Dwell Time Prolongation and Identification of Single Nucleotides Passing through a Solid-State Nanopore by Using Ammonium Sulfate Aqueous Solution.

The ionic current blockades when poly(dT) or dNTPs passed through SiN nanopores in an aqueous solution containing (NH)SO were investigated. The dwell time of poly(dT) in the nanopores in an aqueous solution containing (NH)SO was significantly longer compared to that in an aqueous solution that did not contain (NH)SO. This dwell time prolongation effect due to the aqueous solution containing (NH)SO was also confirmed when dCTP passed through the nanopores.

Label-free enzymatic reaction monitoring in water-in-oil microdroplets using ultra-broadband multiplex coherent anti-Stokes Raman scattering spectroscopy.

We propose a system for monitoring an enzymatic reaction, i.e., dehydrogenation of ethanol catalyzed by alcohol dehydrogenase, in microdroplets using ultra-broadband multiplex coherent anti-Stokes Raman scattering (CARS) spectroscopy.

Boys with attention-deficit/hyperactivity disorder perform wider and fewer finger tapping than typically developing boys - Peer comparisons and the effects of methylphenidate from an exploratory perspective.

Aim: This study aimed to investigate the differences in fine motor and coordination skills between boys with attention-deficit/hyperactivity disorder (ADHD) and typically developing (TD) boys and the effect of methylphenidate (MPH) in boys with ADHD.

Methods: Fourteen boys aged 7-12 years who were diagnosed with ADHD and previously treated with MPH were instructed to tap their thumbs and index fingers together repetitively for 10 s after attaching magnetic sensors. The participants executed "in-phase" and "anti-phase" tapping.

Sub-10-nm-thick SiN nanopore membranes fabricated using the SiOsacrificial layer process.

In our previous studies, ultrathin SiN membranes down to 3 nm in thickness were fabricated using the poly-Si sacrificial layer process, and nanopores were formed in those membranes. The region of the SiN membrane fabricated using this process was small, and the poly-Si sacrificial layer remained throughout the other region. On the other hand, to reduce the noise of the current through the nanopore, it is preferable to reduce the capacitance of the nanopore chip by replacing the poly-Si layer with an insulator with low permittivity, such as SiO.

Low-frequency noise induced by cation exchange fluctuation on the wall of silicon nitride nanopore.

Nanopore-based biosensors have attracted attention as highly sensitive microscopes for detecting single molecules in aqueous solutions. However, the ionic current noise through a nanopore degrades the measurement accuracy. In this study, the magnitude of the low-frequency noise in the ionic current through a silicon nitride nanopore was found to change depending on the metal ion species in the aqueous solution.

Quantitative assessment of fine motor skills in children using magnetic sensors.

Aim: We aimed to establish objective and quantitative data on fine motor development in typically developing children using magnetic sensors.

Methods: The study included 110 Japanese elementary school children volunteers (57 boys, 53 girls). The participants were instructed to tap their thumbs and index fingers together repetitively for 10 s.

Stable fabrication of a large nanopore by controlled dielectric breakdown in a high-pH solution for the detection of various-sized molecules.

For nanopore sensing of various-sized molecules with high sensitivity, the size of the nanopore should be adjusted according to the size of each target molecule. For solid-state nanopores, a simple and inexpensive nanopore fabrication method utilizing dielectric breakdown of a membrane is widely used. This method is suitable for fabricating a small nanopore.

Solid-state nanopores towards single-molecule DNA sequencing.

Nanopore DNA sequencing offers a new paradigm owing to its extensive potential for long-read, high-throughput detection of nucleotide modification and direct RNA sequencing. Given the remarkable advances in protein nanopore sequencing technology, there is still a strong enthusiasm in exploring alternative nanopore-sequencing techniques, particularly those based on a solid-state nanopore using a semiconductor material. Since solid-state nanopores provide superior material robustness and large-scale integrability with on-chip electronics, they have the potential to surpass the limitations of their biological counterparts.

Silicon nitride nanopore created by dielectric breakdown with a divalent cation: deceleration of translocation speed and identification of single nucleotides.

