Scientists in Sweden have achieved a remarkable breakthrough by developing electrodes in living tissues, specifically in the brains, hearts, and caudal fins of zebrafish. This innovation opens up the possibility of integrating biocompatible electronic circuits inside the body to understand and treat neurological diseases.

Overcoming the Incompatibility of Static Bioelectronics

Current bioelectronics relies on a static and fixed design, making it challenging to integrate with living biological signal systems. The solution to this incompatibility is the dynamic creation of soft, electronic conductive materials without a substrate in a biological environment. A team of scientists from the universities of Linköping, Lund, and Göteborg has created a method for this purpose by injecting a gel composed of enzymes used as “assembly molecules” to grow electrodes in biological tissues, including zebrafish and medicinal leeches, and even in food samples such as beef, pork, chicken, and tofu.

The gel contains an oxidase to generate hydrogen peroxide in situ, a peroxidase to catalyze oxidative polymerization, a hydrosoluble conjugated monomer, a polyelectrolyte with counterions for covalent cross-linking, and a surfactant for stabilization. This cocktail of ingredients enables the induction of polymerization and subsequent gelation in different tissue environments.

Creating Fully Integrated Electronic Circuits in Living Organisms

This research could lead to the formation of fully integrated electronic circuits in living organisms, with contact with body substances modifying the gel’s structure and making it electrically conductive. Endogenous chemicals produced by the body are sufficient to trigger electrode development, and unlike previous experiments, genetic modification or external signals such as light or electricity is not necessary.

Targeting Specific Biological Substructures for Nerve Stimulation Interfaces

The scientists demonstrated that this method could target electronic conductive material on specific biological substructures, creating appropriate nerve stimulation interfaces. In experiments on zebrafish and medicinal leeches, the researchers successfully formed electrodes in the brain, heart, and caudal fins, indicating the possibility of creating fully integrated electronic circuits inside biological organisms.

Furthermore, there were no side effects observed in animals as a result of the gel injection. The researchers hope that this bioelectronics advancement will pave the way for a new generation of biocompatible electronic devices that can assist in the treatment of a range of neurological diseases.