A new lateral flow strip assay (LFSA) using a pair of aptamers for the detection of Vaspin

A new lateral flow strip assay (LFSA) using a pair of aptamers has been designed and successfully developed using a pair of aptamers-functionalized with gold nanoparticles (AuNPs). This new LFSA biosensor system utilizes a cognate aptamer duo binding to vaspin, a target protein, at the two different binding sites, and exhibited a sensitive and highly selective response to vaspin. A sandwich-type format in LFSA was developed based on biotin-labeled primary V1 aptamer immobilized on streptavidin coated membrane as a capturing probe and secondary V49 aptamer conjugated with AuNPs as a signaling probe. Using this LFSA, vaspin could be visibly observed within the detectable concentrations of vaspin up to 5 nM in both buffer and serum conditions. The sensitivity of this LFSA developed in this study was ranged from 0.137 to 25 nM in buffer and from 0.105 to 25 nM in spiked human serum, respectively. The limit of detection (LOD) of this LFSA was found to be 0.137 nM and 0.105 nM in buffer and spiked human serum condition, respectively. Therefore, this study has shown successful development of a simple yet effective LFSA for vaspin detection, and this development is not only limited to this target, but also other targets with a pair of aptamers available, without any special and laborious instrumentations. This system will be particularly useful as a screening tool for rapid on-site detection of any targets with a pair of aptamers generated.