Pathogenic Bacterial Detection Using Vertical-Capacitance Sensor Array Immobilized with the Antimicrobial Peptide Melittin.

The rapid and reliable detection of pathogenic bacteria remains a significant challenge in clinical microbiology. Consequently, the demand for simple and rapid techniques, such as antimicrobial peptide (AMP)-based sensors, has recently increased as an alternative to traditional methods. Melittin, a broad-spectrum AMP, rapidly associates with the cell membranes of various gram-positive and gram-negative bacteria.

Funnel Devices Based on Asymmetrically Strained Transition Metal Dichalcogenides.

The strain applied to transition metal dichalcogenides (TMDs) reduces their energy bandgap, and local strains result in a funnel-like band structure in which funneled excitons move toward the most strained region. Herein, a funnel device based on asymmetrically strained WS and MoS is reported. Asymmetric strains are induced by transferring the TMD flakes onto a fork-shaped SU-8 microstructure.

Enhancement of triboelectricity based on fully organic composite films with a conducting polymer.

Triboelectric nanogenerators (TENGs) based on ferroelectric organic materials have advantages of high flexibility, biocompatibility, controllable ferroelectric properties, However, this has limited the electrical output performance due to their lower ferroelectric characteristics than those of inorganic ferroelectric materials. A lot of effort has been made to improve the organic ferroelectric characteristics through composites, surface modifications, structures, Herein, we report TENGs made of ferroelectric composite materials consisting of poly(vinylidene fluoride--trifluoroethylene) (PVDF-TrFE) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). The composite was prepared by simply blending PVDF-TrFE and PEDOT:PSS with a weight ratio from 0% to 60%.

Photothermal inactivation of universal viral particles by localized surface plasmon resonance mediated heating filter membrane.

This study introduces localized surface plasmon resonance (L-SPR) mediated heating filter membrane (HFM) for inactivating universal viral particles by using the photothermal effect of plasmonic metal nanoparticles (NPs). Plasmonic metal NPs were coated onto filter membrane via a conventional spray-coating method. The surface temperature of the HFM could be controlled to approximately 40-60 °C at room temperature, owing to the photothermal effect of the gold (Au) NPs coated on them, under irradiation by visible light-emitting diodes.

Rectifying optoelectronic memory based on WSe/graphene heterostructures.

van der Waals heterostructures composed of two-dimensional materials vertically stacked have been extensively studied to develop various multifunctional devices. Here, we report WSe/graphene heterostructure devices with a top floating gate that can serve as multifunctional devices. They exhibit gate-controlled rectification inversion, rectified nonvolatile memory effects, and multilevel optoelectronic memory effects.

Collective dynamics of neuronal activities in various modular networks.

Modularity is a key feature of structural and functional brain networks. However, the association between the structure and function of modular brain networks has not been revealed. We constructed three types of modular cortical networks in vitro and investigated their neuronal activities.

Large field-of-view nanometer-sectioning microscopy by using metal-induced energy transfer and biexponential lifetime analysis.

Total internal reflection fluorescence (TIRF) microscopy, which has about 100-nm axial excitation depth, is the method of choice for nanometer-sectioning imaging for decades. Lately, several new imaging techniques, such as variable angle TIRF microscopy, supercritical-angle fluorescence microscopy, and metal-induced energy transfer imaging, have been proposed to enhance the axial resolution of TIRF. However, all of these methods use high numerical aperture (NA) objectives, and measured images inevitably have small field-of-views (FOVs).

Electrical antimicrobial susceptibility testing based on aptamer-functionalized capacitance sensor array for clinical isolates.

To prescribe effective antibiotics to patients with bacterial infections in a timely manner and to avoid the misuse of antibiotics, a rapid antimicrobial susceptibility test (AST) is essential. However, conventional AST methods require more than 16 h to provide results; thus, we developed an electrical AST (e-AST) system, which provides results within 6 h. The proposed e-AST is based on an array of 60 aptamer-functionalized capacitance sensors that are comparable to currently available AST panels and a pattern-matching algorithm.

Methotrexate-loaded multifunctional nanoparticles with near-infrared irradiation for the treatment of rheumatoid arthritis.

