A smartphone-based colorimetric reader for bioanalytical applications using the screen-based bottom illumination provided by gadgets

Vashist, Sandeep Kumar; Oordt, Thomas van; Schneider, E. Marion; Zengerle, Roland; Stetten, Felix von; Luong, John H. T.

doi:10.1016/j.bios.2014.08.027

Cited by 210 publications

(108 citation statements)

References 31 publications

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“…To address the limitations of systems that use narrowband LEDs for illumination, others have performed optical measurements of liquid samples using broadband light emitted by flatbed scanners [30][31] or digital displays (e.g., computer monitors, [32][33][34][35][36] tablet computers, 37 and digital photo displays 26 ), and used the image sensors found in flatbed scanners, [30][31] web cameras, [32][33][34][35][36] or smartphone cameras 37 [30][31] The reflectancebased approach, however, is problematic because the variability of the color values across the sample-due to variability and complexity of the optical path length of reflected light-greatly complicates the calculation of absorbance and the precision of measurements. An alternative approach uses the light transmitted through the sample to measure absorbance.…”

Section: Introductionmentioning

confidence: 99%

Broadly Available Imaging Devices Enable High-Quality Low-Cost Photometry

et al. 2015

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This paper demonstrates that, for applications in resource-limited environments, expensive microplate spectrophotometers-which are used in many central laboratories for parallel measurement of absorbance of samples-can be replaced by photometers based on inexpensive and ubiquitous, consumer electronic devices (e.g., scanners and cell-phone cameras). Two devices-i) a flatbed scanner operating in transmittance mode and ii) a camera-based photometer constructed from a cell phone camera, a planar light source, and a cardboard box-demonstrate the concept. These devices illuminate samples in microtiter plates from one side, and use the RGB-based imaging sensors of the scanner/camera to measure the light transmitted to the other side. The broadband absorbance of samples (RGB-resolved absorbance) can be calculated using the RGB color values of only three pixels per micro-well. Rigorous theoretical analysis establishes a well-defined relationship between the absorbance spectrum of a sample and its corresponding RGB-resolved absorbance. The linearity and precision of measurements performed with these low-cost photometers on different dyes that absorb across the range of the visible spectrum, and chromogenic products of assays (e.g., enzymatic, ELISA) demonstrates that these low-cost photometers can be used reliably in a broad range of chemical and biochemical analyses. The ability to perform accurate measurements of absorbance on liquid samples, in parallel and at low cost, would enable testing, typically reserved for well-equipped clinics and laboratories, to be performed in circumstances where resources and expertise are limited.

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Section: Introductionmentioning

confidence: 99%

Broadly Available Imaging Devices Enable High-Quality Low-Cost Photometry

et al. 2015

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“…This simple method resulted in qualified performance in CVD risk assessment and comparable analytical outcomes to standard instrumentation. Moreover, by adding a dark hood and a base holder assembly, direct ELISA with HRP for CRP analysis reached a dynamic range, limit of quantitation (LOQ), EC50, LOD of 0.114 -7.300 ng mL −1 , 0.114 ng mL −1 , 0.198 ng mL −1 , and 0.973 ng mL −1 , respectively [59]. With advances in microfluidics, CMD design development has also advanced to record the variety of immunoassay results capable with microfluidic devices.…”

Section: Immunoassaymentioning

confidence: 99%

Cellphone-based diagnostic devices

Huang¹,

Cheng²

2017

Point-of-Care Diagnostics - New Progresses and Perspectives

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“…Different sensing arrays are developed, like pH indicator blended hydrogel matrix (Devadhasan and Kim 2015), microfluidic paper (Lopez-Ruiz et al 2014) or even graphene-based arrays (Vashist et al 2015a). Next to food industrial applications, devices for mobile health market are also available (Vashist et al 2015b), for example detecting biomarkers in sweat and saliva (Oncescu et al 2013) or perform urine tests (Yetisen et al 2014). …”

Section: Smartphone As An Analytical Device and The Importance Of Ph mentioning

confidence: 99%

Smartphone-Based Extension of the Curcumin/Cellophane pH Sensing Method

2015

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qualitative, quick and low-cost method for pH determination is developed, which provide more sensitive detection, as the bare eye checking. Next to cellophane substrate, curcumin/gelatine sensor arrays are studied, too. Food-industrial and health-care products are targeted with a modular system based on the curcumin-coloured cellophane/gelatine sensor array, a free android application running on a smartphone, together with home-written data analyser software. In situ monitoring and local pH mapping in liquid cell, investigation with curcumin dotted cellophane array and long-time stable, dried curcumin-coloured gelatine capsules are discussed.

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A smartphone-based colorimetric reader for bioanalytical applications using the screen-based bottom illumination provided by gadgets

Cited by 210 publications

References 31 publications

Broadly Available Imaging Devices Enable High-Quality Low-Cost Photometry

Broadly Available Imaging Devices Enable High-Quality Low-Cost Photometry

Cellphone-based diagnostic devices

Smartphone-Based Extension of the Curcumin/Cellophane pH Sensing Method

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