Overcoming Biofilm Barriers in Periodontitis: A Lectin-Targeted Conjugate for Enhanced Antimicrobial Photodynamic...

To address the limited efficacy of conventional antimicrobials against periodontal biofilms by developing a targeted antimicrobial photodynamic therapy (aPDT) platform and evaluating its activity against key periodontal pathogens.

The photosensitizer Rose Bengal was conjugated to the lectin Concanavalin A (ConA-RB). Its synthesis was spectroscopically confirmed. Antibacterial and antibiofilm activity against Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, and Prevotella intermedia was assessed following clinically relevant blue light irradiation, including bacterial uptake, viability, and membrane damage. Biocompatibility with human gingival fibroblasts was also evaluated following both short-term and prolonged exposure.

ConA-RB exhibited significantly superior antibacterial and antibiofilm activity compared to free Rose Bengal. This was attributed to an approximate 4-fold increase in bacterial uptake, mediated by specific lectin-carbohydrate recognition, leading to enhanced localized reactive oxygen species generation and profound membrane damage. ConA-RB effectively inhibited biofilm formation and significantly disrupted mature in vitro biofilms while maintaining favorable biocompatibility in tested cell models.

The ConA-RB bioconjugate is a potent, targeted, and biocompatible aPDT platform that substantially overcomes biofilm barriers. It represents a promising translational strategy for improving the clinical management of periodontitis.

By leveraging targeted photodynamic therapy, this ConA-RB platform offers a precise method to eradicate deep-seated periodontal pathogens and disrupt biofilms without inducing acute cytotoxicity in gingival tissues. This approach holds significant potential to enhance clinical outcomes in periodontitis treatment, particularly in cases resistant to conventional therapy.