Barrier-Free Microfluidic Paper Analytical Devices for Multiplex Colorimetric Detection of Analytes

Chauhan, Ayushi; Toley, Bhushan J.

doi:10.1021/acs.analchem.1c01477

Cited by 20 publications

(12 citation statements)

References 19 publications

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“…Rehydration of the dried reagents after the placement of a distributor layer on top of the sensor layer eliminates lateral convection of the rehydrated reagents in the bottom layer, which causes spatially uniform mixing. A mathematical model of flow patterns in such paper stacks has been presented by our group previously 11 . The device was dismantled 2 minutes after addition of the K2CrO4 solution, and the detector was dried overnight at room temperature (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Our group has recently demonstrated the stacking of a fast-wicking membrane on top of a slow-wicking membrane containing dried reagents as a method for uniformly mixing a liquid with dried reagents over large surfaces areas in paper 10 . We have also demonstrated the application of paper stacking in eliminating the need for hydrophobic barriers in paper analytical devices 11 . Here, we show that paper stacking can be used to synthesize insoluble analytical reagents uniformly over large paper areas.…”

Section: Introductionmentioning

confidence: 97%

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In-situ synthesis of reagents in paper-based analytical devices using paper stacking

Chauhan

Mittal

Toley

2022

Preprint

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This article demonstrates a technique for the in-situ synthesis of an insoluble analytical reagent in paper analytical devices, using paper stacking. Previously, our group has demonstrated that stacking a fast-wicking paper membrane on top of a slow-wicking paper membrane containing dried reagents enables the uniform rehydration of the dried reagents over large areas. This technique is utilized here to fabricate distance-based sweat chloride quantification strips, which requires the synthesis of insoluble silver chromate as an analytical reagent within paper. The in-situ generation of silver chromate for sweat chloride detection was previously accomplished by manually dipping a hydrophobically patterned paper channel into multiple precursor solutions with intermittent washing and drying. Compared to the previous technique, the stacking method obviates the need for i) patterning hydrophobic barriers in paper for creation of flow channels, and ii) multiple dipping steps that need large reagent volumes. The method is amenable to large scale manufacturing as the insoluble reagent can be synthesized uniformly over large paper areas and can then be cut into multiple sensing strips. The developed sensor has a limit of detection of ~0.3 mM and a wide linear dynamic range of 0-120mM for the detection of chloride ion, which enables the diagnosis of cystic fibrosis, characterized by sweat chloride levels greater than 60 mM. This simple technique of in-situ synthesis of insoluble analytical reagents in paper could enable expanding the range of analytical chemistries that may be performed in paper-based analytical devices.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

In-situ synthesis of reagents in paper-based analytical devices using paper stacking

Chauhan

Mittal

Toley

2022

Preprint

Self Cite

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“…Colorimetric detection is most commonly employed in paper-based microfluidic systems, − owing to the ease of signal detection using commonly available absorbance readers for quantitative measurements and by naked eye for qualitative analyte detection. Absorbance-based measurements are less commonly used in flow-based microfluidic systems owing to the short optical path lengths of sub-millimeter to microscale microchannels. , On the other hand, fluorescence-based measurement is the more preferred detection strategy, in both the laboratory and industrial settings.…”

Section: Detection Of Receptor–analyte Reactionsmentioning

confidence: 99%

Toward the Development of Rapid, Specific, and Sensitive Microfluidic Sensors: A Comprehensive Device Blueprint

Sathish

Shen

2021

JACS Au

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Recent advances in nano/microfluidics have led to the miniaturization of surface-based chemical and biochemical sensors, with applications ranging from environmental monitoring to disease diagnostics. These systems rely on the detection of analytes flowing in a liquid sample, by exploiting their innate nature to react with specific receptors immobilized on the microchannel walls. The efficiency of these systems is defined by the cumulative effect of analyte detection speed, sensitivity, and specificity. In this perspective, we provide a fresh outlook on the use of important parameters obtained from well-characterized analytical models, by connecting the mass transport and reaction limits with the experimentally attainable limits of analyte detection efficiency. Specifically, we breakdown when and how the operational (e.g., flow rates, channel geometries, mode of detection, etc.) and molecular (e.g., receptor affinity and functionality) variables can be tailored to enhance the analyte detection time, analytical specificity, and sensitivity of the system (i.e., limit of detection). Finally, we present a simple yet cohesive blueprint for the development of high-efficiency surface-based microfluidic sensors for rapid, sensitive, and specific detection of chemical and biochemical analytes, pertinent to a variety of applications.

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“…Alternatively, the Richards equation has been often employed to study the capillary flow in papers. ,,,,− Perez-Cruz et al modeled imbibition in a filter paper with the Richards equation. In their work, the method of fitting experimental results to the empirical correlation was used to obtain the two-phase flow parameters of capillary pressure P c and relative permeability K r , which were difficult to obtain through experiments, while the unsaturated wetting front was not discussed.…”

Section: Introductionmentioning

confidence: 99%

Spontaneous Imbibition in Paper-Based Microfluidic Devices: Experiments and Numerical Simulations

Wang

Zhu

et al. 2022

Langmuir

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Microfluidic paper-based analytical devices (μPADs) have quickly been an excellent choice for point-of-care diagnostic platforms ever since they appeared. Because capillary force is the main driving force for the transport of analytes in μPADs, low spontaneous imbibition rates may limit the detection sensitivity. Therefore, quantitative understanding of internal spontaneous capillary flow progress is requisite for designing sensitive and accurate μPADs. In this work, experimental and numerical studies have been performed to investigate the capillary flow in a typical filter paper. We use light-transmitting imaging technology to study wetting saturation changes in the paper. Our experimental results show an obvious transition of a saturated wetting front into an unsaturated wetting front as the imbibition proceeds. We find that the single-phase Darcy model considerably overestimates the temporal wetting penetration depths. Alternatively, we use the Richards equation together with the two-phase flow material properties that are obtained from the image-based pore-network modeling of the filter paper. Moreover, we have considered a dynamic term in the capillary pressure due to strong wetting dynamics in spontaneous imbibition. As a result, the numerical predictions of spontaneous imbibition in the paper are significantly improved. Our studies provide insights into the development of a quantitative spontaneous imbibition model for μPADs applications.

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Barrier-Free Microfluidic Paper Analytical Devices for Multiplex Colorimetric Detection of Analytes

Abstract: In recent years, microfluidic paper analytical devices (μPADs) have been extensively utilized to conduct multiplex colorimetric assays. Despite their simple and user-friendly operation, the need for patterning paper

Cited by 20 publications

References 19 publications

In-situ synthesis of reagents in paper-based analytical devices using paper stacking

In-situ synthesis of reagents in paper-based analytical devices using paper stacking

Toward the Development of Rapid, Specific, and Sensitive Microfluidic Sensors: A Comprehensive Device Blueprint

Spontaneous Imbibition in Paper-Based Microfluidic Devices: Experiments and Numerical Simulations

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