Backgrounds: Despite the advances of rheumatoid arthritis (RA) therapeutics, several patients do not receive adequate treatment due to the toxicity and/or insufficient response of drugs. The aim of this study is to design photothermally controlled drug release from multifunctional nanoparticles (MNPs) at a near-infrared (NIR) irradiated site to improve therapeutic efficacy for RA and reduce side effects.

Methods: Au film was deposited onto methotrexate (MTX)-loaded poly(ethylene glycol)-poly(lactic-co-glycolic acid) (PLGA) nanoparticles, resulting in MTX-loaded MNPs.

Tunable Wettability of Graphene through Nondestructive Hydrogenation and Wettability-Based Patterning for Bioapplications.

The wettability of graphene has been extensively studied and successfully modified by chemical functionalization. Nevertheless, the unavoidable introduction of undesired defects and the absence of systematic and local control over wettability by previous methods have limited the use of graphene in applications. In addition, microscale patterning, according to wettability, has not been attempted.

Vertical capacitance aptasensors for real-time monitoring of bacterial growth and antibiotic susceptibility in blood.

For the treatment of bacteremia, early diagnosis and rapid antibiotic susceptibility tests (ASTs) are necessary because survival chances decrease significantly if the proper antibiotic administration is delayed. However, conventional methods require several days from blood collection to AST as it requires three overnight cultures, including blood culture, subculture, and AST culture. Herein, we report a more rapid method of sensing bacterial growth and AST in blood based on a vertical capacitance sensor functionalized with aptamers.

Multilevel MoS Optical Memory with Photoresponsive Top Floating Gates.

Optoelectronic memory devices, whose states can be controlled using electrical optical signals, are receiving much attention for their potential applications in image sensing and parallel data transmission and processes. Here, we report MoS-based devices with top floating gates of Au, graphene, and MoS. Unlike conventional floating gate memory devices, our devices have the photoresponsive floating gate at the top, acting as a charge trapping layer.

Enhanced output performance on LbL multilayer PVDF-TrFE piezoelectric films for charging supercapacitor.

The piezoelectric nanogenerator (PENG) has the potential to become a promising power supply for monitoring and sensors in Internet of Things (IoT) systems through wireless networks. In order to further increase the utilization of energy harvesters in an IoT system, we introduce a novel approach that greatly enhances the piezoelectric output performances by employing the layer-by-layer (LbL) method. Poly(vinylidenefluoride-co-trifluoroethylene) (PVDF-TrFE) polymer film, which has piezoelectric properties and mechanical flexibility, was used for the active layer in PENG.

Label-free and real-time monitoring of human mesenchymal stem cell differentiation in 2D and 3D cell culture systems using impedance cell sensors.

Three dimensional (3D) stem cell culture has recently received considerable attention because it may enable the development of 3D tissue models. In particular, label-free and real-time monitoring of stem cell differentiation is of importance for tissue engineering applications; however, only a few non-invasive monitoring methods are available, especially for 3D cell culture. Here, we describe impedance cell sensors that allowed the monitoring of cellular behaviors in 2D and 3D cell cultures in real-time.

Artificial Synaptic Emulators Based on MoS Flash Memory Devices with Double Floating Gates.

We fabricated MoS-based flash memory devices by stacking MoS and hexagonal boron nitride (hBN) layers on an hBN/Au substrate and demonstrated that these devices can emulate various biological synaptic functions, including potentiation and depression processes, spike-rate-dependent plasticity, and spike-timing dependent plasticity. In particular, compared to a flash memory device prepared on an hBN substrate, the device fabricated on the hBN/Au exhibited considerably more symmetric and linear bidirectional gradual conductance change curves, which may be attributed to the device structure incorporating double floating gate. For the device on the hBN/Au, electron transfers may occur between the floating gate MoS and Au, as well as between the floating gate MoS and the channel MoS, allowing for more control over electron tunneling and injection.

Aptamer-functionalized capacitance sensors for real-time monitoring of bacterial growth and antibiotic susceptibility.

