Dear researcher, Its a interesting question. Bio materials are primarily refer to PVA,PLA, HA and etc which can be imparted in human body for tissue/bone replace. However it also main enpompass with the Hydrophilic nature of the material and its water soluble capacity in human body. Not forgetting the are also now widely use to manufacture environmental friendly packages. As to answer Mary's question, Our skin is general produce melanin(Dark feature of skin) to protect the penetration of UV-A,B,C into body parts. Its would interesting research if Mary could work on some material that possible having a photosensitive which able to produce melanin at high UV intensity and also able to reverse the Melanin conc at low UV concentration. Its possiable, Pls contact me if u needed more info.