Myocardial ischemia reperfusion (IR) injury is closely related to the overwhelming inflammation in the myocardium. Herein, cardiomyocyte-targeted nanotherapeutics were developed for the reactive oxygen species (ROS)-ultrasensitive co-delivery of dexamethasone (Dex) and RAGE small interfering RNA (siRAGE) to attenuate myocardial inflammation. PPTP, a ROS-degradable polycation based on PGE₂-modified, PEGylated, ditellurium-crosslinked polyethylenimine (PEI) was developed to surface-decorate the Dex-encapsulated mesoporous silica nanoparticles (MSNs), which simultaneously condensed siRAGE and gated the MSNs to prevent the Dex pre-leakage. Upon intravenous injection to IR-injured rats, the nanotherapeutics could be efficiently transported into the inflamed cardiomyocytes via PGE₂-assisted recognition of over-expressed E-series of prostaglandin (EP) receptors on the cell membranes. Intracellularly, the over-produced ROS degraded PPTP into small segments, promoting the release of siRAGE and Dex to mediate effective RAGE silencing (72%) and cooperative anti-inflammatory effect. As a consequence, the nanotherapeutics notably suppressed the myocardial fibrosis and apoptosis, ultimately recovering the systolic function. Therefore, the current nanotherapeutics represent an effective example for the co-delivery and on-demand release of nucleic acid and chemodrug payloads, and might find promising utilities toward the synergistic management of myocardial inflammation.

Polymeric micelles have demonstrated wide utility for chemodrug delivery, which however, still suffer from shortcomings such as undesired drug loading, disassembly upon dilution, pre-leakage of drug cargoes during systemic circulation, and lack of cancer-selective drug release. Herein, a poly(ethylene glycol) (PEG)-polyphosphoester-based, reactive oxygen species (ROS)-responsive, core-cross-linked (CCL) micellar system was developed to encapsulate both chemodrug (doxorubicin, Dox) and photosensitizer (chlorin e6, Ce6). The hydrophobic core of the micelles was cross-linked via a thioketal (TK)-containing linker, which notably enhanced the drug loading and micelle stability. In tumor cells, far-red light irradiation of Ce6 generated ROS to cleave the TK linkers and disrupt the micelle cores. As such, micelles were destabilized and Dox release was promoted, which thereafter imparted synergistic anti-cancer effect with ROS-mediated photodynamic therapy. This study provides an effective approach to realize the precise control over drug loading, formulation stability, and cancer-selective drug release using polymeric micelles, and would render promising utilities for the programmed anti-cancer combination therapy.