Our research in the area of biomaterials can be grouped largely into: (i) Engineered extracellular matrix (ECM) mimetics such as biomineralized materials and (ii) Smart materials such as hydrogel actuators, self-healing hydrogels.
Engineered ECM mimetics: It is now well established that ECM-based cues play a critical role in modulating various cellular functions such as adhesion, differentiation, and functional tissue formation, though the underlying mech-anisms remain largely unknown. In an effort to dissect the role of biophysical and biochemical cues of the ECM in directing stem cell commitment, we are developing artificial ECMs recapitulating various physicochemical cues of the native tissue. Our efforts centers on manipulating inter- and intramolecular forces to form structures with intriguing functions and properties. Some examples include develop-ment of hydrogels with varying interfacial properties to regulate adhesion and migration of stem cells, biomaterials for ex vivo expansion of human embryonic stem cells (ESCs) and human induced pluripotent stem cells (iPSCs), scaffold driven biomineralization for bone tissue repair, and hydrogel based actuators for stem cell culture. Besides, directing stem cell fate, we also utilize these engineered biomineralized matrices to understand the molecular mechanism through which the mineralized environment induce osteogenic differentiation of human mesenchymal stem cells to form bone tissue. These studies unraveled a previously unknown mechanism, phosphate-ATP-adenosine metabolic signaling, by which the calcium phosphate (CaP)-rich mineral environment in bone tissues supports bone homeostais. These findings also begin to shed light on the role of ATP metabolism in bone homeostasis, which may be exploited to treat bone metabolic diseases.
Smart/Self-healing hydrogels: Other area of our interest is in designing synthetic materials or hydrogels emulating various attributes of biological systems such as sensitivity, self-organization, and self-healing. Our labortaory is developing new design principles to create smart hydrogels that exhibit unique biomimicking functions such as (1) thermoresponsive volume phase transitions similar to sea cucumbers, (2) self-organization into core-shell hollow structures similar to coconuts, (3) shape memory as exhibited by living organisms, (4) metal ion-mediated cementing similar to marine mussels, and (5) self-healing of cross-linked hydrogels in aqueous environments.