Short peptides are ubiquitous in nature. They are found as hormones, pheromones, antibacterial and antifungal agents in innate immunity systems, toxins, and pesticides. But no one seriously considered that peptides could be useful as scaffold hydrogel materials. There has been a significant change since 1990 after the discovery of an ionic self-complementary peptide as a very interesting repeating segment in a yeast protein. It is now recognized that self-assembling peptides made from 20 natural amino acids have real material properties. Currently, many diverse applications have been developed from these simple and designer self-assembling peptide scaffold hydrogels and are commercially available. Examples include: (1) real 3D tissue cell cultures of diverse tissue cells and various stem cells, (2) reparative and regenerative medicine as well as tissue engineering, (3) 3D tissue printing, (4) sustained releases of small molecules, growth factors, and monoclonal antibodies, and (5) accelerated wound healings of skin and diabetic ulcers as well as instant hemostatic applications in surgery. Self-assembling peptide nanobiotechnology will likely continue to expand in many directions in the coming years.