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Biodegradable two-dimensional nanomaterials could be a significant breakthrough in the field of oncology nanotheranostic agents, which are rapidly emerging as promising candidates for tumor theranostic applications. Herein, a novel biodegradable ferrous sulfide nanosheet (FeS NS) is developed. Compared to the traditional photothermal material, black phosphorus nanosheet (BP NS), FeS demonstrates superior degradability and enhanced photothermal performance, and making it ideal for efficient photothermal therapy (PTT) of tumors. In the acidic tumor microenvironment, FeS degrades and releases H2S, which inhibits mitochondrial respiration and ATP production. This process leads to a reduction in heat shock protein expression, lowering the resistance of tumor cells to photothermal stimulation, and improving the efficacy of PTT. The released Fe2+ exhibits efficient peroxidase activity, triggering ferroptosis in tumor cells. Furthermore, due to its superparamagnetic nature, FeS NSs could accumulate at the tumor site and provide a strong magnetic resonance imaging (MRI) signal for imaging-guided tumor therapy. Overall, as a promising alternative to BP, the FeS NSs are a potentially innovative nanotheranostic agent of tumors, offering a synergistic approach to ferroptosis−PTT with MRI guidance.

Exposure to airborne particulate matter (PM) is a major risk which increases pulmonary diseases such as asthma, chronic bronchitis, or chronic obstructive pulmonary disease (COPD). PM is a complex mixture with physiochemical properties that can vary over time and space, presenting a challenge when attempting to analyze their health risks. In this study, we compared two kinds of commercial PM with real PM to explore an index which takes account of both the diverse physicochemical properties of PM and accurate prediction of their toxicities. Our results indicated that the oxidative potential (OP) of PM significantly affects their cytotoxicity. In comparison to two kinds of commercial PM such as carbon black and SRM-1648a, real ambient PM2.5 induced more significant oxidative stress and ferroptosis, which was closely associated with its higher OP. Notably, the use of radical scavengers like vitamin C and coumarin decreased the OP of PM2.5 effectively, thereby leading to a decrease in its cytotoxic effects. Furthermore, the reduction of OP reversed redox imbalance and alleviated lung damage in vivo. This study provides additional insights into the structure-activity relationship for PM’s toxicity. It also sheds light on further investigations on the detoxication of PM.