Aluminum surface corrosion and the mechanism of inhibitors using pH and metal ion selective imaging fiber bundles.
AuthorsSzunerits S, Walt DR
JournalAnal Chem
PubMed ID11866069
The localized corrosion behavior of a galvanic aluminum copper couple was investigated by in situ fluorescence imaging with a fiber-optic imaging sensor. Three different, but complementary methods were used for visualizing remote corrosion sites, mapping the topography of the metal surface, and measuring local chemical concentrations of H+, OH-, and ... More
Poly(ethylene glycol) hydrogel-encapsulated fluorophore-enzyme conjugates for direct detection of organophosphorus neurotoxins.
AuthorsRussell RJ, Pishko MV, Simonian AL, Wild JR
JournalAnal Chem
PubMed ID10565282
'A simple approach is described for preparing poly-(ethylene glycol) hydrogel materials with encapsulated seminapthofluorescein (SNAFL)-organophosphorus hydrolase enzyme conjugates. Direct determination of enzyme-catalyzed neurotoxin hydrolysis is provided by the self-referencing, pH-sensitive dye SNAFL-1, whose emission spectrum changes at lambda = 550 in response to pH. Using spectrofluorimetry and paraoxon as a ... More
Combined imaging and chemical sensing of fertilization-induced acid release from single sea urchin eggs.
AuthorsMichael KL, Walt DR
JournalAnal Biochem
PubMed ID10469487
We demonstrate a microarray sensor capable of obtaining both chemical and visual information on multiple cells simultaneously with single-cell resolution. The array was fabricated by covalently immobilizing a thin, pH-sensitive polymer layer on the distal end of an optical imaging fiber. The sensor's ability to measure localized chemical dynamics in ... More
A novel fiber-optic pH sensor incorporating carboxy SNAFL-2 and fluorescent wavelength-ratiometric detection.
AuthorsXu Z, Rollins A, Alcala R, Marchant RE
JournalJ Biomed Mater Res
PubMed ID9429091
A fiber-optic pH sensor was prepared using the self-referencing fluorescent pH probe carboxy seminaphtho-fluorescein (SNAFL-2). The ratio of the emission from the base form of this dye and the emission near the isoemissive point is insensitive to variations in the excitation intensity and photobleaching. The carboxy SNAFL-2 and a photoaffinity ... More
Combined imaging and chemical sensing of L-glutamate release from the foregut plexus of the lepidopteran, Manduca sexta.
AuthorsIssberner JP, Schauer CL, Trimmer BA, Walt DR
JournalJ Neurosci Methods
PubMed ID12351201
A new combined imaging and chemical detection sensor for the measurement of localized L-glutamate release at the insect neuromuscular junction (NMJ) is presented. The sensor is comprised of an L-glutamate-sensitive fluorescent gel, spin-coated onto the tip of an optical imaging fiber. The gel is composed of L-glutamate oxidase (GLOD); a ... More
Chlamydia trachomatis serovar L2 is an obligate intracellular bacterium which is internalized in target epithelial cells by endocytosis and resides within a membrane-bound vesicle. Over the next several hours following entry, individual serovar L2-containing vesicles fuse with one another to form a single membrane-bound vesicle (or inclusion) within which the ... More
Hydrogel-based microreactors as a functional component of microfluidic systems.
AuthorsZhan W, Seong GH, Crooks RM
JournalAnal Chem
PubMed ID12349966
A simple two-step method for fabricating poly(ethylene glycol) (PEG) hydrogel-based microreactors and microsensors within microfluidic channels is described. The intrachannel micropatches contain either a dye, which can report the pH of a solution within a fluidic channel, or enzymes that are able to selectively catalyze specific reactions. Analytes present within ... More
Fluoresceinyl-ethylenediamine-ouabain detects an acidic environment in the cardiac glycoside binding site of Na+/K+-ATPase.
AuthorsBrinkmann K, Linnertz H, Amler E, Lanz E, Herman P, Schoner W
JournalEur J Biochem
PubMed ID9363783
To probe the pH value in the microenvironment of the cardiac glycoside-binding site of Na+/K+-ATPase, pH-sensitive fluorescent derivatives of ouabain were synthesized. The fluoresceinyl derivative of ethylenediamino-ouabain (FEDO) had a pKs of 6.0 and showed a H+-dependent fluorescence change, when its ratio of excitation at 490 nm/450 nm was recorded ... More