ROS-scavenging and antibacterial properties of polydopamine-coated, drug-loaded bovine serum albumin nanoparticles

Periodontitis is an inflammatory disease driven by dysbiotic dental plaque and is the leading cause of tooth loss in adults. We aimed to develop a reactive oxygen species (ROS)-responsive drug delivery system based on polydopamine (PDA)-functionalized bovine serum albumin (BSA) nanoparticles (NPs) for the controlled release of minocycline hydrochloride (MH) and to evaluate its synergistic antibacterial and antioxidant effects.

MH-loaded BSA NPs were prepared using a desolventization method followed by PDA coating. The resulting PDA@BSA NPs@MH were characterized in terms of size, morphology, drug loading, and release kinetics. Antibacterial activity against Porphyromonas gingivalis, Streptococcus gordonii, and Fusobacterium nucleatum was assessed using live/dead staining, colony counting, and biofilm assays. ROS-scavenging activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and intracellular ROS assays. Biocompatibility was assessed via cytotoxicity, migration, and hemolysis tests.

PDA@BSA NPs@MH exhibited a uniform spherical morphology (180-200 nm) with 5.68% drug loading. The PDA coating enabled sustained MH release and concentration-dependent DPPH scavenging. The nanoparticles demonstrated potent antibacterial activity (mortality > 77% at high concentrations) and biofilm inhibition (>96%). Intracellular ROS levels were significantly reduced in LPS-stimulated macrophages. Furthermore, no evident cytotoxicity was observed, cell migration was enhanced, and hemolysis rates were <5%.

The PDA@BSA NPs@MH platform integrates MH-mediated antibacterial activity with PDA-mediated antioxidant activity, effectively addressing both bacterial infection and oxidative stress in periodontitis.