This experimental work studies the translocation of bovine serum albumin (BSA) proteins through MoS₂ nanopores. A simple method of device fabrication is developed based on dry-transfer of exfoliated MoS₂ membranes and subsequent TEM drilling, yielding MoS₂ nanopores of a few monolayers thick and diameters as small as ∼11 nm. The current-voltage relation and low-frequency current noise of the devices are characterized. Typical BSA translocation signals that possibly correspond to various orientations are observed in the MoS₂ devices, exhibiting enhanced amplitude and similar characteristics when compared to those from a silicon nitride (SiN_x) control. Furthermore, the statistical data of the signal amplitude and dwell time at various biases are analyzed. These results show opportunities of single-molecular protein analysis using MoS₂ nanopores.

Size and shape are critical discriminators between molecular species and states. We describe a microchip-based high-throughput imaging approach offering rapid and precise determination of molecular properties under native solution conditions. Our method detects differences in molecular weight across at least three orders of magnitude and down to two carbon atoms in small molecules. We quantify the strength of molecular interactions across more than six orders of magnitude in affinity constant and track reactions in real time. Highly parallel measurements on individual molecules serve to characterize sample-state heterogeneity at the highest resolution, offering predictive input to model three-dimensional structure. We further leverage the method’s structural sensitivity for diagnostics, exploiting ligand-induced conformational changes in the insulin receptor to sense insulin concentration in serum at the subnanoliter and subzeptomole scale.

Excessively-long translocation events of single DNAs are experimentally observed using a small nanopore. Solid-state Nano pores on SiNx membranes with pore diameters less than 5nm are fabricated via Transmission Electron Microscopy. The translocation testing system is set up based on patch-clamp and Lab-on-Chip, and translocation experiments of Lambda DNAs are conducted. Stable current traces and single molecular translocation events are achieved. Statistical analysis under various cross-membrane voltages shows typical characteristics of SiNx Nano pores, including event rates, threshold voltages, and noise power-spectrum-density. Particularly, excessively-long dwell time (>100ms) events through <5 nm nanopore are observed and attributed to the interaction between DNAs and pore walls. This characteristic is compared against the basic current-blockage model as well as that of a 10 nm nanopore control experiment, demonstrating additional blockage effects.