Where and when to strike: Spatiotemporally controlled smart nanomedicines for precision antibacterial therapy.

The global rise of antimicrobial resistance calls for new therapeutic approaches that move beyond conventional broad-spectrum antibiotics toward precision-guided nanotherapeutics. This review examines how smart antibacterial nanomedicines achieve better therapeutic outcomes through two key control dimensions: Spatial precision (where) and temporal activation (when). We first discuss active targeting strategies that direct therapeutic payloads to infection sites while sparing healthy tissues. We then analyze microenvironment-responsive mechanisms that keep therapeutic agents inactive until they encounter specific pathological signals. Moving beyond a simple catalog of material properties, we propose a "Hierarchical Intelligence Framework" that organizes nanoparticles along a spectrum of increasing complexity-from basic ligand-guided systems to integrated, logic-responsive nanodevices operating through "Target-Trigger-Treat" protocols. By examining design principles and practical challenges in pharmaceutical development, this work outlines a path toward resistance-overcoming nanomedicines that may reshape infection management in the coming decades.