Fluorescent Probe Detected Active P. gingivalis Enzymes in Periodontitis Plaque

Edited by Dentaltown staff

Researchers have developed a fluorescent probe that lights up in the presence of active gingipains, the enzymes that make Porphyromonas gingivalis destructive, and used it to detect those enzymes in plaque from patients with periodontitis, according to a study published online Sept. 12 in ACS Sensors.

Gingipains are cysteine proteases and the organism’s principal virulence factors. Existing methods generally establish whether P. gingivalis is present rather than whether its enzymes are actively working.

The probe, named Gingitracker, binds covalently to the cysteine residue in the gingipain active site. That binding locks the molecule into a flat configuration by restricting rotation within it, which sharply increases its fluorescence.

Selectivity was the central claim. Quantum yields reached 0.54 against one gingipain type and 0.35 against another, compared with 0.04 against mammalian calpain and 0.03 against trypsin, two control proteases.

In plaque samples from patients with periodontitis, signals from the probe correlated with independent anti-gingipain measurements at r values of 0.73 to 0.83 across separate samples.

The work was led by Hira Aziz and Sungsu Lim at the Korea Institute of Science and Technology in Seoul, with collaborators at Korea University, Seoul National University, Kyung Hee University, the Department of Periodontology at Yonsei University Dental Hospital, the University of Louisville School of Dentistry, and Jagiellonian University in Krakow. The National Research Foundation of Korea, the Ministry of Trade, Industry and Energy, and the Korea Institute of Science and Technology funded the research.

The authors describe Gingitracker as an activity-based tool for detecting gingipains in bacterial and clinical samples. It is a laboratory reagent at this stage, not a chairside diagnostic, and the plaque testing involved a limited set of samples. Validation in larger patient populations would be required before any clinical assay could follow.

Sources:
ACS Sensors, “Fluorescence Turn-On Sensor for Gingipains: Selective Detection of Porphyromonas gingivalis in Periodontal Disease,” published online Sept. 12, 2026: doi.org/10.1021/acssensors.6c02393
ACS Publications article page: pubs.acs.org/acssensors.6c02393
PubMed record, PMID 42731056: pubmed.ncbi.nlm.nih.gov/42731056