title: Fabrication of circular microfluidic network in enzymatically-crosslinked gelatin hydrogel.
abstract: It is a huge challenge to engineer vascular networks in vital organ tissue engineering. Although the incorporation of artificial microfluidic network into thick tissue-engineered constructs has shown great promise, most of the existing microfluidic strategies are limited to generate rectangle cross-sectional channels rather than circular vessels in soft hydrogels. Here we present a facile approach to fabricate branched microfluidic network with circular cross-sections in gelatin hydrogels by combining micromolding and enzymatically-crosslinking mechanism. Partially crosslinked hydrogel slides with predefined semi-circular channels were molded, assembled and in situ fully crosslinked to form a seamless and circular microfluidic network. The bonding strength of the resultant gelatin hydrogels was investigated. The morphology and the dimension of the resultant circular channels were characterized using scanning electron microscopy (SEM) and micro-computerized tomography (μCT). Computational fluid dynamic simulation shows that the fabrication error had little effect on the distribution of flow field but affected the maximum velocity in comparison with designed models. The microfluidic gelatin hydrogel facilitates the attachment and spreading of human umbilical endothelial cells (HUVECs) to form a uniform endothelialized layer around the circular channel surface, which successfully exhibited barrier functions. The presented method might provide a simple way to fabricate circular microfluidic networks in biologically-relevant hydrogels to advance various applications of in vitro tissue models, organ-on-a-chip systems and tissue engineering.
authors.affiliation: State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an 710049, China. Electronic address: jiankanghe@mail.xjtu.edu.cn.
authors.forename: Jiankang
authors.initials: J
authors.lastname: He
authors.affiliation: State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
authors.forename: Ruomeng
authors.initials: R
authors.lastname: Chen
authors.affiliation: State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
authors.forename: Yongjie
authors.initials: Y
authors.lastname: Lu
authors.affiliation: State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhan
authors.affiliation: State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
authors.forename: Yaxiong
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
authors.forename: Dichen
authors.initials: D
authors.lastname: Li
authors.affiliation: State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
authors.forename: Zhongmin
authors.initials: Z
authors.lastname: Jin
mesh_terms: D005780:Gelatin / Q000737:chemistry*; D061307:Human Umbilical Vein Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D020100:Hydrogels / Q000737:chemistry*; D046210:Microfluidic Analytical Techniques / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D020100:Hydrogels; D005780:Gelatin
keywords: Circular channel; Endothelialization; Gelatin hydrogel; Microfluidic network; Tissue engineering