Frequently Asked Questions by Patients

Basics: device and function

1. How does the device work? And how big is the device?

The bioartificial kidney, the size of a coffee cup, consists of two modules that work together to get rid of wastes. First, a hemofilter module processes incoming blood to create a watery ultrafiltrate that contains dissolved toxins as well as sugars and salts. Second, a bioreactor of kidney cells processes the ultrafiltrate and sends the sugars and salts back into the blood. In the process, water is also reabsorbed back into the body, concentrating the ultrafiltrate into “urine,” which will be directed to the bladder for excretion.

2. What is the surgical process like to insert the device? Where can I have the procedure done?

The procedure will be similar to kidney transplant surgery and will require a hospital stay and general anesthesia. Once the bioartificial kidney device is available publicly, the procedure can be completed at any hospital with a trained transplant surgical team.

3. How will the filter be cleaned?

The filter is coated with a special thin biocompatible film to prevent fouling and blood clots. Additionally, the blood flowing over the coated filter surface will also help to keep the membrane free of debris accumulation.

4. How long will the device survive after implantation? Will it have to be replaced?

The device is meant to be permanent and that is what our efforts are pushing towards. Current testing and research suggest that it could be possible for the device to operate for many years without failure. However, if failures occur, the replacement of the filter and/or cells would likely involve a minimally invasive surgery.

5. Will patients still have to take immunosuppressive drugs or anticoagulant after implantation? Will there be a risk of blood clotting?

The cells in the bioreactor are isolated from the patient’s immune system by the scaffold on which they are grown. The coatings on the device work to prevent blood clotting. In earlier human trials of a large-scale, external bioartificial kidney, no anti-rejection drugs were needed, and in recent preclinical experiments, no blood thinners were needed.  So we expect that immunosuppressants and blood thinners will not be required.

6. How are the cells in the bioreactor simultaneously isolated from the immune system but still kept alive?

The immunoisolation is provided by the membranes on which the cells are grown. The cells are grown on a porous scaffold which allows water, salts, glucose, amino acids, and other very small molecules to pass through it freely. These nourish the cells and allow the cells to dispose of small wastes, such as carbon dioxide.

The immune system relies on fairly large molecules to identify and attach foreign intruders, which are a thousand times larger than, say, glucose. They are too large to penetrate the sieve of the membrane supporting the cells.

7. Will patients with Polycystic Kidney Disease and Focal Segmental Glomerulosclerosis (FSGS) be eligible for the bioartificial kidney?

We intend for these patients to be candidates.  In any case where a kidney transplant is needed, we expect that our device will be a viable option.

8. Will the "cell reactor" part of your kidney be able to generate Erythropoietin and eliminate the need for artificial EPO injections?

The kidney cells in the Bioreactor are different than the cells that secrete erythropoetin. Therefore, patients will still require EPO injections.

9. What kind of GFR value would you expect to see once this device gets implanted in you?

While this will be confirmed as we progress through preclinical studies, we anticipate a GFR value of 20-30 ml/min with this device implanted.

10. Can you still get this device if you still have 15% kidney function? Or is it exclusive to those whose kidneys have totally failed?

This is case-specific, so it would depend on the details of a particular patient’s case and will be decided by both the patient and physician.

11. Any predicted side effects?

Adverse side effects that might occur would be similar to side effects known in other procedures involving implanted medical devices. These include complications like infections, surgical trauma,  and scars. Additionally, there might be a need for increased fluid consumption.

12. How much will this device cost?

We anticipate that the device will cost no more than what transplant costs. It is challenging to put a dollar figure on procurement, implantation, and monitoring since we don't know what the business and economic climate will be in the future at the time the device is released.

13. Will this device be covered by insurance?

We will apply for insurance coverage by both Medicare and commercial insurers once the device is in clinical trials. Our analysis suggests that the implantable bioartificial kidney may offer over 50% cost savings compared to dialysis. As such, we anticipate that the device will be attractive to those making coverage decisions.

14. Will this be available internationally?  Or will international patients have to go to the United States for the procedure?

Once the device is released commercially, we will be working to make it available to all patients in need, domestic and international. Clinical trials, however, will likely be conducted in the United States initially because this is where the key research and initial regulatory review will take place.

15. I am waiting for the implantable bioartificial kidney, but my physician or health care provider is recommending that I start dialysis and get on the kidney transplant list.  What should I do?

You should always heed the advice of your physician or other qualified health provider. The bioartificial kidney is still under development and is not yet available to patients. Please do not delay any recommended treatments. While our goal is to provide a revolutionary alternative for kidney failure patients and address the current limitation of donor organs, the bioartificial kidney will not surpass the performance of a natural, healthy kidney.

