Water-Repellent Surface, LEDs, and Nanoparticles Combine for Rapid Microbe, Protein Detection

Researchers at Arizona State University have created a device called Integrascope that can supposedly make detection of infectious diseases and measurement of protein levels cheaper and faster. The system uses a water-repellent surface to form blood into a properly shaped drop that can focus infrared light shone through it. Nanoparticles placed on top of the drop agglutinate in the presence of infectious agents or specific proteins.
Details from an ASU press release:

Garcia and Schneider [Antonia Garcia and John Schneider, lead authors of the study] have demonstrated that superhydrophobic surfaces can shape blood, saliva, urine and other fluids into round drops. The drops can focus light and quickly mix and move microparticles and nanopartices that can be examined to reveal a specific infectious agent or protein.
Superhydrophobicity is a property of materials that repel water, such as ducks’ feather or leaves of the lotus plant. Such materials are used commercially in textiles, building materials and surface coatings.
The new device operates by placing a drop of nanoparticles or microparticles on top of a drop of a patient fluid sample on a superhydrophobic surface. The surface has a small depression that holds the liquid sample in place so that it forms a spherical drop.
The drop acts as a lens due to surface tension. An LED is shined on the drop and the drop shape focuses the light into an intense beam measured by a second LED.
Because the drop is slowly evaporating, Garcia explains, nanoparticles or microparticles quickly begin to stick together when the patient fluid sample contains the infectious agent or protein being targeted. The infectious agent or protein migrates to the center of the drop, leaving the particles that have not yet stuck together to move to the surface.
This leads to the self-mixing action that speeds up the diagnostic process so that detection can occur in less than two minutes, he said.

Press release: Bioengineering design makes health diagnosis simpler, quicker…
Abstract in Nature Precedings: Rapid antigen detection using the liquid sample as a lens and self-mixer for light scattering detection