Titanium Dioxide (TiO₂) Incorporation into Poly(ether sulfone) (PES) Hollow Fiber Membranes (HFMs) Improves Biocompatibility and Separation Performance for Bioartificial Kidney (BAK) and Hemodialysis Applications

Hemodialysis and bioartificial kidney (BAK), which mimic both physical and biological functions, can significantly impact chronic kidney disease (CKD) patients. Here we report on Hollow fiber membranes (HFMs) with enhanced separation of uremic toxins along with enhanced hemocompatibility and biocompatibility that also promote the growth of kidney cells. The improvement arises from the addition of titanium dioxide (0.1, 0.5, 2%) into poly(ether sulfone) (PES) HFMs during fiber spinning, resulting in enhanced growth and proliferation of HEK293 cells, which were able to form spheroids as evidenced by the confocal images. MTT cell viability assay, cell proliferation assay by cell count, live dead assay by flow cytometry, and reactive oxygen species (ROS) study showed metabolically active viable cells, a higher number of cells, and a low ROS level in TiO₂ PES HFMs. The ultrafiltration coefficients of HFMs were high, with the highest (152.86 ± 5.01 mL/(m²·h·mmHg)) being for 2% TiO₂ PES (2TiP), showing the enhanced separation performance and better hemocompatibility (<5% hemolysis limit), and the lowest being for 2TiP (0.057%), with a low value of complement activation and lowest SC5b-9 marker level (10.71 ng/mL). HFMs also showed enhanced separation of toxins such as urea, creatinine, lysozyme, and indoxyl sulfate, proving their capability to remove water-soluble, middle molecular weight and protein-bound toxins. Therefore, the TiO₂-incorporated membranes developed here have promise for hemodialysis and BAK applications.