Electrochemical enzymatic biosensor with long-term stability using hybrid mesoporous membrane.

An acetylcholinesterase-immobilized sensor unit was successfully prepared by encapsulating the enzyme within hybrid mesoporous silica membranes (F127-MST). Through a novel combination with tetracyanoquinodimethane, both acetylcholine and organophosphorus pesticides were successfully detected with high sensitivity. Furthermore, we manufactured the working prototype of an enzyme sensor with this sensor unit for detecting dichlorvos, aldicarb and parathion.

Preparation of copper nitride (Cu3N) nanoparticles in long-chain alcohols at 130-200 °C and nitridation mechanism.

In our laboratory, we are studying copper nitride (Cu3N) nanoparticles as a novel conductive ink that is stable to oxidation and can be metallized at low temperature. In this study, Cu3N nanoparticles prepared via the reaction of copper(II) acetate monohydrate with ammonia gas in long-chain alcohol solvents were characterized by X-ray diffraction analysis, transmission electron microscopy, Fourier transform infrared spectroscopy, and elemental analysis. In addition, we used thermogravimetry-differential thermal analysis to compare the thermal decomposition properties of the prepared Cu3N particles and commercially available Cu3N particles.

Microporous organic-inorganic nanocomposites as the receptor in the QCM sensing of toluene vapors.

We have used novel microporous biphenylene-pillared layered silicates as receptors in a quartz crystal microbalance (QCM) for sensing toluene vapors. The silicate was successfully coated on a QCM electrode modified with 2-aminoethanethiol. The resultant electrode showed quantitative frequency responses due to enhanced adhesion between the silicate and the electrode.

A novel, disposable, screen-printed amperometric biosensor for ketone 3-β-hydroxybutyrate fabricated using a 3-β-hydroxybutyrate dehydrogenase-mesoporous silica conjugate.

A disposable amperometric biosensor for ketone 3-β-hydroxybutyrate (3HB) has been developed successfully. The sensor is based on a screen-printed carbon electrode containing Meldola's Blue (MB) and sensing components containing nicotinamide adenine dinucleotide (NAD(+)) and 3-β-hydroxybutyrate dehydrogenase (3HBDH) immobilized in mesoporous silica (FSM8.0) using an aqueous photo-cross-linkable polymer matrix of polyvinyl alcohol (O-391), and it requires only a small sample volume of 10 μL for the measurement.

An enzyme-encapsulated microreactor for efficient theanine synthesis.

A flow-type microreactor containing glutaminase-mesoporous silica composites with 10.6 nm pore diameter (TMPS10.6) was developed for the continuous synthesis of theanine, a unique amino acid.

Amperometric L-lactate biosensor based on screen-printed carbon electrode containing cobalt phthalocyanine, coated with lactate oxidase-mesoporous silica conjugate layer.

A novel amperometric biosensor for the measurement of L-lactate has been developed. The device comprises a screen-printed carbon electrode containing cobalt phthalocyanine (CoPC-SPCE), coated with lactate oxidase (LOD) that is immobilized in mesoporous silica (FSM8.0) using a polymer matrix of denatured polyvinyl alcohol; a Nafion layer on the electrode surface acts as a barrier to interferents.

Enhancement in thermal stability and resistance to denaturants of lipase encapsulated in mesoporous silica with alkyltrimethylammonium (CTAB).

We assembled a highly durable conjugate with both a high-density accumulation and a regular array of lipase, by encapsulating it in mesoporous silica (FSM) with alkyltrimethylammonium (CTAB) chains on the surface. The activity for hydrolyzing esters of the lipase immobilized in mesoporous silica was linearly related to the concentration of lipase, whereas that of non-immobilized lipase showed saturation due to self-aggregation at a high concentration. The lipase conjugate also had increased resistance to heating when stayed in the silica coupling with CTAB.