The 3D-printing Fabrication And Property Study Of Multi-stimulus Response Hydrogel

Stimulus-responsive hydrogels are a class of polymers that undergo significant changes in color and shape in response to stimuli changes in the external environment such as temperature,p H,light,magnetic field,and ion concentration,and they have a wide range of applications in biomedical,sensor,and actuator fields.Although stimulus-responsive hydrogels have received wide attention from research scholars due to their unique properties,however,the complex hydrogel construction process and the traditional two-dimensional preparation process limit the efficiency,complexity and personalization of hydrogel 3D patterning.The singularity of the stimulus response method and the lag of the preparation method have created great limitations for the practical application of stimulus-responsive hydrogels in the biomedical field.In order to solve the above problems and realize the high-precision preparation of stimulus-responsive hydrogels and the composite of functions,the research of this topic includes the following aspects:（1）Based on the study of the physicochemical properties of SA,Gel and TA,a Gel/SA-TA bio-ink prepared by a simple and environmentally friendly one-pot synthesis method was designed and can be applied to DIW 3D printing.The rheological and curing properties of Gel/SA-TA hydrogels were analyzed,and the influence of Gel,TA and calcium chloride（Ca Cl₂）concentration on the properties of Gel/SA-TA hydrogels was obtained,and the micromorphological and physicochemical properties of Gel/SA-TA hydrogels,such as DIW 3D printability,temperature stimulation responsiveness,shape memory,stretchability and biocompatibility,were obtained.（2）Based on the study of the physicochemical properties of TA,a Gel/SA-TA@Fe³⁺bioink with DIW 3D printability and dual responsiveness to NIR and temperature was designed by introducing Fe³⁺with the source of EDTA-Fe Na in the Gel/SA-TA hydrogel system.The rheological and photothermal properties of Gel/SA-TA@Fe³⁺hydrogel were analyzed,and the influence law of TA and Fe³⁺concentration on the properties of Gel/SA-TA@Fe³⁺hydrogel was obtained,and the micromorphological and physicochemical properties of Gel/SA-TA@Fe³⁺hydrogel such as photothermal stimulation responsiveness,DIW 3D printability,stretchability and biocompatibility were obtained.（3）The conductive properties of Gel/SA-TA@Fe³⁺hydrogels were analyzed,and the laws of the influence of frequency,voltage,NIR stimulation and deformation stimulation on the impedance of Gel/SA-TA@Fe³⁺hydrogels were obtained,and the electrochemical properties of Gel/SA-TA@Fe³⁺hydrogels were obtained.In summary,a bio-ink with photo-thermal stimulation response that can be applied to DIW 3D printing was designed.When the ink is gelated,the resulting composite functional hydrogel has properties such as dual stimulus responsiveness to temperature and NIR,shape memory,stretchability,and biocompatibility,which enables the efficient,high-precision and personalized custom preparation of multi-stimulus-responsive hydrogels and the integration of multi-functional hydrogels.Finally,based on the excellent properties of multi-stimulus-responsive hydrogels,some investigations on their electrical properties are made to open up new ideas for the application of hydrogel materials in wearable flexible sensors.