Electrokinetic Enhancement of Membrane Techniques for Efficient Nanoparticle Separation and Preconcentration.

Efficient separation and preconcentration of nanoparticles are crucial in a wide range of biomedical applications, particularly as target substances continue to diminish in size. In this study, we introduce an electric field-assisted membrane system that synergistically combines oversized-pore membranes with an electrokinetic particle retention mechanism. Utilizing Ti/Au-coated poly(tetrafluoroethylene) (PTFE) membranes, our approach generates electrokinetic forces to effectively separate and retain charged nanoparticles even smaller than the pores, achieving a separation efficiency over 99% and a preconcentration factor of 1.

Anti-counterfeiting labels of photonic crystals with versatile structural colors.

Labels with structural color based on photonic crystals (PCs) have drawn significant attention due to their unique color emission, offering promising solutions for anti-counterfeiting applications. However, to meet the demands of future high-security applications, conventional structural color labels require further improvement. This study introduces a novel approach to fabricate highly encrypted anti-counterfeiting labels by combining close-packed and non-close-packed monolayers of nanoparticles (NPs) onto adhesive surfaces.

Assembling Vertical Nanogap Arrays with Nanoentities for Highly Sensitive Electrical Biosensing.

Nanogap biosensors have emerged as promising platforms for detecting and measuring biochemical substances at low concentrations. Although the nanogap biosensors provide high sensitivity, low limit of detection (LOD), and enhanced signal strength, it requires arduous fabrication processes and costly equipment to obtain micro/nanoelectrodes with extremely narrow gaps in a controlled manner. In this work, we report the novel design and fabrication processes of vertical nanogap structures that can electrically detect and quantify low-concentration biochemical substances.

An angle-compensating colorimetric strain sensor with wide working range and its fabrication method.

The visual response is one of the most intuitive principles of sensors. Therefore, emission and change of the colors are widely studied for development of chemical, thermal and mechanical sensors. And it is still a challenging issue to fabricate them with a simple working mechanism, high sensitivity, good reliability, and a cost-effective fabrication process.

Influence of growth temperature on dielectric strength of AlO thin films prepared via atomic layer deposition at low temperature.

Thin films grown via atomic layer deposition (ALD) suffer from insufficient growth rate and unreliability for temperature-sensitive electronic substrates. This study aimed to examine the growth characteristics and dielectric strength of ALD AlO films grown at low temperatures (≤ 150 °C) for potential application in flexible electronic devices. The growth rate of the AlO films increased from 0.

Fabrication of robust and reusable mold with nanostructures and its application to anti-counterfeiting surfaces based on structural colors.

In this study, we report a method to fabricate molds and flexible stamps with 2D photonic crystal structures. This includes self-assembly of polystyrene particles into monolayer, oxygen reactive ion etching, thin film (chromium (Cr)) deposition, and polydimethylsiloxane replication. By tuning the thickness of Cr layer, reusable master molds with nano bumps or nano concaves could be prepared selectively.

Rapid and simple single-chamber nucleic acid detection system prepared through nature-inspired surface engineering.

Nucleic acid (NA)-based diagnostics enable a rapid response to various diseases, but current techniques often require multiple labor-intensive steps, which is a major obstacle to successful translation to a clinical setting. We report on a surface-engineered single-chamber device for NA extraction and amplification without sample transfer. Our system has two reaction sites: a NA extraction chamber whose surface is patterned with micropillars and a reaction chamber filled with reagents for polymerase-based NA amplification.

High-Throughput Synthesis of Liposome Using an Injection-Molded Plastic Micro-Fluidic Device.

For mass production of liposomes, we designed a plastic micro-channel device on the basis of 5 μm of micro-nozzle array forming T-junction with 100 μm depth of micro-channel. A micro-channel unit for synthesizing liposomes consisted of two micro-nozzle arrays for mixing two solutions as well as delivery and recovery channels for supplying solutions and collecting liposome suspension. The number of micro-nozzles was approximately 2400 for a micro-channel unit, and seven units were applied independently on a micro-channel plate.

Analysis of the Binding of Analyte-Receptor in a Micro-Fluidic Channel for a Biosensor based on Brownian Motion.

