Mass transport through a sub-10 nm single gold nanopore: SERS and ionic current measurement

Abstract

Sub-10 nm single gold nanopore was fabricated at the tip of a glass nanopipette. SERS spectrum of R6G and ionic current blockage of lambda-DNA through the plasmonic nanopore were observed. • The chemically synthesized single gold nanopore with high SERS activity. • Both ionic current and dynamic SERS spectrum were obtained on a plasmonic nanopore. • The present study proved that single molecule transport is quite possibly be detected using the sub-10 nm gold nanopore. Gold nanopore is promising to be used in single molecule sequencing by measuring surface enhanced Raman scattering (SERS) spectrum. To achieve this goal, fabrication of small and size-controllable single gold nanopore is in urgent need. We synthesized gold nanoplates with a sub-10 nm single nanopore at the center, which was then successfully attached at the tip of a glass nanopipette using sulfhydryl silane. The transport of about 1.4 × 10 3 rhodamine 6G molecules was detected using SERS. The current blockage caused by single lambda DNA passing through the nanopore was also observed. The translocation time of lambda DNA through the gold nanopore was much longer than that of lambda DNA through the bare glass nanopipette, revealing the strong DNA-gold nanopore interaction affected the transport behavior of lambda DNA. The observed result further shows that the time resolution of SERS (~ms) may match the transport time of DNA through plasmonic nanopore. The sub-10 nm gold nanopore is possible to be used in single molecule transport detection with the improvement of the nanopore attachment.