Research On Controllable Fabrication Of Bioinspired Smart Porous Membrane By Femtosecond Laser And Their Biomedical Applications

In nature,organisms have gradually developed special scale-span functional interfacial structures.which endow themselves with various features,so as to adapt to the changing environment.For example,the lotus leaf is the product of the perfect combination of two super-wetting properties(superhydrophobicity on the upper surface and superhydrophilicity on the lower surface),which enables the leaflet to float stably on the water.And stomata in plant leaves will respond to the light intensity by opening/closing in order to control material exchange.Inspired by the special features of these living organisms,the Janus porous superwetting membrane and bionic porous gated membrane were proposed,and their potential applications in the biomedical field are explored.Recently,Janus porous superwetting membrane and bionic porous gating membrane have become the burgeoning fields of membrane science research.However,due to the complexity and uncontrollability of the fabrication method and insufficient function of the traditional membrane,the efficiency production and multifunctional application are rather challenging.Here,femtosecond laser processing technology can help us overcome the abovementioned shortcomings of traditional membrane fabrication methods and is widely employed in the field of noval membrane fabrication because of its unparalleled intensity,speediness and precision.In this dissertation,the multifunctional Janus porous superwetting membrane and bionic porous gated membrane are efficiently realized by femtosecond laser processing of biocompatible and responsive composite porous structures,and applied to rapid plasma separation,noval self-pumping wound dressing,drug delivery therapy and other biomedical fields according to the principles of fluid mechanics and bionics.The contents of this dissertation are summarized as follows:1.The surface of titanium is firstly processed by femtosecond laser to controllably form conical hole arrays,and then,the biomimetic Janus porous film is treated with chemical coating modification.To this point,a new method for plasma separation is proposed combined with erythrocyte agglutination reaction.Compared with the existing methods,the purity(99.9%),yield(80%)and efficiency(20 s)of plasma separation are significantly improved,and no loss of glucose and protein or hemolysis is observed during the separation process.Meanwhile,analytes with a rather low concentration in whole blood could be robustly detected.After that,the Janus membrane unidirectional transport model against gravity is constructed to elucidate the novel plasma separation mechanism.2.The composite structure of PDMS and hydrogel is processed by in-situ femtosecond laser etching to fabricate conical microhole arrays,which is applied to self-pumping wound dressing.In the mean time,the unidirectional self-transport effect of different fluid(water,blood and so on)was studied,and it is proved that stretching or bending of Janus hydrogel composite mcbrane(JHCM)is beneficial for the improvement of the transporting performance.Then,through surface morphology and mechanical analysis,the mechanism of synergistical enhanced transport by topological morphology and superwetting characters of JHCM@self-pump wound dressing is discussed.Through bacteriostatic experiment,it is proved that the antibacterial factors contained in hydrogel can effectively prevent bacterial infection.In biological experiments,it’s crystal that JHCM@self-pump wound dressing can effectively absorb biological fluids and accelerate wound healing.Finally,the excellent properties of promoting wound healing,self-pumping,anti-adhesion and thermal management are demonstrated.3.A new pH-responsive hydrogel is prepared,and an intelligent bionic gating system(including two-dimensional membrane and three-dimensional microcapsule)is fabricated by utilizing its expansion-contraction responsive property.Micropores of the intelligent gating porous membrane will open in weak acid(pH<7)and close in weak alkaline(pH>7)through the deformation of hydrogel which is quite sensitive to the change of pH in the microenvironment.By tuning the aperture ratio of gating membrane,the drug diffusion flux can be precisely controlled.At the same time,the mechanism of drug release is illustrated based on drug release kinetics.In addition,the preparation of drug-containing microcapsules has been completed,and its intelligent gating can release the anticancer drug(DOX)on demand,which holds great potential in refroming the anticancer treatment of Hela cells in vitro anti-tumor application.