Background: Nowadays, a new technique such as photodynamic therapy (PDT) is used to achieve effective root canal disinfection
and eliminate Enterococcus faecalis as the most prevalent species associated with secondary endodontic infections and treatment
failures. Employment of an optimized nontoxic photosensitizer (PS) such as indocyanine green (ICG) is a crucial part of this technique;
the current study aimed at improving ICG photodynamic properties through conjugation of ICG into nano-graphene oxide
(nGO) as a new PS, to evaluate the antimicrobial effects of nGO/ICG against E. faecalis.
Methods: The nGO was synthesized based on the modified Hummer method and then, direct loading of ICG onto its surface. The
nGO formation was evaluated using the scanning electron microscope (SEM). The antimicrobial effect of nGO/ICG-PDT against E.
faecalis was assessed by counting colony forming units (CFUs).
Results and Conclusion: The SEM analysis confirmed successful synthesis of nGO. The nGO/ICG-PDT at an incorporated concentration
of 400 µg/mL ICG with irradiation at an energy density of 31.2 J/cm2
showed significant reduction in the number of E. faecalis
higher than PDT based on ICG (1000 µg/mL) (P < 0.05). Since nGO-ICG-PDT showed a significant reduction in the count of E. faecalis
at low concentration of ICG (400 µg/mL), it could be proposed as a new approach to treat endodontic infections, alone or in
combination with conventional root canal treatment.