Treatment of end stage renal disease (ESRD) patients by renal transplant is severely limited by shortage of donor organs, while dialysis is expensive, inconvenient, and confers significant morbidity and mortality. There are nearly 400,000 people in the US who rely on thrice-weekly, in-center hemodialysis, and collectively, this population consumes over $20 billion annually in Medicare-paid healthcare. The prevalence of ESRD is increasing at 5% per year, and the vast majority of patients are unlikely to ever receive a transplant. We recently embarked on the development of an implantable bioartificial kidney that combines a hemofilter constructed from silicon nanopore membranes (SNM) with a bioreactor of human renal tubule cells to mimic nephronal function. In the final envisioned implementation, blood will be filtered in the hemofilter under circulatory system pressure to remove uremic toxins, salts, small solutes, and water. The resulting ultra filtrate will then be processed by the bioreactor to selectively transport most of the salts, and water back into the blood, thereby maintaining volume homeostasis and electrolyte balance. Initial pilot studies supported by a NIH/NIBIB-sponsored Quantum Grant (1R01EB008049) allowed our team to establish fundamental concept feasibility including the development of high-performance SNM filters, anti- fouling thin-film polymer coatings, human renal tubule cell isolation and expansion techniques, and short-term implantable hemofiltration in rodents and pigs as well as wearable cell therapy in sheep. We also identified a number of critical roadblocks to successful development of implantable bioartificial kidney. Among them, a key challenge is long-term blood compatibility of the hemofilter with respect to thrombosis and membrane fouling. The proposed R01 project will attempt to better understand the blood-device interactions spanning across anatomic, histologic, and molecular length scales and their influence on hemofilter biocompatibility. More specifically, we will conduct transport characterization experiments, computational fluid dynamics (CFD) simulations, in vitro radiographic flow mapping, and in vivo animal experiments to evaluate the impact of membrane physicochemical properties on mass transfer characteristics and determine the role of fluid flow anomalies in device thrombosis. Beyond the immediate application to an implantable bioartificial kidney, this work will establish a new generalized testing methodology for implantable devices that are functionally dependent on features at both large (mm-cm) and small (nm-microns) length scales.

Public Health Relevance

We are working to develop an implantable bioartificial kidney for patients who suffering from kidney failure, and are currently on dialysis with little hope for a transplant. Our device combines a nanoscale filter with a bioreactor of cells to mimic the functions of a healthy kidney. This project is aimed at improving device performance and operational lifetime after implantation.

National Institute of Health (NIH)
National Institute of Biomedical Imaging and Bioengineering (NIBIB)
Research Project (R01)
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Biomaterials and Biointerfaces Study Section (BMBI)
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Hunziker, Rosemarie
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University of California San Francisco
Schools of Pharmacy
San Francisco
United States
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Iqbal, Zohora; Moses, Willieford; Kim, Steven et al. (2018) Sterilization effects on ultrathin film polymer coatings for silicon-based implantable medical devices. J Biomed Mater Res B Appl Biomater 106:2327-2336
Feinberg, Benjamin J; Hsiao, Jeff C; Park, Jaehyun et al. (2018) Slit pores preferred over cylindrical pores for high selectivity in biomolecular filtration. J Colloid Interface Sci 517:176-181
Buck, Amanda K W; Goebel, Steven G; Goodin, Mark S et al. (2018) Original article submission: Platelet stress accumulation analysis to predict thrombogenicity of an artificial kidney. J Biomech 69:26-33
Buck, Amanda K W; Groszek, Joseph J; Colvin, Daniel C et al. (2018) Combined In Silico and In Vitro Approach Predicts Low Wall Shear Stress Regions in a Hemofilter that Correlate with Thrombus Formation In Vivo. ASAIO J 64:211-217
Feinberg, Benjamin J; Hsiao, Jeff C; Park, Jaehyun et al. (2017) Silicon nanoporous membranes as a rigorous platform for validation of biomolecular transport models. J Memb Sci 536:44-51
Kensinger, Clark; Karp, Seth; Kant, Rishi et al. (2016) First Implantation of Silicon Nanopore Membrane Hemofilters. ASAIO J 62:491-5
Kim, Steven; Heller, James; Iqbal, Zohora et al. (2016) Preliminary Diffusive Clearance of Silicon Nanopore Membranes in a Parallel Plate Configuration for Renal Replacement Therapy. ASAIO J 62:169-75
Kim, Steven; Feinberg, Benjamin; Kant, Rishi et al. (2016) Diffusive Silicon Nanopore Membranes for Hemodialysis Applications. PLoS One 11:e0159526
Kim, Steven; Fissell, William H; Humes, David H et al. (2015) Current strategies and challenges in engineering a bioartificial kidney. Front Biosci (Elite Ed) 7:215-28
Olorunsola, Olufoladare G; Kim, Steven H; Chang, Ryan et al. (2014) Imaging assessment of a portable hemodialysis device: detection of possible failure modes and monitoring of functional performance. Med Instrum (Luton) 2:

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