Using Light To Create Bioelectronics Inside Body

In a study published in Advanced Science, the researchers describe how they can use light to create electrically conductive materials directly in the body, showing promising results in animal trials.

Bioelectronics is successfully used for treating heart arrhythmia, epilepsy, and neurodegenerative diseases like Parkinson's, to name a few. However, it's well known that today's bioelectrodes and implantation methods require the tissue to adapt to the electrodes, rather than the other way around. This can lead to complications.

This has not been shown before for electrodes formed directly in tissues.

Roger Olsson, professor of chemical biology and drug development at Lund University, explains that current bioelectrodes often lead to complications like inflammation, scarring, and mechanical mismatch, especially in soft tissues like the brain.
"Our goal is to create biocompatible solutions that seamlessly integrate with the body. This study shows that we are on the right path."

To achieve this, the researchers have developed a so-called photopolymerization process* suitable for living organisms. The method uses light-sensitive materials as building blocks to form soft, conductive structures directly in the body. These structures can be tailored to integrate seamlessly with soft tissues like the brain.

"When the tissue is exposed to light - blue, green, or red - a rapid reaction occurs within 5 to 30 minutes, forming a soft material, a hydrogel, that can conduct electricity. This material consists of so-called polymer structures and water," explains Fredrik Ek, the study's lead author.

Fredrik Ek, also a researcher in chemical biology and drug development at Lund University, adds that this technique to use light allows the forming of detailed bioelectronic structures that integrate with the body's cells.

"This has not been shown before for electrodes formed directly in tissues. The created structures are tissue-friendly and biocompatible, making them more suitable than today's bioelectronics for interacting with biological systems, such as regulating the electrical signals of nerves. This could be significant for treating neurological and neurodegenerative diseases," says Fredrik Ek.

The researchers envision that this technology could transform the future of bioelectronic therapies. Unlike traditional implants, these light-created bioelectrodes are minimally invasive during implantation and don't require surgical removal, because they naturally degrade after use. The next step is to move from early trials in zebrafish and chicken embryos to evaluating the concept in larger animal models.

*Photopolymerization is a process in which light is used to initiate and drive the polymerization of monomers (building blocks) into polymers (linked building blocks). When light hits light sensitive monomers, they are activated, starting a chemical reaction that combines them to form a polymer structure. The method is used, among other things, in the production of plastics, circuit boards, logic circuits, and LCD screens, as well as in 3D printing and dental fillings.