Confinement-Induced Charge Branching in Bioinspired Vesicles Enables Self-Validated Photoelectrochemical Sensing.

A fundamental challenge in artificial photosynthesis and sensing is replicating nature's ability to direct energy flow away from destructive pathways. Here, we show that spatial confinement within bioinspired vesicles induces a deterministic charge-branching process between co-assembled porphyrin and carotenoid chromophores. This decouples the excited-state manifold, directing electrons toward the semiconductor for photoelectrochemical conversion while channeling radiative relaxation into a complementary fluorescence pathway. The two orthogonal signals, originating from a single binding event, provide built-in self-validation and effectively suppress false responses. Applied to serum amyloid A detection, the confined interface achieves sub-picogram sensitivity and robust signal stability in human serum. Data analysis confirms that the branched photocurrent dynamics quantitatively report analyte concentration. These findings identify confinement-induced charge branching as a molecular mechanism that enables adaptive and self-validating photoelectronic interfaces mimicking the feedback control of natural photosystems.