D printer creates transformative device for heart treatment

Date:

February 25, 2014

Source:

Washington University in St. Louis

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.

The findings were published online in Nature Communications Feb. 25, 2014.

"Each heart is a different shape, and current devices are one-size-fits-all and don't at all conform to the geometry of a patient's heart," says Efimov, the Lucy & Stanley Lopata Distinguished Professor of Biomedical Engineering. "With this application, we image the patient's heart through MRI or CT scan, then computationally extract the image to build a 3-D model that we can print on a 3-D printer. We then mold the shape of the membrane that will constitute the base of the device deployed on the surface of the heart."

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.

"Currently, medical devices to treat heart rhythm diseases are essentially based on two electrodes inserted through the veins and deployed inside the chambers," Efimov says. "Contact with the tissue is only at one or two points, and it is at a very low resolution. What we want to create is an approach that will allow you to have numerous points of contact and to correct the problem with high-definition diagnostics and high-definition therapy."

Co-leading the team with Efimov is John Rogers, PhD, the Swanlund Chair and professor of materials science and engineering and director of the F. Seitz Materials Research Laboratory at the University of Illinois at Urbana-Champaign. Rogers, who developed the transfer printing technique, developed the sensors using semiconductor materials including silicon, gallium arsenide and gallium nitride, along with metals, metal oxides and polymers.

Recently, Google announced its scientists had developed a type of contact lens embedded with sensors that could monitor glucose levels in patients with diabetes. Efimov says the membrane his team has developed is a similar idea, though much more sophisticated.

"Because this is implantable, it will allow physicians to monitor vital functions in different organs and intervene when necessary to provide therapy," he says. "In the case of heart rhythm disorders, it could be used to stimulate cardiac muscle or the brain, or in renal disorders, it would monitor ionic concentrations of calcium, potassium and sodium." Efimov says the membrane could even hold a sensor to measure troponin, a protein expressed in heart cells and a hallmark of a heart attack. Analysis for troponin is standard of care for patients with suspected heart attacks due to a test developed by Jack Ladenson, PhD, the Oree M. Carroll and Lillian B. Ladenson Professor of Clinical Chemistry in Pathology and Immunology and professor of clinical chemistry in medicine at the School of Medicine.

Ultimately, such devices will be combined with ventricular assist devices, Efimov says. "This is just the beginning," he says. "Previous devices have shown huge promise and have saved millions of lives. Now we can take the next step and tackle some arrhythmia issues that we don't know how to treat."

Graphical depiction of the key steps in device design and fabrication. Scale bar, 2 cm. (b) Images of a representative 3D multifunctional integumentary membrane (3D-MIM) integrated on a Langendorff-perfused rabbit heart.

Calculated pressure distribution induced by a device with total thickness of 150 μm and effective Young’s modulus of 60 kPa under various conditions of volume expansion of a heart geometry.

Representative optical and electrical signals acquired simultaneously from the corresponding numbered electrode locations on a Langendorff-perfused rabbit heart.

Comparative analyse

On statistical data, mortality from diseases of cardiovascular system all the time grows in the world. Studying of the reasons of these diseases showed that one of them are connected with an infection, others have hereditary or congenital character. However the biggest group of diseases in many respects is consequences of addictions and the wrong way of life.

The medicines influencing the main pathogenetic links of these diseases, including the means improving a coronary blood-groove, reducing load of the myocardium, hearts lowering a porebnost in the oxygen, improving processes occurring in it are widely applied. Alsow many who had to address in policlinics, saw the devices intended for performance of very simple physiotherapeutic functions.

Tens years ago in medicine invented the Pacemaker which mission impact on a heart rhythm is. It comes to the rescue to those patients which heart impulses with normal rate aren't capable to generate independently. Roughly speaking, it "the clever battery" for heart.

This device consists of the electronic scheme which generates impulses, wires electrodes, and also the battery which supports the device in working order throughout a long time.

fortunately development of technology doesn't stand still and couple of days ago chemists engineers created the new device on regulation of work of heart.

Using an inexpensive 3-D printer, biochemical engineers have developed a custom-fitted, implantable device with embedded sensors that could transform treatment and prediction of cardiac disorders. The 3-D elastic membrane is made of a soft, flexible, silicon material that is precisely shaped to match the heart’s outer layer of the wall. 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.

The new technology is based on two electrodes which are entered into veins to the patient and predict all diseases the hearts tied with work.

Uniqueness of new equipment is merge of biochemistry to the direction in the field of computer facilities that is listing process in 3D heart format.

Rogers who developed a method of the press of transfer, developed sensors, using semiconductor materials including silicon, arsenide of gallium and gallium nitrate, along with metals, metal oxides and polymers.

Moreover sensors of the device being in chambers of heart will control ionic concentration of calcium, potassium and sodium.

Тhus the new device is an improved version of an old pacemaker and in the future in the world there are much less people suffering cardiovascular diseases.