Advanced supramolecular hydrogels and their applications in the formulation of next-generation bioinks for tissue engineering: A review.

Supramolecular hydrogels are three-dimensional structures composed of cross-linked macromolecules interconnected by dynamic physical bonds, which allow them to absorb and retain significant volumes of water. Their intrinsic properties, such as viscoelasticity, self-healing capabilities, and high water content, render them promising materials for cell-laden scaffolds utilized in bioinks. This review systematically summarizes the current state-of-the-art advancements in hydrogels for tissue engineering, categorizing them based on the nature of their supramolecular interactions. Particular emphasis is placed on the classification of supramolecular hydrogels and their associated properties, including kinetics, mechanical characteristics, responsiveness, and swelling behavior. The review specifically addresses the criteria that hydrogels must fulfill prior to their application in bioinks. Achieving biocompatibility and bioactivity necessitates the careful selection of hydrogel compositions with suitable properties, as well as the incorporation of external organic or inorganic bioactive molecules. Methods for measuring and enhancing biophysical and biochemical properties are discussed in detail, alongside an exploration of the unique requirements of bioinks tailored for each additive manufacturing method. This review paper serves as an instructive resource for the construction and characterization of supramolecular hydrogels, facilitating their application in bioinks for tissue engineering.