TABLE 1.

Summary of the functional and biological modified PEG.

Materials	Compound method	Characters
PEG/PLA	Using lactide as raw material, four-arm PEG as tetrahydroxy initiator and Sn(Oct)2 as catalyst	Good mechanical strength, excellent stability, injectability
PEG/PLGA	Using L-lactide and glycolide as raw material, PEG as tetrahydroxy initiator and Sn(Oct)2 as catalyst	Accurate temperature sensitivity, appropriate degradability
PEG/Alginate	Using PEG-NH2, oxidized alginate, gelatin as raw materials, via Schiff base reaction	Osteogenic function, good biocompatibility, injectability
PEG/Nanoclay	Using PEG diacrylates and nanoclay as raw material, in an ultraviolet light crosslinker	Osteogenic function, good mechanical properties, excellent stability
PEG/CS	Using mPEG-acrylate and CS as raw material, via graft copolymerization	Antibacterial function
PEG/Ag+	Using four-arm-PEG-SH and Ag+ as raw material, via dynamic binding of -SH to Ag+	Antibacterial function, excellent self-healing, injectability
PEG/Hyaluronic acid	Using PEG, poly (N-(2-hydroxypropyl) methacrylamide lactate), hyaluronic acid as raw material, via Michael addition reaction	Osteogenic function, good stability, temperature sensitivity