The latest artificial organs are set to bring hope to patients with no other options. It’s a matter of life or death. These organs must replicate complex functions, taking decades in the making. Imma Perfetto investigates the latest in this lifesaving medical research. This article originally appeared in the Cosmos Print Magazine, March 2025.
Almost two decades ago in the intensive care unit of Brisbane’s Prince Charles Hospital, biomedical engineer Daniel Timms was watching his father’s health decline. It was 2006 and the only way Gary Timms could communicate was by writing on a piece of paper.
Gary Timms had been diagnosed with heart failure 5 years prior, following a heart attack at just 50 years of age. The event galvanised his son to begin the long and complicated journey towards inventing a device that could replace the function of his father’s failing heart – a Total Artificial Heart (TAH).
“There was a period of time where [Dad’s] health declined, and then he was in the hospital, the same hospital that I was working [at] with the surgeons and clinicians that were looking after him,” says Daniel Timms, who is now the founder and chief technical officer of the US-based medical device company BiVACOR.
Timms couldn’t build a heart in time to save his dad, who passed shortly after being admitted to hospital that final time. But the dream was finally realised in July last year. His invention – a 650-gram titanium pump that whooshes blood around the body using magnetic levitation (MAGLEV) technology – was implanted in a human for the first time.
“The first time when the patient woke up and could write ‘I want a soda’ or he could communicate with his family was a pretty surreal moment for me,” says Timms.
The BiVACOR TAH kept the patient alive and well for 8 days before a heart transplant became available.
Gary and Daniel Timms after Daniel graduated with his PhD in Gary died 6 months later. Credit: Supplied by Daniel Timms.
When hearts fail
About 64 million people are affected by heart failure worldwide. The most common causes are heart attack and coronary heart disease, though there are numerous others.
There is no cure and only about 7,000 heart transplants are performed each year. This heartbreaking gap between donor organ supply and demand isn’t unique, as patients with all kinds of end-stage organ failure can be left waiting years for lungs, livers, and kidneys, and many die on the waiting list.
Still, if a patient wins the transplant lottery, they must remain on immunosuppressing drugs for the rest of their life and contend with all the side-effects that entails, such as increased risk of cancer and infection.
Artificial organs like the BiVACOR TAH can offer a lifeline to these people until they can receive a new organ. And, eventually, they may even replace transplants entirely.
Daniel Timms, founder and chief technical officer of BiVACOR, performing a Total Artificial Heart blood loop test. Credit: BiVACOR.
What are artificial organs?
Though they may seem futuristic, humans have had a long history with artificial organs; devices designed to replace or augment the function or appearance of a missing, diseased, or otherwise incompetent part of the body.
The first organ part to appear in the archaeological record – a wooden prosthetic big toe – was discovered on an Egyptian mummy dating to 3,000-2,700 years ago. It’s an example of a mechanical artificial organ, constructed of inanimate materials such as wood, plastics, and metals. Today they’re a little more high-tech.
Cochlear implants have been sending sound information to the auditory centres in the brains of hearing-impaired people since the late 1970s. Bionic eyes capable of restoring some sight to people with profound vision loss due to retinal degeneration have received regulatory approval too, though none are commercially available at present.
Artificial pancreases are changing the game for people living with diabetes too. Granted, these systems sit outside the body and aren’t completely hands off, requiring users to count carbohydrates and manually begin some insulin doses. But researchers at the Australian Artificial Pancreas Program are developing an algorithm that could use a patient’s history to assess the likelihood of upcoming food and exercise activities, and even learn as those habits change, to make the technology completely autonomous.
When it comes to alternatives for patients with end-stage organ failure, things become much more complicated. Despite extensive work since the 1980s to develop implantable artificial lungs, none have passed early-stage development yet. Bulky devices called extracorporeal membrane oxygenators (ECMO) can temporarily take over the job of oxygenating the blood and pumping it around the body for patients with lung failure. But these technologies can only be used for a limited time – days to weeks – and are not a permanent solution.
Dialysis remains the only alternative to transplant for patients with end stage renal disease. But in addition to only performing the blood filtration function of kidneys, the procedure is costly, time-consuming, and associated with poor patient quality of life. So, several groups are tackling the challenge of developing portable, wearable, and even implantable mechanical artificial kidneys. Already, an external dialysis machine designed for home use and travel has been tested in human trials, as has a small (roughly 2kg) automated machine which sits inside the abdomen for continuous use. But mimicking all the functions of biological systems as complex as the kidneys might require a step into the squishier side of artificial organs – incorporating living human cells.
