of AFB1 in maize. The amounts of PMs, the condition for activating carboxyl groups of PMs, the amount of monoclonal antibody (mAb), and the volume of the immune probe were optimized to enhance the performance PMs-ICA for point-of-care testing of AFB1 in maize. The PMs-ICA showed the cut-off value of 1 ng/mL in phosphate buffer (PB) and 6 µg/kg in maize samples, respectively. The quantitative limit of detection (qLOD) was 0.27 and 1.43 µg/kg in PB and maize samples, respectively. The accuracy and precision of the PMs-ICA were evaluated by analysis of spiked maize samples with recoveries of 96.0% to 107.6% with coefficients of variation below 10%. In addition, the reliability of PMs-ICA was confirmed by the liquid chromatography-tandem mass spectrometry method. The results indicated that the PMs-ICA could be used as a sensitive, simple, rapid point-of-care testing of AFB1 in maize.

scholarly journals Smartphone-Based Chemiluminescent Origami µPAD for the Rapid Assessment of Glucose Blood Levels

Biosensors ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 381
Author(s):  
Donato Calabria ◽  
Martina Zangheri ◽  
Ilaria Trozzi ◽  
Elisa Lazzarini ◽  
Andrea Pace ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Rapid Assessment ◽  
Blood Levels ◽  
Blood Samples ◽  
3D Printed ◽  
Diagnostic Applications ◽  
Catalyzed Oxidation

Microfluidic paper analytical devices (µPADs) represent one of the most appealing trends in the development of simple and inexpensive analytical systems for diagnostic applications at the point of care (POC). Herein, we describe a smartphone-based origami µPAD for the quantitative determination of glucose in blood samples based on the glucose oxidase-catalyzed oxidation of glucose leading to hydrogen peroxide, which is then detected by means of the luminol/hexacyanoferrate(III) chemiluminescent (CL) system. By exploiting the foldable µPAD format, a two-step analytical procedure has been implemented. First, the diluted blood sample was added, and hydrogen peroxide was accumulated, then the biosensor was folded, and a transport buffer was added to bring hydrogen peroxide in contact with CL reagents, thus promoting the CL reaction. To enable POC applicability, the reagents required for the assay were preloaded in the µPAD so that no chemicals handling was required, and a 3D-printed portable device was developed for measuring the CL emission using the smartphone’s CMOS camera. The µPAD was stable for 30-day storage at room temperature and the assay, displaying a limit of detection of 10 µmol L−1, proved able to identify both hypoglycemic and hyperglycemic blood samples in less than 20 min.

scholarly journals Detector-Free Photothermal Bar-Chart Microfluidic Chips (PT-Chips) for Visual Quantitative Detection of Biomarkers

2021 ◽  
Author(s):  
Wan Zhou ◽  
Guanglei Fu [email protected] ◽  
Xiujun Li
Keyword(s):  
Whole Blood ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Clinical Diagnostics ◽  
Detection Sensitivity ◽  
Quantitative Detection ◽  
Microfluidic Chips ◽  
Analytical Instruments ◽  
Photothermal Effects ◽  
On Chip

<p>The volumetric bar-chart microfluidic chips (V-Chips) driven by chemical reaction-generated gas provide a promising platform for point-of-care (POC) visual biomarker quantitation. However, multiple limitations are encountered in conventional V-Chips, such as costly and complex chip fabrication, complicated assembly, and imprecise controllability of gas production. Herein, we introduced nanomaterial-mediated photothermal effects to V-Chips, and for the first time developed a new type of V-Chip, <u>p</u>hoto<u>t</u>hermal bar-chart microfluidic <u>c</u>hip (PT-Chip), for visual quantitative detection of biochemicals without any bulky and costly analytical instruments. Immunosensing signals were converted to visual readout signals via photothermal effects, the on-chip bar-chart movements, enabling quantitative biomarker detection on a low-cost polymer hybrid PT-Chip with on-chip scale rulers. Four different human serum samples containing prostate-specific antigen (PSA) as a model analyte were detected simultaneously using the PT-Chip, with the limit of detection of 2.1 ng/mL, meeting clinical diagnostic requirements. Although no conventional signal detectors were used, it achieved comparable detection sensitivity to absorbance measurements with a microplate reader. The PT-Chip was further validated by testing human whole blood without the color interference problem, demonstrating good analytical performance of our method even in complex matrixes and thus the potential to fill a gap in current clinical diagnostics that is incapable of testing whole blood. This new PT-Chip driven by nanomaterial-mediated photothermal effects opens a new horizon of microfluidic platforms for instrument-free diagnostics at the point of care.</p>

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