Paper-Based Multiplexed Colorimetric Device for the Simultaneous Detection of Salivary Biomarkers

In this study, we describe a monolithic and fully integrated paper-based device for the simultaneous detection of three prognostic biomarkers in saliva. The pattern of the proposed multiplexed device is designed with a central sample deposition zone and three identical arms, each containing a pre-treatment and test zone. Its one-step fabrication is realized by CO2 laser cutting, providing remarkable parallelization and rapidity (ca. 5 s/device). The colorimetric detection is based on the sensitive and selective target-induced reshaping of plasmonic multibranched gold nanoparticles, which exhibit a clear spectral shift (and blue-to-pink color change) in case of non-physiological concentrations of the three salivary biomarkers. A rapid and multiplexed naked-eye or smartphone-based readout of the colorimetric response is achieved within 10 min. A prototype kit for POCT testing is also reported, providing robustness and easy handling of the device.

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Preparation of porphyrin modified CO9S8 nanocomposites and application for colorimetric biosensing of H2O2

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424618500918 ◽

2018 ◽

Vol 22 (09n10) ◽

pp. 935-943 ◽

Cited By ~ 11

Author(s):

Yan Gao ◽

Chunqiao Jin ◽

Miaomiao Chen ◽

Xixi Zhu ◽

Min Fu ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Catalytic Activity ◽

Peroxidase Activity ◽

Catalytic Mechanism ◽

Color Change ◽

Colorimetric Detection ◽

Buffer Solution ◽

Hydrogen Peroxide Detection ◽

Steady State Kinetics ◽

One Step

Hydrogen peroxide detection has been widely applied in the fields of biology, medicine, and chemistry. Colorimetric detection of hydrogen peroxide has proven to be a fast and convenient method. In this work, 5,10,15,20-tetrakis(4-chlorophenyl) porphyrin modified Co[Formula: see text]S[Formula: see text] nanocomposites (H[Formula: see text]TClPP-Co[Formula: see text]S[Formula: see text] were prepared via a facile one-step hydrothermal method. H[Formula: see text]TClPP-Co[Formula: see text]S[Formula: see text] nanocomposites were demonstrated to possess an enhanced mimetic peroxidase activity toward the substrate, 3,3[Formula: see text],5,5[Formula: see text]-tetramethylbenzidine (TMB), which can be oxidized to oxTMB (oxidized TMB) in a buffer solution of hydrogen peroxide with a color change from colorless to blue. The catalytic activity of H[Formula: see text]TClPP-Co[Formula: see text]S[Formula: see text] was further analyzed by steady-state kinetics, and H[Formula: see text]TClPP-Co[Formula: see text]S[Formula: see text] had high affinity towards both TMB and H[Formula: see text]O[Formula: see text]. Furthermore, fluorescence and ESR data revealed that the catalytic mechanism of the peroxidase activity of H[Formula: see text]TClPP-Co[Formula: see text]S[Formula: see text] is due to hydroxyl radicals generated from decomposition of H[Formula: see text]O[Formula: see text]. Based on the catalytic activity of H[Formula: see text]TClPP-Co[Formula: see text]S[Formula: see text], a sensitive colorimetric sensor of H[Formula: see text]O[Formula: see text] with a detection limit of 6.803 [Formula: see text]M as well as a range of 7–100 [Formula: see text]M was designed.

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One-Step Hydrothermal Synthesis of N, Fe-Codoped Carbon Dots as Mimic Peroxidase and Application on Hydrogen Peroxide and Glucose Detection

Journal of Nanomaterials ◽

10.1155/2020/1363212 ◽

2020 ◽

Vol 2020 ◽

pp. 1-11

Author(s):

Yan Li ◽

Yuhui Weng ◽

Shikong Lu ◽

Meihua Xue ◽

Bixia Yao ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Photoelectron Spectroscopy ◽

Carbon Dots ◽

Color Change ◽

Limit Of Detection ◽

Colorimetric Detection ◽

Catalytic Efficiency ◽

Transmission Electron ◽

One Step ◽

First Time

In this paper, N, Fe-codoped carbon dots (N, Fe-CDs) were synthesized from β-cyclodextrin, ethylenediamine, and ferric chloride for the first time using a convenient one-step hydrothermal method. The obtained N, Fe-CDs were characterized by various methods including transmission electron microscopy, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy. The N, Fe-CDs exhibited better catalytic activity than horseradish peroxidase (HRP) and caused an evident color change for 3,3′,5,5′-tetramethylbenzidine in the presence of H2O2. Kinetic experiments show that the apparent Km value for the N, Fe-CDs with TMB (0.40 mM) or H2O2 (0.35 mM) as the substrate was lower than that of HRP (0.43 and 3.70 mM), suggesting that the N, Fe-CDs have a much higher affinity for TMB and H2O2 than HRP. The Km/Vmax value for the N, Fe-CDs (21.74×103·s for H2O2) is significantly lower than that for HRP (42.53×103·s), suggesting that the N, Fe-CDs have a stronger catalytic efficiency for H2O2 than HRP. Furthermore, a highly efficient and sensitive colorimetric detection method for glucose was developed using the N, Fe-CDs as mimic peroxidase to detect the hydrogen peroxide generated by the oxidation of glucose by glucose oxidase. The limit of detection for H2O2 and glucose was found to be 0.52 and 3.0 μM, respectively. The obtained N, Fe-codoped carbon dots, which possess simulated peroxidase activity, can potentially be used in the field of biotechnology.

