Development of Magnetorotation as a Signal Transduction Method for Protein Detection.

[摘要] The concentration of protein biomarkers in the bloodstream can be an effective indicator of disease processes. Rapid, simple, portable and inexpensive diagnostic devices can improve healthcare by increasing access to protein-based diagnostic technologies, shifting them from centralized laboratories to decentralized point-of-care locations. This dissertation describes the development of two signal transductions methods, Label-Acquired Magnetorotation (LAM), and its successor, Bead Assembly Magnetorotation (BAM) as a magnetic bead-based signal transduction mechanism for decentralized protein diagnostic applications. LAM and BAM use the concentration of the target protein to mediate the formation of a magnetic bead assembly. LAM is performed by taking 1 μm magnetic beads and 10 μm nonmagnetic spheres, functionalizing them with affinity molecules against the target protein, mixing them with a solution containing the protein, and then allowing the protein to mediate the attachment of the 1 μm magnetic beads to the 10 μm nonmagnetic spheres. In an asynchronously rotating magnetic field, the rotational frequency of the nonmagnetic sphere depends on the number of attached magnetic beads, which depends on the concentration of the protein. BAM is performed by taking the same functionalized 1 μm magnetic beads, mixing them with a solution containing the protein, and then plating 1 μL inverted droplets of the solution on a Teflon-coated slide. As the beads fall through the solution to the bottom of the droplet, the protein mediates the formation of the beads into an assembly. In the case of high protein concentration, the beads form a loosely-packed assembly. In the case of no or low protein concentration, and the beads form a tightly-packed assembly. In an asynchronously rotating magnetic field, the rotational period of the assembly will depend on its packing density, which depends on the concentration of the protein. This thesis discusses the development of LAM and BAM, where BAM yields one of the lowest limits of detection ever reported for the protein thrombin. Additionally, it discusses the development of a portable laser-and-photodiode diagnostic platform prototype, as well as attempts to translate BAM into serum. A separate project shows the use of aptamers as affinity molecules for a gel electrophoresis platform.

[发布机构] University of Michigan

[效力级别] Biomedical Engineering

[关键词] Bead Assembly Magnetorotation;Biomedical Engineering;Engineering;Biomedical Engineering