Hydrogels are commonly used materials that can absorb lots of water/fluid and swell in the water. They feature crosslinked structures with biocompatibility for 3D printing-based medical applications. Polyethylene glycol (PEG) is a hydrophilic polymer that has low toxicity. PEG-based hydrogel has good biocompatibility and has been widely used in 3D printing applications as biomaterial ink to produce vessels and cartilages. Its derivative, polyethylene glycol diacrylate (PEGDA), is also applicable to tissue engineering of vascular constructs . Poly(vinyl alcohol) (PVA) is a water soluble polymer that can form PVA-based hydrogel as a biomaterial for 3D printing applications such as vascular and cartilage tissue engineering. Poly(lactic-co-glycolic acid) (PLGA) is the co-polymer made from lactic acid and glycolic acid. PLGA has been used for bone and cartilage implants due to its low melting point (120 °C) and biocompatibility.