Accoustic Wave Sample Prep:

Further information:
Accoustic Wave Sample Prep

Bead-Based Sensors:
Magnetic microspheres impregnated with chromophoric dyes or Quantum Dots (QD) could be used to develop sensitive tests for chem-bio-threat agents (CB-Agent). Sensor development is further facilitated through the specific and very high affinity (Kd = 10-15M) interaction between streptavidin and biotin. A variety of magnetic microspheres (mbeads) may be impregnated with QD or dyes for barcoding. The surface of the microspheres are functionalized with streptavidin protein. Biotinylated antibodies to various chem-bio-threat agents may then be stably anchored to the mbeads. A complete "sandwich" is generated when the CB-Agent binds to the antibody followed by the binding of a second antibody that has an optical signature. The ratio of the optical signature (fluorescence, chemiluminescence or absorption) in the presence and absence of the CB-Agent is an indicator for a particular agent. Multiple antibodies anchoring to the same mbead or mixing mbeads containing several different antibodies directed toward various CB-Agents and internal barcoding confers multiplexing capabilities.

Further information:
Magnetic and Optically Active Microspheres

Cell-Based Sensors:
The goal of this project is the development of genetically tailored cells and bio-compatible self-assembly approaches enabling whole cell sensors in patterned fluidic architectures for chemical and biological sensing. Combining genetics and molecular biology techniques, we have designed three reporter: promoter constructs that are integrated directly into the yeast chromosome that produce green, cyan, and red fluorescent protein in response to cholera toxin exposure. In addition, hyperspectral imaging was used to determine if we could spectrally resolve the fluorescence response from more than one cell line. Three strains of the genetically modified yeast cell lines expressing green, cyan, and yellow fluorescent protein were mixed and successfully imaged. These images show the ability of multivariate data analysis to generate auto fluorescence-free images of live cells and interrogate multicolor fluorescence protein species which can be used as probes to identify a number of chem, bio, and nuclear signatures.

Further information:
Cell-Based Sensors

Deoxyribozyme Detection:

Further information:
Deoxyribozyme Detection

Further information:
Electrocatalytic Nanoparticles

Further information:
Electrochemical Biosensor Arrays

Electroneedles:
In medical diagnostics, quick, precise, and accurate results are desirable for point of care use. Sandia National Laboratories' ElectroNeedles (R) proved a platform capable of detecting up to 50 individual analytes real-time and in-vivo with out pain to the patient.

Further information:
ElectroNeedles

Fluorescence Detection:
Geometries of nature are the subject of intense interest to chemists, biologists, physicists and mathematicians. Examples of natural geometries are found in living organisms (sea shells, for example) and among molecular components. Supra-molecular self-assembled aggregates yield interesting geometries through a collection of molecules held together by non-covalent bonds such as electrostatic forces, hydrogen bonding, or hydrophobic interactions, to provide homogeneous or heterogeneous assemblies. Certain cyanine dyes form molecular aggregates that are either the J- or H-type depending on their chemistry and sample milieu. H-aggregates have a blue-shifted absorption band, relative to the monomeric dye absorption wavelength. J-aggregates have a narrower, red-shifted absorption band, compared to the monomer; J-aggregates display sharp, intense fluorescence emission. Spectral properties of J- and H-aggregates make them attractive candidates for developing a variety of chem-bio-sensing applications.

Further information:
Supramolecular Self-Assembly

Photonic Biosensors:
In this project, we combine bio-assay technologies with Sandia's own state-of-art photonics technologies to develop a compact, planar, arrayable, optically based biosensor with unprecedented sensitivity. The sensor devices, fabricated in Sandia's Microelectronics Development Laboratory, employ guided wave structures enhanced by the addition of ring-resonators. Overall sensitivity is further enhanced by using gold or quantum dot nanoparticles as the attached optical reporter tags to amplify the optical response, with a goal of being able to detect as little as one bound DNA strand.

Further information:
Photonic Biosensors

SH-SAW Biosensors:
A particular class of acoustic wave devices, known as shear horizontal surface acoustic wave (SH-SAW) sensors, is well suited for the detection of biological agents in liquid environments. These devices have the dual advantages of high sensitivity, down to picograms/cm2, and high specificity, conferred by biological receptors such as antibodies, peptides, and nucleic acids. We have demonstrated the detection of bacteria, viral particles, and proteins with these sensors. Handheld biodetection systems incorporating these microsensors are under development.

Further information:
SH-SAW Biosensors