Researchers develop flexible bioresorbable monitor for cardiac patients


Researchers have developed a soft, fully bioresorbable, transparent microelectrode array (MEA) for monitoring heart disease and dysfunction.

Outlining the design, fabrication, characterisation and validation of the device in a paper published today in Science Advances, Zhiyuan Chen (The George Washington University, Washington DC, USA) and colleagues state that their design could serve as the basis for technologies for post-surgical monitoring and treatment of temporary patient pathological conditions in clinical scenarios such as myocardial infarction (MI), ischaemia and transcatheter aortic valve implantation (TAVI).

“Several serious complications, including atrial fibrillation and heart block, can follow cardiac surgeries or catheter-based therapies,” said Igor Efimov (Northwestern University, Evanston, USA), an experimental cardiologist who co-led the study. “Current post-surgical monitoring and treatment of these complications require more sophisticated technology than currently available. We hope our new device can close this gap in technology. Our transient electronic device can map electrical activity from numerous locations on the atria and then deliver electrical stimuli from many locations to stop atrial fibrillation as soon as it starts.”

The device consists of US Food and Drug Administration (FDA)-approved bioresorbable and biocompatible materials that eventually dissolve in the body. Key components, outlined in the Science Advances paper, include a transparent and flexible polylactic-co-glycolic acid (PLGA) substrate, an electron beam lithography (EBL)–patterned transparent molybdenum (Mo) nanogrid, a photolithography-determined interconnect layer, and a soft lithography–defined transparent PLGA encapsulation layer.

Studies of the device on rat and human hearts have demonstrated its capability in functions including colocalised multiparametric spatiotemporal electrical/optical mapping of critical cardiac physiological parameters, such as heart rhythm, biopotentials, oxygenation, metabolic state, calcium homeostasis, activation propagation pattern, and myocardial conduction and contraction, the authors state.

The work builds on Efimov’s previous research to develop cardiac implants to monitor and temporarily pace the heart. In 2021, Efimov and John A Rogers (Northwestern University, Evanston, USA) introduced a transient pacemaker, published in Nature Biomedical Engineering. Early in 2023, Efimov’s team unveiled a graphene “tattoo” for treating cardiac arrhythmia, details of which were published in Advanced Materials.

“After heart surgeries, surgeons sometimes insert temporary wires, which are connected to external current generators, to provide electrical stimulation during temporary heart block caused by the surgery,” Efimov said. “Recently, we developed a bioresorbable pacemaker to replace such a wire. Postoperative atrial fibrillation requires a more complicated approach based on a multi-electrode array for sensing and stopping atrial fibrillation. Now, we present a novel technology to achieve this goal.”

After a clinically relevant period, the device dissolves into benign products. Similar to absorbable stitches, the device degrades and then completely disappears through the body’s natural biological processes. The device’s bioresorbable nature could reduce healthcare costs and improve patient outcomes by avoiding complications from surgical extraction and lowering infection risks, according to the researchers.

“Many deaths that occur following heart surgery or a heart attack could be prevented if doctors had better tools to monitor and treat patients in the delicate weeks and months after these events take place,” added Luyao Lu (The George Washington University, Washington DC, USA), who co-led the work with Efimov. “The tool developed in our work has great potential to address unmet needs in many programmes of fundamental and translational cardiac research.”

The study was supported by the National Science Foundation and the National Institutes of Health.




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