A new kind of ingestible, paper-based battery has been developed that can temporarily power medical devices inside the body before safely breaking down. In trials on pigs, the device delivered a maximum voltage of 1.84 volts and powered medical tools for up to three days. This technology could one day allow devices to monitor medication use or deliver electrical treatments without needing to be removed from the body. Ingestible medical devices are used to deliver treatments and monitor their effects directly inside the body, and can also be used for therapies involving electrical stimulation or detecting biological substances. Most current ingestible devices rely on traditional batteries, such as alkaline or lithium-ion, which are usually removed after use due to potential health risks. These batteries can leak harmful chemicals, causing tissue damage or even chemical burns. Ingesting these batteries accidentally can lead to serious injuries, such as perforations in the esophagus. To reduce these risks, researchers have proposed devices that can pass through the digestive system and be naturally excreted. However, if the components are not biodegradable, they can contribute to electronic waste. A study published on September 21 in the journal Nature Chemical Engineering describes a new ingestible battery developed by researchers at the Massachusetts Institute of Technology (MIT). This battery is designed to degrade safely after providing energy to medical devices. The researchers note that it is a "bioresorbable battery platform" that can power advanced ingestible electronics. The battery, made of magnesium and molybdenum trioxide, delivers up to 1.84 volts and was tested for two purposes: powering wireless monitoring tags for medication tracking and delivering electrical stimulation to treat gastric issues. During trials on pigs, the battery powered a wireless tag in the esophagus, allowing communication with a receiver over a distance of 1.5 meters. It also powered a capsule that delivered electrical stimulation to the stomach for 20 minutes, a method being explored for conditions like delayed gastric emptying. No tissue damage was observed during the trials. However, the study involved a limited number of animals, and the circuit used for stimulation was not biodegradable, requiring further development. The researchers believe this work could lead to safer, more environmentally friendly medical devices that do not contribute to electronic waste in the body.