Hemostatic adhesive hydrogels as sealants for surgical operations are one of the focus of the researches in the field of injectable materials. Herein, we evaluated the potential application of a mechanically robust nanocomposite hydrogel with significant adhesion strength and shorter blood clotting time. This hydrogel was composed of thiolated gelatin (Gel-SH) and gelatin methacrylate (GelMA) as the main matrix to support cell viability and proliferation, while polydopamine functionalized Laponite (R) (PD-LAP) were introduced to the structure to improve the mechanical properties, adhesion strength, and blood clotting. This hydrogel formed via Michael reaction between Gel-SH and GelMA, and covalent interaction between PD-LAP and hydrogel. Results revealed that presence of PD-LAP significantly controlled the swelling ratio, biodegradability, and mechanical properties of nanocomposite hydrogels. Tensile and compressive strength of nanocomposite hydrogels were measured in the range of 22-84 kPa and 54-153 kPa, respectively. Furthermore, nanocomposite hydrogels revealed excellent recovery ability, strong tissue adhesiveness and significantly less blood clotting time than Gel-SH/GelMA hydrogel (2.25 min). In the culture with L929 fibroblasts cells, viability more than 97% and high proliferation after 5 days of culture was estimated. The simplicity, low-cost, tunable mechanical properties, short blood clotting time, and cytocompatibility of the hydrogels composed of Gel-SH, GelMA, and PD-LAP highlight its potential as hemostat sealants. (C) 2019 Elsevier Inc. All rights reserved.