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One-Step Polylactic Acid Screen-Printing Microfluidic Paper-Based Analytical Device: Application for Simultaneous Detection of Nitrite and Nitrate in Food Samples

Chemosensors ◽

10.3390/chemosensors7030044 ◽

2019 ◽

Vol 7 (3) ◽

pp. 44 ◽

Cited By ~ 1

Author(s):

Siriwan Teepoo ◽

Supattra Arsawiset ◽

Pitchayatida Chanayota

Keyword(s):

Polylactic Acid ◽

Screen Printing ◽

Colorimetric Detection ◽

Simultaneous Detection ◽

Reference Method ◽

Cost Effective ◽

Food Samples ◽

Device Fabrication ◽

Experimental Conditions ◽

One Step

In this work, we report a one-step approach for fabricating screened-printed microfluidic paper-based analytical devices (μPADs) using polylactic acid as a new hydrophobic material. A polylactic acid solution was screen printed onto chromatography papers to create hydrophobic patterns for fluidic channels. The optimal polylactic acid concentration for successful device fabrication is 9% w/v. The μPADs were fabricated within 2 min and provided high reproducibility and stability. The utility of polylactic acid screen-printing was demonstrated for the simultaneous detection of nitrite and nitrate using colorimetric detection. Under optimized experimental conditions, the detection limits and the linear ranges, respectively, were 1.2 mg L−1 and 2–10 mg L−1 for nitrite and 3.6 mg L−1 and 10–50 mg L−1 for nitrate. The detection times for both ions were found to be within 12 min. The developed μPAD was applied for the simultaneous determination of these ions in food samples, and no significant differences in the analytical results were observed compared to those of the reference method. The polylactic acid screen-printing approach presented here provides a simple, rapid, and cost-effective alternative fabrication method for fabricating μPADs.

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Colorimetric Detection of Cr3+ in Aqueous Solution Based on Cofunctionalized Silver Nanoparticles Modified with 4-Nitrobenzenethiol and 4-Mercaptobenzoic Acid

NANO ◽

10.1142/s1793292015500952 ◽

2015 ◽

Vol 10 (07) ◽

pp. 1550095 ◽

Cited By ~ 4

Author(s):

Zhikun Zhang ◽

Ying Zhou ◽

Jing-Kui Yang ◽

Peilong Wang ◽

Xiaoou Su ◽

...

Keyword(s):

Silver Nanoparticles ◽

Color Change ◽

Colorimetric Detection ◽

Ligand Interaction ◽

Bright Yellow ◽

Colorimetric Response ◽

Icp Ms ◽

Highly Sensitive ◽

Highly Sensitive Detection ◽

Good Agreement

A new method has been proposed to realize the visual detection of Cr 3+ using 4-nitrobenzenethiol (4-NBT) and 4-mercaptobenzoic acid (4-MBA) modified silver nanoparticles ( AgNPs ). The presence of Cr 3+ induces the aggregation of AgNPs through cooperative metal–ligand interaction, resulting in a color change from bright yellow to purple. Consequently, Cr 3+ could be monitored by colorimetric response of AgNPs by a UV-Vis spectrophotometer or even naked eyes. We firstly used ethylene diamine tetraacetic acid (EDTA) as a masking agent to selectively detect Cr 3+, and other metal ions have little influence on the Cr 3+– AgNPs system. The cofunctionalized AgNPs exhibited a highly sensitive detection limit of Cr 3+, which is as low as 5 × 10-9 mol L-1, and the absorbance ratio (A600nm/A387nm) is linear with the concentration of Cr 3+ ranging from 5 × 10-9 mol L-1 to 2 × 10-6 mol L-1 with a coefficient of 0.993. Particularly, the sensor has been further evaluated to monitor the concentration of Cr 3+ in drinking water, the recovery was in good agreement with those obtained by ICP-MS, indicating that this proposed method is successfully applied in real samples.

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Screen-Printed Sensors for Colorimetric Detection of Hydrogen Sulfide in Ambient Air

Sensors ◽

10.3390/s19051182 ◽

2019 ◽

Vol 19 (5) ◽

pp. 1182 ◽

Cited By ~ 5

Author(s):

Laura Engel ◽

Karina Tarantik ◽

Carolin Pannek ◽

Jürgen Wöllenstein

Keyword(s):

