The central engineering challenge is deceptively simple to state. A battery must store and deliver meaningful energy, yet every component—anode, cathode, electrolyte, separator, current collector and packaging—must remain stable during operation and then degrade predictably into products the body can metabolize or excrete. Conventional lithium-ion chemistry fails this test on nearly every count: lithium is reactive, the organic electrolytes are toxic, and the metal casings persist indefinitely. Designing around those constraints requires rethinking the battery from first principles, choosing electrode materials from the palette of biologically tolerated elements and finding ionic chemistries that function in aqueous, physiological environments.

Among the most promising strategies reported in recent work are metal–air and metal-based cells built around magnesium, zinc, iron, molybdenum and tungsten. Zinc, in particular, has attracted attention because it is an essential trace nutrient, electrochemically well behaved in neutral aqueous media, and yields benign zinc ions and hydroxide species upon discharge. Magnesium offers a higher theoretical voltage and specific capacity and is already widely used in biodegradable orthopedic implants, giving clinicians a long safety track record to draw upon. Pairing these metals with cathodes made from oxides, phosphates or even bio-derived molecules such as iodine and quinones allows researchers to assemble complete cells whose every element participates in the body’s normal biochemistry.

Electrolytes present a subtler problem. The medium through which ions shuttle must conduct well, resist premature self-discharge, and dissolve cleanly afterward. Teams have explored hydrogels cross-linked from natural polymers, salt-loaded chitosan membranes, phosphate-buffered solutions held within biodegradable pouches, and solid polymer electrolytes based on polyethylene glycol and polylactic acid. The encapsulation strategy matters as much as the chemistry: a transient battery is only as transient as its slowest-dissolving layer. Researchers have therefore developed multilayer packaging from polyanhydrides, polycaprolactone and silk fibroin, tuning film thickness and crystallinity so that the operational lifetime can be programmed from days to months, much as drug-eluting stents control their release kinetics.

Power output has long been the Achilles heel of resorbable energy storage, since aqueous chemistries deliver lower cell voltages than lithium systems. The field has responded with clever circuit-level solutions. Stacking individual cells in series within a single package boosts voltage to the levels needed by microcontrollers, radios and sensors, while parallel arrays extend operating time. Reports of transient batteries generating on the order of one to a few volts, sufficient to power cardiac pacemakers in large animal models and to drive wireless transmission from implantable sensors, have shifted the conversation from feasibility to engineering refinement. Energy densities approaching levels useful for clinical devices have been demonstrated in packages small enough to fit within the capsule formats familiar from swallowable diagnostics.

The ingestible application is arguably the most immediate. Electronic capsules that sample the gastrointestinal tract, deliver drugs on schedule, or monitor pH, temperature and pressure currently contain rigid, persistent hardware. A power source that dissolves after a defined period means the device can be designed to break apart and pass or absorb without intervention, reducing the risk of retained foreign bodies and simplifying regulatory pathways. Transient batteries have been engineered to survive the acidic environment of the stomach, activate in the intestine, and maintain output long enough to complete a diagnostic or therapeutic mission before their hydrogel electrolytes swell, weaken and finally dissolve into the surrounding fluid.

Implanted applications raise the stakes in different ways. Temporary pacemakers intended to support patients after cardiac surgery, biodegradable sensors for monitoring wound healing, and stimulators for nerve regeneration all require power for days to weeks and none of the encumbrance of permanent hardware. In animal studies, resorbable battery packs have successfully paced hearts at clinically relevant rates and then degraded over weeks with no significant inflammatory response, the degradation products appearing at concentrations well within physiological tolerance. Surgeons and cardiologists watching these demonstrations see a path to devices that avoid the extraction procedures, infections and device erosion complications that complicate conventional implants.

Safety evaluation is where laboratory promise meets biological reality, and the field has been accumulating the necessary evidence. Biocompatibility testing of the constituent materials—zinc, magnesium, molybdenum, tungsten, silk, chitosan, PLGA and related polymers—shows degradation products that are cleared renally or metabolized into water and carbon dioxide. Histological examination of implantation sites typically reveals a mild, transient foreign-body response that resolves as the materials disappear. The critical design parameter is the balance of dissolution rates: the battery must not release its stored electrochemical charge or its degradation products faster than tissue clearance mechanisms can handle, a constraint that drives careful control of surface area, porosity and protective coatings.

Manufacturing and integration remain open questions on the road to commercialization. Many laboratory devices are assembled by hand from foils, films and gels; scaling to consistent, sterile, high-volume production demands reel-to-reel deposition, laser micromachining and packaging methods borrowed from flexible electronics. Integration with ultrathin silicon sensors, biodegradable antennas and dissolvable interconnects is advancing rapidly, driven by parallel progress in transient semiconductor research. As these threads converge, researchers envision complete diagnostic and therapeutic systems—power, electronics, antenna and all—that are implanted or swallowed, perform their function, and vanish, leaving nothing behind but a small, harmless chemical trace.

For patients, the implications extend beyond convenience. Eliminating extraction surgeries removes anesthesia risks, costs and anxiety; for pediatric and elderly populations especially, any procedure avoided is meaningful. For health systems, self-erasing devices could reduce long-term follow-up burdens. The research community is candid that clinical adoption will require years of validation, standardization of degradation timelines and regulatory frameworks adapted to hardware that is designed to fail safely. But the trajectory is clear: energy storage is joining the broader movement toward medical technology that respects the body’s own temporality, delivering function precisely when it is needed and then, quietly and completely, disappearing.

Subject of Research: Development of biodegradable, transient power sources for ingestible and implantable bioelectronics

Article Title: Bioresorbable batteries for transient ingestible bioelectronics

Article References: Say, M. G., Erus, A., Morgan, L., Cai, Y., Moon, I., Park, Y.-G., DeBruyn, B., Kang, Z., Parvataneni, K., Akouissi, O., Girand, O., You, S. S., Pettinari, A., Guevara, A., Laidlaw, B., Schmidt, K., Fabian, N., Hayward, A., & Traverso, G. (2026). Bioresorbable batteries for transient ingestible bioelectronics. Nature Chemical Engineering. https://doi.org/10.1038/s44286-026-00443-7

Image Credits: AI Generated

DOI: 10.1038/s44286-026-00443-7

Keywords: bioresorbable batteries, transient electronics, ingestible devices, biodegradable implants, zinc battery, magnesium anode, hydrogel electrolyte, biocompatibility, implantable sensors, transient pacemaker, biomedical engineering, dissolvable electronics