Photoresponsive Vaccine‐Like CAR‐M System with High‐Efficiency Central Immune Regulation for Inflammation‐Related Depression

Abstract Increasing evidence suggests that activation of microglia‐induced neuroinflammation plays a crucial role in the pathophysiology of depression. Consequently, targeting the central nervous system to reduce neuroinflammation holds great promise for the treatment of depression. However, few drugs can enter the brain via a circulatory route through the blood–brain barrier (BBB) to reach the central nervous system efficiently, which limits the pharmacological treatment for neuropsychiatric diseases. Herein, a light‐responsive system named UZPM, consisting of blue‐emitting NaYF 4 :Yb, Tm@zeolitic‐imidazolate framework (UCNP@ZIF‐8), photoacid (PA), and melatonin (MT) is developed to address the above issues. Meanwhile, UZPM is introduced into macrophages by functional liposomes fusion and modified with hydroxylamine groups on the cell surface. Aldehyde‐modified cytotoxic T‐lymphocyte‐associated protein‐4 (CTLA‐4) is used as a chimeric antigen receptor (CAR) targeting group to modify the surface of macrophages by aldehyde/hydroxylamine condensation to precisely target central M1‐type microglia (CAR‐M‐UZPM). Both in vitro and in vivo experiments demonstrate that the CAR‐M‐UZPM drug delivery system can efficiently penetrate the BBB, targeting centrally activated microglia, and thus, inhibiting the M1‐type polarization of microglia, producing continuous vaccine‐like anti‐inflammatory effects that prevent the occurrence and development of inflammation‐related depression.