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

Use of three-dimensional bioprinting for thein vitroengineering of tissues hasboomed during the pastfive 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 complexextracellular environment needed to tune cell behavior, as required for tissue and organformation. Processes such as cell aggregation, migration, and tissue patterning should bedynamically monitored, and progress is being made in these areas, most prominently derivedfrom nanoscience. We review recent developments in tissue bioprinting, cellularized bioinkformulation, and cell tracking, from both chemistry and cell biology perspectives. Weconclude that an interdisciplinary approach including expertise in polymer science,nanoscience, and cell biology/tissue engineering is required to drive further advancementsin thisfield toward clinical application.