As one of the most effective treatments of end-stage liver disease, liver transplantation still suffers from a shortage of donor organs or a low degree of engraftment. Thus, alternatives to liver transplantation, such as liver support systems, have to be extensively explored. In this study, a novel liver microtissue with an inner gear-like structure, which achieved a larger body surface area, was designed and manufactured to improve hepatic functional restoration. The liver-specific bioinks were developed by combining photocurable methacrylated gelatin (GelMA) with liver decellularized extracellular matrix (dECM), and human-induced hepatocytes (hiHep cells) were encapsulated to form cell-laden bioinks. The mechanical properties, swelling, and cytocompatibility of GelMA/dECM bioinks were carefully characterized before 3D printing. Then, the digital light process (DLP)-based bioprinting was used to fabricate the liver microtissue, and liver dECM was found to improve both the printability and cell viability of GelMA bioinks. hiHep cells were also found to spread farther and have better hepatocyte-specific functions (albumin secretion and urea) in the liver microtissue when liver dECM was added to the GelMA bioinks. Our results provide a promising liver dECM-based cell-laden bioink for liver microtissue fabrication, which would be a potential liver tissue engineering product to help restore hepatic functions.

作为终末期肝病最有效的治疗方法之一，肝移植仍存在供体器官不足或移植程度低的问题。因此，必须广泛地探索替代肝移植的替代方法，例如肝支持系统。在这项研究中，设计并制造了一种具有内部齿轮状结构的新型肝微组织，该组织实现了较大的体表面积，从而改善了肝功能的恢复。通过将可光固化的甲基丙烯酸明胶（GelMA）与肝脏脱细胞的细胞外基质（dECM）结合来开发肝脏特异性生物墨水，并将人诱导的肝细胞（hiHep细胞）封装起来，形成充满细胞的生物墨水。在3D打印之前，已仔细表征了GelMA / dECM生物墨水的机械性能，溶胀和细胞相容性。然后，基于数字光处理（DLP）的生物打印技术被用于制造肝脏微组织，并且发现肝脏dECM可以改善GelMA生物墨水的可印刷性和细胞活力。当将肝脏dECM添加到GelMA生物墨水中时，还发现hiHep细胞在肝脏微组织中传播得更远，并且具有更好的肝细胞特异性功能（白蛋白分泌和尿素）。我们的结果为肝微组织制造提供了一种有希望的基于肝dECM的细胞载生物墨水，这将是帮助恢复肝功能的潜在肝组织工程产品。当将肝脏dECM添加到GelMA生物墨水中时，还发现hiHep细胞在肝脏微组织中传播得更远，并且具有更好的肝细胞特异性功能（白蛋白分泌和尿素）。我们的结果为肝微组织制造提供了一种有希望的基于肝dECM的细胞载生物墨水，这将是帮助恢复肝功能的潜在肝组织工程产品。当将肝脏dECM添加到GelMA生物墨水中时，还发现hiHep细胞在肝脏微组织中传播得更远，并且具有更好的肝细胞特异性功能（白蛋白分泌和尿素）。我们的结果为肝微组织制造提供了一种有希望的基于肝dECM的细胞载生物墨水，这将是帮助恢复肝功能的潜在肝组织工程产品。