Recent progress of intelligent hydrogels for tissue engineering

Tissue engineering (TE) covers a broad range of applications, including repairing or replacing portions of or whole tissues such as bone, cartilage, blood vessels, bladder, skin, muscle, etc. For effective TE, it requires a thorough knowledge about cells, engineering materials, and suitable biochemical and physiochemical factors to improve or replace biological functions. 1 Tissues require mechanical structural support to adhere, develop, differentiate, and ultimately perform specific biochemical functions. The term “regenerative medicine” is often used synonymously with TE; TE aims to create functional constructs that could improve the function of the 218damaged tissues or whole organs. Regenerative medicine (RM) is an ocean in which TE is a small part of it, RM utilizes the self-healing mechanisms of the body incorporated with a biomaterial to aid in tissue repair. Stem cells are unspecialized quiescent cells which could be reprogrammed and tamed according to our need;^{2, 3} TE and RM are emerging as a promising cure for Alzheimer’s, spinal cord injury, muscular dystrophy, rheumatic arthritis, and type 1 diabetes,^{4, 5, 6, 7, 8, 9, 10} thereby shifting the paradigm of curing an ailment instead of treating it. Stem cells cannot do a great wonder on its own; it requires a supportive material, that is, scaffold that could hold the stem cell providing an extracellular matrix (ECM) condition such as skeletal framework and growth factors.