| Natural polymer hydrogels are regarded as one of the best candidates for soft tissue repair of human organs because of their excellent biocompatibility,biodegradability and low immune rejection.However,the lack of mechanical strength matched with natural tissue and relatively limited function have greatly constrained its application.To address this challenge,lots of effort were focus on reinforcing the mechanical strength and function of gelatin methacryloyl(GelMA)hydrogels with excellent bioactivity and hope to find new approaches for constructing multi-functional natural polymer hydrogel scaffold with good biocompatibility and mechanical strength.For the purpose of preparing hydrogel with good mechanical properties and biocompatibility simultaneously,a new “three-armed” host-guest supermolecule was efficiently fabricated through host-guest interactions.This host-guest supramolecule(HGSM)can not only be used as a versatile cross-linker for a variety of natural polymer hydrogels,but also be used to build a novel supramolecular hydrogel(HGSMGel)by photo-initiated self-crosslinking reaction.The hydrogel has outstanding mechanical strength(Young’s modulus: 9.13 MPa),anti-compression,fatigue resistance and silcing-resistance properties owing to the presence of host-guest interaction and chemical covalent networks within HGSMGel,which provides a good energy dissipation mechanism when suffering a force.Moreover,the reversibility of host guest interactions between HGSM makes hydrogels have fast self-healing property.Meawhile,The performances of good biocompatibility and histocompatibility gives it significant functional advantage over traditional hydrogels.Subsequently,this new "three-armed" host-guest supermolecule was utilized to reinforce the GelMA hydrogel and 3D(three dimensional)printing technology was employed to construct a host-guest supramolecular GelMA hydrogel(HGGelMA)with host-guest interactions and chemical covalent crosslinked networks.Similarly,the introduction of HGSM improves the energy dissipation of the GelMA hydrogel scaffold when subjected to external force.The mechanical strength of HGGelMA hydrogel increased by 5.73 times(0.63 MPa)compared with pristine GelMA hydrogel and makes it more compatible with modulus of major natural soft tissue.Additionally,HGGelMA hydrogel also has good rapid self-healing ability that it can recover almost 80% strength within 60 minutes after being broken.Besides,the HGGelA hydrogel scaffold still retains good bioactivity and histocompatibility.Finally,based on the multi-component composite crosslinking enhancement mechanism,the 3D printed HAGelMA hydrogel scaffold was fabricated by the multi-component crosslinked copolymerization of hyaluronan methacrylate(HAMA)and GelMA.This method improved the printable performance and mechanical strength of GelMA(specifically,the young modulus increased to 1 MPa),and meets the requirement for mechanical environment of various natural soft tissues.In terms of functionalization,polylysine and heparin(HNP)were successfully modified on the surface of the hydrogel scaffold via layer-by-layer self-assembly(LBL),which endows HAGelMA-HNP scaffold with the ability of promoting vascularization and antibacterial property.In vitro and in vivo experiments show that HAGelMA and HAGelMA-HNP have superb bioactivity and histocompatibility.HAGelMA-HNP scaffold could rapidly promote tissue and micro-vessel regeneration.This study provides new strategy for the repair of organ tissue,such as the myocardium,liver.In conclusion,the purpose of this paper is to solve the problems in practical application of natural polymer hydrogels for tissue engineering.Based on the enhancement mechanism of multi-level crosslinked and multi-component composite crosslinked network,the multifunctional GelMA hydrogel scaffold with good bioactivity and mechanical strength were constructed via 3D printing technology.It provides a reference for promoting the application of natural polymer hydrogels in tissue repair and reconstruction engineering. |
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