Conjugated Polymer/Graphene Oxide Complexes for Photothermal Activation of DNA Unzipping and Binding to Protein

DNA–protein interactions control DNA transcription, recombination, restriction, and replication, which play an important role in regulating life activities. We developed a new strategy to photothermally regulate DNA unzipping and binding to single-stranded binding protein (SSBP) based on the hybrid systems of graphene oxide (GO) and conjugated polymer. GO is applied as the photothermal modulator to activate the unzipping of dsDNA into ssDNA. Upon near-infrared (NIR) laser irradiation, the thermal melting transition of DNA is promoted, which results in much farther distance between poly[(9,9-bis(6′-N,N,N-trimethylammonium)hexyl)-fluorenylene phenylene dibromide] (PFP) and fluorescein labeled at the terminus of the DNA in comparison to that of dsDNA before NIR irradiation in the presence of GO. Therefore, the fluorescence resonance energy transfer (FRET) efficiency for PFP/fluorescein becomes weaker upon irradiation. Moreover, FRET efficiency could readily recover when the unzipped DNA hybridizes with SSBP....