> ## Content Index > Fetch the complete content index at: https://research-pop.com/llms.txt > Use this file to discover other available public pages before exploring further. # MIT and Harvard Medical School teams build a bioresorbable paper battery for ingestible electronics - URL: https://research-pop.com/mit-and-harvard-medical-school-teams-build-a-bioresorbable-paper-battery-for-ingestible-electronics/ - Published: 2026-09-23T08:40:34.000Z - Updated: 2026-09-23T08:40:34.000Z - Author: ResearchPOP - Tags: Chemistry ![](https://storage.ghost.io/c/7c/5e/7c5e0911-739b-4a35-94eb-3e810bf78ba7/content/images/2026/09/Screenshot-2026-09-23-at-10.17.29.png) Source: [https://www.nature.com/articles/s44286-026-00443-7](https://www.nature.com/articles/s44286-026-00443-7?ref=research-pop.com) ## At a glance Ingestible electronics can monitor the gastrointestinal tract, communicate wirelessly or deliver electrical therapy, but conventional batteries raise safety and retrieval concerns if a device ruptures or remains in the body. Researchers at MIT, Brigham and Women’s Hospital, Harvard Medical School, the Broad Institute and the Koch Institute report a magnesium–molybdenum trioxide paper battery designed to operate for a defined period and then gradually degrade. The battery reaches a peak open-circuit voltage of 1.84 V and powers two capsule-scale demonstrations in swine. One is a battery-assisted radio-frequency identification, or RFID, tag that detects an ingestion event. The other is an electroceutical capsule that delivers gastric electrical stimulation. Together, the experiments connect battery chemistry, encapsulation, gastric retention, wireless communication and electrical therapy within one transient device platform. ## Background Power is a central constraint for ingestible and implantable electronics. Conventional alkaline and lithium-ion cells require robust packaging, and accidental exposure of their components can damage tissue. For devices intended to pass through the gastrointestinal tract within one to three days, bioresorbability can provide an additional safety margin. For devices deliberately retained in the stomach for multiday sensing or therapy, gradual degradation may also reduce the need for endoscopic retrieval. Magnesium combines a high theoretical capacity with biodegradability, but an ingestible battery must meet several requirements at once. It needs to provide a useful voltage, survive gastric conditions during its intended operating window, fit inside a capsule and break down predictably afterwards. The authors designed two Mg–MoO₃ battery formats: a 7.5 mm-diameter cell for a standard size 000 capsule and a larger-area version for devices with higher power requirements. ## Research question The study examines whether a bioresorbable battery can remain functional for several days in the stomach and supply enough energy for practical wireless tracking and electroceutical operation before its components gradually degrade. ## Inside the study The battery pairs an AZ31 magnesium-alloy anode with a paper cathode containing MoO₃, cellulose nanofibrils and activated carbon. A biodegradable ionic liquid prepared from choline chloride and lactic acid serves as the electrolyte. The paper-based construction supports compact assembly, while the magnesium and molybdenum oxide provide the electrochemical reaction needed to generate current. ![](https://storage.ghost.io/c/7c/5e/7c5e0911-739b-4a35-94eb-3e810bf78ba7/content/images/2026/09/Screenshot-2026-09-23-at-10.17.42.png) The team used beeswax and candelilla wax to control contact with gastric fluid. These natural-wax layers delay fluid penetration during the functional period. Once the protection is lost, the battery layers begin to delaminate and the components dissolve or fragment. Encapsulation is thus part of the timing mechanism rather than only a passive outer package. The size 000 battery produced an open-circuit voltage of about 1.77 V and an areal capacity of 2 mAh cm⁻² at 0.2 mA cm⁻². The larger cell reached an open-circuit voltage of about 1.84 V and a maximum capacity of 3.5 mAh at the same current density. Under continuous discharge, the larger format maintained approximately 1.6 V for one day. ![](https://storage.ghost.io/c/7c/5e/7c5e0911-739b-4a35-94eb-3e810bf78ba7/content/images/2026/09/Screenshot-2026-09-23-at-10.17.54.png) The researchers then followed both battery formats in swine stomachs. The cells remained identifiable over three days while their voltage and energy density declined gradually. The size 000 battery decreased from about 1.7 V to 1.35 V, while the larger-area battery decreased from about 1.8 V to 1.45 V. These measurements show that the encapsulated cells retained electrochemical output during a multiday gastric residence