Mussel-inspired nanocellulose scaffold for antibacterial and anti-inflammatory coating for clear aligners

Aesthetic demands in contemporary dentistry have driven the widespread adoption of clear aligners (CAs), yet their polymeric substrates lack intrinsic antibacterial and anti-inflammatory functionality, predisposing the periodontium to inflammation during prolonged wear. Here, we present a multifunctional surface coating for PETG-based CAs, comprising dopamine-grafted TEMPO-oxidized bacterial cellulose nanofibers (TOBC-DA), curcumin (Cur), and polyvinyl alcohol (PVA), applied via a facile spin-coating process. TOBC-DA serves as a bioadhesive matrix that forms a robust, long-lasting bond with PETG while maintaining chemical stability in simulated oral conditions. Incorporation of Cur endows the coating with potent antibacterial and anti-inflammatory activity, and PVA enhances Cur solubility to ensure uniform film formation. The resulting composite layer-measuring under 5 μm in thickness-preserves the optical transparency, dimensional fidelity, and mechanical integrity of PETG. Structurally, the cross-linked TOBC-DA network and PVA backbone confer enhanced wear resistance and fracture resistance without compromising flexibility. Functionally, the hydrophilic surface repels early colonizers such as P. gingivalis, while sustained Cur release disrupts bacterial cell membranes and downregulates pro-inflammatory mediators (IL-6, TNF-α, MMP-9) in periodontal tissues. This work demonstrates a clinically translatable coating strategy that integrates aesthetic preservation with active periodontal protection, offering a promising route to improve oral health outcomes during CAs therapy.