Supplementary Material for: Bovine Serum Albumin Dialysis Removes Protein-Bound Toxins from Human Serum Albumin Solution: Theory and Benchtop Validation

Introduction: Adding a binder to dialysate improves the removal of protein bound toxins (PBTs). Systems that use dialysate with human serum albumin (HSA) to remove PBTs show promise for improving treatment in liver failure and other fields. HSA-based systems are difficult to scale due to scarce donor blood and expensive recombinant options. We investigate bovine serum albumin (BSA) as an alternative. Methods: Computational modeling predicted the impact of dialysate side BSA concentration on the removal of three PBTs (bilirubin, cholic acid, and indoxyl sulfate). We validated our predictions using a blood analog solution with HSA and PBTs. This solution was dialyzed against dialysate with BSA at various concentrations. HSA dialysate was tested as a positive control. Results: The model accurately predicts toxin removal. For bilirubin removal, the percent error of the prediction is less than 6%. For cholic acid and indoxyl sulfate, the percent error is higher because final concentration values are small. However, the square root of the sum of squares error of the prediction did not exceed 0.13 mg/g and 0.25 mg/g, respectively. PBT removal by BSA matched or exceeded results observed with HSA. The model accurately predicted the benefit of increased BSA concentration. Conclusions: This model will allow binder dialysis optimization, enabling personalized dialysis dosing for maximum PBT removal. Using BSA can overcome the scarcity of HSA, enabling large scale treatment.