Tag Archives: Roberto Peralta

Powered by light: a battery-free pacemaker

I think it looks more like a potato than a heart but it does illustrate how this new battery-free pacemaker would wrap around a heart,

Caption: An artist’s rendering shows how a new pacemaker, designed by a UArizona-led team of researchers, is able to envelop the heart. The wireless, battery-free pacemaker could be implanted with a less invasive procedure than currently possible and would cause patients less pain. Credit: Philipp Gutruff

An October 27, 2022 news item on ScienceDaily announces a technology that could make life much easier for people with pacemakers (Comment: In the image, that looks more like a potato than a heart, to me),

University of Arizona engineers lead a research team that is developing a new kind of pacemaker, which envelops the heart and uses precise targeting capabilities to bypass pain receptors and reduce patient discomfort.

An October 27, 2022 University of Arizona news release (also on EurekAlert) by Emily Dieckman, which originated the news item, explains the reasons for the research and provides some technical details (Note: Links have been removed),

Pacemakers are lifesaving devices that regulate the heartbeats of people with chronic heart diseases like atrial fibrillation and other forms of arrhythmia. However, pacemaker implantation is an invasive procedure, and the lifesaving pacing the devices provide can be extremely painful. Additionally, pacemakers can only be used to treat a few specific types of disease.

In a paper published Wednesday [October 26, 2022] in Science Advances, a University of Arizona-led team of researchers detail the workings of a wireless, battery-free pacemaker they designed that could be implanted with a less invasive procedure than currently possible and would cause patients less pain. The study was helmed by researchers in the Gutruf Lab, led by biomedical engineering assistant professor and Craig M. Berge Faculty Fellow Philipp Gutruf.

Currently available pacemakers work by implanting one or two leads, or points of contact, into the heart with hooks or screws. If the sensors on these leads detect a dangerous irregularity, they send an electrical shock through the heart to reset the beat.

“All of the cells inside the heart get hit at one time, including the pain receptors, and that’s what makes pacing or defibrillation painful,” Gutruf said. “It affects the heart muscle as a whole.”

The device Gutruf’s team has developed, which has not yet been tested in humans, would allow pacemakers to send much more targeted signals using a new digitally manufactured mesh design that encompasses the entire heart. The device uses light and a technique called optogenetics.

Optogenetics modifies cells, usually neurons, sensitive to light, then uses light to affect the behavior of those cells. This technique only targets cardiomyocytes, the cells of the muscle that trigger contraction and make up the beat of the heart. This precision will not only reduce pain for pacemaker patients by bypassing the heart’s pain receptors, it will also allow the pacemaker to respond to different kinds of irregularities in more appropriate ways. For example, during atrial fibrillation, the upper and lower chambers of the heart beat asynchronously, and a pacemaker’s role is to get the two parts back in line.

“Whereas right now, we have to shock the whole heart to do this, these new devices can do much more precise targeting, making defibrillation both more effective and less painful,” said Igor Efimov, professor of biomedical engineering and medicine at Northwestern University, where the devices were lab-tested. “This technology could make life easier for patients all over the world, while also helping scientists and physicians learn more about how to monitor and treat the disease.”

Flexible mesh encompasses the heart

To ensure the light signals can reach many different parts of the heart, the team created a design that involves encompassing the organ, rather than implanting leads that provide limited points of contact.

The new pacemaker model consists of four petallike structures made of thin, flexible film, which contain light sources and a recording electrode. The petals, specially designed to accommodate the way the heart changes shape as it beats, fold up around the sides of the organ to envelop it, like a flower closing up at night.

“Current pacemakers record basically a simple threshold, and they will tell you, ‘This is going into arrhythmia, now shock!'” Gutruf said. “But this device has a computer on board where you can input different algorithms that allow you to pace in a more sophisticated way. It’s made for research.”

Because the system uses light to affect the heart, rather than electrical signals, the device can continue recording information even when the pacemaker needs to defibrillate. In current pacemakers, the electrical signal from the defibrillation can interfere with recording capabilities, leaving physicians with an incomplete picture of cardiac episodes. Additionally, the device does not require a battery, which could save pacemaker patients from needing to replace the battery in their device every five to seven years, as is currently the norm.

Gutruf’s team collaborated with researchers at Northwestern University on the project. While the current version of the device has been successfully demonstrated in animal models, the researchers look forward to furthering their work, which could improve the quality of life for millions of people.

