In-situ on-fabric one-touch colorimetric detection using aptamer-conjugated gold nanoparticles

We have found that the close proximity among aptamer conjugated gold nanoparticles due to aptamer-target-aptamer binding can occur and result in a color change on fabric pads. In this study, we used aptamer-conjugated gold nanoparticles as a colorimetric transducer and successfully performed in situ onfabric colorimetric detection of thrombin using aptamer-conjugated gold nanoparticles. Gold nanoparticles immobilized with two model aptamers, thrombin binding aptamer (TBA) 15 and TBA 29, respectively, are closely attracted to each other by binding to thrombin. We found that this close proximity among gold nanoparticles occurred not only in solution, but also on fabric pads in the presence of a target protein. The detection sensitivity of this on-fabric colorimetric detection was in a femto-molar range without any specialized amplification process or equipment. Considering that prior diagnosis kits require a complicated fabrication process, this in-situ on-fabric diagnosis system is more stable and cost effective and could be utilized for the on-site diagnosis of various biomarkers by using aptamers instead of antibodies.