Abstract

Bioprinting Multicellular Structure to Advance Vascularized 3D Tissue Engineering

Alisa Morss, Associate Professor, Drexel University

3D vascularized tissue engineering would enable mechanistic study of healthy and diseased tissues, deliver a powerful platform for drug screening, and potentially provide a replacement for diseased tissues. The standard 3D tissue biofabrication process is layer-by-layer printing of a bioink composed of cells within a matrix material. While this process allows cells to be printed in a specific pattern to guide them towards the desired 3D structure, it relies primarily on cellular self-assembly into a 3D architecture that hopefully recapitulates the in vivo tissue. Unfortunately, cellular self-assembly may take days or weeks, may require complex spatial and temporal environmental cues, or may not occur when two cell types are co-cultured together. Because of these challenges, critical features of the tissue microenvironment cannot be recapitulated, and therefore cell-cell interactions cannot be studied in a physiologically relevant in vitro model. In this research, we created a new bioprinting paradigm in which multicellular structures that recapitulate in vivo architecture were used to create a 3D vascularized breast cancer tissue model. The multicellular structures were either grown in vitro prior to printing, or they were derived from tissues (e.g., breast organoids). Our method decreases the time between bioprinting and experimental assay from weeks to days; increases physiological relevance by allowing the investigator to more precisely control tissue architecture; and enables the use of primary human tissues together with stromal cells and local extracellular matrix.