Related Experiment Video
Updated: Jul 15, 2025
Concurrent Quantification of Cellular and Extracellular Components of Biofilms
Published on: December 10, 2013
Effects of DJK-5 and chlorhexidine on exopolysaccharide volume and pH in oral biofilms
Binwen Chen1,2, He Liu2, Zhejun Wang2
1Department of Stomatology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei Province, China.
Background:
Exopolysaccharides (EPS) are essential constituents of the extracellular matrix within oral biofilms and are significantly influenced by the local microenvironment. This study aimed to investigate the impact of two distinct antimicrobial agents, DJK-5 and chlorhexidine (CHX), on the EPS volume and pH levels in oral biofilms.
Methods:
Oral biofilms obtained from two donors were cultured on hydroxyapatite discs for durations of 3 days, 1 week, 2 weeks, 3 weeks, and 4 weeks. Subsequently, these biofilms were subjected to treatment with 10 µg/mL DJK-5 or 2% CHX for 3 min. The impact of these antimicrobial treatments on factors such as the proportion of dead bacterial, in situ pH, and EPS volume within the biofilms was assessed using corresponding fluorescent probes. The examination was carried out utilizing confocal laser scanning microscopy, and the resulting images were analyzed with a focus on the upper and lower layers of the biofilm, respectively.
Results:
DJK-5 exhibited a more potent bactericidal effect compared to CHX across the 3-day to 4-week duration of the biofilm (P < 0.05). The biofilms were acidic, with the upper layer being less acidic than the lower layer (P < 0.05). Both antimicrobial agents increased the pH, but DJK-5 had a greater effect than CHX (P < 0.05). The volume of EPS was significantly lower in DJK-5 treated biofilms compared to that of CHX, regardless of age or layer (P < 0.05).
Conclusion:
DJK-5 exhibited superior effectiveness in reducing viable bacteria and EPS volume, as well as in raising extracellular pH, as compared to chlorhexidine.
