Design of a fluorescence aptaswitch based on the aptamer modulated nano-surface impact on the fluorescence particles†
The concept of DNA based stabilization of nanostructures to enhance the surface reactivity has been the focus of great interest in the design of colorimetric aptaswitches. Whereas, colorimetric methodologies have limited sensitivity, this concept is rarely considered for other sensing approaches such as those based on fluorescence detection. In this paper, we have investigated the impact of reversible assembly of a single strand DNA aptamer on nanoparticle surface chemistry, involving target tuneable electrostatic and steric repulsion phenomena for fluorescence based detection of molecular interactions. In the same context, literature reported fluorescence based aptamer assays are prone to certain limitations such as complicated labelling chemistry, low conjugation yield, low binding affinity and elevated cost per assay. Alternatively, our designed aptaswitch capitalizes on the surface chemistry of nanoparticles to quench the response of fluorescence particles, eliminating the need of bioconjugation with a fluorophore. As a proof of concept, the proposed methodology was used for the detection of ochratoxin A with TiO2 nanoparticles as a representative nanomaterial. We expect that this concept may pave a new way to probe aptamer-target binding events, since any nanomaterials with fluorescence quenching characteristics can be regulated in the same manner.