16. The Kidney Project's Facebook page mentions something called iHEMO.  What is iHEMO?

iHemo uses the implantable bioartificial kidney’s blood filter (Hemofilter) to perform hemodialysis. iHemo will simplify dialysis and reduce its risks by creating permanent connections between the patient’s blood vessels and the Hemofilter, eliminating the need for needles and keeping all blood processing within the body, with only dialysate cycling in and out. The Hemofilter is implanted, attached to the patient’s circulatory system via vascular grafts, and connected to an external bedside dialysate pump through a catheter.

iHemo is a “stepping stone” on the way to the bioartificial kidney that will allow patients to benefit from the advantages of our silicon membrane filtration technology at the earliest possible opportunity. With iHemo, patients will be able to perform hemodialysis conveniently and safely from the comfort of their homes.

17. Why did The Kidney Project partner with Home Dialyzors United (HDU), and American Association of Kidney Patients (AAKP), and what do these partnerships mean?

In spring of 2017, The Kidney Project announced a new partnership with Home Dialyzors United (HDU). In summer of 2018, we partnered with the American Association of Kidney Patients (AAKP). We are very excited about the opportunities these partnerships bring and see them as important milestones for The Kidney Project.

Partnerships with patient-advocacy groups, such as HDU and AAKP, allow The Kidney Project to access the opinions and the unique perspectives of kidney disease patients, helping to improve the bioartificial kidney device for all users. The FDA (Food and Drug Administration) encourages medical device developers to incorporate patient perspectives, acknowledging that their voice is often unheard in the medical device development process.

HDU works tirelessly within today’s legal and medical systems to advocate for and inform dialysis patients about their options for dialysis care. We have partnered with HDU because of their advocacy experience and their deep understanding of the daily obstacles presented to dialysis patients and their loved ones.

AAKP is the largest kidney patient organization in the country and works closely with Federal government payors, regulators, and quality experts to help officials understand patient needs and risk tolerance. The Kidney Project’s partnership with AAKP has allowed us access to AAKP’s membership to obtain crucial insights into ESRD patients’ lived experiences and preferences for next-generation renal replacement therapies.


18. What is the status of preclinical testing?

The Kidney Project is in the midst of extensive preclinical testing for the Hemofilter. Preclinical testing for the Bioreactor has just begun.

Results from preclinical testing of the Hemofilter are encouraging. We have successfully implanted small-scale versions of the Hemofilter component into large animal models for up to 1 month. The animals responded well, without serious complications. These studies have given us enough safety data to begin an application to the FDA for a first-in-human study to evaluate material safety. We are now working towards demonstrating the function and safety of the full-size clinical version of the Hemofilter in large animals with compromised kidney function for 30 days.

19. How long will clinical trials take to complete?

There are several required steps in the clinical trials process and the full process will likely take a few years.

Our initial clinical trial is a material safety test of the Hemofilter. During this trial, we will confirm that all the materials in our Hemofilter component are safe for human blood exposure. This is the first step of many to receive FDA approval for a completed bioartificial kidney device.

Once our initial clinical trial is complete and the data analyzed, we will apply for a pilot study to test the Hemofilter’s functional components, specifically its ability to sufficiently remove toxins from human blood. We will then conduct a pivotal study to definitively demonstrate safety and effectiveness of the implanted Hemofilter.

An expedited series of clinical trials will then be required for the combined Hemofilter and Bioreactor device (the bioartificial kidney). After these trials are completed successfully, the bioartificial kidney will be available to the public.

20. What is the current timeline of clinical trials? Why have there been delays? 

It is difficult to predict timelines due to uncertainties in fundraising, the regulatory process, and technical challenges that can come up along the way. In the best-case scenario, we may be ready to begin the Hemofilter material safety study in 2022. This scenario assumes that we have sufficient funding and no unanticipated scientific, technical, or regulatory drawbacks.

Years ago, when we projected that clinical trials would begin by 2020, it was our most favorable scenario at the time. Our projected timeline has always been dependent on obtaining the required funding, and not encountering unanticipated scientific hurdles.

In 2020, the global community faced the COVID-19 pandemic. Our timeline for starting the first clinical trials was inevitably adversely impacted. Our lab operated at significantly reduced capacity for more than a year. We also faced supply chain interruptions and backlogs at testing facilities. Starting in the summer of 2021, we have been able to resume laboratory activities at full capacity.

We are committed to advancing the development of the bioartificial kidney to patients as quickly as our resources and capabilities allow. We appreciate your patience, understanding, and continued support of The Kidney Project.

21. What are the development challenges (long term and short term)?

The Kidney Project is an ambitious and expensive project. In the short term, our primary challenge is funding the research and development. A significant hurdle is procuring enough money to complete the preclinical studies for both device components and build full-scale prototypes for the first rounds of in-human studies.

The long-term challenges center around keeping the device operating trouble-free after implantation beyond a few months. Some problems won’t become clear until we do clinical trials, so for now, we are looking at ways to increase the lifetime of the cells in the Bioreactor as well as ways to minimize, or even eliminate, thrombus formation (blood clotting). We will get a better handle on the long-term challenges once we begin to gather data from the clinical-scale devices.

