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Hydrogel is a versatile material that can be manipulated to achieve the desired physicochemical properties, such as stiffness, pore size, and viscoelasticity. Traditionally, these properties have been controlled through parameters such as concentration and pH adjustments. In this study, we focused on exploring the potential of hydrolyzed silk fibroin (HSF) as a molecular weight-modulating agent to control the physicochemical properties of double-composite hydrogels. We developed a synergistic dual-crosslinked hydrogel by combining ionically crosslinked silk fibroin with gellan gum (GG). The hydrolysis of silk fibroin not only enhanced its hydrophilicity but also enabled adjustments in its mechanical properties, including the pore size, initial modulus elasticity, and relaxation time. Moreover, biocompatibility assessments based on cell viability tests confirmed the potential of these hydrogels as biocompatible materials. By highlighting the significance of developing an HSF/GG dual-crosslinked hydrogel, this study contributes to the advancement of novel double-composite hydrogels with remarkable biocompatibility. Overall, our findings demonstrate the capability of controlling the mechanical properties of hydrogels through molecular weight modulation via hydrolysis and highlight the development of a biocompatible HSF/GG dual-crosslinked hydrogel with potential biomedical applications. [ABSTRACT FROM AUTHOR]

The cytocompatibility of biological and synthetic materials is an important issue for biomaterials. Gelatin hydrogels are used as biomaterials because of their biodegradability. We have previously reported that the mechanical properties of gelatin hydrogels are improved by cross-linking with polyrotaxanes, a supramolecular compound composed of many cyclic molecules threaded with a linear polymer. In this study, the ability of gelatin hydrogels cross-linked by polyrotaxanes (polyrotaxane–gelatin hydrogels) for cell cultivation was investigated. Because the amount of polyrotaxanes used for gelatin fabrication is very small, the chemical composition was barely altered. The structure and wettability of these hydrogels are also the same as those of conventional hydrogels. Fibroblasts adhered on polyrotaxane–gelatin hydrogels and conventional hydrogels without any reduction or apoptosis of adherent cells. From these results, the polyrotaxane–gelatin hydrogels have the potential to improve the mechanical properties of gelatin without affecting cytocompatibility. Interestingly, when cells were cultured on polyrotaxane–gelatin hydrogels after repeated stress deformation, the cells were spontaneously oriented to the stretching direction. This cellular response was not observed on conventional hydrogels. These results suggest that the use of a polyrotaxane cross-linking agent can not only improve the strength of hydrogels but can also contribute to controlling reorientation of the gelatin. [ABSTRACT FROM AUTHOR]

In this paper, a cartilage acellular-matrix (CAM) is chosen as a biomaterial for an effective antiadhesive barrier to apply between injured tissue and healthy tissues or organs. CAM is cross-linked using glutaraldehyde to create a cross-linked CAM (Cx-CAM) film. Cx-CAM has higher elastic modulus and toughness and more hydrophobic surface properties than CAM before cross-linking. Small intestinal submucosa (SIS), cross-linked SIS (Cx-SIS) as a negative control, and Seprafilm as a positive control are used in an experiment as adhesion barriers. Human umbilical vein endothelial cells (HUVECs) on SIS, Cx-SIS, or in a culture plate get attached and effectively proliferate for 7 days, but Cx-CAM and Seprafilm allow for little or no attachment and proliferation of HUVECs, thus manifesting antiadhesive and antiproliferative effects. In animals with surgical damage to the peritoneal wall and cecum, Cx-CAM and Seprafilm afford little adhesion and negligible inflammation after seven days, as confirmed by hematoxylin and eosin staining and macrophage staining, in contrast to an untreated-injury model, SIS, or Cx-SIS film. Cx-CAM significantly suppresses the formation of blood vessels between the peritoneal wall and cecum, as confirmed by CD31 staining. Overall, the newly designed Cx-CAM film works well as an antiadhesion barrier and has better anti-tissue adhesion efficiency. [ABSTRACT FROM AUTHOR]