This study experimentally analyses the binding characteristics of analytes mixed in liquid samples flowing along a micro-channel to the receptor fixed on the wall of the micro-channel to provide design tools and data for a microfluidic-based biosensor. The binding or detection characteristics are analyzed experimentally by counting the number of analytes bound to the receptor, with sample analyte concentration, sample flow rate, and the position of the receptor along the micro-channel length as the main variables. A mathematical model is also proposed to predict the number of analytes transported and bound to the receptor based on a probability density function for Brownian motion.

Gas-Permeable Inorganic Shell Improves the Coking Stability and Electrochemical Reactivity of Pt toward Methane Oxidation.

Solid oxide fuel cells produce electricity directly by oxidizing methane, which is the most attractive natural gas fuel, and metal nanocatalysts are a promising means of overcoming the poor catalytic activity of conventional ceramic electrodes. However, the lack of thermal and chemical stability of nanocatalysts is a major bottleneck in the effort to ensure the lifetime of metal-decorated electrodes for methane oxidation. Here, for the first time, this issue is addressed by encapsulating metal nanoparticles with gas-permeable inorganic shells.

Electrical, Structural, Optical, and Adhesive Characteristics of Aluminum-Doped Tin Oxide Thin Films for Transparent Flexible Thin-Film Transistor Applications.

The properties of Al-doped SnO films deposited via reactive co-sputtering were examined in terms of their potential applications for the fabrication of transparent and flexible electronic devices. Al 2.2-atom %-doped SnO thin-film transistors (TFTs) exhibit improved semiconductor characteristics compared to non-doped films, with a lower sub-threshold swing of ~0.

Specific capture, recovery and culture of cancer cells using oriented antibody-modified polystyrene chips coated with agarose film.

Agarose gel can be used for three dimensional (3D) cell culture because it prevents cell attachment. The dried agarose film coated on a culture plate also protected cell attachment and allowed 3D growth of cancer cells. We developed an efficient method for agarose film coating on an oxygen-plasma treated micropost polystyrene chip prepared by an injection molding process.

Nano sand filter with functionalized nanoparticles embedded in anodic aluminum oxide templates.

Since the ancient Egyptians had used sand as filter media for water purification, its principle has been inherited through generations and it is still being used now in industries. The sand filter consists of sand literally, and the voids within the sand bed are the pores for filtration. Here we present a filtration principle using nanoparticles, so that the voids between the nanoparticles can be considered as effective pores in nanoscale dimension.

Rapid identification of health care-associated infections with an integrated fluorescence anisotropy system.

Health care-associated infections (HAIs) and drug-resistant pathogens have become a major health care issue with millions of reported cases every year. Advanced diagnostics would allow clinicians to more quickly determine the most effective treatment, reduce the nonspecific use of broad-spectrum antimicrobials, and facilitate enrollment in new antibiotic treatments. We present a new integrated system, polarization anisotropy diagnostics (PAD), for rapid detection of HAI pathogens.

Molecular Dynamics Simulation of the Effect of Angle Variation on Water Permeability through Hourglass-Shaped Nanopores.

Water transport through aquaporin water channels occurs extensively in cell membranes. Hourglass-shaped (biconical) pores resemble the geometry of these aquaporin channels and therefore attract much research attention. We assumed that hourglass-shaped nanopores are capable of high water permeation like biological aquaporins.

Automated lipid membrane formation using a polydimethylsiloxane film for ion channel measurements.

A black lipid membrane (BLM) is a powerful platform for studying the electrophysiology of cell membranes as well as transmembrane proteins. However, BLMs have disadvantages in terms of stability, accessibility, and transportability, which preclude their industrial applications. To resolve these issues, frozen membrane precursor (MP) was devised to improve the transportability and storability of BLMs.

Synthetic biomimetic membranes and their sensor applications.

Synthetic biomimetic membranes provide biological environments to membrane proteins. By exploiting the central roles of biological membranes, it is possible to devise biosensors, drug delivery systems, and nanocontainers using a biomimetic membrane system integrated with functional proteins. Biomimetic membranes can be created with synthetic lipids or block copolymers.

Controlling mold releasing propensity--the role of surface energy and a multiple chain transfer agent.

As the desired feature size of mold-assisted lithography decreases rapidly efficient demolding process becomes more challenging due to strong adhesion between polymeric resists and fine-featured molds. We synthesized new macromolecular additives and investigated the effects of surface energy and contraction of resist materials on demolding propensity by monitoring the adhesion force between the resist and the applied mold. The resist's surface energy was controlled, as inferred from water contact angle measurements, by chemically modifying its hydroxyl functionality.