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.
Because the fluid sample becomes integrated with the simple LEDs and microelectronics, the researchers call the new device design the Integrascope.
Garcia and Schneider have built several laboratory prototype devices based on the design and have demonstrated how the device can be used to measure C Reactive Protein in human serum, which is an indicator of a variety of inflammatory conditions when the protein is present at high levels.
High levels of protein can indicate cell and tissue damage, inflammation, disruption in kidney function, or an immune system that is pumping out antibodies due to an infection or autoimmune disease. Low protein levels can indicate malnutrition or the presence of diseases that prevent the body from producing sufficient blood protein.
The device also can be used to provide an indication of overall health by measuring total protein in human serum, saliva and urine.
Development of the device was sparked during Schneider's studies for his doctoral degree, as he experimented with shining an LED on a drop of liquid resting on a superhydrophobic surface. He was trying to see if he could detect changes in light transmission that would tell whether a protein was present in the liquid.
"To our surprise," Garcia said
|Contact: Joe Kullman|
Arizona State University