Multiroute Synthesis Of PVA/TiO₂ Composite Membrane And Its Feasibility Application Study As Wound Dressing

Every year there are hundreds of millions of people,such as skin damage and the infected the emergence of functional wound dressing provides a solution for this problem,wound dressings need to have good biocompatibility and non-toxic,biodegradable,moisturizing,oxygen permeability,hygroscopicity and appropriate mechanical strength and so on,according to the actual application situation of slightly lay particular stress on the function of different dressing.Existing wound dressings are made of multi-polymer materials,but their mechanical properties and antibacterial ability need to be further improved.The combination of nanoparticles and polymers can effectively improve the mechanical strength of the dressing,and nanoparticles can be used as an additional antibacterial agent and the synergistic effect of polymers to improve antibacterial ability.Polyvinyl alcohol（PVA）is a hydrophilic polymer,which is easy to prepare thin films,but its water resistance is poor.Titanium dioxide（Ti O₂）has photocatalytic activity,can degrade pollutants or kill bacteria,and has the advantages of cheap,simple preparation,good biocompatibility and reusable.In view of the potential advantages of PVA and Ti O₂ in dressing preparation,this paper prepared PVA/TiO₂ composite film by simple ducting method and electrostatic spinning technology.The water resistance of PVA was improved by chemical crosslinking.After that,Ti O₂ was transformed from granular to nanowires with higher specific surface area by low-temperature hydrothermal method,which effectively improved its catalytic efficiency.In this paper,PVA/TiO₂ composite membrane was synthesized by four routes and characterized and evaluated to study the feasibility of applying composite membrane to wound dressing.The main work is as follows:（1）Preparation and characterization of PVA/TiO₂ composite membranePVA film and PVA-Ti O₂ composite film were prepared by simple flow-casting method and electrostatic spinning technology,and a layer of Ti O₂ was coated on the surface of PVA film.Then,the composite film and intermediate products were characterized by SEM,EDS,FT-IR and XRD,and the crosslinking effect and permeability of the composite film were evaluated.The results show that the blade casting process film with porous structure after lyophilization,electrostatic spinning fiber membrane pore is more,the water thermal response success on the surface of composite membrane was generated Ti O₂nanowires,EDS and XRD results show that PVA/TiO₂ successful composite,material after crosslinking water resistance,solvent resistance and mechanical strength has improved greatly,there is no clear water imbibition is reduced,The air permeability of the fiber membrane is good.（2）Drug loading,release behavior and antibacterial activity of PVA/TiO₂ composite membraneTetracycline hydrochloride was used as a model drug to evaluate the drug loading and drug release capacity of PVA/TiO₂ composite membrane.The results showed that the adsorption capacity of PVA/TiO₂ composite membrane after hydrothermal treatment was significantly stronger than that before hydrothermal treatment.The drug loading rate and drug encapsulation rate of four composite membranes were all above 28%.Comparing drug loading and drug release data,it can be seen that there is little difference in drug loading capacity between flow spinning film and electrospinning film,but drug release rate of electrospinning film is higher than flow spinning film,because electrospinning film has larger specific surface area and more pores,which is easy to release drugs.The antibacterial ability of the drug-loaded composite membrane was evaluated by co-culture of the composite membrane with Escherichia coli.The results showed that the composite membrane loaded with tetracycline hydrochloride showed excellent antibacterial effect on Escherichia coli.（3）In vitro biocompatibility evaluation of PVA/TiO₂ composite membraneThe composite membrane was co-cultured with mouse fibroblast L929.The effect of composite membrane on cell viability was evaluated by MTT and cell staining after 1 and 3days.The results showed that four kinds of hydrothermal composite membranes had no toxic effect on cells,could promote cell proliferation and spread well on the material.It shows that the composite membrane has good biocompatibility.In summary,the PVA/TiO₂ composite film synthesized in this paper has simple preparation method,high mechanical strength,good air permeability,water absorption ability,good biocompatibility,and can promote cell proliferation.Moreover,it has certain drug release and antibacterial ability,and is expected to be applied in the field of wound dressing as a new material.