Nanopore DNA sequencing with a solid-state nanopore requires deceleration of the ultrafast translocation speed of single-stranded DNA (ssDNA). We report an unexpected phenomenon: controlled dielectric breakdown (CBD) with a divalent metal cation, especially Ca2+, provides a silicon nitride nanopore with the ability to decelerate ssDNA speed to 100 μs per base even after solution replacement. This speed is two orders of magnitude slower than that for CBD with a conventional monovalent metal cation.

Challenges of Single-Molecule DNA Sequencing with Solid-State Nanopores.

A powerful DNA sequencing tool with high accuracy, long read length and high-throughput would be required more and more for decoding the complicated genetic code. Solid-state nanopore has attracted many researchers for its promising future as a next-generation DNA sequencing platform due to the processability, the robustness and the large-scale integratability. While the diverse materials have been widely explored for a solid-state nanopore, silicon nitride (SiN) is especially preferable from the viewpoint of mass production based on semiconductor fabrication process.

KRAS genotyping by digital PCR combined with melting curve analysis.

Digital PCR (dPCR) has been developed as a method that can quantify nucleic acids more sensitively than real-time PCR. However, dPCR exhibits large fluctuations in the fluorescence intensity of the compartment, resulting in low accuracy. The main cause is most likely due to insufficient PCR.

Identification of four single-stranded DNA homopolymers with a solid-state nanopore in alkaline CsCl solution.

DNA sequencing via solid-state nanopores is a promising technique with the potential to surpass the performance of conventional sequencers. However, the identification of all four nucleotide homopolymers with a typical SiN nanopore is yet to be clearly demonstrated because a guanine homopolymer rapidly forms a G-quadruplex in a typical KCl aqueous solution. To address this issue, we introduced an alkaline CsCl aqueous solution, which denatures the G-quadruplex into a single-stranded structure by disrupting the hydrogen-bonding network between the guanines and preventing the binding of the K+ ion to G-quartets.

Two-step breakdown of a SiN membrane for nanopore fabrication: Formation of thin portion and penetration.

For the nanopore sensing of various large molecules, such as probe-labelled DNA and antigen-antibody complexes, the nanopore size has to be customized for each target molecule. The recently developed nanopore fabrication method utilizing dielectric breakdown of a membrane is simple and quite inexpensive, but it is somewhat unsuitable for the stable fabrication of a single large nanopore due to the risk of generating multiple nanopores. To overcome this bottleneck, we propose a new technique called "two-step breakdown" (TSB).

Total hepatocellular disposition profiling of rosuvastatin and pitavastatin in sandwich-cultured human hepatocytes.

This study describes the total disposition profiling of rosuvastatin (RSV) and pitavastatin (PTV) using a single systematic procedure called D-PREX (Disposition Profile Exploration) in sandwich-cultured human hepatocytes (SCHH). The biliary excretion fractions of both statins were clearly observed, which were significantly decreased dependent on the concentration of Ko143, an inhibitor for breast cancer resistance protein (BCRP). Ko143 also decreased the basolateral efflux fraction of RSV, whereas that of PTV was not significantly affected.

Discrimination of three types of homopolymers in single-stranded DNA with solid-state nanopores through external control of the DNA motion.

To achieve DNA sequencing with solid-state nanopores, the speed of the DNA in the nanopore must be controlled to obtain sequence-specific signals. In this study, we fabricated a nanopore-sensing system equipped with a DNA motion controller. DNA strands were immobilized on a Si probe, and approach of this probe to the nanopore vicinity could be controlled using a piezo actuator and stepper motor.

A Customized Online Nutrition Guidance System Is Effective for Treating Patients with Nonalcoholic Fatty Liver Disease by Supporting Continuity of Diet Therapy at Home: A Pilot Study.

Continuity is required for diet therapy, but it depends on patients. We examined the utility of a new tool, the customized online nutrition guidance system, in patients with nonalcoholic fatty liver disease (NAFLD). Seven patients plotted their body weight (BW) and marked a customized task card on completion for 90 days on a website.

