➀ MIT researchers have achieved a significant breakthrough in electronics by demonstrating the ability to 3D print resettable fuses, which are key components of active electronics typically requiring semiconductors; ➁ This breakthrough could lead to semiconductor-free electronics manufacturing, democratizing production for businesses, labs, and homes; ➂ The resettable fuses are made from a biodegradable polymer doped with copper nanoparticles, performing similarly to semiconductor transistors.