Wet-spinning fabrication of shear-patterned alginate hydrogel microfibers and the guidance of cell alignment.

You Yang,Xiaolu Liu,Yunhu He,Dan Wei,Hongsong Fan,Likun Guo,Jing Sun,Xingdong Zhang,Zhenzhen Guo,Meiling Zhong

doi:10.1093/rb/rbx017

Abstract

Native tissue is naturally comprised of highly-ordered cell-matrix assemblies in a multi-hierarchical way, and the nano/submicron alignment of fibrous matrix is found to be significant in supporting cellular functionalization. In this study, a self-designed wet-spinning device appended with a rotary receiving pool was used to continuously produce shear-patterned hydrogel microfibers with aligned submicron topography. The process that the flow-induced shear force reshapes the surface of hydrogel fiber into aligned submicron topography was systematically analysed. Afterwards, the effect of fiber topography on cellular longitudinal spread and elongation was investigated by culturing rat neuron-like PC12 cells and human osteosarcoma MG63 cells with the spun hydrogel microfibers, respectively. The results suggested that the stronger shear flow force would lead to more distinct aligned submicron topography on fiber surface, which could induce cell orientation along with fiber axis and therefore form the cell-matrix dual-alignment. Finally, a multi-hierarchical tissue-like structure constructed by dual-oriented cell-matrix assemblies was fabricated based on this wet-spinning method. This work is believed to be a potentially novel biofabrication scheme for bottom-up constructing of engineered linear tissue, such as nerve bundle, cortical bone, muscle and hepatic cord.

Highlights

The hierarchical structures of the human body include various types of fiber-shaped 3 D cellular construct such as blood vessels, neural pathways and muscle fibers [1]
The parameters and materials for a typical spinning process are as follows: (1) 2 wt% sodium alginate aqueous solution was prepared as the hydrogel prepolymer, which will be sprayed out from the spinneret driven by the syringe pump, and the perfusion rate Q is set at 10 ml/h; (2) 2/3 of the receiving pool was filled with 100 mM CaCl2 aqueous solution to serve as coagulation solution of the hydrogel microfiber here; (3) the collection roller of receiving pool was equipped on an electric motor and the rotation rate x was set at 80 rpm, which would produce shear force to alginate flow by driving the circling flow of CaCl2 aqueous solution
Alginate hydrogel microfibers with aligned submicron topography were denoted as “shear-patterned fiber (SP fiber)”, which was spun at condition of 10 ml/h perfusion rate of alginate and 80 rpm rotation rate of receiving pool; Alginate hydrogel microfibers with non-aligned submicron topography was denoted as “simple-extruded fiber (SE fiber)”, which was prepared by extruding at condition of 10 ml/h perfusion rate of alginate and 0 rpm rotation rate of receiving pool; And cells cultured on petri dishes was set as blank control group denoted as “petri dish”

Summary

Introduction

The hierarchical structures of the human body include various types of fiber-shaped 3 D cellular construct such as blood vessels, neural pathways and muscle fibers [1]. For these native linear tissues, the performance of their specific biofunction essentially depends on the multi-hierarchical characteristics: Local micro- and nanoscale orientation and topographic pattern of the matrix provide potential cues for cell signalling, adhesion, growth and differentiation, to constitute the functional micro-units, which further assemble in aligned way to form functionalized tissue with special mechanical and biological properties in macro scale.

Methods

Results

Conclusion