Design and characterization of novel electrochemical biosensors

Miscellaneous · Wed Jan 01 00:00:00 EST 1992

OSTI ID:7236011

Naser, N

This dissertation describes various novel approaches for fabricating fast responding, sensitive and selective biocatalytic sensors. One avenue is aimed at evaluating new plant tissues (rich with enzymatic activity in its own natural environment) within a carbon paste matrix or packed within the micropores of reticulated vitreous carbon. New self-supported open-tubular tissue bioreactors were also designed. The biocatalytic activity of these whole cells was employed for biosensing assays and for in-situ elimination of potential interferences via enzymatic consumption. Catalytic modified electrodes were developed to promote catalytic activity toward important analytes with a sluggish redox process. Such electrodes relied on the use of metal-dispersed carbon which lowered substantially the overvoltage. A new and rapid bulk modification scheme, based on incorporating the modifier within a rigid graphite-wax matrix was introduced. The new fabrication strategy was illustrated for the immobilization of electrocatalysts, enzymes and tissues. Effective organic-phase biosensors were developed and evaluated. They relied on the biocatalytic activity of Ta brockii alcohol dehydrogenase and of various plant tissues for rapid biosensing of secondary alcohols and phenolic compounds in non-aqueous media, respectively. Significant gains in the sensitivity of an alcohol sensor were obtained via biocatalytic preconcentration of intermediary products followed by a stripping measurement step. Peatmoss and Russian-thistle modified electrodes were developed for the preconcentration and quantitation of copper and gold ions from dilute solutions. These electrodes offered lower detection limits than algae-modified electrodes. Enzyme electrodes were fabricated by the physical entrapment of enzymes within a conducting polymer coating, onto band nanoelectrodes made of polyacrylonitrile films. The microdistribution of the enzyme in such coatings was investigated by scanning tunneling microscopy.

• Research Organization: New Mexico State Univ., Las Cruces, NM (United States)
• OSTI ID: 7236011
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BIOLOGICAL MATERIALS
CATALYTIC EFFECTS
BIOREACTORS
DESIGN
ELECTRODES
CHEMICAL ANALYSIS
ELECTROCATALYSTS
ELECTROCHEMISTRY
IMMOBILIZED ENZYMES
SENSITIVITY
CATALYSTS
CHEMISTRY
MATERIALS
400102* - Chemical & Spectral Procedures
400400 - Electrochemistry