Fluorometric Detection of Streptavidin with a Cationic Conjugated Polymer and Hairpin DNA Probe

Abstract

AbstractA simple and rapid method for streptavidin (SA) detection is developed based on a cationic conjugated polymer (CCP)‐mediated fluorescence resonance energy transfer (FRET) between poly [(9,9‐bis(6′‐N, N, N‐trimethylammonium) hexyl) fluorenylene phenylene (PFP) and SYBR Green I (SG I). A hairpin DNA labeled with biotin at the 3′ terminus was designed for the binding of SA and SYBR Green I (SG I) so that an amplified signal of emission fluorescence was detected as the CCP‐mediated FRET was induced in the presence of SA. The calibration curve exhibited a linear correlation between fluorescence intensity and SA concentration from 0 to 40 nM, and the linear regression equation was y=0.0467x+0.5814, with a correlation coefficient (R2) of 0.9927, and the detection limit was 0.5 nM. Further investigations showed that the method exhibited a significantly high specificity for the target protein and a satisfactory practical performance when human serum samples spiked with SA were tested. The results suggest that this strategy is practically applicable as it may enable an effective tool for studies on the ligand‐protein interactions as well as the qualitative and quantitative detection of proteins.