Label-free colorimetric aptasensor for highly sensitive and selective detection of proteins by using PNA/DNA hybrids and a cyanine dye
Economical, fast and sensitive detection of proteins is essential to biomedical research as well as clinical diagnosis. Here, we demonstrated a label-free colorimetric aptasensor that uses PNA/DNA hybrids and a cyanine dye (DiSC2(5)) for highly sensitive and selective detection of proteins in aqueous solution. This protocol, based on the difference in the binding interactions of DiSC2(5) with PNA and the PNA/DNA hybrid causing different colors, can be applied for the detection of proteins. This sensing platform can specifically detect thrombin, our example analyte, with a detection limit of 0.4 nM. Moreover, the assay does not involve any chemical modification and enzyme amplification, and hence it is convenient, fast and low-cost. In principle, this approach can be used to detect proteins with specific aptamers by simply changing the sequences of the probe DNA for specific targets. Furthermore, this sensing platform provides a promising approach for the analysis of target proteins at point-of-care in resource-limited settings.