We tested the long-standing hypothesis that synaptotagmin 1 is the Ca2+ sensor for fast neurosecretion by analyzing the intracellular Ca2+ dependence of large dense-core vesicle exocytosis in a mouse strain carrying a mutated synaptotagmin C2A domain. The mutation (R233Q) causes a twofold increase in the KD of Ca2+-dependent phospholipid binding to the double C2A-C2B domain of synaptotagmin. Us...

Utilizing a simple fluidic structure, we demonstrate the improved performance of oxidase-based enzymatic biosensors. Electrolysis of water is utilized to generate bubbles to manipulate the oxygen microenvironment close to the biosensor in a fluidic channel. For the proper enzyme reactions to occur, a simple mechanical procedure of manipulating bubbles was developed to maximize the oxygen level ...

An amperometric acetone sensor was developed by using an electrodeposited Pb electrode in a sodium tartrate electrolyte. The major factors determining the electrode and sensing characteristics such as the applied potential, electrodeposition current density, electrodeposition temperature, agitation rate, and sensing temperature were explored. The best conditions for preparation of the electrode...

Amine oxidase (EC 1.4.3.6) was purified from pea (Pisum sativum) seedlings with the aim of characterizing its catalytic properties. The specific activity and selectivity of the enzyme were studied with an oxygen sensor by following the kinetics of the amine oxidation reaction, catalysed by the enzyme. The enzyme catalytic constants were calculated from the transient signal of the oxygen sensor ...

A systematic study was carried out to investigate the effect of ionic liquid in solid polymer electrolyte (SPE) and its layer morphology on the characteristics of an electrochemical amperometric nitrogen dioxide sensor. Five different ionic liquids were immobilized into a solid polymer electrolyte and key sensor parameters (sensitivity, response/recovery times, hysteresis and limit of detection...

Methylamine dehydrogenase (MADH) may be immobilized in a polypyrrole (PPy) film on an electrode surface and used as an amperometric sensor for the determination of histamine. Using site-directed mutagenesis, phenylalanine 55 on the alpha subunit of MADH was converted to alanine. This alphaF55A MADH exhibits a 400-fold lower Km value for histamine than does native MADH when assayed in solution. ...

A soft contact-lens amperometric glucose sensor as novel non-invasive device of body sensor network was fabricated and tested. Also, the sensor was utilized to tear glucose monitoring. The sensor was constructed by immobilizing GOD onto a flexible oxygen electrode, which was fabricated using “Soft-MEMS” techniques onto a functional polymer membrane. In purpose of bioinstrumentation, adhesive ag...