Polymers built inside the body through blood-catalyzed chemistry allow on-demand brain control

The 19th-century science fiction novel Frankenstein explores the idea of combining artificial materials with human body components, purely as a matter of imagination. Two centuries later, such concepts have become integral to our medical science. Synthetic materials and devices can interface with the body's electrical and chemical systems to restore function—from regulating neural activity in neurodegenerative disorders to managing heart rhythm in cardiovascular diseases.