Hearing loss has many causes including genetic disorders, extended exposure to dangerously loud sounds and normal aging. Hearing aids can’t repair the damage regardless of the cause. Taking a different approach that uses biology and technology, researchers at Princeton are developing a bionic ear that contains biological and electronic materials, including bovine or cow cells, silicone, and silver nanoparticles. The structure of cartilage cells from cows is similar to that of human cells, and bovine cells are much easier to obtain.
Looking for a better answer for amputees, researchers have turned to nature’s expert in limb regeneration, the salamander. The human body initially reacts similarly to that of a salamander. We immediately form a scar to prevent the open wound from infections and major blood loss, but our bodies stop there. Unlike the salamanders, we cannot reactivate or naturally form a blastema to regenerate a new limb in a few weeks.
Scientists and engineers at MIT are striving to change the design of artificial limbs which are difficult to use and extremely painful. Their efforts are benefiting from studies on a very curious insect model: the horsehead grasshopper that can move its limbs without relying on any muscles. They studied denervated grasshopper limbs that were flexed at different angles and found that a “passive joint force” moves limbs to their original positions when flexed.