To prevent spread of infection and antibiotic resistance, fast and accurate diagnosis of bacterial infection and subsequent administration of antimicrobial agents are important. However, conventional methods for bacterial detection and antibiotic susceptibility testing (AST) require more than two days, leading to delays that have contributed to an increase in antibiotic-resistant bacteria. Here, we report an aptamer-functionalized capacitance sensor array that can monitor bacterial growth and antibiotic susceptibility in real-time.

Dielectric imaging for differentiation between cancer and inflammation in vivo.

In this study, we develop an in vivo dielectric imaging technique that measures capacitance using pin-type electrode arrays. Compared to normal tissues, cancer tissues exhibit higher capacitance values, allowing us to image the cancer region and monitor the chemotherapeutic effects of cancer in real-time. A comparison with the histopathological results shows that the in vivo dielectric imaging technique is able to detect small tumors (<3 mm) and tumor-associated changes.

Analysis of Tertiary Interactions between SART3 and U6 Small Nuclear RNA Using Modified Nanocapillaries.

We employed modified glass nanocapillaries to investigate interactions between the RNA-binding protein, known as cell carcinoma antigen recognized by T cells-3 (SART3), and the noncoding spliceosome component, U6 small nuclear RNA (snRNA), at the single-molecule level. We functionalized the nanocapillaries with U6 snRNA fragments, which were hybridized to DNA molecules and then covalently attached to the nanocapillary surface. When transported through the modified nanocapillaries, two different SART3-derived constructs, HAT-RRM1-RRM2 and RRM1-RRM2, exhibited resistive ionic current pulses with different dwell times, which represented their different binding affinities to tethered U6 snRNAs.

MoWSe-Based Schottky Junction Photovoltaic Cells.

We developed Schottky junction photovoltaic cells based on multilayer MoWSe with x = 0, 0.5, and 1. To generate built-in potentials, Pd and Al were used as the source and drain electrodes in a lateral structure, and Pd and graphene were used as the bottom and top electrodes in a vertical structure.

Multilevel Nonvolatile Memristive and Memcapacitive Switching in Stacked Graphene Sheets.

We fabricated devices consisting of single and double graphene sheets embedded in organic polymer layers. These devices had binary and ternary nonvolatile resistive switching behaviors, respectively. Capacitance-voltage (C-V) curves and scanning capacitance microscopy (SCM) images were obtained to investigate the switching mechanism.

Memristive Switching in Bi(1-x)Sb(x) Nanowires.

We investigated the memristive switching behavior in bismuth-antimony alloy (Bi(1-x)Sb(x)) single nanowire devices at 0.1 ≤ x ≤ 0.42.

Selective Detection of Single-Stranded DNA Molecules Using a Glass Nanocapillary Functionalized with DNA.

We describe glass nanocapillaries with single-stranded DNA molecules (ssDNA) covalently attached to the capillary surface. These DNA-functionalized nanocapillaries selectively facilitate the translocation of target ssDNA that is complementary to the probe ssDNA. In addition, the complementary target ssDNA exhibits an event duration time longer than that of the noncomplementary target ssDNA.

Real-time monitoring of 3D cell culture using a 3D capacitance biosensor.

Three-dimensional (3D) cell cultures have recently received attention because they represent a more physiologically relevant environment compared to conventional two-dimensional (2D) cell cultures. However, 2D-based imaging techniques or cell sensors are insufficient for real-time monitoring of cellular behavior in 3D cell culture. Here, we report investigations conducted with a 3D capacitance cell sensor consisting of vertically aligned pairs of electrodes.

Metal-insulator crossover in multilayered MoS2.

The temperature dependence of electrical transport properties was investigated for multilayered MoS2 field effect transistor devices with thicknesses of 3-22 nm. Some devices showed typical n-type semiconducting behavior, while others exhibited metal-insulator crossover (MIC) from metallic to insulating conduction at finite temperatures. The latter effect occurred near zero gate voltage or at high positive gate voltages.

Macrophage Differentiation from Monocytes Is Influenced by the Lipid Oxidation Degree of Low Density Lipoprotein.

LDL plays an important role in atherosclerotic plaque formation and macrophage differentiation. However, there is no report regarding the oxidation degree of LDL and macrophage differentiation. Our study has shown that the differentiation into M1 or M2 macrophages is related to the lipid oxidation level of LDL.