Aggregation-State Engineered Melamine-Carbon Dots: Ultrasensitive Ethanol Quantification for Diagnosing and Classifying of Auto-Brewery Syndrome.

As a crucial biomarker in physiological systems, ethanol manifests dual health impacts through both exogenous intake and endogenous biosynthesis by gut microbiota. Current detection methods face challenges in balancing sensitivity and practicality for clinical applications. We developed a micelle-assisted fluorescence sensing platform (SCH-NPs) through rational self-assembly of hydrophobic carbon dots (H-CDs) and sodium cholate (SC), addressing two fundamental limitations in physiological ethanol detection: impractical low limit of detection (LOD) and poor physiological stability. The micellar core creates a confined microenvironment for ultrasensitive detection (LOD = 50 nM) across 0-2.75 mM dynamic range, exhibiting 50 nM LOD with 3-order magnitude enhanced sensitivity versus state-of-the-art fluorescence platforms. Meanwhile, the surfactant shell provides hydrophilic protection enabling stable operation in complex biofluids (blood/bacterial medium). Molecular dynamics simulations revealed that ethanol penetration modulates H-CDs' intramolecular rotation restriction and π-π stacking interactions, inducing a characteristic fluorescence transition from red (aggregated state) to blue (dispersed state). Clinical validation demonstrated superior performance in identifying Klebsiella pneumoniae strains with differential ethanol metabolic capacities (low, <20 mM; high, >40 mM) from autobrewery syndrome patients. This microbial metabolite-responsive platform bridges gut microbiota dysbiosis with ethanol-related pathologies, offering a molecular diagnostic paradigm for personalized management of autobrewery syndrome and other metabolic disorders.