Diagnostic Platform Detects Periodontal Pathogens

The diagnostic platform will allow dentists and medical laboratories to prepare samples quickly and then analyze the bacteria rapidly.

Scientists at the Fraunhofer Institute (Leipzig, Germany) have collaborated with two companies, BECIT GmbH (Bitterfeld-Wolfen, Germany) and ERT-Optik (Ludwigshafen, Germany) to develop a lab-on-a-chip module called ParoChip. All the steps in the process including the duplication of DNA sequences and their detection, take place directly on the platform, which consists of a disk-shaped microfluidic card that is around six centimeters in diameter.

Samples are taken using sterile, toothpick-shaped paper points, after which the bacteria are removed from the point and their isolated DNA injected into reaction chambers containing dried reagents. There are eleven such chambers on each card, each featuring the reagent for one of the eleven periodontal pathogens. The total number of bacteria is determined in an additional chamber, via polymerase chain reaction (PCR).

In order to generate the extremely quick changes in temperature that are required for PCR, the disk-shaped plastic chip is attached to a metal heating block with three temperature zones and mechanically turned so it passes over these zones. This causes a fluorescent signal to be generated that is measured by a connected optical measuring device featuring a fluorescence probe, a photo detector, and a laser diode. The key benefit is that the signal makes it possible not only to quantify each type of bacterium and thus determine the severity of the inflammation, but also to establish the total number of all the bacteria combined. This enables doctors to fine-tune an antibiotic treatment accordingly.

Dirk Kuhlmeier, PhD, a scientist the Fraunhofer Institute, said, "Until now, analysis took around four to six hours. With ParoChip it takes less than 30 minutes. This means it's possible to analyze a large number of samples in a short amount of time. As the connected optical measuring system allows us to quantify bacteria, ParoChip is also suited to the identification of other bacterial causes of infection, such as food-borne pathogens or those that lead to sepsis." Already available as a prototype, ParoChip is initially intended for use in clinical laboratories.

Related Links:
Fraunhofer Institute
BECIT GmbH
ERT-Optik