ARPA-H invested up to $25.8 million in UC San Diego: the goal is to use 3D bioprinting to make a patient-specific liver and ease the chronic transplant shortage
In the United States, liver failure remains among the most severe and highest-risk conditions in medicine: when the disease progresses to the end stage, transplantation is for some patients the only therapy that saves life in the long term. In practice, however, the availability of donor organs has for years not kept pace with needs, so patients enter an uncertainty in which outcomes are decided by medical urgency, compatibility, logistics, and time. In that context, the Advanced Research Projects Agency for Health (ARPA-H), an agency within the U.S. Department of Health and Human Services (HHS), is launching a new phase of investment in the development of bioprinted organs in mid-January. On January 12, 2026, ARPA-H announced that it is awarding teams under the PRINT program, an initiative aimed at producing personalized and immunologically matched organs “on demand,” with the ambition of reducing long-term dependence on donation and waiting lists.
One of the projects that fits this strategy is led by the University of California San Diego (UC San Diego), and the value of the support, according to publicly released data, is up to $25,771,771 with a planned duration of 60 months. The support is tied to ARPA-H Award Number D25AC00432-00 and is directed at developing a fully functional, patient-tailored 3D bioprinted liver. The central concept is an “organ made to order” grown from the patient’s cells, which—according to the project’s vision—would reduce the need for donors while also potentially reducing the need for lifelong immunosuppressive drugs after transplantation. Public project descriptions particularly emphasize that such an approach, if successful, could change the core logic of transplant medicine: instead of relying on a rare resource, an organ would be made deliberately for a specific patient, with greater control over compatibility.
PRINT: an attempt to change the transplantation paradigm
ARPA-H describes the PRINT program (Personalized Regenerative Immunocompetent Nanotechnology Tissue) as an attempt to solve the chronic organ shortage by combining bioprinting, regenerative medicine, and large-scale cell manufacturing, rather than relying exclusively on donors. In its January 12, 2026 announcement, ARPA-H states that it wants to enable the production of replacement organs that are immunologically and blood-type matched to the recipient, and it highlights the ambition that in the future production could be measured in hours. In that text, the agency emphasizes several problems of today’s system: long waits, the fact that some patients do not survive to receive a transplant, and that even after transplantation there is lifelong therapy with drugs that prevent rejection but have serious side effects and high costs. ARPA-H also stresses that transplants typically have a limited lifespan and that complications are common, which means the question of a “new liver” does not end with the surgical procedure itself.
PRINT is conceived as a portfolio of multiple teams, and ARPA-H states that the total value of the program is up to $176.8 million over five years. It is specifically emphasized that these are so-called “performer awards,” not classic grants, and that amounts per team are conditioned on achieving “aggressive and accelerated” development milestones. At the program level, ARPA-H explains on its PRINT page three key technical areas: generating the required cell types (from a blood sample, biopsy, or biobank), then producing them in large quantities, and the biofabrication of organs itself with safety and efficacy testing. That structure matters because it clearly suggests the bioprinting-organs problem is not just the “printer,” but an entire chain that includes cell biology, manufacturing, engineering, and regulatory validation.
Why the liver remains a priority: the disease is common and treatment options are limited
The liver is an organ with great regenerative capacity, but when chronic disease lasts for years, it can reach a point where function irreversibly collapses. At that moment the patient enters a high-risk zone, with complications such as bleeding, severe infections, encephalopathy, and other conditions that can quickly become fatal. In CDC summary statistics, it is stated that in the U.S. millions of adults have diagnosed liver disease, which further explains why the liver transplant problem is structurally large. CDC reports on causes of death also place chronic liver disease and cirrhosis among the leading causes of death nationally, showing this is a serious public-health burden rather than a niche problem. For some patients, therapies can slow disease progression, but they cannot replace the function of a terminally damaged organ. In such cases, transplantation becomes the only option that changes the prognosis in the long term.