Print on demand organs
The Kidney Project in the United States is developing a bioreactor that houses kidney cells. These bioreactors could perform various functions, such as balancing the body’s fluids and releasing hormones to regulate blood pressure. The team is aiming to combine this with a haemofilter – silicon membranes that can remove waste from the blood – in an implantable device. The haemofilter would require no external connections or power sources to function. A small-scale prototype has already been successfully tested in lambs and pigs.
But 3D-bioprinting may even allow scientists to print whole, bespoke bioartificial organs one day. Extrusion bioprinting, an approach that functions much like squeezing toothpaste out of a tube, has already been used by US company 3DBio Therapeutics to create living ear tissue. A collagen bioink containing human cartilage cells was pushed through a nozzle and built-up layer by layer to create the structure of an outer ear. In 2022, it was implanted in a 20-year-old woman who had been born with microtia – a rare congenital condition in which one or both outer ears are absent or underdeveloped.
“My personal, ultimate goal is to print a kidney,” says David Collins, head of the Collins BioMicrosystems Laboratory in the University of Melbourne’s Department of Biomedical Engineering.
“I have a cousin, and he has had 2 kidney transplants now. He’s taken one from one of his brothers, he’s taken one from one of his sisters. He’s actually run out of siblings now. So, he needs his current kidney transplant to keep on going for a while, at least until I can print a new one for him.”
Kidney-shaped model that has been printed with 7.2 million cells per mL. Credit: Supplied.
Collins believes that his team’s new 3D bioprinting technology, Dynamic Interface Printing (DIP), could one day allow them to replicate the extraordinary cellular complexity of the kidney. The kidney “does not function unless you have a very particular arrangement of cells that repeat thousands and tens of thousands of times over. This is called the nephrons. The resolutions that we would need to recreate that kidney structure [is] on the order of single cells.”
DIP uses light to cure the liquid printing medium, trapping suspended cells in a solid structure. A particular wavelength of light triggers a chemical reaction, causing individual chemical units (monomers) in the liquid to link up into chains (polymers).
This light shines down from the printhead through a bubble in the liquid. As the bubble is lifted vertically, each layer of the printed structure is added on top of the last. But the bubble isn’t just moving vertically, it’s also vibrating. These sound waves continuously mix the medium so that there’s a constant influx of new liquid to be cured, so that cells don’t settle at the bottom of the mix.
“[DIP] represents something that is about 100 times faster than anything else that’s come before,” says Collins. Practically, this means that structures can be created on timelines of seconds to minutes, rather than hours. The technique can even do away with printing on solid surfaces by layering a thicker liquid below the printing solution. The bio-printed structure sits within the liquid without sinking, throughout the entire process. This means the print can be as soft and flexible as needed and it won’t collapse. And, since DIP can be carried out directly into conventional laboratory plates or wells, there’s no need to risk damage by transferring delicate structures around.
Even before DIP might replicate the immense complexity of a kidney, Collins sees it as an incredibly useful technology for pharmaceutical testing. “We would be creating [hundreds] of tissue models… that replicate a structure and the cellular arrangement that we would find in the native human tissues… and we’d be screening panels of drugs against these libraries of tissue models.”
A step further might involve producing these models for personalised drug screening – using individual patients’ cells to determine the best course of treatment for their particular illness.
“There’s a whole host of things that we can do to apply [DIP] to the human body before we actually start printing organs, per se,” says Collins. “So, for example, in plastic and reconstructive surgery. It would be very interesting to use that as the first test case for printing structures that then we can put in the human body.”
David Collins, head of the Collins BioMicrosystems Laboratory, next to a Dynamic Interface Printing setup. Credit: Courtesy of David Collins.
The decade of artificial hearts
Where some artificial organs are still in their infancy, people have been implanting mechanical hearts for decades. Originally, researchers attempted to replicate the way the natural heart beats – by squeezing blood out of compressed sacs – and by using one-way valves and moving parts to pump the blood around the body. The first was implanted in 1969 in a human who lived with the device for just 64 hours. Today, only the SynCardia TAH is approved for use as a temporary stopgap until a transplant becomes available.
“Unfortunately, though, moving sacks and membranes and valves beating once a second, is [thousands] of times a day, is millions and millions of times a year. Eventually that’s going to break and wear out,” explains Timms. The BiVACOR TAH is designed to be different.
“[The] approach that we’re taking here is doing away with mimicking how mother nature pumps blood around and instead using the rapidly spinning disc that’s magnetically levitated. That eliminates that durability concern, which is essential for an artificial heart, and instead propels the blood around the body with no valves and no membranes.”
With only a single moving part, the flow paths through the device can also be controlled to eliminate areas for blood to stagnate and clot, lowering the chance that a patient will suffer from stroke – a major complication of existing devices.
