Naked-eye quantitative aptamer-based assay on paper device

Paper‐based point‐of‐care test with xeno nucleic acid probes

“…For example, amine‐terminated capture DNA oligonucleotides were hybridized with adenosine specific aptamer, when the aptamer recognizes and binds the adenosine, the aptamer‐adenosine complex is released from the SP surface. And then, the exposed short DNA strand hybrids with probes which terminally modified with biotin molecules, subsequently, glucose oxidase (GOx) tags via biotin‐streptavidin reactions were adopted for naked‐eye quantitative readout (Figure a1; Y. Zhang et al, ). In this assay, SPs were covalently modified with NA probes could be magnetically isolated from mixture preparation solutions, and the probes were magnetically assembled and patterned on the supporting substrate.…”

Lab-on-a-Chip Systems for Aptamer-Based Biosensing

“…However, its lack of sensitivity limits its usage in applications requiring high accuracy such as the detection of rare cancer cells in blood sample [53]. Recently, Zhang et al created an aptamer-based colorimetric biosensor for achieving naked eye quantitative assay on paper, which relies on measuring the length of the colored region in a strip-like µPAD or counting the number of colorless detection microzones in a multi-zone µPAD [90]. Figure 13 shows the schematic illustration of the naked-eye aptamer-based paper microfluidic assay for the detection of adenosine based on the measurement of a colored region as well as counting of the colorless microzones in a wax-patterned 12-zone µPAD.…”

Chromatographic paper-based analytical devices using an oxidized paper substrate

“…2 Different types of detection schemes based on visual judgment have been reported, and these have included timebased, [3][4][5][6] distance-based, [7][8][9][10] and zone-counting forms of detection. 5,[11][12][13] Time-based detection was demonstrated by the Philips and Zhang groups using enzymatic reactions in which a color change occurred at different times depending on the concentration of the analytes. 3,4 Conversely, Henry's group developed a distance-based PAD that can quantify analytes without capturing images via a scanner or a digital camera.…”

“…[7][8][9][10] Zhang's group employed both the measurement of reaction time and a count of the number of detection zones that changed color. 5,6,13 We have also reported titrations with PADs wherein the endpoint can be judged by counting the number of detection zones with the color change of an indicator. 11,12 Countingbased methods are also applicable to a quantitative immunoassay.…”