Spatial patterning strategies for liver tissue engineering: Biofabrication technologies and applications.

The liver is composed of hepatocytes and non-parenchymal cells arranged in precise spatial patterns that enable more than 500 metabolic, synthetic, and detoxification functions. Replicating this hierarchical structure and dynamic multicellular organization is essential for applications in drug development and regenerative medicine. Here, we review biofabrication strategies that encode spatial control in engineered liver tissues. We begin with native hepatic architecture and cell sources, then evaluate self-assembled and engineered aggregates, soft lithography, electrospun scaffolds, three-dimensional bioprinting, and microfluidic systems in terms of their ability to capture physiological features such as zonation, polarity, and vascular or biliary networks. Hybrid approaches that integrate multiple modalities to enhance complexity and function are also highlighted. We next discuss how human liver models are advancing drug metabolism and toxicity screening, disease modeling, and potential therapeutic applications. Finally, we examine current limitations and future directions, emphasizing challenges of scalability, reproducibility, and standardization, along with emerging opportunities in volumetric bioprinting, machine learning-guided design, and regulatory qualification of liver microphysiological systems. Collectively, engineered liver models are poised to play an increasingly critical role in bridging in vitro and in vivo applications as advances in biofabrication bring them closer to clinical and regulatory translation.