In Vitro Antioxidant And Anti-inflammatory Properties Of Selenium-doped Carbon Quantum Dots

Background and Objective:Periodontitis is a chronic inflammatory disease caused by plaque that can result in loss of soft tissue attachment and progressive alveolar bone resorption,ultimately leading to loosening and loss of teeth.Selenium is a multipotent biotrophic with anti-inflammatory,antioxidant,immunomodulatory,and bone-enhancing functions,however,its low solubility,poor biocompatibility,narrow therapeutic window,and high cytotoxicity limit its application.Carbon quantum dots are novel carbon-based nanomaterials with the advantages of simple synthesis,high biocompatibility,good water solubility,and easy modification.Selenium-doped carbon quantum dots（SeCQDs）are expected to be safe and versatile selenium nanomaterials for dental applications.This study aimed to explore the in vitro antioxidant and anti-inflammatory effects of SeCQDs and to find a promising new drug for the treatment of periodontitis.Methods:SeCQDs were synthesized via the hydrothermal treatment of L-selenocysteine.Transmission electron microscopy and dynamic light scattering were applied to observe the size,morphology,and potential of SeCQDs;X-ray photoelectron spectroscopy was used to obtain the elemental composition and content of SeCQDs;UV-Vis absorption spectra of SeCQDs were examined using UV-Vis spectroscopy;fluorescence properties of SeCQDs were studied using fluorescence spectroscopy.The biosafety of SeCQDs on MC3T3-E1 cells and RAW264.7 cells were analyzed by CCK-8 assay.The antioxidant effect was detected by DCFH-DA fluorescence staining,cell proliferation,and SOD activity assay in the model of H₂O₂-induced MC3T3-E1oxidative injury.Under osteogenic induction and H₂O₂ damage conditions,osteogenic properties were analyzed by ALP staining and q PCR to determine the gene levels of osteoblast differentiation markers,including Runx2,OPN,and OPN.Macrophage inflammation was stimulated by P.gingivalis-LPS.Gene expression levels of pro-inflammatory cytokines such as TNF-α,IL-1β,IL-6,and i NOS were detected by q PCR.TNF-αprotein response levels were measured by ELISA.NO levels were measured by nitrate reductase assay and intracellular ROS levels were analyzed by DCFH-DA fluorescent staining.Results:SeCQDs were easily synthesized via the hydrothermal treatment of L-selenocysteine.CCK-8 assay suggested that SeCQDs had a low-toxic and excellent biocompatibility.DCFH-DA fluorescence staining,cell proliferation,and SOD activity assay showed that SeCQDs exhibit a promising potential in scavenging ROS in the model of H₂O₂-induced MC3T3-E1 cells.ALP staining,as well as multiple osteoblast differentiation markers,including Runx2,OPN,and OPN,were significantly increased demonstrating that SeCQDs could rescue H₂O₂-induced osteoblasts dysfunction.Treatment of Porphyromonas gingivalis lipopolysaccharide-induced RAW264.7 cells with SeCQDs suppressed gene and protein levels of pro-inflammatory cytokines,including TNF-α,IL-1β,IL-6,and i NOS,as well as scavenging intracellular ROS.Conclusion:SeCQDs nanoparticles were successfully synthesized by a one-step hydrothermal method.50～200μg/m L of SeCQDs have good biological compatibility and can exert antioxidant and anti-inflammatory functions as potential drugs for the treatment of periodontitis.