Effect Of Electrospinning Fiber Diameter And Arrangement On Macrophage Activation

In recent years,the application of biomaterials in the field of tissue engineering has attracted much attention,such as: scaffolds with functions of promoting tissue regeneration and remodeling,biosensors for detecting physiological indicators,and carriers for constructing drug delivery.But it is inevitable that any biological material is implanted in the body,it will cause the body’s non-specific immune response.The immune response involves the release of multiple cytokines and the alternation of cell types.Among them,macrophages have phenotypic and functional diversity,which determines the direction of the entire immune response.Importantly,the direction of the immune response is the key to the function of biomaterials and tissue remodeling.Therefore,exploring the interaction between the scaffold structure and macrophages is of great significance for guiding the direction of the immune response in the process of tissue repair.The micro-nano fiber scaffold prepared by electrospinning technology has a wide range of applications in the field of tissue engineering repair.However,there are few studies on how electrospun fiber scaffolds accurately regulate the behavior of macrophages.Therefore,five sizes and two structures(500 nm-10 μm diameter oriented and random arranged fibers)of fiber scaffolds were prepared by electrospinning technology.In order to evaluate the immunomodulatory function and direction of macrophages,the effects of different fiber size and structure on the behavior of macrophages in different repair periods were explored in vivo and in vitroIn vitro studies have found that the surface structure and spatial structure of biomaterials can play a role in the early and late stages of cell culture respectively,and guide the morphology of macrophages to change to varying degrees.Compared with other scaffolds,the oriented arrangement of fibrous scaffolds of intermediate size(5μm in diameter)can promote the formation of macrophage elongated morphology in the early and late stages of culture.The change in the morphology of macrophages leads to an increase expression of marker proteins and related factors of alternatively activated macrophages(M2 type).In vivo experiments show that the ratio of M2/M1 inside the scaffolds with fiber diameter ≥5 μm is higher than that of the thin fiber scaffolds,and the high M2/M1 ratio is beneficial to the formation of new blood vessels.Combining the results of both in vivo and in vitro,among the 10 structures prepared in this study,the oriented fiber scaffold with a diameter of 5 μm is more conducive to guiding the polarization of functional M2 macrophages.In conclusion,we can guide the phenotype and functional transformation of macrophages by controlling the size and structure of biomaterials,and reveal the way in which the size and structure of electrospun fiber scaffolds regulate the behavior of macrophages.It will provide some theoretical basis to spinning technology-based scaffold design and clinical application.