Parallel Evaluation of Melting Temperatures of DNAs in the Arrayed Droplets through the Fluorescence from DNA Intercalators.

Parallel evaluation of melting temperatures (T's) of DNA molecules in multiple floating droplets (20 μm in diameter) was demonstrated. The T values were evaluated from the melting curves which were observed through the fluorescence from the DNA intercalators. The T values measured in the droplets corresponded well to those measured in the bulk, indicating the validity of the measurement.

Immunoglobulin G (IgG)-Based Imaging Probe Accumulates in M1 Macrophage-Infiltrated Atherosclerotic Plaques Independent of IgG Target Molecule Expression.

Purpose: Vulnerable plaques are key factors for ischemic diseases. Thus, their precise detection is necessary for the diagnosis of such diseases. Immunoglobulin G (IgG)-based imaging probes have been developed for imaging biomolecules related to plaque formation for the diagnosis of atherosclerosis.

Size-Selective Harvesting of Extracellular Vesicles for Strategic Analyses Towards Tumor Diagnoses.

Extracellular vesicles (EV), typified by exosomes or microvesicles, are expected to be effective diagnostic markers for cancers. The sizes of the vesicles range from 20 to 1000 nm, but the size-dependent variations of the contents of EVs are still poorly understood. We succeeded in the size-selective harvesting of the vesicles by utilizing the molecular weight-dependent characteristics of a variety of polyethylene glycols (PEG) as precipitating reagents and analyzed the antigens displayed on the surfaces of the vesicles and the miRNAs included in the vesicles from each size group.

Slowing the translocation of single-stranded DNA by using nano-cylindrical passage self-assembled by amphiphilic block copolymers.

We report a novel approach to slow the translocation of single-stranded DNA (ssDNA) by employing polyethylene oxide (PEO) filled nano-cylindrical domains as transportation channels. DNA strands were demonstrated to electrophoretically translocate through PEO filled cylindrical domains with diameters of 2 and 9 nm, which were self-assembled by amphiphilic liquid crystalline block copolymers. The average translocation rate of ssDNA strands was effectively reduced to an order of 10 μs per nucleotide, which was 1-2 orders slower than that attained by utilizing conventional solid-state nanopore devices.

Integrated solid-state nanopore platform for nanopore fabrication via dielectric breakdown, DNA-speed deceleration and noise reduction.

The practical use of solid-state nanopores for DNA sequencing requires easy fabrication of the nanopores, reduction of the DNA movement speed and reduction of the ionic current noise. Here, we report an integrated nanopore platform with a nanobead structure that decelerates DNA movement and an insulating polyimide layer that reduces noise. To enable rapid nanopore fabrication, we introduced a controlled dielectric breakdown (CDB) process into our system.

Multichannel detection of ionic currents through two nanopores fabricated on integrated Si3N4 membranes.

Integration of solid-state nanopores and multichannel detection of signals from each nanopore are effective measures for realizing high-throughput nanopore sensors. In the present study, we demonstrated fabrication of Si3N4 membrane arrays and the simultaneous measurement of ionic currents through two nanopores formed in two adjacent membranes. Membranes with thicknesses as low as 6.

Novel multiple assessment of hepatocellular drug disposition in a single packaged procedure.

Unlabelled: Better prediction of drug disposition prior to the clinical trial is critical for the efficient development of new drugs. The purpose of this study is to develop a novel multiple assessment methodology of hepatocellular drug disposition from drug uptake to efflux including biliary and basolateral excretion, in a single packaged procedure. We started a sandwich culture using rat primary hepatocytes.

Side-gated ultrathin-channel nanopore FET sensors.

A side-gated, ultrathin-channel nanopore FET (SGNAFET) is proposed for fast and label-free DNA sequencing. The concept of the SGNAFET comprises the detection of changes in the channel current during DNA translocation through a nanopore and identifying the four types of nucleotides as a result of these changes. To achieve this goal, both p- and n-type SGNAFETs with a channel thicknesses of 2 or 4 nm were fabricated, and the stable transistor operation of both SGNAFETs in air, water, and a KCl buffer solution were confirmed.