*Review* **Advances in Hemostatic Hydrogels That Can Adhere to Wet Surfaces**

**Wenli Han and Shige Wang \***

School of Materials and Chemistry, The University of Shanghai for Science and Technology, No. 516 Jungong Road, Shanghai 200093, China

**\*** Correspondence: sgwang@usst.edu.cn

**Abstract:** Currently, uncontrolled bleeding remains a serious problem in emergency, surgical and battlefield environments. Despite the specific properties of available hemostatic agents, sealants, and adhesives, effective hemostasis under wet and dynamic conditions remains a challenge. In recent years, polymeric hydrogels with excellent hemostatic properties have received much attention because of their adjustable mechanical properties, high porosity, and biocompatibility. In this review, to investigate the role of hydrogels in hemostasis, the mechanisms of hydrogel hemostasis and adhesion are firstly elucidated, the adhesion design strategies of hemostatic hydrogels in wet environments are briefly introduced, and then, based on a comprehensive literature review, the studies and in vivo applications of wet-adhesive hemostatic hydrogels in different environments are summarized, and the improvement directions of such hydrogels in future studies are proposed.

**Keywords:** hydrogel; hemostasis mechanism; wet adhesion mechanism; application
