INS and diabetes mellitus: We placed the diseases described in the studies into the following four categories: (1) skin diseases and skin care (n = 19, 50.0%); (2) vaccine delivery (n = 11, 28.9%); (3) insulin delivery for the treatment of diabetes (n = 5, 13.2%); and (4) others (n = 3, 7.9%, two osteoporosis and one migraine).