The prototype looks like this,

Caption: The device uses light and a technique called optogenetics, which modifies cells that are sensitive to light, then uses light to affect the behavior of those cells.. Credit: Philipp Gutruff

Here’s a link to and a citation for the paper,

Wireless, fully implantable cardiac stimulation and recording with on-device computation for closed-loop pacing and defibrillation by Jokubas Ausra, Micah Madrid, Rose T. Yin, Jessica Hanna, Suzanne Arnott, Jaclyn A. Brennan, Roberto Peralta, David Clausen, Jakob A. Bakall, Igor R. Efimov, and Philipp Gutruf. Science Advances 26 Oct 2022 Vol 8, Issue 43 DOI: 10.1126/sciadv.abq7469

This paper is open access.

Osseosurface (bone) electronics

A November 19, 2021 news item on ScienceDaily announced a class of electronic devices that can grow on bone surfaces,

A team of University of Arizona researchers has developed an ultra-thin wireless device that grows to the surface of bone and could someday help physicians monitor bone health and healing over long periods. The devices, called osseosurface electronics, are described in a paper published Thursday [November 18, 2021] in Nature Communication

Caption: Osseosurface electronic devices, which attach directly to the bone, could one day help physicians monitor bone health. One is show here applied to a synthetic bone in the Gutruf Lab at the University of Arizona. Credit: Gutruf Lab

A November 18, 2021 University of Arizona (UArizona) news release, also on EurekAlert, by Emily Dieckman, which originated the news release, delves further into the work (Note: Links have been removed),

“As a surgeon, I am most excited about using measurements collected with osseosurface electronics to someday provide my patients with individualized orthopedic care – with the goal of accelerating rehabilitation and maximizing function after traumatic injuries,” said study co-senior author Dr. David Margolis, an assistant professor of orthopedic surgery in the UArizona College of Medicine – Tucson and orthopedic surgeon at Banner – University Medical Center Tucson.

Fragility fractures associated with conditions like osteoporosis account for more days spent in the hospital than heart attacks, breast cancer or prostate cancer. Although not yet tested or approved for use in humans, the wireless bone devices could one day be used not only to monitor health, but to improve it, said study co-senior author Philipp Gutruf, an assistant professor of biomedical engineering and Craig M. Berge faculty fellow in the College of Engineering.

“Being able to monitor the health of the musculoskeletal system is super important,” said Gutruf, who is also a member of the university’s BIO5 Institute. “With this interface, you basically have a computer on the bone. This technology platform allows us to create investigative tools for scientists to discover how the musculoskeletal system works and to use the information gathered to benefit recovery and therapy.”

Because muscles are so close to bones and move so frequently, it is important that the device be thin enough to avoid irritating surrounding tissue or becoming dislodged, Gutruf explained.

“The device’s thin structure, roughly as thick as a sheet of paper, means it can conform to the curvature of the bone, forming a tight interface,” said Alex Burton, a doctoral student in biomedical engineering and co-first author of the study. “They also do not need a battery. This is possible using a power casting and communication method called near-field communication, or NFC, which is also used in smartphones for contactless pay.”

Ceramic Adhesive Grows to Bone

The outer layers of bones shed and renew just like the outer layers of skin. So, if a traditional adhesive was used to attach something to the bone, it would fall off after just a few months. To address this challenge, study co-author and BIO5 Institute member John Szivek – a professor of orthopedic surgery and biomedical engineering – developed an adhesive that contains calcium particles with an atomic structure similar to bone cells, which is used as to secure osseosurface electronics to the bone.

“The bone basically thinks the device is part of it, and grows to the sensor itself,” Gutruf said. “This allows it to form a permanent bond to the bone and take measurements over long periods of time.”

For instance, a doctor could attach the device to a broken or fractured bone to monitor the healing process. This could be particularly helpful in patients with conditions such as osteoporosis, since they frequently suffer refractures. Knowing how quickly and how well the bone is healing could also inform clinical treatment decisions, such as when to remove temporary hardware like plates, rods or screws.

Some patients are prescribed drugs designed to speed up bone healing or improve bone density, but these prescriptions can have side effects. Close bone monitoring would allow physicians to make more informed decisions about drug dosage levels.

To give you an idea of the device’s scale,

The device is as thin as a sheet of paper and roughly the size of a penny. Courtesy of Gutruf Lab

Here’s a link to and a citation for the paper,

Osseosurface electronics—thin, wireless, battery-free and multimodal musculoskeletal biointerfaces by Le Cai, Alex Burton, David A. Gonzales, Kevin Albert Kasper, Amirhossein Azami, Roberto Peralta, Megan Johnson, Jakob A. Bakall, Efren Barron Villalobos, Ethan C. Ross, John A. Szivek, David S. Margolis & Philipp Gutruf. Nature Communications volume 12, Article number: 6707 (2021) DOI: https://doi.org/10.1038/s41467-021-27003-2 Published: 18 November 2021

This paper is open access.