Fabrication Factory for Tubular Vascular Tissue Mimics based on Automated Rolling Manipulation and Thermo-Responsive Polymers

Abstract

This study presents a novel methodology for fabrication of tubular vascular tissue mimics by an automated factory using thermoresponsive polymers which have temperature-induced reversible phase transition characteristics; Poly(N-Isopropylacrylamide)-Grafted Gelatin (PNIPAM-gelatin), PNIPAM and gelatin. The custom-designed factory consists of a moving tray, a roller unit driven by rack-and-pinion mechanics, and a local temperature-control unit. PNIPAM-gelatin serves as the matrix, providing temperature-dependent adhesion and detachment of cell sheets. We describe two prototypes of vascular tissue mimics: a tubular medial tissue mimic composed of randomly oriented Smooth Muscle Cells (SMCs), and a hierarchically structured vascular tissue mimic (intimal/medical tissue mimics) composed of longitudinally oriented Endothelial Cells (ECs) on the luminal surface and circumferentially oriented multilayered SMCs in the outer layer. We observed these prototypes under electron microscopes and a Confocal Laser-Scanning Microscope (CLSM). An advanced model of our prototype factory would have the potential to produce high-quality on-demand vascular grafts without incorporating any foreign materials.