Ultrafast Polymer Dynamics through a Nanopore.

Ultrathin nanopore sensors allow single-molecule and polymer measurements at sub-microsecond time resolution enabled by high current signals (∼10-30 nA). We demonstrate for the first time the experimental probing of the ultrafast translocation and folded dynamics of double-stranded DNA (dsDNA) through a nanopore at 10 MHz bandwidth with acquisition of data points per 25 ns (150 MB/s). By introducing a rigorous algorithm, we are able to accurately identify each current level present within translocation events and elucidate the dynamic folded and unfolded behaviors.

Silicon Nitride Nanopores Formed by Simple Chemical Etching: DNA Translocations and TEM Imaging.

We demonstrate DNA translocations through silicon nitride pores formed by simple chemical etching on glass substrates using microscopic amounts of hydrofluoric acid. DNA translocations and transmission electron microscopy (TEM) prove the fabrication of nanopores and allow their characterization. From ionic measurements on 318 chips, we report the effective pore diameters ranging from zero (pristine membranes) and sub-nm to over 100 nm, within 50 μm diameter membranes.

Deoxyribonucleic Acid Extraction from Mars Analog Soils and Their Characterization with Solid-State Nanopores.

Life detection on Mars is an important topic that includes a direct search for biomarkers. This requires instruments for biomarker detection that are compact, lightweight, and able to withstand operations in space. Solid-state nanopores are excellent candidates that allow fast single-molecule detection.

Protein-enabled detection of ibuprofen and sulfamethoxazole using solid-state nanopores.

Enabled by proteins, we present an all-electrical method for rapid detection of small pharmaceuticals (ibuprofen and sulfamethoxazole [SMZ]) in aqueous media using silicon nitride pores. Specifically, we use carrier proteins, bovine serum albumin (BSA), and take advantage of their interactions with two small drug molecules to form BSA-drug complexes which can be detected by nm-diameter pores, thereby confirming the presence of small pharmaceuticals. We demonstrate detection of ibuprofen and SMZ at concentrations down to 100 nM (∼21 μg/L) and 48.

Detection of single analyte and environmental samples with silicon nitride nanopores: Antarctic dirt particulates and DNA in artificial seawater.

Nanopore sensing is a powerful tool for the detection of biomolecules. Solid-state nanopores act as single-molecule sensors that can function in harsh conditions. Their resilient nature makes them attractive candidates for taking this technology into the field to measure environmental samples for life detection in space and water quality monitoring.

Nanoscale surface curvature modulates nanoparticle-protein interactions.

Rational optimization of nanoparticle (NP) surfaces is essential for successful conjugation of proteins to NPs for numerous applications. Using surface-roughened NPs (SRNPs) and quasi-spherical NPs (QSNPs) as two model nanostructures, we examined the effects of local surface curvature on protein conformation and interfacial behaviors by circular dichroism (CD) spectroscopy, fluorescence emission spectroscopy (FES), and isothermal titration calorimetry (ITC). The surface of SRNPs consisted of a mixture of undercoordinated and close-packed surface atoms at the highly curved and locally flat surface regions, respectively, whereas QSNPs were primarily enclosed by {100} and {111} facets covered with close-packed surface atoms.

Mitigating effects of osmolytes on the interactions between nanoparticles and supported lipid bilayer.

To maintain osmotic balance, cells usually produce neutral solutes (i.e., osmolytes), together with charged species to cope with salinity stress.