Hi! Tissues in the body are composed of many different types of proteins. One of the designs I am currently working on replicates some of the ways nature puts these proteins together. By copying nature's 'design rules' we've been able to create our own novel materials. So the short answer to this long explanation is they are protein based (though not all of my designs are. It entirely depends on what we're trying to do).

An excellent question regarding the immune response. Part of this is trying to match what our body can already tolerate though this is difficult! My materials have shown low immune response so far though we are trying to probe that further currently and see if we can modify our materials to 'calm down' an inflammatory response too.