Traditional Chinese Medicine Borneol-Based Polymeric Micelles Intracerebral Drug Delivery System for Precisely Pathogenesis-Adaptive Treatment of Ischemic Stroke

The scarcity of effective neuroprotective agents and the presence of blood-brain barrier (BBB)-mediated extremely inefficient intracerebral drug delivery are predominant obstacles to the treatment of cerebral ischemic stroke (CIS). Herein, ROS-responsive borneol-based amphiphilic polymeric NPs are constructed by using traditional Chinese medicine borneol as functional blocks that served as surface brain-targeting ligand, inner hydrophobic core for efficient drug loading of membrane-permeable calcium chelator BAPTA-AM, and neuroprotective structural component. In MCAO mice, the nanoformulation (polymer: 3.2 mg·kg, BAPTA-AM: 400 µg·kg) reversibly opened the BBB and achieved high brain biodistribution up to 12.7%ID/g of the total administered dose after 3 h post single injection, effectively restoring intracellular Ca and redox homeostasis, improving cerebral histopathology, and inhibiting mitochondrial PI3K/Akt/Bcl-2/Bax/Cyto-C/Caspase-3,9 apoptosis pathway for rescuing dying neurons (reduced apoptosis cell from 59.5% to 7.9%). It also remodeled the inflammatory microenvironment in cerebral ischemic penumbra by inhibiting astrocyte over-activation, reprogramming microglia polarization toward an anti-inflammatory phenotype, and blocking NF-κB/TNF-α/IL-6 signaling pathways. These interventions eventually reduced the cerebral infarction area by 96.3%, significantly improved neurological function, and restored blood flow reperfusion from 66.2% to ≈100%, all while facilitating BBB repair and avoiding brain edema. This provides a potentially effective multiple-stage sequential treatment strategy for clinical CIS.