Electrochemical nanoliter vial and magnetoelastic films as sensing platforms

Sensing platforms allow the development of a wide variety of (bio)sensors. These platforms are essentially a transducer coupled with an immobilization method for integration of particular recognition moieties. Detailed in this dissertation are the fabrication and demonstration of a small volume electrochemical platform, which can be used in conjunction with various recognition systems to produce nanoliter range (bio)sensors. Also, the use of magnetoelastic transduction is explored for use as a sensing platform for electrochemical depositions and mass-changing biological reactions.; Nanoliter-range electrochemical cells have been microfabricated utilizing in tandem the techniques of screen-printing and excimer laser micromachining. Layers of conducting and insulating thick film inks are placed onto a substrate and a small vial is ablated into the layers by laser pulses to produce the nanocells. These “electrochemical nanovials” represent a versatile platform from which small volume sensing and detection systems can be developed. An example of this is the incorporation of enzymes to produce nanoliter amperometric biosensors. These biosensor can be produced either by immobilizing an enzyme in the working electrode carbon thick-film matrix or immobilization within an electropolymerized conducting polymer. To demonstrate this use of the platform, the enzyme glucose oxidase (GOx) has been used.; Magnetoelastic alloy films have been used as a working electrode in an electrochemical cell. This material allows magnetic interrogation of electrochemical deposition. Increases in pyrrole deposition were monitored by magnetoelastic transduction. This technique provides a novel approach by which one can monitor electrochemical processes. Additionally, self-assembled monolayers (SAM) of carboxylic acid-terminated alkanethiols have been attached to gold-coated magnetoelastic strip to form the basis of system for monitoring biochemical processes. The covalent linking of a β-galactosidase to the SAM was achieved via a carbodiimide linker. Taking advantage of an enzymatic reaction resulting in the precipitation of an insoluble product has also been used to demonstrate the magnetoelastic strip/SAM systems ability to determine enzyme kinetic parameters.