22. What can be done to speed up the research and development process?

Our progress is driven by two components: time required to conduct scientific analysis and development, and funding. The scientific analysis and development process cannot necessarily be forced into a faster pace. Because we are developing a novel device and are held to the safety standards of the FDA, we must maintain scientific rigor and technical excellence in a logical order without skipping steps.

However, additional funding allows us to hire more personnel, purchase additional equipment, and generally complete tasks faster. Therefore, donations, investments, and federal funding all help to speed up the research and development process.

23. When will the device be ready after clinical trials?

During the clinical trials, we will be working with manufacturers to discuss and manage the details of commercial production. Once clinical trials are complete, the device will be made available for patients as soon as possible, we hope within a few months of FDA approval.


24. What kind of federal funding do you receive? How do you get more?

In 2015 The Kidney Project was awarded $6 million from the National Institute of Health (NIH) to be distributed over the next four years -- $1.5 million per year. In addition, The Kidney Project has received almost $7 million from various federal agencies in the United States including NIH, National Aeronautics and Space Administration (NASA) and the Department of Defense (DOD). These agencies have provided funding for the basic research and groundwork behind the artificial kidney. Since we are now beyond the basic research phase, we are outgrowing our federal funding options and need the help of industry partners and investors to complete development and commercialize. However, the challenge is that many medical device investors want to see data from clinical studies before they will consider providing funding.

25. Why do you not have a lot of investors? Is it too risky for them?

Investors have expressed interest in our project and have indicated its potential. They have also commented that their comfort with investing in our project would increase significantly once we can show them human safety studies. We are working towards getting this data as quickly as we can with the funds raised via grants and donations.

26. Is it worth contacting our government officials to ask for more funding to your project?

Absolutely! The Kidney Project’s artificial kidney will enhance patient outcomes and quality of life while also lowering healthcare costs. Writing to your congressional representatives lets them know about The Kidney Project's potential impact and importance to patients.

27. How can I make a donation? (Domestically and Internationally)


Make a gift.


  1. Make checks payable to UCSF Foundation.
  2. Include allocation instructions on the memo line: The Kidney Project.
  3. Send gifts by U.S. Mail to:

    P.O. Box 45339
    San Francisco, CA 94145-0339


Call toll-free 877-499-UCSF (877-499-8273) to charge by phone.

Clinical trials: before and after

28. Do you have a waitlist for clinical trials? How do I sign up?

There is no official waitlist because we do not know yet when clinical trials will begin. If you are interested in being notified once our trials do start enrolling, complete this form to submit your information into our confidential database:


We will contact everyone in our database after we receive clinical trial approval. If you submitted an interest form, we received your information and there is nothing further you need to do.

Please note that the interest list does not guarantee anyone’s participation. It just ensures that you will be notified when enrollment has opened. Participant selection will be made by our team of doctors based on specific clinical eligibility criteria to be finalized during the FDA review process. It is not necessary to be on the list to be considered. We will also announce trial openings via ClinicalTrials.gov and our social media pages once we are ready to begin enrollment.

29. What are the criteria for choosing the first group of clinical trials patients? Who decides who will participate? If I donate, will that increase my chances of participation?

Patient selection for trials will be based on the trial inclusion criteria, which will be developed by our medical team and reviewed and approved by the FDA and our Institutional Review Board (IRB). Until FDA and IRB review takes place, we are unable to release the specific patient involvement criteria. Patient selection is led by our medical colleagues with no involvement from The Kidney Project management or staff. While donations are appreciated and serve a vital role in our project’s funding, donations have absolutely no influence on selection for trials. This is to protect the integrity of our research and ensure that all participant decisions are made for medically and scientifically sound reasons.

30. Where will the clinical trials take place?

Clinical trials will likely take place at multiple locations within the United States. The location of each trial cannot be confirmed until trial approval is granted. The first clinical trial will likely take place in San Francisco, California, or Nashville, Tennessee, as these are the locations where the majority of The Kidney Project team is currently based.

31. Will stage 4 patients be accepted?

The initial clinical trials will concentrate on End Stage Renal Disease Patients.

32. Will international patients be considered?

International patients will certainly be considered. However, due to the study logistics and the need for the long-term follow-up, it is likely that most participants will be U.S.-based.

33. Will there be a trial for pediatric patients?

Safety will be our main concern during the initial phase of clinical trials, so we do not intend to use vulnerable populations, such as children, until after we have positive and consistent data from clinical trials with adults.

34. Will the clinical trials be fully funded or will the patients need to help funding their participation?

Our intention is that our clinical trials will be fully funded. We will know more details after the successful completion of our first clinical trial and will update everyone accordingly.

35. Where can I find updates regarding the progress of the project?

Our Facebook page is a great place to stay informed about our progress. You can also follow us on Instagram, Twitter, and YouTube:

Facebook: @ArtificialKidney

Instagram: @ArtificialKidney⁠ ⁠ ⁠

Twitter: @KidneyProject⁠ ⁠

YouTube: @TheKidneyProject

In addition, we keep an archive of news stories on our site at News and Events.

Please contact us at [email protected] if you don’t find your question answered above!