The nuclear pore complex (NPC) is a large multifunctional protein complex with an eight-fold symmetrical torus-like structure spanning the double lipid bilayer of the nuclei of eukaryotic cells. Mimicking the NPC function is quite a challenge but open new perspectives in the filtration area. The NPC features have been reproduced by grafting native nucleoporines (Nups) inside track-etched polycarbonate membranes. The chemistry is quite challenging, and difficult to scale up, but the resulted nanopores were selective and function in a similar manner than the NPC. Still, analysis of the function of the Nup-decorated nanopores did not provide any microscopic information’s upon the filtration process. We suggest replacing the Nups used in the previous work by poly(2-alkyloxazoline) chains to reproduce the high selectivity of NPC. Poly(2-methyloxazoline) (PMeOx) and poly(2-isopropyloxazoline) (PiPOx) with an aminophenyl chain-end were successfully synthesized by cationic ring opening polymerization, with various molar. Then electrografting, using by the diazonium electrografting process, of the PMeOx or PiPOx, was conducted to obtain well-defined polymer brushes at the entrance of the nanopores, that were characterized by AFM, XPS and zero-mode waveguide technique (ZWT). The translocation process of DNA studied by ZWT was analyzed using a suction model characterizing the interaction of the translocating macromolecule and the wall of the pore, and the local organization of the polymer chains inside the nanopore. On the other hand, electric detection evidenced the diffusion of ions as a function of the nature of the grafted polymers in the nanopore. The polymer brush weakly and reversibly crosslinks inside the nanopore and thus forms a sieve-like gel. The LCST of PiPOx unables a commutation of the nanopores from a selective filtration to a quasi-free diffusion of nanoparticles inside the nanopores.

Mimicking nucleopore by track-etched polycarbonate membranes modified by poly(2-alkyloxazoline)

2019 Spring National Meeting

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