Recently, microRNA (miRNA) detection in blood has attracted attention as a new early detection technology for cancer. The extraction of target miRNA is a necessary preliminary step for detection; however, currently, most extraction methods extract all RNA from the blood, which limits the detection selectivity. Therefore, a method for the selective extraction and detection of target miRNA from blood is very important.
View Article and Find Full Text PDFFor the detection and monitoring of live bacteria, we propose a biochemical corrosion monitoring (BCM) sensor that measures galvanic current by using a Ag/C sensor comprising silver and carbon comb electrodes. The deposition of an suspension containing an LB liquid medium on the Ag/C sensor increased the galvanic current. The time required for the current to reach 20 nA is defined as .
View Article and Find Full Text PDFPolymerase chain reaction (PCR) assays are used to diagnose various infectious diseases such as Coronavirus disease 2019 by detecting the nucleic acids of the pathogen. However, in practice, the yield of the extraction process and the inhibition of the reverse transcription reaction and PCR by foreign substances reduce the sensitivity and may yield false negative results. The sensitivity of the PCR test can be improved by using technologies that can reliably capture the target nucleic acid and remove foreign substances.
View Article and Find Full Text PDFHerein, to improve the current density and sensitivity for biofuel cell and glucose sensing application, a bioanode based on redox polymer (PEI-Fc) binding polydopamine (PDA) coated MWCNTs (PEI-Fc/PDA/MWCNTs) nanocomposite and glucose oxidase (GOD) was fabricated. PDA/MWCNTs nanocomposite was prepared by spontaneous self-polymerization of dopamine on MWCNTs surface and the PEI-Fc/PDA/MWCNTs nanocomposite was prepared by a simple self-assembly method. The PEI-Fc/PDA/MWCNTs nanocomposite and the resulting bioanode were fully characterized.
View Article and Find Full Text PDFBiodevices in which biomolecules such as enzymes and antibodies are immobilized on the surface of electrode materials are capable of converting chemical energy into electrical energy, and are expected to contribute to solving energy problems and developing medical measurements especially as biobatteries and biosensors. Device performance depends on the interface formed between the biomolecule layer and electrode material, and the interface is required to simultaneously achieve a highly efficient enzymatic reaction and electron transfer. However, when enzymes were immobilized on a material surface, the enzymes undergoes a structural change due to the interaction between the enzyme and the electrode surface, making it difficult to maximize the function of the enzyme molecule on the material surface.
View Article and Find Full Text PDFAlthough multicopper oxidase from the hyperthermophilic archaeon Pyrobaculum aerophilum (McoP) can be particularly useful in biotechnological applications, e.g., as a specific catalyst at the biocathode of biofuel cells (BFCs), owing to its high stability against extremely high temperatures and across a wide range of pH values, this application potential remains limited due to the enzyme's low catalytic activity.
View Article and Find Full Text PDFEnzymes from hyperthermophilic archaea are potential candidates for industrial use because of their superior pH, thermal, and long-term stability, and are expected to improve the long-term stability of biofuel cells (BFCs). However, the reported multicopper oxidase (MCO) from hyperthermophilic archaea has lower redox potential than MCOs from other organisms, which leads to a decrease in the cell voltage of BFCs. In this study, we attempted to positively shift the redox potential of the MCO from hyperthermophilic archaeon Pyrobaculum aerophilum (McoP).
View Article and Find Full Text PDFBiofuel cells generate electric energy using an enzyme as a catalyst for an electrode but their stability and low battery output pose problems for practical use. To solve these problems, this study aimed to build a long-lasting and high-output biocathode as a catalyst using a highly stable hyperthermophilic archaeal enzyme, multi-copper oxidase, from Pyrobaculum aerophilum (McoP). To increase output, McoP was oriented and immobilized on single-walled carbon nanotubes (SWCNT) with a high specific surface area, and the electrode interface was designed to achieve highly efficient electron transfer between the enzyme and electrode.
View Article and Find Full Text PDFThe number density and the arrangement of metal nanoparticles in composite materials have a significant effect on their performance and hence their suitability for use in sensors and devices. Forming one-dimensional arrays of metal nanoparticles is one way of controlling their number density and arrangement in the devices. In this study, we fabricated one-dimensional arrays of gold nanoparticles by adsorbing them on linearly distributed hard segments present on the surfaces of segmented polyurethane nanofibers, which were produced by electrospinning under a stretching force.
View Article and Find Full Text PDFMicro total analysis system (μTAS) is expected to be applied in various fields. In particular, since electrochemical measurement is inexpensive and easy, electrochemical measurement can be integrated with a microchannel. However, electrochemical detection sensitivity in a microchannel is lowered because the diffusion of the detection target is limited.
View Article and Find Full Text PDFObjective: The construction of a novel bioanode based on L-proline oxidation using a cascade reaction pathway comprised of thermostable dehydrogenases.
Results: A novel multi-enzymatic cascade pathway, containing four kinds of dehydrogenases from thermophiles (dye-linked L-proline dehydrogenase, nicotinamide adenine dinucleotide (NAD)-dependent Δ-pyrroline-5-carboxylate dehydrogenase, NAD-dependent L-glutamate dehydrogenase and dye-linked NADH dehydrogenase), was designed for the generation of six-electrons from one molecule of L-proline. The current density of the four-dehydrogenase-immobilized electrode, with a voltage of + 450 mV (relative to that of Ag/AgCl), was 226.
For increasing the output of biofuel cells, increasing the cooperation between enzyme reaction and electron transfer on the electrode surface is essential. Highly oriented immobilization of enzymes onto a carbon nanotube (CNT) with a large specific surface area and excellent conductivity would increase the potential for their application as biosensors and biofuel cells, by utilizing the electron transfer between the electrode-molecular layer. In this study, we prepared a CNT-enzyme complex with highly oriented immobilization of enzyme onto the CNT surface.
View Article and Find Full Text PDFIn this study, multicopper oxidase (MCO) was immobilized on multiwalled carbon nanotubes (MWCNTs) at two different orientations, and the electrochemical properties of the resulting cathodes were investigated. Using N- or C-terminal His-tagged MCO and MWCNTs, we constructed two types of cathodes. We assumed that the distance between the type 1 (T1)Cu of the C-terminal His-tagged MCO and the MWCNT surface was lesser than that between the T1Cu of the N-terminal His-tagged MCO and the MWCNT surface.
View Article and Find Full Text PDFObjectives: The life of biobatteries remains an issue due to loss of enzyme activity over time. In this study, we sought to develop a biobattery with a long life using a hyperthermophilic enzyme.
Results: We hypothesized that use of such hyperthermophilic enzymes would allow for the biofuel cells to have a long battery life.