An external controller and 2 rechargeable batteries, each with 5 hours of charge, provide power to the internal device via a driveline tube through the skin into the abdomen. And it only requires about half the amount of power as a laptop.
Last year, the BiVACOR TAH was implanted in 5 patients – in a US Food and Drug Administration (FDA)-approved, first-in-human, Early Feasibility Study. The participants were monitored in-hospital as they awaited suitable donor hearts.
“The fourth patient, I believe it was, he’s a little bit of an older gentleman… he was an engineer and was a tinkerer, kind of like my dad was,” Timms recalls. “It was good to see it progress through to a stage where the patient was completely recovered and could have continued on with the device for a long time.”
While the FDA reviews this initial data, Timms says they are looking to conduct more implants in Australia. This will be done in partnership with the Artificial Hearts Frontiers Program (AHFP), which was recently awarded a $50 million grant from the Australian Government’s Medical Research Future Fund.
Shaun Gregory, AHFP Co-Director and biomedical engineer (who incidentally undertook his honours research with Timms at QUT) says the program aims to develop a solution for all patients with heart failure. “The way we plan to do that is work with the industry partner, BiVACOR, to help them to develop parts of their Total Artificial Heart to generate a new Left Ventricular Assist Device (LVAD)… and also develop a much smaller, long-term device [the Mini-Pump].” These devices do not replace a failing heart but support it instead.
Shaun Gregory, Artificial Hearts Frontiers Program co-director. Credit: Courtesy of Shaun Gregory.
LVADs are a treatment option for roughly half of heart failure patients, who live with what’s known as reduced ejection fraction (HFrEF), which typically means that they have an enlarged heart. “They don’t have much blood flow going through. Their heart muscles are really quite big and stretched,” explains Gregory.
These LVADs can be implanted into the left ventricle (chamber) of such a heart to increase blood flow out of it. Unfortunately, no equivalent device exists for the roughly 50% of people who live with heart failure with preserved ejection fraction (HFpEF). “Their heart is similar sized but has a thick and stiffer wall… which means it has a really small cavity,” says Gregory. “It’s hard to get these [LVAD] devices in there, because they don’t really fit. We need a different solution for them.” The team at AHFP is developing a whole new device, the Mini-Pump, for this purpose.
But these devices don’t exist in isolation. The interdisciplinary team – which includes cardiologists, cardiac surgeons, engineers, biological scientists, and industrial designers – is designing an entire ecosystem of peripheral technologies to support their use. This includes remote monitoring systems which allow clinicians to keep an eye on their patients’ safety outside of the hospital; durable and infection-resistant drivelines; better surgical tools and clinical training platforms for the surgeons implanting them; and more.
“We want to be able to have better wearable systems where the patients are more comfortable,” says Gregory.
“We want to have better manufacturing of these devices to make them cheaper and more mass producible. We want to have better models to test these things in. We want to make them more blood friendly.” But ensuring that such a device will work perfectly inside an environment as complex as a human chest, without a single fault for a decade or more, will take time. The plan is to release all 3 devices – the BiVACOR TAH, LVAD, and Mini-Pump – in a staggered approach over the coming decade.
The Left Ventricular Assist Device (LVAD) and Mini-Pump, for patients with late-stage heart failure. Credit: Courtesy of Shaun Gregory.
According to Timms, the next steps for the BiVACOR TAH will involve applying for a US-FDA clinical trial in which patients can leave the hospital with their implant. “The following year, we’ll be looking to do a clinical trial with the FDA, where those patients will either get a transplant or they’ll stay on the device for two years or longer, essentially the destination of their life.” Destination therapies are long-term solutions, rather than transitional treatments. Timms firmly believes that the BiVACOR TAH will be a destination therapy for patients with end-stage heart failure: “It’s just a matter of time before we get there.”
Ultimately, the key to eliminating the need for donor hearts is by guaranteeing patients the same quality of life as if they received a transplant. For instance, while the TAH’s MAGLEV system can already detect a patient’s motion, the flow it produces remains relatively constant. This isn’t the case for a real heart, which can change its force and rate of contraction based on what the body needs. By incorporating a smart algorithm, the artificial heart devices could potentially allow for an automatic ramping of speed during exercise or even a reduction in blood flow during sleep.
The driveline supplying power to the device is also an open wound, essentially, and requires constant cleaning to prevent infections. Transferring power wirelessly through the skin might prove to be the solution.
“In the artificial heart field, I think we are slowly moving towards what I call forgettable devices,” says Gregory. “Devices that go into patients where they almost don’t realise that they have them anymore… I think that’s quite exciting.”