A Novel Synergistic Carvacrol-Graphene Oxide-Chitosan Nanocomposite for Effective Root Canal Disinfection

Persistent microorganisms such as Enterococcus faecalis and Candida albicans remain within complex root canal microanatomy and biofilms, compromising disinfection and leading to endodontic failure. This study aimed to develop and characterize a carvacrol (CV)-graphene oxide (GO)-chitosan (CV@GO-CS) nanocomposite with potential application in root canal disinfection.

The CV@GO-CS nanocomposite was synthesized and evaluated for physicochemical properties, encapsulation efficiency (EE%), and release kinetics. Cytocompatibility was assessed using L929 fibroblast viability assays, and cell migration was evaluated by scratch tests. Antimicrobial efficacy was determined against E. faecalis and C. albicans through MIC/MBC and MIC/MFC measurements and checkerboard synergy assays.

CV@GO-CS exhibited a hydrodynamic diameter of ~190 nm (polydispersity index [PDI] 0.24) and a zeta potential of + 22.3 mV. EE% and loading capacity (LC%) were 88.6% ± 3.6% and 46.9% ± 0.9%, respectively. CV release followed a biphasic profile, with ~45% released at 24 h and ~82% at 96 h. At a concentration of 50 µg/mL-which exceeds the determined minimum bactericidal/fungicidal concentrations-L929 fibroblast viability exceeded 95%, and wound closure was significantly enhanced compared with controls. Antimicrobial testing showed MIC/MBC values of 25 μg/mL against E. faecalis and MIC/MFC values of complete inhibition of C. albicans at 10 μg/mL.

The CV@GO-CS nanocomposite demonstrated favorable physicochemical characteristics, high cytocompatibility, and strong antimicrobial activity against key endodontic pathogens. These findings support its potential as a sustainable, biocompatible platform for sustained-release root canal disinfectants or intracanal medicaments; however, efficacy against endodontic biofilms remains to be established, and further preclinical evaluation in biofilm and ex vivo models is warranted.