Responsive Polymers with Contraction-arisen Helicity and Biomimetic Membrane-spanning Transport Functions

Responsive polymers have attracted increasing attention for prospective design of smart materials. The development of multifunctional responsive materials is very dependent on polymeric structures that can be manipulated with the change of microenvironment at the molecular level. Herein, we report a type of responsive coordination polymers(RCPs) consisting of dual phenanthroline-oxadiazole(DPO) units and metal Zn2+ ions, which can contract from linear structure into topologically helical structure driven by hydrophobic effect while changing the microenvironment from nonpolar solvent to aqueous media. The symmetry breaking of RCPs was confirmed by circular dichroism(CD) spectra and atomic force microscope(AFM) images, clearly demonstrating the intramolecularly contraction-arisen helicity. Moreover, RCPs can intelligently adapt different microenvironments by changing their conformations, as evidenced by a demonstration of biomimetic lipid bilayer-based vesicle experiments. Furthermore, RCPs show significant concentration-dependent transmembrane transport functions, implying that RCPs are able to span cellular membranes to form channels inside the hydrophobic lipid bilayers. At the same time, the electrophysiological conductance experiments further underpin the biomimetic transport functions and channel-based conduction mechanism of RCPs. This study demonstrates an important paradigm of responsive polymers performing microenvironment-induced conformational change and thereof unique functions, and thus provides valuable insights on the development of functional responsive materials.