离子穿越细胞膜的过程对许多生命过程至关重要。环状3'，5'-腺苷一磷酸（cAMP）结合并调节环核苷酸门控通道蛋白的功能，其直接介导Na+ /Ca2+的跨膜行为。这启发我们开发基于cAMP响应性聚合物设计的仿生cAMP调节离子纳米通道。在与cAMP的特异性氢键相互作用的驱动下，基于精氨酸的智能共聚物膜显示出对cAMP的显著的吸附，并且可以清晰地区分cAMP与其他核苷酸，伴随着聚合物链从收缩状态到肿胀状态的可逆构象转变。受益于这些特征，位于共聚物修饰的阳极氧化铝（AAO）膜上的纳米通道的动态选通行为可以通过cAMP精确控制。敏感的反应性（10 pmol·L-1）和对cAMP的高特异性，高可控性和令人满意的可逆性揭示了生物分子响应聚合物在仿生纳米通道和纳米器件中的巨大潜力。

CAMP-modulated biomimetic ionic nanochannels based on smart polymer

Zhixiang Chen, Taolei Sun and Guangyan Qing*

J. Mater. Chem. B, 2019, 7, 3710.

DOI: 10.1039/c9tb00639g

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, 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.