Evaluation of PDA‑PLL Nanoparticles for siRNA Delivery and ROS Scavenging in Rat Osteoarthritis

Hao Hu,1,2,* Guiju Chen,3,* Yang Hu,1,* Nannan Ding,3,* Guorui Jin,2 Hui Xing,4,5 Wenming Tao11Department of Orthopedics, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei, People’s Republic of China; 2The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Bioinspired Engineering and Biomechanics Center (BEBC), School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, People’s Republic of China; 3Department of Pharmacy, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei, People’s Republic of China; 4Department of Obstetrics and Gynecology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei, People’s Republic of China; 5Hospital Administration Office, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei, People’s Republic of China*These authors contributed equally to this workCorrespondence: Wenming Tao, Email wenmingtao100@163.com Hui Xing, Email huixing1969@163.comIntroduction: Osteoarthritis (OA) is a prevalent chronic inflammatory disease in which elevated TNF-α and excessive reactive oxygen species (ROS) play central roles. These two pathological factors mutually reinforce each other—TNF-α induces ROS production while ROS upregulates TNF-α expression—forming a vicious cycle that propels disease progression. However, current therapies offer only symptomatic relief without halting this process. To address this, we developed polydopamine-poly(L-lysine) (PDA-PLL) nanoparticles as a dual-functional platform that combines PDA-mediated ROS scavenging with PLL-facilitated TNF-α siRNA delivery.Methods: PDA-PLL nanoparticles were synthesized and systematically characterized, and then their gene transfection efficiency and ROS scavenging capacity were evaluated. Finally, their therapeutic efficacy against OA was assessed in chondrocytes and in animal models.Results: Biocompatibility was evidenced by low in-vitro cytotoxicity and the absence of systemic toxicity in rats by hematology, biochemistry, and histopathology. Agarose gel electrophoresis demonstrated their strong nucleic acid loading capability, and fluorescence imaging further revealed that PDA-PLL nanoparticles enabled highly efficient gene transfection in OA chondrocytes. PDA-PLL nanoparticles exhibited dose-dependent scavenging of O2•−, •OH, and H2O2 in cell-free assays and lowered intracellular ROS in OA chondrocytes; critically, co-delivery of TNF-α siRNA further reduced ROS versus PDA-PLL alone. Consistent with these findings, the PDA-PLL+TNF-α siRNA group showed stronger suppression of inflammatory genes, greater restoration of matrix-preserving genes, and enhanced cytoprotection compared with PDA-PLL alone. In rat OA, PDA-PLL+siRNA outperformed PDA-PLL alone, with macroscopic and histological outcomes approaching the sham group.Conclusion: This work presents PDA-PLL nanoparticles as a multifunctional therapeutic system that unites efficient gene delivery with potent ROS scavenging. Their synergistic action resulted in significant protection of chondrocytes and potent therapeutic efficacy in OA models.Keywords: osteoarthritis, reactive oxygen species, gene delivery, TNF-α siRNA, nanoparticle