Bioprinting has emerged as a cutting-edge technology to overcome the shortage of tissues and organs by the precise deposition of living cells and biomaterials into three-dimensional (3D) biomimetic constructs. However, the inadequate choice of bioinks has limited its widespread implementation and clinical transformation. Natural polymers, such as chitosan and alginate, are commonly used as bioinks due to their biocompatibility, biodegradability and similarity to extracellular matrix (ECM). These natural polymers are usually limited by their mechanical strength and have less tunable mechanical characteristics. Instead, synthetic polymers offer adjustable mechanical properties and good printability, and they are often used as sacrificial materials in 3D bioprinting. Hybrid hydrogels consisting of Pluronic F127 (PF) and natural polymers have been suggested to have good printability and rheological behaviors. However, PF tends to be cytotoxic at concentrations required for good printability. Another synthetic copolymer which comprises poly(2-methyl-2-oxazoline) (POx) (A-block) and poly(2-n-propyl-2-oxazine) (POzi) (B-block) was investigated as the potential alternative for PF. In this work, two different hybrid platforms consisting of synthetic POx-b-POzi /natural polymer (chitosan or alginate) and PF /natural polymer (chitosan or alginate) were formulated. The main focus of the study were on their printability and the potential of POx-b-POzi to replace PF as a sacrificial material in 3D bioprinting. POx-b-POzi and PF-based hybrid hydrogels were formulated and their printability was evaluated by rheology, mechanical compression, and 3D printing and printability assessment tests. The results showed that both POx-b-POzi and PF based hybrid hydrogels can be printed into different 3D structures, and the printed structures were successfully crosslinked. Although, the printability assessment tests and rheology showed that PF based hydrogels exhibits greater printability, POx-b-POzi also meets the critical requirements for bioinks.
