A highly sensitive 27-MHz quartz-crystal microbalance, on which a 10-30-mer oligonucleotide was immobilized as probe molecule, employed to detect hybridization of complementary oligonucleotides in aqueous solution. From frequency decreases (mass increases due the hybridization) with passage time, kinetic parameters such association constants (K(a)) and binding dissociation rate (k(1) k(-1)) could be obtained, well (hybridization) amount at nanogram level (delta m). Kinetic studies were...

This study is the first report demonstrating proof-of-concept for a hydrogel-based touch sensor pad used non-invasive extraction and detection of sweat components. The device was composed an electrochemical L-lactate biosensor covered with agarose gel in phosphate buffer saline. When human skin contacts gel, continuously extracted into followed by in-situ potentiometric without controlled conditions. novel type expected to enable simple, daily periodic monitoring biomarkers advanced personal...

A heterologous expression system of the blue coppeiv-eontaining nitrite reductase from Alcaligenes xylosoxidans GIFU1051 (AxgNIR) was constructed, and purified recombi-nant enzyme characterized. All characteristic spectroscopic properties activity native ArgNIR were retained in copper-reconstituted protein expressed Escherichia coli, indicating correct coordination two types Cu (type 1 2) recombinant enzyme. Moreover, conserved nonco-ordinate residues, Asp98 His255, located near type 2 site...

By using a 27-MHz piezoelectric quartz oscillator connected with vector network analyzer, we obtained resonance frequency decreases (-DeltaFwater) and energy dissipation increases (DeltaDwater) during binding of biotinylated bovine serum albumin, ssDNA, dsDNA, pullulan to NeutrAvidin-immobilized crystal microbalance (QCM) plate in aqueous solution, as well the wet air phase (98% humidity, -DeltaFwet DeltaDwet) dry (-DeltaFair DeltaDair). -DeltaFwater indicates total mass molecule, bound...

Abstract A printed extended‐gate‐type organic transistor‐based enzyme sensor for the continuous monitoring of D‐glucose has been developed through a simple modification electrical circuit. The is composed glucose oxidase (GOx)/Prussian blue (PB)‐modified extended‐gate electrode and an Ag/AgCl reference electrode, which are connected to gate source electrodes transistor, respectively. GOx/PB‐modified were short‐circuited by external resistor spontaneously induce redox cycling PB. Continuous...

This review describes recent advances in biosensors for non-invasive human healthcare applications, especially focusing on sweat analysis, along with approaches fabricating these based printed electronics technology. Human contains various kinds of biomarkers. The relationship between a trace amount biomarkers partially partitioned from blood and diseases has been investigated by omic analysis. Recent progress wearable or portable enabled periodic continuous monitoring some while supporting...

During the immobilization process of proteins onto an Au-surface a 27 MHz quartz crystal microbalance (QCM) in aqueous solutions, apparent large frequency changes (ΔFwater) were observed compared with those air phase (ΔFair) due to interaction surrounding water proteins. On basis energy-transfer model for QCM, added mass solution [(−ΔFwater)/(−ΔFair) − 1] could be explained by frictional forces at interface solutions. When values various plotted against relating friction (antimobility), such...

For translation initiation in bacteria, the Shine-Dalgarno (SD) and anti-SD sequence of 30S subunit play key roles for specific interactions between ribosomes mRNAs to determine exact position region. However, also must dissociate from region slide toward downstream during mRNA translation. Translation enhancers upstream SD sequences mRNAs, which likely contribute a direct interaction with ribosome protein S1, enhance yields biosynthesis. Nevertheless, mechanism effect initiate is still...

The hydration and viscoelastic properties of synthetic polymer brushes on a substrate were evaluated using 27 MHz piezoelectric quartz-crystal microbalance based admittance analysis (QCM-A). (−ΔFwater)/(−ΔFair) values, which indicate the hydrodynamic water (bound vibrated water) ratio per unit mass, ΔDwater/(−ΔFair) (energy dissipation mass), obtained for low- high-density each polymer. These values indicated that low-density chains had different properties, depended chemical features In...