The transplant problem is not only medical but also systemic. Data on waiting lists and transplants in the U.S. are collected within the OPTN/UNOS system, and HRSA’s organdonor.gov platform notes in its overviews that the number of people on organ transplant waiting lists is very high. The OPTN/SRTR Annual Data Report, which covers national trends, highlights a continuous inflow of new candidates onto waiting lists, showing that demand persists even in years when the number of transplants rises. In its materials, ARPA-H additionally emphasizes that “thousands of patients” in the U.S. die each year waiting for an organ, and that shortages result from a combination of factors: geographic distance, the need to match blood type and tissue characteristics, and low donation rates. In the liver context the problem is especially hard because for this organ there is no permanent mechanical “replacement” comparable to dialysis in kidney failure. That is why a solution promising a stable source of functional liver tissue is seen not only as a scientific innovation but also as a potential public-policy instrument: reducing mortality on waiting lists and reducing pressure on the donation system.
The UC San Diego project: an interdisciplinary team and the goal of an “organ made to order”
The project lead at UC San Diego is Prof. Shaochen Chen from the Aiiso Yufeng Li Family Department of Chemical and Nano Engineering at the Jacobs School of Engineering. University profiles describe him as a researcher focused on biomaterials, tissue engineering, 3D bioprinting, and regenerative medicine, with an emphasis on advanced techniques for rapid fabrication of biological structures. According to the publicly available project description, the goal is to create a full-size liver that would be transplantable and tailored to the patient’s anatomy, with the organ built from the patient’s own cells to reduce the risk of immune rejection. Project descriptions also emphasize the idea that such an approach could reduce the need for lifelong immunosuppression, which today carries significant risks and costs. The project is publicly described as the culmination of decades of bioprinting work in Chen’s lab, with an emphasis on the speed and resolution of tissue fabrication.
The project is highly interdisciplinary and brings together engineering and clinical competencies. The collaboration description cites experts in liver biology, medical imaging, liver surgery and transplantation, and artificial intelligence, and among the co-investigators are David Berry, Ahmed El Kaffas, Padmini Rangamani, Bernd Schnabl, and Claude Sirlin from the UC San Diego School of Medicine as well as Rose Yu from the Jacobs School of Engineering. The clinical part of the project also mentions Prof. Gabriel Schnickel, chief of transplantation and hepatobiliary surgery at UC San Diego Health, who speaks publicly about the potential to bring a long-held vision of the transplant community closer to reality. In the team, according to available information, “hard” disciplines such as engineering and computational methods are combined with “soft” clinical needs, where it must ultimately be proven that the organ can function safely in the body. Precisely for that reason, medical imaging and modeling play an important role, because for a liver it is not enough to have the correct “shape” but also a functional internal architecture.
How a living liver is bioprinted: bioink, light, and the blood-vessel problem
Bioprinting differs substantially from conventional 3D printing of plastic or metal. Instead of hard materials, bioinks are used—biomaterials that can carry living cells while enabling their survival, growth, and organization into tissue. In the approach associated with Chen’s lab, a key role is played by digitally controlled light patterns that solidify cellular material layer by layer. Such a “projection” principle enables precise fabrication of fine micro-architecture, and micro-architecture is what separates a “piece of tissue” from an organ that has physiological function. Public technology descriptions emphasize that complex structures can be produced very quickly compared with slower methods, which is important when attempting to scale toward a full-size organ. But speed alone is not enough: the organ must also be biologically viable, which means materials and procedures must be compatible with cells and allow them to form stable tissue.
The biggest obstacle in bioprinting a full organ almost always comes down to the same question: how to build a vascular network that can supply tissue with oxygen and nutrients. Without that, thicker pieces of tissue die from the inside, so an organ can look convincing but cannot function as a transplant. In its project description, UC San Diego states that the team has included artificial intelligence in the design and manufacturing process to engineer sophisticated vascular networks, which is one of the key challenges when moving from small samples to a full-size organ. In practice, that means a “pipeline” must be designed through which blood can flow without blockage while the tissue receives what it needs to survive. This problem is both medical and engineering: one must consider channel diameters, branching, pressures, flow, and compatibility with natural circulation. That is exactly why incorporating computational methods and AI into design becomes crucial when the goal is set at the level of a transplantable organ.
