Study On The Controllable Construction Of The Spatial Distribution Of Charge On The Surface Of Materials And Its Biological Effects

Electricity plays an important role in life activities.The interaction between cells and between cells and materials is accompanied by the transmission of electrical signals.Electrical stimulation can regulate the colonization and function of cells,and accelerate wound healing and tissue regeneration.As a new generation of "smart" biomaterials,electroactive biomaterials can effectively provide electrical signals,and their electrical properties can be used as a strong cue for the microenvironment,which affects life activities positively.When biological materials enter the body,proteins from surrounding body fluids will spontaneously adsorb to the surface of the material,thereby mediating subsequent cellular behavior.Therefore,the regulation of the amount and the spatial specificity of the protein adsorption on the implant surface is critical to mediate subsequent cellular behavior.Different from the surface regulation strategy of traditional biomaterials,in this study,a model of spatial distribution of surface charges was constructed to achieve the regulation of protein selective spatial adsorption and the subsequent mediation of cell behavior through its electrical properties.At present,the treatment methods for tissue damage are mostly passive,and rarely participate in the regulation of endogenous cell behavior.Although existing studies have shown that electrical signals are very important in wound healing and tissue regeneration,there are still many difficulties in practical application,because the current equipment for applying electrical stimulation is mainly wired device and the operation is complicated.Based on the constructed space distribution charge model and its regulatory function in the previous work,a composite hydrogel with space distribution of electroactive bismuth oxychloride nanosheets was designed materials to promote tissue regeneration through the constructed photoelectric microenvironment.This strategy provides a controllable,wireless,and effective new strategy for clinical treatment,which has broad application prospects.The main research contents of this topic are as follows:(1)Based on the electrical characteristics of potassium sodium niobate piezoelectric ceramics(KNN),the spatial distribution of the phases on the surface of the ceramic was achieved by the phase transformation induced by the focused laser beam.After polarization,the zones with different phase showed significant differences in surface charge density.Through phase analysis and the results of scanning kelvin probe force microscopy(SKPM),it has been proved that a material with spatial distribution of surface charge has been successfully constructed and used as a theoretical model.By studying the effect on protein adsorption regularity and cell behavior,the results showed that the electrical characteristics of the model can regulate the selective spatial adsorption of proteins and promote cell proliferation,spreading and migration.This study could provide a new method for the regulation of cell behavior and has guiding significance for the design of biological materials.(2)Based on the constructed model of the spatial distribution of surface charge and its regulatory function in the previous work,using the concept of photoelectric properties of bismuth oxychloride,a composite hydrogel material with spatial distribution of bismuth oxychloride nanosheets was prepared.Under light conditions,the composite hydrogel produced a significant photocurrent,the photoelectric effect occurred at the spatial sites where the bismuth oxychloride nanosheets were located,combined with the good biomimetic matrix of the hydrogel,which provided a photoelectric microenvironment for the wound to improved cell activity and accelerated wound healing.This study could provide a new strategy for non-invasive treatment and precise regulation of biological activities.