RESUMO
Voltage-biased solid-state nanopores are well established in their ability to detect and characterize single polymers, such as DNA, in electrolytes. The addition of a pressure gradient across the nanopore yields a second molecular driving force that provides new freedom for studying molecules in nanopores. In this work, we show that opposing pressure and voltage bias enables nanopores to detect and resolve very short DNA molecules, as well as to detect near-neutral polymers.
Assuntos
DNA/química , DNA/efeitos da radiação , Membranas Artificiais , Nanoporos/ultraestrutura , Biopolímeros/química , Biopolímeros/efeitos da radiação , DNA/ultraestrutura , Campos Eletromagnéticos , Eletroporação/métodos , Teste de Materiais , Modelos Químicos , Modelos Moleculares , Movimento (Física) , Tamanho da Partícula , PressãoRESUMO
Solid-state nanopores have been fabricated and used to characterize single DNA and protein molecules. Here we describe the details on how these nanopores were fabricated and characterized, the nanopore sensing system setup, and protocols of using these nanopores to characterize DNA and protein molecules.
Assuntos
Biopolímeros/análise , Nanoestruturas , DNA/análise , DNA/química , Desenho de Equipamento , Microscopia de Força Atômica , Microscopia Eletrônica de Transmissão , Peso Molecular , Nanoestruturas/ultraestrutura , Nanotecnologia , Conformação de Ácido Nucleico , Proteínas/análise , Compostos de SilícioRESUMO
As population growth continues to outpace development of water infrastructure in many countries, desalination (the removal of salts from seawater) at high energy efficiency will likely become a vital source of fresh water. Due to its atomic thinness combined with its mechanical strength, porous graphene may be particularly well-suited for electrodialysis desalination, in which ions are removed under an electric field via ion-selective pores. Here, we show that single graphene nanopores preferentially permit the passage of K(+) cations over Cl(-) anions with selectivity ratios of over 100 and conduct monovalent cations up to 5 times more rapidly than divalent cations. Surprisingly, the observed K(+)/Cl(-) selectivity persists in pores even as large as about 20 nm in diameter, suggesting that high throughput, highly selective graphene electrodialysis membranes can be fabricated without the need for subnanometer control over pore size.