Development of Manganese Carbonyl Loaded Upconversion Nanoparticles for Near-Infrared-Triggered Carbon Monoxide and Mn²⁺ Delivery

Photoactivatable carbon monoxide-releasing molecules (CORMs), typically based on transition-metal carbonyl complexes, have reliance on activation by UV or visible light that restricts their biomedical applications. To address this limitation, a near-infrared (NIR)-responsive nanoplatform is presented based on upconversion nanoparticles (UCNPs) loading with manganese carbonyl complex Mn-2(CO)(10) that concurrently releases CO and manganese ion (Mn2+). With the UCNPs, the more tissue-penetrable NIR is used to locally generate UV light for photodecomposition of Mn-2(CO)(10) into CO and manganese oxide (MnOX), after which MnOX is reduced to Mn2+ by the overexpressed glutathione in cancer cells. Moreover, the released Mn2+ can serve as a magnetic resonance imaging contrast agent to monitor the NIR-controlled corelease of CO and Mn2+ in real time. Therefore, this nanoplatform can provide a potential strategy for NIR-enabled spatiotemporally release of CO and Mn2+, enhancing the controlled delivery and biomedical application of CORMs.