Treatment of acute experimental toxoplasmosis using a promising therapy: Nitrogen-doped carbon dots

Toxoplasmosis remains a severe threat to immunocompromised patients, pregnant women, and newborns. This study presents the first comprehensive evaluation of N-doped carbon dots (CDNs) as a novel therapeutic agent against acute murine toxoplasmosis together with in vivo immunological and biochemical evaluation. CDNs were prepared via green hydrothermal method using orange juice and comprehensively characterized. Their in vitro cytotoxicity and antioxidant activities were also assessed. The efficacy of CDNs was tested in male Swiss Albino mice infected with virulent Rh strain of Toxoplasma gondii. Mice received 300 mg/kg CDNs orally for six days starting 4 hours post-infection (PI). Treatment effects were evaluated through survival, parasite burden and parasite viability analyses, ultrastructural, immunological (IFN-γ, IL-10), biochemical (liver and kidney functions, oxidative stress, and apoptosis-releated markers), and histological assessments. CDNs prolonged survival of infected treated mice up to 13 days PI compared with 9 days in infected control, reduced parasite burden by 98.2% and viability by 81% and caused severe tachyzoite damage. They also restored immunological and biochemical markers. Importantly, non‑infected treated mice showed no signs of toxicity and maintained normal liver and kidney histology, emphasising safety of CDNs. This work highlights, for the first time, the potent antiparasitic efficacy and biosafety of the prepared CDNs as well as their dual redox-modulating behaviour, positioning them as promising candidates for parasitic infection management and green nanomedicine development.