A Simple and Sensitive “Dipstick” Test in Serum Based on Lateral Flow Separation of Aptamer‐Linked Nanostructures

Abstract

A quick plunge: By using lateral flow devices as a platform to separate aptamer‐assembled nanoparticle (NP) aggregates, highly sensitive and selective colorimetric sensors were constructed that mimic litmus paper tests. Detection of cocaine in serum was also realized.

Aptamer-based biosensors for biomedical diagnostics

“…While this pre-treatment step slows the overall workflow of the sensor, the sensor detects aminoglycoside at clinically relevant concentrations (2-6 µM) pad, a glass fiber conjugation pad, a membrane, and an absorption pad ( Figure 6A). 146 The aptamerlinked and biotin-labeled AuNP aggregates were spotted on the conjugation pad, and streptavidin was immobilized on the membrane as a thin line to capture biotinylated AuNPs. When the wicking pad of the device is dipped into a solution containing adenosine, the AuNPs are disassembled and migrate along the membrane to be captured, forming a red line.…”

Absorbance enhancement in microplate wells for improved-sensitivity biosensors

“…Despite their diversity in terms of format -ranging from standard cuvettes (Kuang et al, 2007) to multiwell microplates (Gillespie and Ainsworth, 2007), optical fibers (Malcik et al, 2005) or dipsticks (Liu et al, 2006) -the detection principle indistinctively bares on measuring changes in absorbance, as the physical response to a specific chemical reaction or biological recognition event. The most popular representative of colorimetric tests is the so-called enzymelinked immunosorbent assay, referred to as ELISA, which combines high throughput and high sensitivity for quantitative or semiquantitative detection of a large number of analytes (Martinez, 2011;Plested et al, 2003).…”

“…metal ions (Liu and Lu, 2003) or pH (Chen et al, 2008)) or biological (e.g. ssDNA (Mao et al, 2009;Sato et al, 2003), adenosine (Liu et al, 2006)) factors that control this mechanism. On the other side, some metal oxide NPs such as iron oxide (Fe 3 O 4 ) have been shown to exhibit an intrinsic mimetic peroxidase activity (Gao et al, 2007) which enabled their use as detection labels in ELISA or in H 2 O 2 -based melamine sensors (Ding et al, 2010).…”

Gold Nanoparticle-Based Colorimetric Sensors for Detection of DNA and Small Molecules

“…These elements include DNA, 77,78 enzymes, [79][80][81] and antibodies 82,83 that have been deposited on the paper surface for the sensing of a wide range of chemical and biochemical species including small molecules, 79,84 heavy metal ions, 67,80,85 carbohydrates, 76 or target molecules found on the surface of individual cells 83 or even whole organisms such as fungi, bacteria, and viruses. 82,86 The biorecognition elements can be delivered to the surface of these paper-based platforms by spotting, 77 inkjet printing, 80 vaccum filtration, 84 layer-by-layer (LbL) assembly, 81 dip-casting, 79 soaking, [67][68][69]85 or patterned microfluidics.…”

“…204 Aptamers have the potential to surpass antibodies as affinity reagents due to several advantages. First, aptamers can be isolated against almost any target, including proteins, 205 viruses, 206,207 cell-surface markers, [208][209][210][211] small molecules, 78,212,213 and metal ions. 27,214 In contrast, it can be difficult to generate antibodies against non-immunogenic targets such as ions and small molecules.…”