Influence of the iodine content of nitrogen- and iodine-doped carbon dots as a peroxidase mimetic nanozyme exhibiting antifungal activity against C. albicans

Nitrogen- and iodine-doped carbon dots (I-CDs) were synthesized as peroxidase mimics for the antifungal disinfection of Candida albicans ( C. albicans ). The prepared I-CDs samples exhibited peroxidase-like activity in the presence of exogenous H 2 O 2 . The peroxidase-like activities and antifungal effects of the I-CDs samples were enhanced by increasing their iodine content from 0.1599 g to 0.4796 g. The antifungal activity of the I-CDs (i.e., 2.72 mg/mL) against C. albicans reached > 90% in the presence of exogenous H 2 O 2 (0.5 mM) under visible light irradiation for 120 min. The in vitro experimental results showed the excellent photocatalytic antifungal activity of the designed system against C. albicans . It was theorized that this system promotes the formation of reactive oxygen species, including hydroxyl radicals (·OH), which can successfully inhibit the growth of C. albicans . The antifungal effect of the synergistic I-CDs/H 2 O 2 system on C. albicans could be attributed to the combined effects of its peroxidase-like and photocatalytic activities; the increased activities appeared to be closely related to the iodine content. The results of the present study are expected to broaden the biological applications of the I-CDs and elucidate the relationship between the iodine content and peroxidase-like enzymatic and antifungal activities of the I-CDs.