Intrinsically Stretchable Microelectronic Fibers and Their Assemblies as Multifunctional Bioelectronic Interfaces for Whole Organs

A soft, stretchable, multifunctional bioelectronic interface can be used to monitor and/or modulate an entire organ, such as a stomach, heart, bladder, or spinal cord. The interface's softness translates to reduced mechanical mismatch with the tissue, and the interface's stretchability reduces interfacial stress with dynamically expanding and contracting organs. The electronics are stretchable thanks in part to liquid-metal conductors sealed within hollow channels of elastomeric fibers embedded in the interface. The liquid metal is largely strain-insensitive, non-toxic, and has a melting point of less than 37° C., so it remains liquid when implanted in a mammalian body. The liquid metal conductors connect microelectronic components, such as micro light-emitting diodes (μLEDs), electrodes, photodiodes, and temperature sensors, to a flexible printed circuit board (fPCB) at one end of the fiber. The interface may include other microelectronic components, such as piezoelectric strain sensors, that are also coupled to the fPCB.