Preparation Strategies, Applications, and Evaluation Systems of Tough Biohydrogels

Biohydrogels show great application potential in cutting-edge fields. However, the inherent weak mechanical properties of traditional hydrogels greatly limit their practical applications. In recent years, tough biohydrogels have developed rapidly, but the emerging strengthening strategies have not been systematically summarized or categorized, nor has a standard evaluation system been established. We innovatively categorize the existing strengthening strategies into three core types: dynamic sacrificial interactions, intrinsic optimization of network structures, and the construction of multi-scale heterogeneous structures. This article aims to provide a comprehensive overview of the preparation strategies and applications of tough biohydrogels, and to establish an evaluation system for such hydrogels. The focus of this article is on: 1) how to scientifically classify preparation strategies to guide future experiments, 2) how to apply them in the biomedical field, and 3) what standards hydrogels must meet to be considered tough biohydrogels. In addition, this article summarizes the challenges facing this field and offers insights into future development directions, especially on how to achieve breakthroughs in hydrogel performance through multi-strategy synergy and expand their applications in biomedical and other fields, with the aim of providing theoretical guidance for the rational design of the next generation of tough biohydrogels.