Harvard scientists have created a type of cyborg tissue by embedding a three-dimensional network of functional, biocompatible, nanoscale wires into engineered human tissues.

The research addresses a concern that has long been associated with work on bioengineered tissue: how to create systems capable of sensing chemical or electrical changes in the tissue after it has been grown and implanted. The system might also represent a solution to researchers’ struggles in developing methods to directly stimulate engineered tissues and measure cellular reactions.

The process of building the networks is similar to that used to etch microchips. Beginning with a two-dimensional substrate, researchers laid out a mesh of organic polymer around nanoscale wires, which serve as the critical sensing elements. Nanoscale electrodes, which connect the nanowire elements, were then built within the mesh to enable nanowire transistors to measure the activity in cells without damaging them. Once completed, the substrate is then dissolved, leaving researchers with a netlike sponge, or a mesh, that can be folded or rolled into a host of three-dimensional shapes. Finally, the networks are porous enough to allow seeding them with cells and encourage those cells to grow in 3-D cultures.

Using heart and nerve cells, the Harvard research team successfully engineered tissues containing embedded nanoscale networks without affecting the cells’ viability or activity. Using the embedded devices, the researchers were then able to detect electrical signals generated by cells deep within the tissue, and to measure changes in those signals in response to cardio- or neuro-stimulating drugs.