At the same time, projects like these raise additional questions: how to ensure the mechanical stability of the tissue, how to control cell maturation after bioprinting, and how to standardize function and safety tests before transplantation is even contemplated. At the ARPA-H level, the PRINT program therefore emphasizes safety and efficacy testing as an integral part of biofabrication, not as an afterthought. In other words, the goal is not only to “make an organ,” but to prove that it works in a predictable way, that it is safe, and that it can be produced under controlled conditions. Without such testing, bioprinting remains a laboratory demonstration rather than a therapy. That is why project success is also measured by the ability to standardize the process, not only to achieve one “impressive” prototype.
From 2016 to today: from tissue models for the lab to the ambition of transplantation
UC San Diego has been mentioned in the field of liver-tissue bioprinting for almost a decade. In 2016, the University of California reported that a team from San Diego produced a 3D bioprinted sample of liver tissue that, although small, mimicked key liver structures and functions and was intended for personalized drug testing and disease study. Such models are not transplantable organs, but they were an important demonstration that complex liver tissue can be shaped and kept functional under controlled conditions. At that time the focus was on giving the laboratory a realistic “piece” of human tissue with which it could better predict the effect of therapies and understand disease. Even then, this had great value, because personalization of drug testing and disease modeling are considered areas with significant clinical potential. But the step toward transplantation is qualitatively different, because it involves integrating an organ into a living organism, long-term function, and safety.
Today the goal shifts to a new level: a full-size liver must survive in the human body, connect to blood vessels, and long-term take over metabolic functions without which life is not possible. In that transition, a “translational” layer is also important—moving the technology from the lab toward industrial systems. In that sense, publicly available corporate announcements mention that the startup Allegro 3D, associated with the DLP approach to bioprinting, was acquired by BICO, a group that in the bioprinting segment manages the CELLINK brand. In addition, in 2023 CELLINK announced a partnership with UC San Diego to establish a center of excellence for 3D bioprinting, indicating that infrastructure and industrial interest exist. For a project targeting clinical use, such infrastructure matters because it enables scaling, standardization, and reproducibility, without which there is no regulatory pathway. At the same time, it shows bioprinting is no longer viewed only as an academic curiosity, but as a technology that is attempting to take root in industrial processes.
Allele Biotech and iPSC production: a “cell factory” without which there is no organ
For liver bioprinting, access to multiple cell types in large quantities and at quality that can meet clinical standards is crucial. That is precisely where Allele Biotechnology & Pharmaceuticals comes in, a company that on January 13, 2026 announced that it is joining as an industry partner of the UC San Diego project. In that announcement, it states that Allele will generate iPSC lines under conditions that meet GMP standards and develop differentiation into multiple cell types needed for a liver, including hepatocytes, cholangiocytes, endothelial precursors, and other cell populations. The company also emphasizes that it has specialized manufacturing capacity and regulatory-compliant facilities, which is key for moving from “laboratory” to “clinical” quality. According to that announcement, the goal is to develop cell manufacturing with high yields and lower costs, which is an important prerequisite if the technology is ever to be applied more broadly. Otherwise, even a successful prototype remains a therapy available only to a few.
In the same public description, Allele emphasizes the use of mRNA reprogramming and recalls the scientific background of iPSC technology, which in the broader context of regenerative medicine received a strong boost after the 2012 Nobel Prize for work on cell reprogramming. The essence of this approach is that from a starting sample, through controlled procedures, one obtains a “source” of cells that can then be directed into the specific types needed for an organ. For liver bioprinting this is critical because the liver is not homogeneous tissue: to function, it needs multiple cell populations that cooperate in precise spatial organization. That is why the project description emphasizes producing different cell types and plans that, when reaching the full-size organ phase, quantities will be measured in tens of billions of cells per organ. Those numbers, though they sound abstract, illustrate the difference between a laboratory sample and a transplantable organ: the scale of production itself becomes one of the greatest challenges.
