Severe acute kidney injury (AKI) is associated with high mortality. Current blood purification technologies fail to replace the biological functions of renal tubular epithelial cells (RTECs), such as active transport, acid–base homeostasis, and endocrine regulation. The integration of viable RTECs into an extracorporeal circuit to construct a bioartificial kidney represents a potential strategy for renal functional support. However, its translation is constrained by the rapid loss of seed cell phenotypes, immune and coagulation activation triggered by conventional materials, and a lack of in vivo validation in large animal models. However, three key challenges hinder its clinical translation, which this study seeks to address: the rapid loss of seed cell phenotypes, immune and coagulation activation triggered by conventional materials, and a lack of in vivo validation in large animal models.

We engineered a renal tubule assist device (RAD) that integrates viable cells with a functionalized interface. First, we established an immortalized human proximal tubule cell line [immortalized renal tubular epithelial cell line (iRTEC)] and achieved scalable expansion using a microcarrier system. Second, we fabricated a cell-supporting interface [chlorogenic acid/poly-L-lysine-modified pristine nanofibrous membrane (CA/PLL-PNF)] with antioxidant properties and enhanced hemocompatibility via the layer-by-layer self-assembly of PLL and CA onto polyacrylonitrile nanofibrous membranes. Finally, we assembled these components into a flat-plate bioreactor and evaluated its extracorporeal performance in a Bama miniature pig model after bilateral nephrectomy.

iRTECs were stably expanded on microcarriers while maintaining a proximal tubule phenotype, and these cells outperformed existing cell lines in terms of amino acid hydrolysis and transmembrane transport, acid–base regulation, water transport, and endocrine responsiveness. With respect to the supporting interface, CA/PLL-PNF effectively scavenged diverse free radicals and mitigated cellular oxidative stress. Proteomic analysis confirmed that this modification remodeled the plasma protein corona, which significantly reduced the adsorption of complement and coagulation factors. In the bilaterally nephrectomized pig model, the RAD safely maintained extracorporeal circulation for 4 h—the duration of routine clinical dialysis—and preserved internal homeostasis. The antioxidant interface significantly attenuated circulating lipid peroxidation during treatment. Compared with hemofiltration alone, the RAD significantly enhanced the clearance of middle-molecule toxins (β₂-microglobulin) and reduced proinflammatory cytokine levels at the outlet, demonstrating its capacity for the active modulation of local inflammation.

This study established a renal support platform that integrates viable cells and functional materials. The device exhibited multidimensional biological efficacy in toxin clearance and internal homeostasis regulation and achieved stable extracorporeal circulation in a preclinical large animal model, which provides experimental evidence for advanced organ support strategies in the setting of severe AKI.