Lab-on-a-Chip for Periodontal Disease

From the researchers at Sandia National Lab comes a novel microfluidic immunoassay device:

According to a paper in the March 27 issue of PNAS (The Proceedings of the National Academy of Sciences), a recently completed pilot study conducted with the University of Michigan shows that a Sandia National Laboratories handheld device determined in minutes — from a tiny sample of saliva alone — not only if a patient has gum disease but quantitatively how advanced the disease is…
Using a disposable lab-on-a-chip cartridge, the device makes use of a molecular sieve made out of a polyacrylamide gel. The location of the sieve in the microfluidic chips is determined using photo-lithographical methods adapted from the semiconductor industry. The gel is porous, with very small openings. A low electrical current (measured in micro-amps) is passed through the gel and a process called electrophoresis moves charged proteins through it. The gel has a gelatin-like consistency and, by permitting the easy passage of smaller molecules and slowing the passage of larger ones, quickly separates proteins contained in the saliva. Prior to this separation, the proteins are brought into contact with specific antibodies chosen on their ability to bind to the biomarkers. The antibodies are pre-labeled with fluorescent molecules attached to them. Interrogation by laser of these combined molecules — fluorescent antibody and fluorescent antibody bound to the biomarker — determines the amount of biomarker present, indicating the degree of periodontitis.

Press release: Sandia handheld instrument assesses dental disease in minutes …
Paper: Microfluidic immunoassays as rapid saliva-based clinical diagnostics [PNAS]