Dual-action nanoconjugate for overcoming r-tPA -resistant clots

Clot resistance to pharmacological thrombolysis remains a critical challenge in ischemic stroke (IS) management. Thrombus heterogeneity, particularly the presence of thrombolysis-resistant domains composed of dense fibrin and non-fibrin components, including neutrophil extracellular traps (NETs), significantly limits the efficacy of recombinant tissue-type plasminogen activator (r-tPA) and its variant, Tenecteplase (TNK). Consequently, novel therapeutic strategies are urgently required. Emerging evidence suggests that co-administration of deoxyribonuclease I (DNase I) with r-tPA can degrade DNA fibers and enhance clot lysis. In this study, we optimized a previously developed theranostic agent--iron oxide microparticles coated with polydopamine--by dual-grafting both r-tPA and DNase to target resistant thrombi. Using functional ultrasound imaging (fUS) during the acute phase of IS, we demonstrated accelerated reperfusion with this dual-functionalized platform in a r-tPA resistant IS model. Furthermore, MRI analysis confirmed a significant reduction in lesion volume at 24 hours, correlating with improved functional recovery five days post-ischemia.