A simple and compact smartphone-based device for the quantitative readout of colloidal gold lateral flow immunoassay strips

Xiao, Wei; Huang, Chao; Xu, Fei; Yan, Junjie; Bian, Hongfen; Fu, Qiangqiang; Xie, Kai‐Xin; Wang, Lei; Tang, Yong

doi:10.1016/j.snb.2018.03.110

Cited by 85 publications

(51 citation statements)

References 42 publications

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“…This part of the test system performs several important functions: even distribution of sample and direction of its movement to the conjugate at a certain rate. Furthermore, the pad acts as a filter to remove unwanted elements of biosubstrates such as red blood cells [10] , [35] – [37] .…”

Section: Lfia-platforms: Types and Formatsmentioning

confidence: 99%

“…To maintain the capillary effect, a cellulose absorbent pad is placed at the distal end of the test strip, which is necessary to remove excess reagents and prevent the reverse flow of the liquid. The application of this pad allows use of a large sample size, thus, increasing the sensitivity of the test [35] , [38] , [40] .…”

Section: Lfia-platforms: Types and Formatsmentioning

confidence: 99%

“…Their efficiency has increased significantly with the development of readout technologies and the invention of devices providing transduction of color intensity of indicator lines into a semi-quantitative and quantitative result. In the former case, the result is shown as low, medium, or high; in the latter case, numerical values of analyte concentration depending on the density of test line are displayed [32] , [35] – [39] .…”

Section: Lfia-platforms: Types and Formatsmentioning

confidence: 99%

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Six decades of lateral flow immunoassay: from determining metabolic markers to diagnosing COVID-19

2020

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Technologies based on lateral flow immunoassay (LFIA), known in some countries of the world as immunochromatographic tests, have been successfully used for the last six decades in diagnostics of many diseases and conditions as they allow rapid detection of molecular ligands in biosubstrates. The popularity of these diagnostic platforms is constantly increasing in healthcare facilities, particularly those facing limited budgets and time, as well as in household use for individual health monitoring. The advantages of these low-cost devices over modern laboratory-based analyzers come from their availability, opportunity of rapid detection, and ease of use. The attractiveness of these portable diagnostic tools is associated primarily with their high analytical sensitivity and specificity, as well as with the easy visual readout of results. These qualities explain the growing popularity of LFIA in developing countries, when applied at small hospitals, in emergency situations where screening and monitoring health condition is crucially important, and as well as for self-testing of patients. These tools have passed the test of time, and now LFIA test systems are fully consistent with the world's modern concept of ‘point-of-care testing’, finding a wide range of applications not only in human medicine, but also in ecology, veterinary medicine, and agriculture. The extensive opportunities provided by LFIA contribute to the continuous development and improvement of this technology and to the creation of new-generation formats. This review will highlight the modern principles of design of the most widely used formats of test-systems for clinical laboratory diagnostics, summarize the main advantages and disadvantages of the method, as well as the current achievements and prospects of the LFIA technology. The latest innovations are aimed at improving the analytical performance of LFIA platforms for the diagnosis of bacterial and viral infections, including COVID-19.

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Section: Lfia-platforms: Types and Formatsmentioning

confidence: 99%

Section: Lfia-platforms: Types and Formatsmentioning

confidence: 99%

Section: Lfia-platforms: Types and Formatsmentioning

confidence: 99%

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Six decades of lateral flow immunoassay: from determining metabolic markers to diagnosing COVID-19

2020

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“…A 3D-printed support equipped with a sample application hole was used to provide the supporting strength and insulation required for electric connections ( Figure 10 C). Several 3D-printed supports for mobile phone-assisted diagnostics have been developed [ 118 , 119 , 120 ], in addition to equipment pieces that can lower the cost of current diagnostic strategies [ 19 , 121 , 122 ] without compromising performance.…”

Section: Applications Of 3d Printing In Diagnosticsmentioning

confidence: 99%

3D-Printed Biosensor Arrays for Medical Diagnostics

2018

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While the technology is relatively new, low-cost 3D printing has impacted many aspects of human life. 3D printers are being used as manufacturing tools for a wide variety of devices in a spectrum of applications ranging from diagnosis to implants to external prostheses. The ease of use, availability of 3D-design software and low cost has made 3D printing an accessible manufacturing and fabrication tool in many bioanalytical research laboratories. 3D printers can print materials with varying density, optical character, strength and chemical properties that provide the user with a vast array of strategic options. In this review, we focus on applications in biomedical diagnostics and how this revolutionary technique is facilitating the development of low-cost, sensitive, and often geometrically complex tools. 3D printing in the fabrication of microfluidics, supporting equipment, and optical and electronic components of diagnostic devices is presented. Emerging diagnostics systems using 3D bioprinting as a tool to incorporate living cells or biomaterials into 3D printing is also reviewed.

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“…Users can use a smartphone to acquire an image of the test kits, process the image, display and transfer the results, and organize the data through the internet. In recent years, several smartphone-based LFA readers were developed using the phone’s CMOS camera to capture the LFA image and employ an external or internal light source (either in reflection or transmission modes), and an external housing attachment for minimizing light intensity variations [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. After the LFA image is acquired by the smartphone camera, the raw red, green, and blue (RGB) image is converted into a gray-scale image.…”

Section: Introductionmentioning

confidence: 99%

Significant Sensitivity Improvement for Camera-Based Lateral Flow Immunoassay Readers

Saisin

Amarit

Somboonkaew

et al. 2018

Sensors

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Recent developments in smartphone-based strip readers have further improved the performances of lateral flow test kits. Most smartphone cameras encode an unaltered and nonlinear power-law transfer function that maps the light intensity to a pixel value; this poses some limitations for camera-based strip readers. For faint-color test lines which are almost as white such as with nitrocellulose pads, the slope of the transfer function is low. Therefore, it is difficult to differentiate between the faint test lines and the white background. We show that by manually setting the camera exposure time—instead of using the automatic settings—to the high-slope region of the transfer function, the reader’s sensitivity can be improved. We found that the sensitivity and the limit of detection of the Acidovorax avenae subsp. citrulli (Aac) test kit were enhanced up to 3-fold and 5-fold, respectively, when using the readers at the optimal camera settings, compared to the automatic mode settings. This simple technique can be readily applied to any existing camera-based colorimetric strip reader to significantly improve its performance.

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A simple and compact smartphone-based device for the quantitative readout of colloidal gold lateral flow immunoassay strips

Cited by 85 publications

References 42 publications

Six decades of lateral flow immunoassay: from determining metabolic markers to diagnosing COVID-19

Six decades of lateral flow immunoassay: from determining metabolic markers to diagnosing COVID-19

3D-Printed Biosensor Arrays for Medical Diagnostics

Significant Sensitivity Improvement for Camera-Based Lateral Flow Immunoassay Readers

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