An antigen-targeting assay for Lyme disease: Combining aptamers and SERS to detect the OspA protein.

Lyme disease is the fastest growing vector-borne disease in the United States. However, current testing modalities are ill suited to detection of Lyme disease, leading to the diagnosis of many cases after treatment is effective. We present an improved, direct method Lyme disease diagnosis, where the Lyme specific biomarker Outer Surface Protein A (OspA) in clinical serum samples is identified using a diagnostic platform combining surface enhanced Raman scattering (SERS) and aptamers.

Improved cell sensitivity and longevity in a rapid impedance-based toxicity sensor.

A number of toxicity sensors for testing field water using a range of eukaryotic cell types have been proposed, but it has been difficult to identify sensors with both appropriate sensitivity to toxicants and the potential for long-term viability. Assessment of bovine pulmonary artery endothelial cell (BPAEC) monolayer electrical impedance with electric cell-substrate impedance sensing (ECIS) showed promise in a previous systematic evaluation of toxicity sensor technologies. The goal of the study reported here was to improve toxicant responsiveness and field portability of this cell-based toxicity sensor.

Prolonged stochastic single ion channel recordings in S-layer protein stabilized lipid bilayer membranes.

S-layer proteins are commonly found in bacteria and archaea as two-dimensional monomolecular crystalline arrays as the outermost cell membrane component. These proteins have the unique property that following disruption by chemical agents, monomers of the protein can re-assemble to their original lattice structure. This unique property makes S-layers interesting for utilization in bio-nanotechnological applications.

Development of a mast cell-based biosensor.

A mast cell-based biosensor has been developed to enable the use of these cells in numerous applications including pharmaceutical screening, environmental monitoring, clinical diagnosis and homeland security. Rat basophilic leukemia (RBL) mast cells offer excellent potential for biosensor applications because they are robust and undergo a dramatic exocytotic response within minutes of antigen addition. To monitor mast cell activation, fluorescent dyes were loaded into the cells and used as indicators of alkalinization of secretory granules, calcium fluxes or generation of reactive oxygen species.

Detection of single bacterial pathogens with semiconductor quantum dots.

Semiconductor quantum dots (QDs) have been used in a simple fluorometric assay to detect single cells of the pathogenic Escherichia coli O157:H7 serotype. Composed of CdSe/ZnS core/shell QDs conjugated to streptavidin, this system exhibits 2 orders of magnitude more sensitivity than a similar assay using a common organic dye. Selectivity for this pathogenic bacterial strain over a common lab strain (E.

In situ measurement of degranulation as a biosensor based on RBL-2H3 mast cells.

A direct degranulation assay has been developed to enable the use of RBL mast cells as a biosensor for screening chemical libraries for drug discovery and environmental toxicity evaluation. Release of beta-hexosaminidase into the extracellular milleu is widely used to characterize cellular components and mechanisms involved in stimulated exocytosis, including those initiated by crosslinking of IgE receptors on mast cells. To adapt this versatile assay for high throughput screening, we developed a direct, in situ method in which beta-hexosaminidase detection is carried out in a single step, convenient for multi-sample processing and thus for biosensor applications.