cAMP-modulated biomimetic ionic nanochannels based on a smart polymer†
The flow of ions across the cell membrane is essential to many life processes. Cyclic 3′,5′-adenosine monophosphate (cAMP) binds to and regulates the function of cyclic nucleotide-gating channel proteins, which directly mediate the Na+/Ca2+ transmembrane behaviours. This inspires us to develop a biomimetic cAMP-modulated ionic nanochannel based on a cAMP-responsive polymer design. Driven by specific hydrogen bonding interactions with cAMP, an arginine-based smart copolymer film displays remarkable adsorption toward cAMP and can clearly discriminate cAMP from other nucleotides, accompanied with reversible conformational transition of the polymer chain from a contracted state to a swollen one. Benefiting from these features, dynamic gating behaviours of the nanochannels located on the copolymer-modified anodic aluminum oxide (AAO) membrane could be precisely manipulated by cAMP. Sensitive responsiveness (10 pmol L−1) and high specificity toward cAMP, high controllability and satisfactory reversibility reveal the great potential of biomolecule responsive polymers in biomimetic nanochannels and nanodevices.