An Integrated Approach to a Portable and Low‐Cost Immunoassay for Resource‐Poor Settings

Sia, Samuel K.; Linder, Vincent; Parviz, Babak A.; Siegel, Adam; Whitesides, George M.

doi:10.1002/anie.200353016

Cited by 282 publications

(228 citation statements)

References 22 publications

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“…The concentration of protein in urine, for example, can be used to distinguish between different renal diseases: nephrotic syndrome ( There are many portable and quantitative devices for detecting disease. 2,[13][14][15] The platforms for these assays range from pressure-driven 8,14 or centrifugal force-driven microfluidic devices, 16 to "dip-stick" immunochromatographic assays. 8,13,15,17,18 The need remains, however, for more effective systems, and especially for systems designed specifically for the conditions in the developing world.…”

Section: Introductionmentioning

confidence: 99%

Simple Telemedicine for Developing Regions: Camera Phones and Paper-Based Microfluidic Devices for Real-Time, Off-Site Diagnosis

et al. 2008

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This article describes a prototype system for quantifying bioassays, and for exchanging the results of the assays digitally with physicians located off-site. The system uses paper-based microfluidic devices for running multiple assays simultaneously, camera phones or portable scanners for digitizing the intensity of color associated with each colorimetric assay, and established communications infrastructure for transferring the digital information from the assay site to an offsite laboratory for analysis by a trained medical professional; the diagnosis then can be returned directly to the healthcare provider in the field. The microfluidic devices were fabricated in paper using photolithography, and were functionalized with reagents for colorimetric assays. The results of the assays were quantified by comparing the intensities of the color developed in each assay with those of calibration curves. An example of this system quantified clinically relevant concentrations of glucose and protein in artificial urine. The combination of patterned paper, a portable method for obtaining digital images, and a method for exchanging results of the assays with off-site diagnosticians offers new opportunities for inexpensive monitoring of health, especially in situations that require physicians to travel to patients (e.g., in the developing world, in emergency management, and during field operations by the military) to obtain diagnostic information that might be obtained more effectively by less valuable personnel.

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Section: Introductionmentioning

confidence: 99%

Simple Telemedicine for Developing Regions: Camera Phones and Paper-Based Microfluidic Devices for Real-Time, Off-Site Diagnosis

et al. 2008

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“…[20][21][22][23][24][25][26][27][28][29] For example, we and others have constructed low-cost photometers based on this principle to measure i) antibodies against HIV in serum, 21 ii) hemoglobin [22][23] in blood, and iii) fluoride 27 and mercury 29 in water samples.…”

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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“…We are especially interested in devices to be used in resource poor environments-e.g., in healthcare in developing countries, by first responders and the military, and in analogous problems-where portability and ruggedness are key concerns. [6][7][8] Here we describe an example of an integrated microfluidic device that performs several of the basic functions required from a portable analytical system (introduction, filtering and mixing of the analytes) automatically and with power only from a hand-operated source of vacuum. The device can be fabricated using a single layer of micro-molding, and it operates efficiently without using electrical power.…”

Section: Introductionmentioning

confidence: 99%

Mixing with bubbles: a practical technology for use with portable microfluidic devices

et al. 2006

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This paper demonstrates a methodology for micromixing that is sufficiently simple that it can be used in portable microfluidic devices. It illustrates the use of the micromixer by incorporating it into an elementary, portable microfluidic system that includes sample introduction, sample filtration, and valving. This system has the following characteristics: (i) it is powered with a single hand-operated source of vacuum, (ii) it allows samples to be loaded easily by depositing them into prefabricated wells, (iii) the samples are filtered in situ to prevent clogging of the microchannels, (iv) the structure of the channels ensure mixing of the laminar streams by interaction with bubbles of gas introduced into the channels, (v) the device is prepared in a single-step soft-lithographic process, and (vi) the device can be prepared to be resistant to the adsorption of proteins, and can be used with or without surface-active agents.We fabricated the device (Figs. 1a) in a polydimethylsiloxane (PDMS) slab sealed to a PDMS substrate. We chose to use PDMS because it is the most useful material for testing concepts in microfluidics, and because it is easily coupled with

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An Integrated Approach to a Portable and Low‐Cost Immunoassay for Resource‐Poor Settings

Cited by 282 publications

References 22 publications

Simple Telemedicine for Developing Regions: Camera Phones and Paper-Based Microfluidic Devices for Real-Time, Off-Site Diagnosis

Simple Telemedicine for Developing Regions: Camera Phones and Paper-Based Microfluidic Devices for Real-Time, Off-Site Diagnosis

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

Mixing with bubbles: a practical technology for use with portable microfluidic devices

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