Igor Efimov (Washington University, St. Louis)
25 February 2014. Engineers and medical researchers at Washington University in St. Louis and University of Illinois in Champaign used a three-dimensional printer to create a membrane that fits over the heart, with electronic components to monitor its functions. The team led by Washington University’s Igor Efimov and Illinois’s John Rogers published its findings today in the journal Nature Communications (paid subscription required).
The researchers, which include colleagues from Northwestern University, universities of Texas and Alberta, and institutions in China, Korea, and Singapore sought to create a device that could fit snugly over the outer heart wall without the need for adhesives or sutures to hold it in place. The goal of the system is to provide a platform for multiple circuits that can monitor cardiac functions, and if necessary deliver therapy, better than current devices.
Efimov explains that current technologies for treating heart rhythm disorders, such as atrial fibrillation, have two electrodes that are inserted through the veins and contact heart tissue at only one or two points inside the heart chamber. “What we want to create,” says Efimov in a Washington University statement, “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.”
The Washington University-Illinois team designed an elastic soft-plastic membrane that fits over the heart, but must be custom made to exactly match each patient’s heart geometry. The researchers use CT or MRI scans to create an image and determine dimensions of the heart, then apply computational techniques to build a 3-D model. That model is then fed into a conventional 3-D printer that prints the membrane.
Rogers, a materials scientist, developed techniques for transfer printing of circuits on flexible membrane surfaces. In this project, the circuits printed on the membrane are made from silicon, gallium arsenide, and gallium nitride. The researchers reported on physiological tests of the device in the lab with extracted hearts.
In addition to sensor circuits for pH, temperature and mechanical strain, the membrane can also support controllers for electrical, thermal, and optical stimulation. The membrane can support as well a sensor for troponin, a protein released when the heart is damaged, and can serve as an indicator of a heart attack. Tests for troponin, developed by a Washington University colleague, now require a separate blood sample.
The technology need not be restricted to heart functions, says Efimov. “Because this is implantable” he notes, “it will allow physicians to monitor vital functions in different organs and intervene when necessary to provide therapy. 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.”
In 2008, Efimov founded Cardialen Inc., a company in St. Louis and Minneapolis that licenses and commecializes discoveries from Washington University, and where he serves as the company’s chief scientific advisor. Rogers is the holder of some 80 patents and founder of several companies commercializing his lab’s research.
Read more:
- New Process Speeds 3-D Printing of Multiple Materials
- 3-D Printing, Computer Model Generate Synthetic Bone Matter
- PET/MRI Scanning Technique Devised to Track 3-D Motion
- Synthetic Tissue Created with Water, Lipids, 3-D Printing
- Anatomical Models 3-D Printed from Tomography Scans
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