Eller, Michael J.

Abstract Accurate, noninvasive biomarkers for diagnosis and longitudinal monitoring of metabolic dysfunction–associated steatohepatitis (MASH) remain an urgent unmet clinical need. Here, we describe an electrochemical immunoassay that involves capturing hepatic extracellular vesicles (EVs) on antibody-modified electrodes followed by detecting EV-borne biomarkers using redox active gold nanoparticles (AuNPs). The intensity of electrochemical redox signal represents a quantitative measure of biomarker abundance. Three MASH-associated biomarkers—S100A11, TNF-α, and TGF-β1—were analyzed on hepatic EVs to assess steatotic, inflammatory, and fibrotic states of the diseased liver. The electrochemical signals for individual biomarkers were added into a composite EV MASH score. Plasma samples from 28 patients with MASH, 22 healthy controls, and 27 patients with non-MASH liver disease were scored in this manner, revealing 100% accuracy in the training cohort and >90% accuracy in an independent validation cohort. Our electrochemical immunosensor represents a minimally invasive liquid liver biopsy, offering a promising alternative to solid liver biopsies for screening and monitoring of MASH. One Sentence Summary Circulating hepatic extracellular vesicles carry biomarkers of liver injury enabling accurate, minimally invasive MASH diagnosis in blood.