period. The first device demonstration was a battery-assisted RFID capsule. A molybdenum antenna, RFID chip, interconnects and the size 000 battery were assembled inside a 1.37 cm³ capsule. The electronic and power components occupied only part of the capsule, leaving about 76% of its internal volume available for a possible payload. Operating at 915 MHz, the tag could be read from as far as 4 m in air under the reported test conditions. In the swine oesophagus, a reader positioned 1.5 m away detected a step change in received signal strength as the capsule moved from air into tissue. The change provided a wireless marker that the capsule had been ingested. ![](https://storage.ghost.io/c/7c/5e/7c5e0911-739b-4a35-94eb-3e810bf78ba7/content/images/2026/09/Screenshot-2026-09-23-at-10.18.01.png) The battery and molybdenum antenna are designed to degrade. The RFID chip, which has an area of approximately 18 mm², is not bioresorbable in the present system and is expected to pass naturally through the gastrointestinal tract. The demonstration combines transient structural and power components with a small conventional electronic element. The second demonstration was an electroceutical capsule for gastric stimulation. The device combines molybdenum electrodes, biodegradable connections, the battery and a low-power stimulation board. A single battery supported continuous stimulation for about three days. Connecting two batteries in parallel extended the operating period to about seven days. ![](https://storage.ghost.io/c/7c/5e/7c5e0911-739b-4a35-94eb-3e810bf78ba7/content/images/2026/09/Screenshot-2026-09-23-at-10.18.09.png) In the swine experiments, 20 minutes of gastric electrical stimulation produced a maximum increase in plasma ghrelin of about 50%. Across three swine models, the reported increase was 36.3% ± 12.85%. Histological examination did not show significant stimulation-related tissue damage at the sampled sites. The authors note that the stimulation printed circuit board is not yet biodegradable, leaving the control electronics as a separate target for further development. ## Takeaways and outlook The study develops the Mg–MoO₃ paper battery from an electrochemical component into a power source for functional ingestible devices. The same battery chemistry supports a wireless ingestion-tracking capsule and a gastric-stimulation system, while natural-wax encapsulation defines the multiday interval during which the cells remain operational. The swine experiments connect the battery’s gradual voltage decline with device functions under physiologically relevant conditions. The RFID study shows wireless detection during ingestion, and the electroceutical study shows sustained power delivery for gastric stimulation over several days. Further development will require consistent manufacturing, closer control over functional lifetime and degradation throughout the gastrointestinal tract, and broader safety and pharmacokinetic studies. Fully bioresorbable RFID and stimulation electronics also remain engineering goals. The work provides a platform for matching transient power delivery with the intended lifetime of ingestible sensing and therapeutic systems. ## About the researchers Mehmet Girayhan Say (MIT) is the first author. Ada Erus and Leeban Morgan (MIT) are equal contributors. Giovanni Traverso (MIT, Brigham and Women’s Hospital, Harvard Medical School, the Broad Institute and the Koch Institute) is the corresponding author. The other authors are Yubin Cai, Injoo Moon, Young-Geun Park, Brady DeBruyn, Ziliang Kang, Krishna Parvataneni, Outman Akouissi, Olivia Girand, Siheng Sean You, Andrew Pettinari, Ashley Guevara, Benedict Laidlaw, Kailyn Schmidt, Niora Fabian, Alison Hayward. ## Original research Mehmet Girayhan Say, Ada Erus, Leeban Morgan, Yubin Cai, Injoo Moon, Young-Geun Park, Brady DeBruyn, Ziliang Kang, Krishna Parvataneni, Outman Akouissi, Olivia Girand, Siheng Sean You, Andrew Pettinari, Ashley Guevara, Benedict Laidlaw, Kailyn Schmidt, Niora Fabian, Alison Hayward and Giovanni Traverso. “Bioresorbable batteries for transient ingestible bioelectronics.” *Nature Chemical Engineering* (2026). DOI: [10.1038/s44286-026-00443-7](https://doi.org/10.1038/s44286-026-00443-7?ref=research-pop.com). Published online 21 September 2026\. Open access. --- ## Research POP Notes This article reflects the independent interpretation of the Research POP team and does not represent the views of the authors, their institutions or the journal. If you identify any inaccuracies or have concerns regarding the content, figures or attribution, please contact us at [team.researchpop@gmail.com](mailto:team.researchpop@gmail.com). We will review the matter promptly and make corrections or remove the relevant material where appropriate.