Hydrogen Sulfide ◽

Color Change ◽

Colorimetric Detection ◽

Preliminary Test ◽

Ambient Air ◽

Sensitive Material ◽

Long Term Stability ◽

Colorimetric Response ◽

Vis Spectroscopy ◽

Printed Sensors

A fast and sensitive method to monitor hydrogen sulfide (H2S) in ambient air based on a visible color change of a printed disposable sensor has been developed. As gas-sensitive material, an immobilized copper(II) complex of the azo dye 1-(2-pyridylazo)-2-naphtol (H-PAN) was synthesized and prepared in an ethyl cellulose matrix for screen printing. If H2S is present in ambient air, the gas sensitive layer changes its color from purple to yellow. A pre-primed polyethylene (PE) foil and a coated offset paper served as the printing substrate. The colorimetric response to the target gas was measured by UV/Vis spectroscopy in reflection at H2S concentrations between 1 to 20 ppm. Possible cross-sensitivities of the printed sensors towards methane (CH4), formaldehyde (CH2O), carbon monoxide (CO), ammonia (NH3), and nitrogen dioxide (NO2), as well as the long-term stability was investigated. Furthermore, reflection measurements of the Cu-PAN complex on an amorphous silica powder under gas admission served as preliminary test for the subsequent paste development.

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Functionalized Silver Nano-Sensor for Colorimetric Detection of Hg2+ Ions: Facile Synthesis and Docking Studies

Sensors ◽

10.3390/s18082698 ◽

2018 ◽

Vol 18 (8) ◽

pp. 2698 ◽

Cited By ~ 8

Author(s):

Kollur Shiva Prasad ◽

Govindaraju Shruthi ◽

Chandan Shivamallu

Keyword(s):

Silver Nanoparticles ◽

Color Change ◽

Colorimetric Detection ◽

Docking Studies ◽

Facile Synthesis ◽

Colorimetric Response ◽

Yellow Color ◽

Deep Yellow ◽

Uv Visible ◽

Average Size

In the present study, we describe the facile synthesis of silver nanoparticles (AgNPs) and their nanostructures functionalized with 2-aminopyrimidine-4,6-diol (APD-AgNPs) for Hg2+ ion detection. The promising colorimetric response of APD-AgNPs to detect Hg2+ ions was visible with naked eyes and spectroscopic changes were examined by using a UV-Visible spectrophotometer. The aggregation of APD-AgNPs upon addition of Hg2+ ions was due to the chelation effect of the functionalized nanostructures and results in a color change from pale brown to deep yellow color. The probing sensitivity was observed within five minutes with a detection limit of about 0.35 µM/L. The TEM images of APD-AgNPs showed polydispersed morphologies with hexagonal, heptagonal and spherical nanostructures with an average size between 10 to 40 nm. Furthermore, the sensing behavior of APD-AgNPs towards Hg2+ ions detection was investigated using docking and interaction studies.

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Faculty Opinions recommendation of One-step, multiplex, real-time PCR assay with molecular beacon probes for simultaneous detection, differentiation, and quantification of human T-cell leukemia virus types 1, 2, and 3.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.713998082.789502847 ◽

2012 ◽

Author(s):

Sanjay Tyagi

Keyword(s):

T Cell ◽

Real Time Pcr ◽

Molecular Beacon ◽

Leukemia Virus ◽

Simultaneous Detection ◽

Cell Leukemia ◽

Pcr Assay ◽

Human T Cell ◽

T Cell Leukemia Virus ◽

One Step

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Essential properties and pitfalls of colorimetric Reverse Transcription Loop-mediated Isothermal Amplification as a point-of-care test for SARS-CoV-2 diagnosis

Molecular Medicine ◽

10.1186/s10020-021-00289-0 ◽

2021 ◽

Vol 27 (1) ◽

Author(s):

Bruna de Oliveira Coelho ◽

Heloisa Bruna Soligo Sanchuki ◽

Dalila Luciola Zanette ◽

Jeanine Marie Nardin ◽

Hugo Manuel Paz Morales ◽

...

Keyword(s):

Viral Load ◽

Internal Control ◽

Reverse Transcription ◽

Color Change ◽

Point Of Care ◽

Colorimetric Detection ◽

False Negative ◽

Isothermal Amplification ◽

Clinical Samples ◽

Loop Mediated Isothermal Amplification

Abstract Background SARS-CoV-2 Reverse Transcription Loop-mediated Isothermal Amplification (RT-LAMP) colorimetric detection is a sensitive and specific point-of-care molecular biology technique used to detect the virus in only 30 min. In this manuscript we have described a few nuances of the technique still not properly described in the literature: the presence of three colors clusters; the correlation of the viral load with the color change; and the importance of using an internal control to avoid false-negative results. Methods To achieve these findings, we performed colorimetric RT-LAMP assays of 466 SARS-CoV-2 RT-qPCR validated clinical samples, with color quantification measured at 434 nm and 560 nm. Results First we determinate a sensitivity of 93.8% and specificity of 90.4%. In addition to the pink (negative) and yellow (positive) produced colors, we report for the first time the presence of an orange color cluster that may lead to wrong diagnosis. We also demonstrated using RT-qPCR and RT-LAMP that low viral loads are related to Ct values > 30, resulting in orange colors. We also demonstrated that the diagnosis of COVID-19 by colorimetric RT-LAMP is efficient until the fifth symptoms day when the viral load is still relatively high. Conclusion This study reports properties and indications for colorimetric RT-LAMP as point-of-care for SARS-CoV-2 diagnostic, reducing false results, interpretations and optimizing molecular diagnostics tests application.

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