Bioprinting: Mechanical Stabilization and Reinforcement Strategies in Regenerative Medicine.

Abstract

Bioprinting describes the printing of biomaterials and cell-laden or cell-free hydrogels with various combinations of embedded bioactive molecules. It encompasses the precise patterning of biomaterials and cells to create scaffolds for different biomedical needs. There are many requirements that bioprinting scaffolds face, and it is ultimately the interplay between the scaffold's structure, properties, processing, and performance that will lead to its successful translation. Among the essential properties that the scaffolds must possess - adequate and appropriate application-specific chemical, mechanical, and biological performance, the mechanical behavior of hydrogel-based bioprinted scaffolds is the key to their stable performance in vivo at the site of implantation. Hydrogels that typically constitute the main scaffold material and the medium for the cells and biomolecules are very soft and often lack sufficient mechanical stability, which reduces their printability and, therefore, the bioprinting potential. The aim of this review paper is to highlight the reinforcement strategies that are used in different bioprinting approaches to achieve enhanced mechanical stability of the bioinks and the printed scaffolds. Enabling stable and robust materials for the bioprinting processes will lead to the creation of truly complex and remarkable printed structures that could accelerate the application of smart, functional scaffolds in biomedical settings.