Embedded 3D Printing of Ultrasound-Compatible Arterial Phantoms with Biomimetic Elasticity

Here, a class of ink materials and an embedded 3D printing strategy for the fabrication of macroscale elastic tissue-mimetic constructs are presented. Novel inks composed of 10 wt% glycidyl methacrylated poly(vinyl alcohol) (PVAGMA) with different degrees of substitution (DOS) and 4 wt% cellulose nanocrystals (CNCs) (PVAGMA(DOS)/CNC) with strong shear-thinning property are developed. By controlling the DOS of PVAGMA, hydrogels with desired mechanical stiffness mimicking that of healthy and diseased artery are designed to construct vascular phantoms. Cyclic tensile tests and in vitro hemodynamic study performed on phantoms demonstrate their excellent mechanical stability and low hysteresis. The burst pressure is found to be about 273 mmHg for PVAGMA2/CNC and 102 mmHg for PVAGMA4/CNC and the printed vascular phantoms are able to withstand 863K cycles over 10 days. Further, their suitability for ultrasonic imaging is demonstrated. Via B-mode imaging, it is found that the vessel strains under a pulsatile flow are 11.7 +/- 1.0% and 6.5 +/- 1.5% for PVAGMA2/CNC and PVAGMA4/CNC vessels, respectively, perfectly matching the behaviors of healthy and atherosclerotic arteries. It exemplifies that the ink materials and printing strategy can have broad applications in biomedical research, especially for the fabrication of complex elastic tissue phantoms.