news digest ♦ Novel Devices
of a patient’s heart,” says Efimov. “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 three million to five 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,” says Efimov, also a professor of radiology and of cell biology and physiology at the School of Medicine. “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, 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 GaAs, GaN and silicon, 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.
when necessary to provide therapy,” he adds. “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, 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.”
This work has been described in detail in the paper, “3D multifunctional integumentary membranes for Spatiotemporal cardiac measurements and stimulation across the entire epicardium,” by Xu L et al in Nature Communications, 5 (3329). doi:10.1038/ncomms4329
Funding for this research was provided by the National Institutes of Health R01 HL115415, R01 HL114395 and R21 HL112278; the Frederick Seitz Materials Research Laboratory and Centre for Microanalysis of Materials at the University of Illinois at Urbana-Champaign.
This article was adapted from one written by Beth Miller at the University of Washington.
Physicists discover ‘quantum droplet’ in GaAs
A new quasiparticle by exciting gallium arsenide with an ultrafast red laser initially form excitons
JILA physicists used an ultrafast laser and help from German theorists to discover a new semiconductor quasiparticle - a handful of smaller particles that briefly condense into a liquid-like droplet.
An example of the 3-D elastic membrane being developed by Efimov and his team
“Because this is implantable, it will allow physicians to monitor vital functions in different organs and intervene
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www.compoundsemiconductor.net March 2014
Quasiparticles are composites of smaller particles that can be created inside solid materials and act together in a predictable way. A simple example is the exciton, a pairing, due to electrostatic forces, of an electron and a so-called ‘hole,’ a place in the material’s energy structure
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