A Minimally Invasive Diagnostic Platform Compatible with Tissue and Serum Analysis for Early Detection of Non-Alcoholic Fatty Liver Disease

Abstract Non-alcoholic fatty liver disease (NAFLD), one of the most prevalent chronic liver diseases, initially manifests as simple hepatic steatosis. Without timely intervention, it can progress to cirrhosis and ultimately hepatocellular carcinoma. Early diagnosis and intervention are therefore essential for slowing disease progression and reducing the risk of complications. However, effective minimally invasive methods for the early diagnosis of NAFLD remain limited in clinical practice, posing substantial challenges to large-scale screening. Emerging evidence indicates that during NAFLD progression, the mitochondrial membrane potential in hepatocytes gradually declines, accompanied by increasing spatial disorganization and pronounced alterations in the polarity of the mitochondrial microenvironment. Inspired by these findings, we developed a mitochondria-targeted, polarity-sensitive near-infrared fluorescent diagnostic system for the early detection of NAFLD. A series of probes (BS-X) were designed and synthesized based on a hemicyanine−triphenylamine fluorescent scaffold. Through comprehensive evaluation combining in vitro experiments and theoretical calculations, BS-1 was identified as the optimal probe, exhibiting excellent photophysical properties, low cytotoxicity, and high sensitivity to polarity variations. BS-1 efficiently targeted mitochondria (R = 0.89) and enabled real-time monitoring of dynamic changes in mitochondrial microenvironmental polarity. Notably, BS-1 enabled the detection of distinct disease-associated signals in both liver tissue and serum samples from NAFLD mice as early as one week after disease induction, achieving synchronous detection in hepatic tissue and serum and providing a novel molecular diagnostic tool for the early diagnosis of NAFLD.