Table 3.

Control of chemical properties of hydrogels for TE applications.

Original hydrogels	Approaches	Applications and Performance	References
HA, alginate, chitosan, and PEG	Modifying hydrogel precursors with RGD peptides	Promoted cell adhesion and viability, enhanced cell proliferation and differentiation	Lee et al., 2015; Kim et al., 2016; Long et al., 2017; Sun et al., 2017
Polyacrylamide	Hybridization with GelMA	Improved biocompatibility of synthetic hydrogels	Han et al., 2017
PEG	Hybridization with HA	Increased chondrocyte number and sGAG and collagen production	Skaalure et al., 2014; Fu et al., 2017
PEG	Covalently tethered transforming growth factor-beta 1 (TGF-β1) to PEG hydrogel through thiol-ene reaction	Increased chondrogenic matrix deposition by immobilization of TGF-β1	Sridhar et al., 2014; Mao et al., 2017
GelMA	Hybridization with nanosilicates	Promoted osteogenic differentiation of preosteoblasts in a growth-factor-free microenvironment	Xavier et al., 2015
GelMA Collagen/Alginate	Hybridization with multiwalled CNTs Gold nanorod	Improved cell adhesion and maturation; enhanced cardiac tissue regeneration, exhibiting strong spontaneous and stimulated synchronous beating	Shin et al., 2013; Navaei et al., 2016a; Izadifar et al., 2018
Polyacrylamide	Hybridization with graphene oxide	Enhanced proliferation and myogenic differentiation of C2C12 cells, and combining electrical stimulation further enhanced myogenic gene expression	Jo et al., 2017