A pumpless liver-on-a-chip for drug hepatotoxicity analysis
This study presents the development and validation of an innovative microfluidic liver-on-a-chip device utilizing gravity-driven perfusion for the evaluation of drug hepatotoxicity. This research involved the construction of a hydrogel-based coculture chip that integrates liver parenchymal and stellate cells within a tri-channel configuration. The assembly and operation of the liver-on-a-chip and its accompanying custom rocker were straightforward. The chip maintained high cell viability and continuous liver albumin synthesis over extended culture durations. Acetaminophen, a hepatic injury-inducing drug, was utilized as a positive control in hepatic toxicity assays on the chip. The liver chip exhibited hepatotoxic responses comparable to those observed in 2D models. Furthermore, in this study we evaluated the effects of two plant-derived natural compounds, aristolochic acid I (AA) and its ana-log aristolactam AII (AL), in both 2D cell models and the liver-on-a-chip system. Aristolochic acid I, known for its hepatorenal toxicity, was observed to cause hepatotoxicity in both the 2D models and on the chip. Flow cytometry and mRNA sequencing results confirmed the propensity of these compounds to induce liver cell apoptosis. Notably, aristolactam AII, previously consid-ered nontoxic, provoked a significant decrease in the hepatic functionality marker albumin exclusively in the liver chip but not in 2D models, indicating the liver chip's enhanced sensitivity to toxic substances. In summary, this pumpless liver-on-a-chip offers a simple yet powerful tool for drug hepatotoxicity studies. Overall design: In order to evaluate the hepatotoxicity of two natural compounds aristolochic acid I (AA) and aristolactam AII (AL), these compounds at the concentration of 30 µM were used to treat two liver cell lines HepG2 and LX2. Each cell line has three groups: AA, AL and DMSO control group and each group has three replicates. mRNAs were sequenced after 48 hours of  compounds exposure.