As a means of reliably measuring intracellular pH, we have precisely targeted 5(and 6-) carboxyseminaphthorhodafluor to cellular subcompartments. This was accomplished by combining the well-established pH-sensitive dye with a protein-based reporter system. When expressed in cells, the reporter protein is designed to covalently bind ligands composed of a functional group and a reactive linker. I...

A novel capacitive field-effect sensor for the direct determination of organophosphorus pesticides by the enzyme organophosphorus hydrolase (OPH) is presented. The enzyme OPH hydrolyses organophosphorus compounds catalytically, thus releasing Hþ ions. By means of a silicon-based field-effect sensor, which consists of a layer sequence of Al/p-Si/SiO2 with alternative pH-sensitive materials (Ta2O...

A highly porous optical-fiber cladding was developed for evanescent-wave fiber sensors, which contains sensor molecules, maintains guiding conditions in the optical fiber, and is suitable for sensing in aqueous environments. To make the cladding material (a poly(ethylene) glycol diacrylate (PEGDA) polymer) highly porous, a microsphere templating strategy was employed. The resulting pore network...

The Field Effect sensors are broadly used for detecting various target analytes in chemical and biological solutions. We report the conditions under which the pH sensitivity of an Ion Sensitive Field Effect transistor (ISFET) sensor can be significantly enhanced. Our theory and simulations show that by using pH buffer solutions containing counter-ions that are beyond a specific size, the sensor...

The ability to accurately measure real-time pH fluctuations in-vivo could be highly advantageous. Early detection and potential prevention of bacteria colonization of surgical implants can be accomplished by monitoring associated acidosis. However, conventional glass membrane or ion-selective field-effect transistor (ISFET) pH sensing technologies both require a reference electrode which may su...

A fluorescent colorimetric pH sensor was developed by a polymerization of a monomeric fluorescein based green emitter (SM1) with a monomeric 2-dicyanomethylene-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran derived red emitter (SM2) in poly(2-hydroxyethyl methacrylate)-co-polyacrylamide (PHEMA-co-PAM) matrices. Polymerized SM1 (PSM1) in the polymer matrices showed bright emissions at basic conditions...

We report simple and effective methods to develop long-term, stable silicon nanowire-based pH sensors and systematic studies of the performance of the developed sensors. In this work, we fabricate silicon nanowire pH sensors based on top-down fabrication processes such as E-beam lithography and conventional photolithography. In order to improve the stability of the sensor performance, the senso...

For an example of a silicon-based micromachined analyzer, we describe a combined PO2, PCO2, and pH sensor designed for extracorporeal blood gas monitoring. The clinically well-accepted amperometric (PO2) and potentiometric (PCO2, pH) sensing principles are used, realized in a planar and miniaturized form on a single silicon chip (6 x 22 mm). The transducer part of the chip is fabricated by stan...

A new polyvinyl choloride (PVC) membrane sensor for cerium (III) was prepared based on 4,13-didecyl-1,7,10,16-tetraoxa-4,13-diazacyclooctadecane (kryptofix22DD) as an ionophore. The sensor exhibites a linear concentration range of 1.0×10-6 to 1.0×10-1 M, with a Nernstian slope of 18.0±1.0 mV/decade, and a detection limit of 9.7×10-7 M. It has a fast response tim...

Fault diagnosis (FD) and data fusion (DF) technologies implemented in the LabVIEW program were used for a ruthenium dioxide pH sensor array. The purpose of the fault diagnosis and data fusion technologies is to increase the reliability of measured data. Data fusion is a very useful statistical method used for sensor arrays in many fields. Fault diagnosis is used to avoid sensor faults and to me...