Arizona State University researchers have demonstrated a way to dramatically simplify testing patients for infectious diseases and unhealthy protein levels. Testing instrumentation developed by Antonia Garcia, a professor in the School of Biological and Health Systems Engineering, and John Schneider, a bioengineering graduate student researcher, promises to make the procedure less costly and produce results in less time. Current testing is slow and expensive because of the complications of working with blood, saliva, urine, and other biological fluids, said Garcia. The new method uses common light-emitting diodes (LEDs) and simple microeletronic amplifiers rather than more technologically intensive and costly lasers and robotics.
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 (water-repellent) surface. The surface has a depression that holds the liquid sample in place so that it forms a spherical drop, which 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.
Click here for the full story .
