Trends in Tissue Bioprinting, Cell-Laden Bioink Formulation, and Cell Tracking

Use of three-dimensional bioprinting for the in vitro engineering of tissues has boomed during the past five years. An increasing number of commercial bioinks are available, with suitable mechanical and rheological characteristics and excellent biocompatibility. However, cell-laden bioinks based on a single polymer do not properly mimic the complex extracellular environment needed to tune cell behavior, as required for tissue and organ formation. Processes such as cell aggregation, migration, and tissue patterning should be dynamically monitored, and progress is being made in these areas, most prominently derived from nanoscience. We review recent developments in tissue bioprinting, cellularized bioink formulation, and cell tracking, from both chemistry and cell biology perspectives. We conclude that an interdisciplinary approach including expertise in polymer science, nanoscience, and cell biology/tissue engineering is required to drive further advancements in this field toward clinical application.