Paper-based standard addition assays

Chaplan, Cory A.; Mitchell, Haydn T.; Martinez, Andres W.

doi:10.1039/c4ay00205a

Cited by 47 publications

(40 citation statements)

References 25 publications

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“…Concurrent with the development of colorimetric assays on microPADs, several methods for quantifying the resulting colorimetric signal on the devices were developed. One promising approach is the use of digital image colorimetry, in which a digital image of the results of a colorimetric assay is obtained, and then the pixel intensity of the color is measured [67,68]. The images could be obtained using a scanner, a digital camera or, most interestingly in the context of portable point-of-care diagnostic assays, a camera phone [42].…”

Section: Applications Of Paper-based Microfluidic Devicesmentioning

confidence: 99%

“…The images could be obtained using a scanner, a digital camera or, most interestingly in the context of portable point-of-care diagnostic assays, a camera phone [42]. The results can be calibrated through either external calibration or standard addition and can typically produce results with relative errors and relative standard deviations within ten percent [68].…”

Section: Applications Of Paper-based Microfluidic Devicesmentioning

confidence: 99%

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Paper-based diagnostic devices

Schultz

Noxon

Sisley

et al. 2017

Portable Biosensors and Point-of-Care Systems

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Section: Applications Of Paper-based Microfluidic Devicesmentioning

confidence: 99%

Section: Applications Of Paper-based Microfluidic Devicesmentioning

confidence: 99%

Paper-based diagnostic devices

Schultz

Noxon

Sisley

et al. 2017

Portable Biosensors and Point-of-Care Systems

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“…The problem is that unless the calibration standards and the sample are tested under the same conditions, the calibration curve may not be valid. 7,26 An obvious way to overcome this problem is to test the external standards at the same time as the sample is tested, and this work introduces a simple way of doing so. Third is the development of methods for storing reagents for use with microPADs for extended periods of time.…”

Section: Micropad Challengesmentioning

confidence: 99%

An Investigation of Poly(n-Isopropylacrylamide) for Applications With Microfluidic Paper-Based Analytical Devices

Mitchell¹

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An Investigation of Poly(N-isopropylacrylamide) for Applications withMicrofluidic Paper-based Analytical Devices Haydn T. Mitchell N, N′-methylenebisacrylamide-crosslinked poly(N-isopropylacrylamide), also known as P(NIPAM), was developed as a fluid delivery system for use with microfluidic paper-based analytical devices (microPADs). MicroPADs are postage-stamp-sized devices made out of paper that can be used as platforms for low-cost, simple-to-use point-of-care diagnostic assays. P(NIPAM) is a thermally responsive polymer that absorbs aqueous solutions at room temperature and will expel the solutions to microPADs when heated. The fluid delivery characteristics of P(NIPAM) were assessed, and P(NIPAM) was able to deliver multiple solutions to microPADs in specific sequences or simultaneously in a laminar-flow configuration. P(NIPAM) was then shown to be suitable for delivering four classes of reagents to microPADs: small molecules, enzymes, antibodies and DNA. P(NIPAM) successfully delivered a series of standard concentrations of glucose (0 -5 mM) to microPADs equipped to perform a colorimetric glucose assay. The results of these tests were used to produce an external calibration curve, which in turn was used to determine accurately the concentrations of glucose in sample solutions. P(NIPAM) successfully delivered fluorescein-labeled IgG and fluorescein-labeled oligonucleotides (20 base pairs) to microPADs in a variety of concentrations. P(NIPAM) also successfully delivered horseradish peroxidase (HRP) to microPADs, and it was determined that HRP could be stored in P(NIPAM) for 35 days v with minimal loss in activity. The combination of P(NIPAM) with microPADs will allow for more complex assays to be performed with minimal user input, will facilitate the preparation of external calibration curves in the field, and may be useful in extending the shelf life of microPADs by stabilizing reagents.vi

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“…13,38 This can either be addressed by making the lighting and camera conditions under which the images are taken constant, by introducing an external standard, or by using a methodology such as standard-addition. 39 A final and important challenge facing microPADs involves the ability (or lack thereof) of paper to stabilize assay reagents (particularly enzymes) long-term, especially for quantitative tests. 13 Figure 1.1.6 gives the first study of enzymatic shelf life on microPADs.…”

Section: Current Challenges Facing Microfluidic Paper-based Analyticamentioning

confidence: 99%

“…In addition, the product of the HRP-ABTS assay will result in an even distribution of colored product in the test zone and does not exhibit a 'coffee-ring' effect. 39 Reagents in water, buffer, or IPA were added to microPAD wells through the use of a Steps one through three were performed following the completion of the photolithographic process.…”

Section: Horseradish Peroxidase Assaymentioning

confidence: 99%

Stabilization of Horseradish Peroxidase Using Epoxy Novolac Resins for Applications with Microfluidic Paper-Based Analytical Devices

Chaplan¹

Self Cite

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Microfluidic paper-based analytical devices (microPADs) are an emerging platform for point-of-care diagnostic tests for use by untrained users with potential applications in healthcare, environmental monitoring, and food safety. These devices can be developed for a multitude of different tests, many of which employ enzymes as catalysts. Without specialized treatment, some enzymes tend to lose their activity when stored on microPADs within 48 hours, which is a major hurdle for taking these types of devices out of the laboratory and into the real world. This work focused on the development of simple methods for stabilizing enzymes by applying polymers to chromatography paper. The longterm stabilization was exlored and SU-8 of various concentrations was found to stabilize horseradish peroxidase for times in excess of two weeks. A variety of microPAD fabrications, enzyme dispensing methods, and substrate delivery techniques were explored.

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Paper-based standard addition assays

Cited by 47 publications

References 25 publications

Paper-based diagnostic devices

Paper-based diagnostic devices

An Investigation of Poly(n-Isopropylacrylamide) for Applications With Microfluidic Paper-Based Analytical Devices

Stabilization of Horseradish Peroxidase Using Epoxy Novolac Resins for Applications with Microfluidic Paper-Based Analytical Devices

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