Injectable sodium alginate/4-arm polyethylene glycol-lipoic acid double-network hydrogel loading Ca2+-tannic acid nanocomposite treats periodontitis via anti-bacteria, ROS scavenging and osteogenesis.

The inflammatory environment of periodontitis with bacteria, excessive reactive oxygen species (ROS) and limited regenerative capacity of alveolar bone makes reconstruction of periodontium become a huge challenge. The present strategies, such as local debridement and antibiotic injection, are difficult to solve above problems completely. Thus, to reverse the progression of the disease, Ca2+-tannic acid nanocomposites loaded into injectable sodium alginate/4-arm polyethylene glycol-lipoic acid hydrogel (CaTA@Gel) were fabricated, including Ca2+‑sodium alginate (SA) ionic crosslinking and radical polymerization of lipoic acid-modified 4-arm polyethylene glycol (PEG-SS4) under UV illumination. In our results, the double networks of hydrogel not only had good mechanical property, but also sustainedly released CaTA nanocomposites which could inhibit bacteria, scavenge ROS due to TA, and promote osteogenesis of bone mesenchymal stem cells (BMSCs) via Ca2+. The antibacterial rates of CaTA (1 mg/mL) against E. coli and S. aureus were 97.3 ± 1.25 % and 96.7 ± 2.57 %, respectively. Meanwhile, ·OH and ·O2- could be inhibited obviously by CaTA (100 μg/mL), whose inhibition rate were 59.6 ± 2.98 % and 62.4 ± 3.12 %, respectively. Finally, the up-regulation of osteogenetic genes and successful alveolar bone regeneration in rat models indicated this injectable nanocomposite hydrogel provided a promising strategy for the treatment of periodontitis.