A multifunctional nanoplatform for dexamethasone delivery and dual-mode colorimetric/fluorescent sulfide ion detection to alleviate juvenile sepsis

Juvenile sepsis is a fatal hyperinflammatory syndrome marked by excessive cytokine release, for instance IL-6 and TNF-α, causing multiple organ failure. Although dexamethasone (Dex) is a potent anti-inflammatory drug, its juvenile application is limited by low bioavailability and systemic side effects. Hydrogen sulfide (H₂S), derived from sulfide ions (S 2 ⁻), plays a dual role in inflammation, making its dynamic monitoring clinically valuable. Here, we constructed a multifunctional theranostic nanoplatform—OAP–ATPMS–1@CP1@Dex—which combines octenyl succinic anhydride–modified polysaccharide (OAP) with a dysprosium-based coordination polymer (CP1) exhibiting peroxidase-like activity and fluorescence at 450 nm. In the presence of H₂O₂, CP1 catalyzes TMB oxidation to oxTMB, inducing a fluorescence inner filter effect; S 2 ⁻ inhibits this reaction, enabling sensitive dual-mode S 2 ⁻ detection as an indirect H₂S indicator. The nanosystem accumulates at inflammatory sites via the EPR effect, enabling controlled Dex release to suppress cytokine overproduction while minimizing toxicity. This platform integrates targeted anti-inflammatory therapy with real-time inflammatory signal sensing, offering a precise treatment strategy for juvenile sepsis.