Using an inexpensive 3-D printer, biomedical engineers have developed a custom-fitted, implantable device with embedded sensors that could transform treatment and prediction of cardiac disorders.
Igor Efimov, PhD, at the School of Engineering & Applied Science at Washington University in St. Louis and an international team of biomedical engineers and materials scientists have created a 3-D elastic membrane made of a soft, flexible, silicon material that is precisely shaped to match the heart’s epicardium, or the outer layer of the wall of the heart. Current technology is two-dimensional and cannot cover the full surface of the epicardium or maintain reliable contact for continual use without sutures or adhesives.
The team can then print tiny sensors onto the membrane that can precisely measure temperature, mechanical strain and pH, among other markers, or deliver a pulse of electricity in cases of arrhythmia. Those sensors could assist physicians with determining the health of the heart, deliver treatment or predict an impending heart attack before a patient exhibits any physical signs.
It is about 10-15 years away from being made available to humans, but the revolutionary device might be a long-term solution to normally catastrophic events like heart attacks. It may help prevent heart attacks in humans.
The figure above is a graphical depiction of the steps researchers took to design and create the 3-D elastic membrane that is shaped precisely to match the epicardium of the heart. The top row, from left to right, shows the rabbit heart, the 3-D printed model, the membrane, then the membrane integrated with the heart. The large center photo shows the sensors on the membrane on the heart. The bottom row, from left to right, shows the different sensors that can be used in the membrane.
Ultimately, the membrane could be used to treat diseases of the ventricles in the lower chambers of the heart or could be inserted inside the heart to treat a variety of disorders, including atrial fibrillation, which affects 3 million to 5 million patients in the United States.
The sensors track tissue movement and use the signals the nervous system, would normally send to the heart to regulate pulse.
This methodology allows the device to keep the heart beating even when a heart attack or arrhythmia occurs.
‘When it senses such a catastrophic event as a heart attack or arrhythmia, it can also apply a high definition therapy,’ biomedical engineer Igor Efimov told St. Louis Public Radio.
‘It can apply stimuli, electrical stimuli, from different locations on the device in an optimal fashion to stop this arrhythmia and prevent sudden cardiac death.’
The electrical stimuli regulate the heart’s movement, which means blood will keep flowing and more people will keep living.
The video shows a rabbit heart that has been kept beating outside of the body in a nutrient and oxygen-rich solution. The new cardiac device — a thin, stretchable membrane imprinted with a spider-web-like network of sensors and electrodes — is custom-designed to fit over the heart and contract and expand with it as it beats.
Means for high-density multiparametric physiological mapping and stimulation are critically important in both basic and clinical cardiology. Current conformal electronic systems are essentially 2D sheets, which cannot cover the full epicardial surface or maintain reliable contact for chronic use without sutures or adhesives. Here we create 3D elastic membranes shaped precisely to match the epicardium of the heart via the use of 3D printing, as a platform for deformable arrays of multifunctional sensors, electronic and optoelectronic components. Such integumentary devices completely envelop the heart, in a form-fitting manner, and possess inherent elasticity, providing a mechanically stable biotic/abiotic interface during normal cardiac cycles. Component examples range from actuators for electrical, thermal and optical stimulation, to sensors for pH, temperature and mechanical strain. The semiconductor materials include silicon, gallium arsenide and gallium nitride, co-integrated with metals, metal oxides and polymers, to provide these and other operational capabilities. Ex vivo physiological experiments demonstrate various functions and methodological possibilities for cardiac research and therapy.