Sensor devices that can be fabricated on a flexible plastic film produced at low cost using inkjet-printing technology are suitable for point-of-care applications. An organic field-effect transistor (OFET)-based biosensor function as potentiometric electrochemical sensor. To investigate the usefulness of an OFET-based biosensor, we demonstrated detection 1,5-anhydroglucitol (1,5-AG) and glucose, which monosaccharides used biomarkers diabetes. combined with Prussian blue (PB) electrode,...

pH-Dependent kinetic parameters (kon, koff, and kcat) of protein (myoglobin) hydrolyses catalyzed by exo-enzyme (carboxypeptidase P, CPP) were obtained using a protein-immobilized quartz crystal microbalance (QCM) in acidic aqueous solutions. The formation the enzyme−substrate (ES) complex (kon), decay ES (koff), product (kcat) could be analyzed transient kinetics as mass changes on QCM plate. Kd (koff/kon) value was different from Michaelis constant Km calculated (koff + kcat)/kon due to...

Conformational changes of calmodulin (CaM) by additions Ca(2+) ions and bindings CaM-binding peptides to Ca(2+)/CaM followed conformational were monitored a CaM-immobilized 27 MHz quartz-crystal microbalance (QCM) with an admittance analysis. Both the binding change events could be detected from time-dependence frequency decreases (mass increases) energy dissipation (elasticity increases), respectively. When injected QCM cell on which biotinylated CaM was immobilized avidin-biotin...

Nucleic acid amplification reactions such as polymerase chain reaction (PCR), which uses a DNA to amplify individual double-stranded fragments, are useful technique for visualizing the presence of specific genomes. Although fluorescent labeling method is mainly used with amplification, other detection methods should be considered further improvements, miniaturization and cost reduction, reaction-monitoring devices. In this study, quartz-crystal microbalance (QCM) method, can measure...

A completely reversible dithiol-disulfide conversion regulates the recognition properties of macrocycle 1. Whereas open form 1A recognizes Ag+ ion selectively and can transport them across a membrane, closed 1B lacks this ability entirely. This concept could be basis for development other receptors with variable properties.

Catalytic DNA cleavage reactions by an ATP-dependent deoxyribonuclease (DNase) from Micrococcus luteus were monitored directly with a DNA-immobilized 27-MHz quartz-crystal microbalance (QCM). The QCM is very sensitive mass-measuring device in aqueous solution, as the frequency decreases linearly increasing mass on electrode at nanogram level. Three steps hydrolysis reactions, including (1) binding of DNase to end double-stranded (dsDNA) (mass increase), (2) degradation one strand dsDNA 3'...

The efficiency of protein synthesis is often regulated post-transcriptionally by sequences within the mRNA. To investigate reactions translation, we established a system that allowed real-time monitoring using cell-free translation mixture and 27 MHz quartz-crystal microbalance (QCM). Using an mRNA encoded fusion polypeptide comprising streptavidin-binding peptide (SBP) tag, portion Protein D as spacer, SecM arrest sequence, could follow binding SBP while it was displayed on 70S ribosome, to...

A highly sensitive 27 MHz quartz crystal microbalance instrument with an automatic flow injection system was developed to obtain realistic minimal frequency noise (±0.05 Hz) and a stable signal baseline (±1 Hz/h) by controlling the temperature of each part in (QCM) using three Peltier devices resolution ±0.001 °C optimizing prevent fluctuation internal pressure QCM. The improved QCM enabled detection small mass changes such as binding biotin streptavidin-immobilized high signal-to-noise...

Two series of poly(vinyl amine) (PVAm)-based block copolymers with zwitterionic and thermoresponsive segments were synthesized by the reversible addition–fragmentation chain transfer polymerization. A mixture two copolymers, poly(N-acryloyl-l-lysine) (PALysOH) poly(N-isopropylacrylamide) (PNIPAM), which have same cationic PVAm but different shell-forming segments, used to prepare mixed polyplex micelles DNA. Both PVAm-b-PALysOH PVAm-b-PNIPAM showed low cytotoxicity, characteristic assembled...