Research On 3D Molding Process Technology Based On Herbaceous Nano-cellulose/collagen Composite Material

At present,3D printing technology has been widely developed and applied in aerospace and other industrial fields.However,with the rapid development of 3D printing technology in the direction of life sciences,3D printing technology has become widely used in multidisciplinary areas such as tissue engineering and medicine.The new technology,which can print biomaterials into a three-dimensional bioscaffold structure according to a preset digital structure model,can be applied to the regeneration and reconstruction of soft tissues such as skin.Due to the high resolution,precision,and freedom of 3D printing technology,the casualties of skin and soft tissue injuries that occur in fires or car accidents,due to the shortage of human skin from the source and immune rejection in allogenic skin Next,artificial skin scaffolds are prepared using 3D printing technology,and then seed cell culture is performed to artificially cultivate substitutes such as skin or soft tissue.Moreover,due to the long preparation cycle of the donor skin prepared by traditional tissue engineering technology and the difficulty of the skin source,the 3D printing technology has become a research hotspot in tissue engineering and medicine.With the depletion of non-renewable resources and the increasing concern of human beings for environmental protection issues,the nanocellulose/collagen composite hydrogel as a hydrophilic polymer material has many water or water molecules as dispersion media.The three hydrophilic grid structures have good hydrophilicity,biocompatibility,and non-toxic degradation products.And its water content after water absorption can reach more than 90%,and its situation is not only similar to the extracellular matrix,but also very similar in chemical composition.It is more suitable as a material for the preparation of skin scaffolds,and thus for cells in the nanometer Survival on skin scaffolds made from cellulose/collagen composites creates a good bar.In view of the material properties of the nanocellulose/collagen composite hydrogel,a low temperature deposition condensation technique was used to construct a 3D printed skin scaffold.Firstly,from the preparation of nano-cellulose/collagen composite hydrogels,cellulose/collagen composite hydrogels with different cellulose and collagen solid content were prepared,and the nano-cellulose/collagen composite hydrogels were analyzed.Material properties;analysis of 3D printing process technology of nano-cellulose/collagen composite hydrogel was performed,followed by 3D printing technology of skin support and study of characteristic parameters in the printing process.Secondly,the fluent simulation analysis of the hydrogel 3D printing extrusion process was carried out,and the extrusion speed of the 3D printing nozzle under different pressure and viscosity conditions was simulated,and the velocity variation curve of the hydrogel material during the extrusion process of the nozzle was obtained.Obtained 3D-printed material viscosity and extrusion pressure for the cellulose/collagen composite hydrogel,and then performed on a Fluent simulation using a Bio-Architect 3D biometric printer developed by Hangzhou Jinuofei Biotechnology Co.,Ltd.Experiments,contrasting observations of simulations and experimental results,obtained an optimum printing pressure of 0.10-0.12 MPa and a material viscosity of 45Pa.s.Thirdly,the nano-cellulose/collagen composite skin stent prepared by a 3D bioprinter was subjected to scanning electron microscopy and mechanical strength tests,and on this basis,the most suitable skin stent printed cellulose concentration was obtained.By changing the solid content of the hydroCOL,the barrel temperature of the 3D bioprinter,the temperature of the bench,and the cross-linking time with genipin,etc.,the 3D printing characteristic parameters suitable for the preparation of the high-strength porous scaffold were obtained.The chemical structure of the hydroCOL was studied by XRD diffraction and FTIR spectroscopy,and the CCK-8 experiment,Hoechst 33342/PI double staining experiment,2,4,6-trinitrobenzene sulfonic acid(TNBS)analysis and measurement of the skin scaffold Cross-linking efficiency,cytotoxicity,and biocompatibility.The 10%-CNF/COL-5 composite hydrogel printed stents can organize engineered skin scaffolds.Finally,the design requirements of the 3D bioprinter and the principle of the 3D printhead were analyzed.The overall structure of the 3D printhead was improved by designing the low temperature deposition condensation technique and the characteristics of the cellulose/COLatin composite hydroCOL.After comparative experiments,the improved nozzle can produce a skin stent with excellent structure.