Diagnostics for the developing world

Mabey, David; Peeling, Rosanna W.; Ustianowski, Andrew; Perkins, Mark D.

doi:10.1038/nrmicro841

Cited by 897 publications

(710 citation statements)

References 36 publications

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“…The inexpensive and clean optical glass parts can be laminated into devices with various chamber and fluid transport features. Despite growing interest in developing "lab-ona-chip" devices for inexpensive DNA isolation [2,3] [6] the utility of readily available, unmodified glass surfaces in DNA capture chambers has not been described. Several devices have been designed to miniaturize the sample sizes for micro-PCR analysis [7], and silica based DNA capture surfaces have been engineered with higher binding capacity.…”

Section: Discussionmentioning

confidence: 99%

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Capture of genomic DNA on glass microscope slides

Nanassy

Haydock

Reed

2007

Analytical Biochemistry

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It is well known that DNA strands bind to silica surfaces in the presence of high concentrations of chaotropic salts. We developed simple methods to evaluate binding and recovery of DNA on flat glass microscope slides and compared their properties to commercially available silica "spin columns". Surprisingly, genomic DNA was recovered efficiently from untreated glass slides. Binding and elution times from glass slides were optimized in experiments with DNA samples of various sizes and defined buffers. Average DNA recovery from 500 ng of input genomic DNA varied from 25-53 % for the glass slide protocol. Yields were comparable to spin columns. Human serum albumin and plasma components decreased DNA binding to glass several-fold in a concentration dependent manner. These results support the concept of using flat glass slides as DNA purification surfaces in microfluidics devices for PCR sample preparation. Keywords DNA extraction; silica surfaces; PCR; microfluidicsThe use of powdered glass or other high surface area silica materials has been widely adopted as a basic technique for purifying DNA from biological samples [1]. DNA strands bind efficiently to silica particles in the presence of high concentrations of chaotropic salts such as guanidinium thiocyanate or sodium perchlorate. After washing away contaminating substances with high salt buffers, the bound DNA is released from the silica surface in the presence of water or low salt buffer. The recovered DNA is suitable for use in PCR or other amplification methods. These methods are used extensively in medical diagnostics and forensics, in recombinant technology and for molecular genetics.Silica-based DNA purification is compatible with microfluidic diagnostic devices. Such "lab on a chip" devices may help bring the benefits of PCR-based molecular diagnosis to users and point-of-care settings that lack the capacity for standard laboratory-based DNA purification [2] [3]. In such applications there are significant pressures to keep costs low. Therefore, DNA purification devices must be designed to use the least expensive materials possible, and without unnecessary engineering. Early researchers showed that the curved inner surfaces of glass test tubes could be used to purify DNA from agarose gels, but their binding capacity was deemed too small for most preparative experiments [4]. Currently, it is standard practice to maximize DNA binding surface area, for example by using silica glass bead matrices. However, such engineering measures may not be necessary to achieve satisfactory DNA purification yields.

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Section: Discussionmentioning

confidence: 99%

“…Such "lab on a chip" devices may help bring the benefits of PCR-based molecular diagnosis to users and point-of-care settings that lack the capacity for standard laboratory-based DNA purification [2] [3]. In such applications there are significant pressures to keep costs low.…”

mentioning

confidence: 99%

Capture of genomic DNA on glass microscope slides

Nanassy

Haydock

Reed

2007

Analytical Biochemistry

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“…1 The clinical analyses carried out in developed economies, however, are often not directly applicable in developing economies. This translational problem has two components: i) current analytical systems are too expensive, large, complicated, or dependent on infrastructure to be broadly accessible in developing economies, or practically located in inaccessible regions; 2 and ii) developing economies do not have enough trained medical personnel to distribute the analytical systems to inaccessible regions.…”

Section: Introductionmentioning

confidence: 99%

“…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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“…A detailed TPP describes the minimally acceptable and ideal product characteristics and specifications for target population, performance, specimen type and volume, storage conditions, time to results, nature of results, and other parameters [10,11]. The ASSURED criteria (Affordable, Sensitive, Specific, User-friendly, Rapid and robust, Equipment-free, Delivered to those who need it) [12] set out basic test requirements, but how a test achieves those criteria is dependent on the features included by the manufacturer and their usability in the hands of the intended users. There are limited data available on HIVST prototypes.…”

Section: Introductionmentioning

confidence: 99%

What Should the Ideal HIV Self-Test Look Like? A Usability Study of Test Prototypes in Unsupervised HIV Self-Testing in Kenya, Malawi, and South Africa

et al. 2014

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HIV self-testing (HIVST) is increasingly being sought and offered globally, yet there is limited information about the test features that will be required for an HIV self-test to be easy to use, acceptable to users, and feasible for manufacturers to produce. We conducted formative usability research with participants who were naïve to HIVST using five prototypes in Kenya, Malawi, and South Africa. The tests selected ranged from early-stage prototypes to commercially ready products and had a diverse set of features. A total of 150 lay users were video-recorded conducting unsupervised self-testing and interviewed to understand their opinions of the test. Participants did not receive a test result, but interpreted standardized result panels. This study demonstrated that users will refer to the instructions included with the test, but these can be confusing or difficult to follow. Errors were common, with less than 25 % of participants conducting all steps correctly and 47.3 % of participants performing multiple errors, particularly in sample collection and transfer. Participants also had difficulty interpreting results. To overcome these issues, the ideal HIV self-test requires pictorial instructions that are easy to understand, simple sample collection with integrated test components, fewer steps, and results that are easy to interpret.

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Diagnostics for the developing world

Cited by 897 publications

References 36 publications

Capture of genomic DNA on glass microscope slides

Capture of genomic DNA on glass microscope slides

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

What Should the Ideal HIV Self-Test Look Like? A Usability Study of Test Prototypes in Unsupervised HIV Self-Testing in Kenya, Malawi, and South Africa

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