What success could change and what the key open questions are
If, within the five-year project, it were truly shown that it is possible to produce a functional, transplantable, patient-specific liver, the consequences would be far-reaching. In theory, dependence on donors, waiting lists, and geographic constraints would be reduced, and some patients could receive an organ at a time when they are still stable enough for surgery and recovery. Another potential gain would be immunological: an organ made from the patient’s cells could reduce the need for lifelong immunosuppression, which in practice would mean fewer infections, fewer side effects, and better long-term quality of life. In the PRINT description, ARPA-H emphasizes exactly that goal: an organ that does not require lifelong anti-rejection drugs. Public project descriptions also cite the potential to reduce the costs of treating chronic patients, although such claims will have to be confirmed through testing and clinical studies. At the health-system level, such technology could in the long run also mean more stable access to transplantation, less dependent on fluctuations in donation and logistics.
But precisely because the potential is large, the standard of proof will be exceptionally high. Open questions include the long-term functionality of a bioprinted liver, the stability of the vascular system and perfusion, risks such as thrombosis, and standardizing production so that every organ is reproducible and comparable. Regulation further complicates the path: it will be necessary to clearly define criteria for quality, safety, and monitoring, and clinical trials will have to show benefit relative to existing options. In the PRINT program, ARPA-H emphasizes from the outset that milestones are aggressive and accelerated, but that does not change the fact that for a transplanted organ, safety criteria will be among the strictest in medicine. In addition, ethical and logistical issues must be considered: from access to manufacturing capacity to fair distribution of the technology once it leaves the lab. That is why it is realistic to expect that, even with substantial funding, the path to routine clinical transplantation will be multi-phase.
And while organ bioprinting is often perceived as a distant future, with this program ARPA-H is signaling that it wants to accelerate the transition from “promising science” to verifiable technology. The UC San Diego project, which combines engineering platforms, clinical expertise, and industrial cell manufacturing, is now entering a five-year cycle in which every phase will have to show that an organ is not only possible to “build,” but also to keep functional, safe, and reproducible. For patients who are waiting for a transplant today, this does not mean an immediate solution, but it does mean that at the national level investment is being directed at technology that targets the very core of the problem: dependence on rare donors and the constraints of immune compatibility. If some of those promises are confirmed in practice, transplant medicine could enter a period in which the concept of a “waiting list” gradually changes, and an organ becomes a therapy that can be planned rather than only hoped for.
Sources:- ARPA-H – official announcement on awarding teams under the PRINT program (January 12, 2026) (link)
- ARPA-H – PRINT program description, goals, and technical axes (bioprinting personalized organs without immunosuppression) (link)
- Business Wire – Allele Biotech on the partnership with UC San Diego, the project up to $25.8 million, and the role of iPSC/GMP manufacturing (January 13, 2026) (link)
- CDC (NCHS) – FastStats: chronic liver disease and cirrhosis (summary indicators) (link)
- CDC (NCHS) – National Vital Statistics Reports: leading causes of death in the U.S. (context for chronic liver disease and cirrhosis) (link)
- organdonor.gov (HRSA) – statistics on organ donation and waiting lists in the U.S. (link)
- SRTR – OPTN/SRTR Annual Data Report: national transplant and waiting-list trends (link)
- University of California – report on 3D bioprinted functional liver tissue (2016, a research milestone) (link)
- Jacobs School of Engineering (UC San Diego) – Prof. Shaochen Chen profile and research areas (link)
- BICO – announcement of the acquisition of Allegro 3D and the DLP/Digital Light approach to bioprinting (technology translation context) (link)
- CELLINK – partnership with UC San Diego on a center of excellence for 3D bioprinting (2023) (link)
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