Synthesis of antibacterial hydrogel based on PLGA - carbon dots microspheres for endodontic treatment

Objectives: Bacterial contamination in the root canals and necrotic dental pulp is known as a major cause of unsuccessfully treated teeth. The antibacterial properties of injectable hydrogel based on PLGA - carbon dots microspheres were investigated in the present study.

Methods: Carbon dots (CDs) based on ammonium hydrogen citrate was synthesized by using hydrothermal reaction. 3D flow-focusing microfluidic platforms was used for the production of poly (D, L-lactide-co-glycolide) (PLGA) - CDs microspheres. Subsequently, the produced microspheres were dispersed in 3 wt % of sodium alginate solution. This hydrogen was cast and cross-linked with the calcium chloride solution (5 wt %). The toxicity of PLGA - CDs microspheres and the hydrogen on dental pulp stem cell was studied by WST assay kit. Also, the antibacterial properties of PLGA - CDs microspheres and the hydrogen against Streptococcus mutans and Staphylococcus aureus were investigated by the minimum inhibitory concentration (MIC) and disc diffusion method (DDM) method.

Results: SEM and 3D laser microscope analysis show that monodisperse PLGA - carbon dots microspheres in a size range of 18 – 40 μm was produced by the microfluidic platforms. Rheological properties of alginate for different concentration of PLGA - CDs microspheres were also investigated. The biocompatible and nontoxic of the microspheres with a maximum dose of 5 mg/ml was proved by cell toxicity assay. 20 ng/ml and 23 ng/ml of PLGA - carbon dots microspheres were the minimum inhibitory concentration for Streptococcus mutans and Staphylococcus aureus respectively.

Conclusions: The proposed hydrogel based on PLGA - carbon dots microspheres showed an excellent potential application to be used in the endodontic treatment.