Breakthrough soft robotics could redefine artificial heart technology

Breakthrough soft robotics could redefine artificial heart technology

A groundbreaking soft robotic heart could transform treatment for end-stage heart failure and bring us closer than ever to fully functioning, biocompatible artificial organs.

Study: A soft artificial hybrid heart. Photo credit: Africa Studio/Shutterstock.com

The researchers developed a total artificial hybrid heart by soft robotics that can open new horizons in heart failure and transplant medicine. The article containing the first proof of concept of this novel discovery is published in the journalNature communication.

background

End-stage heart failure is associated with a high mortality rate. The disease is treatable through heart transplantation; However, the unavailability of donor hearts is the main disadvantage. This limitation has led to the development of total artificial hearts and left ventricular assist devices.

These artificial devices have poor biocompatibility because the materials used to design them are not derived from the patient's body. Additionally, these devices do not physically work to circulate blood throughout the body. These factors can induce blood clot formation, which can subsequently lead to complications related to blood flow.

Percutaneous propulsion devices, which are required to power and connect currently available cardiac devices to an external source, have a high risk of infection and significantly impact a patient's quality of life. These complications currently limit the clinical use of the total artists currently available.

In the current study, researchers developed a hybrid total artist in which the pump power comes from soft robotics to physiologically advance the blood. They called the device a “hybrid heart.”

Hybrid heart – design and working principle

Researchers designed this new generation of total artists with the idea that the device should mimic the structure and function of the human heart. The human heart has two chambers, the left and right ventricles, which are separated by a septum (a partition). The synchronous contraction of the ventricles and septum results in blood being expelled from the circulating ventricles.

Like the human heart, the hybrid heart contains two artificial chambers separated by a soft pneumatic muscle (septum). The ventricles and septum are made of nylon coated with thermoplastic polyurethane. Notably, the design also includes multiple non-detailable wires arranged in a closed loop that play a key role in mimicking the heart's coordinated contractions by distributing forces across both ventricles.

Supramolecular coatings are applied to the thermoplastic polyurethane-coated nylon material to improve biocompatibility.

Positive or negative air pressure is used to inflate and deflate the septum. As the septum inflates during systole, its inner diameter increases, allowing more wire to be wrapped around it. This squeezes the ventricles to eject blood like a natural heart. As the septum empties during diastole, the ventricles passively refill.

The specific length and number of wires around each ventricle can be adjusted to change the cardiac output of each chamber, thereby adapting the requirements to the requirements of different physiological conditions or diseases. This adjustability could be important to adapt the device to individual patient requirements, for example in pulmonary hypertension.

In early trials, the soft robotic system demonstrated the ability to generate pressure curves similar to those in natural heartbeats, giving the device a more lifeless pumping rhythm.

A robotic actuation mechanism provides the required pressure profile for the septum of the hybrid heart. The actuation mechanism translates control signals into physical actions within a system. This soft robotic combat mechanism does not rely on electronics to generate a heartbeat. Instead, it autonomously and passively converts the constant flow of a continuous air pump into pressure pulses that generate the heartbeat for the hybrid heart.

However, the overall system also includes electronic components for power and control, particularly in future fully implantable versions.

Functional validation

Laboratory testing of the hybrid heart under physiological conditions revealed that the device mimics the pumping physiology of the human heart and its left ventricle can pump 5.7 liters of blood per minute (cardiac output) at a heart rate of 60 beats per minute. Because the left ventricle cardiac output should be higher than the right ventricle, the right ventricle cardiac output of the device was adjusted to 5 liters per minute by adjusting the length of the wires around the right ventricle.

The hybrid heart was further tested in animals by surgically implanting the device in the pericardial space. The device was responsible for all animal blood flow during a test period of 50 minutes.

The animal test was a short-term experiment, not a long-term implant, providing an initial proof-of-concept for the device's functionIn vivo.

However, in the acute animal test, cardiac output was lower thanin vitro(Approximately 2.3 liters per minute at 65 bpm), reflecting the early stage of the device, proof-of-concept nature and expected technical limitations.

The results showed that the thermoplastic polyurethane-coated nylon material used in the hybrid heart is non-toxic, has improved biocompatibility, and has strong anti-thrombogenic properties due to their supramolecular coatings.

animal andin vitroTesting showed a significant reduction in platelet adhesion and thrombosis compared to uncoated materials, supporting the potential for long-term blood compatibility.

In laboratory and animal experiments, an open pneumatic system was used to actuate the hybrid hearts. However, a fully implantable, closed fluidic driving system has been developed for future clinical use. This system consisted of an implanted continuous flow air pump, an air reservoir, and a soft robotic actuation system connected to the septum in a closed circulation loop.

The closed fluidic system was integrated into a transcutaneous energy transfer (TET) system to wirelessly provide electrical energy to the pump. The external Tet coil placed on the patient's skin exceeded the force in the subcutaneously implanted internal Tet coil while the skin remained intact.

This approach can potentially reduce the risk of infection and improve patients' quality of life by allowing them to temporarily disconnect from a power source and engage in activities such as showering or swimming.

Testing of this closed fluidic system revealed that when the continuous flow pump was powered, the hybrid heart automatically started beating at a heart rate of 35 bpm and produced a relatively low cardiac output compared to that produced by the conventional driving system.

This limitation was attributed in the initial experiments to the available power of the TET system, which was not a fundamental barrier to the technology. The research found that increasing input energy should improve cardiac output, and researchers are currently working on this.

Furthermore, the hybrid heart demonstrated adaptive physiological properties. Preload and afterload sensitivity means the hybrid heart can adjust its output in response to blood pressure and volumes like a natural heart. This is achieved passively, mimicking the Frank-Starling mechanism, whereby the heart increases production in response to increased filling, without the need for complex sensors or electronics.

The design also allows for individual configuration of the device, e.g. B. Changing the wire length and position tailored to individual patient requirements.

While the proof of concept is promising, the work is still in its infancy. The device was built on prototyping materials rather than medical-grade components, and further long-term animal studies will be required to fully validate the technology's safety, durability and performance.

Before clinical use, all key components, including the fully implantable version and the tissue engineering coatings, require extensive further testing, including long-term animal studies.

Meaning

The study provides the first evidence that soft robotic techniques can successfully develop a biocompatible artificial heart that can deliver adequate cardiac output under physiological conditions.

The hybrid heart developed in the study can overcome the shortcomings of currently available total artificial hearts and potentially provide both anti-thrombogenic surfaces and support for tissue integration.

For example, in the future, coating technology could be further developed to include molecules that actively encourage the body's cells to colonize the device and form a functional inner lining. This dual approach to reducing blood clotting and supporting the body's tissue integration could reduce the need for lifelong anticoagulation therapy.

Although the hybrid heart is not yet ready for clinical use and requires further thorough testing and optimization, it shows how soft robotics and biomimetic engineering can provide safer, functional and more adaptable artificial hearts for those in late-stage heart failure.

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