Fig. 1: Fabrication and characterization of the DNAzyme-functionalized glass nanopipettes.

a Orai channels with Ca²⁺ selective permeability in nature. b Biomimetic nanochannels constructed by DNAzyme-functionalized nanopipettes. DNAzyme 1: Mg²⁺ specific DNAzyme. Substrate 1: substrate strand of DNAzyme 1 with a cholesterol tail. DNAzyme 2: Zn²⁺ specific DNAzyme with an amino tail. Substrate 2: substrate strand of DNAzyme 2 with a carboxyl tail. c Left: Interconvertible control of wettability and charge of the inner wall via metal ions and DNAzyme-substrates between four different permeability states. Right: four different states corresponding to different hydrophilicity and rectification features on the surface of the inner wall. State 1: hydrophobization, negative rectification. State 2: hydrophobization, negative rectification. State 3: hydrophobization, positive rectification. State 4: hydrophilization, positive rectification. d Reagents needed for state conversion of artificial nanochannels corresponding to A to L in c. e SEM images of nanopipettes before and after DNAzyme modification. Up: nanopipettes functionalized with DNAzyme via aldehyde modification to bind with amino group-labeled DNAzyme. Down: nanopipettes functionalized with DNAzyme via Au cladding modification to bind with thiol-labeled DNAzyme. Experiments were repeated three times independently with similar results. f Current-voltage (I–V) curves measured in a single nanopipette showing the modification procedure based on linkage between (I) aldehyde-modified inner surface and amino group-labeled DNAzyme and (II) Au cladding modified inner surface and thiol-labeled DNAzyme. (III) & (IV) I–V curves showing the stability of a DNA-functionalized nanopipette after different times corresponding to (I) & (II). (V) and (VI) I–V curves measured in a DNA-functionalized nanopipette upon different rounds of washing corresponding to (I) & (II). Scale bar: 500 nm. Source data are provided as a Source Data file.