During his Ph.D. course, Dr. Seung Hun Park studied the modification and synthesis of natural and synthetic polymers. He synthesized polymers for injectable hydrogels which had applications in tissue engineering. Injectable hydrogels can be implanted in vivo in a minimally invasive manner, can fill the complex cavities of target sites, and can be loaded with cells and regulatory factors for therapy. However, regulatory factors loaded in injectable hydrogels are often rapidly released with an initial burst, which causes insufficient treatment of tissues or inefficient differentiation of stem cells. To remedy this issue, he worked on modifying polymers to chemically immobilize the regulatory factors on the hydrogel. Through in vitro and in vivo experiments, he confirmed that regulatory factors immobilized on hydrogels induced more effective differentiation of stem cells as compared to hydrogels with physically loaded regulatory factors. These findings are expected to have a substantial impact on the development of future hydrogels in the field of tissue engineering.