Preparation And Performance Of Copper-loaded Eggshell Membrane-based Nanomaterials

Copper-based nanomaterials are attractive to researchers due to their low cost and unique electrical,chemical and thermal properties and they have a wide range of applications in catalysis,sensors and biomedicine,etc.However,the materials prepared by traditional methods have poor dispersibility and it is difficult to prepare the unique structure.Therefore,the exploration of the preparation methods of functional materials has important research significance.In recent years,a natural biomass resource-eggshell membrane(ESM)has attracted wide attention from researchers.It is a sustainable renewable biological material,composed of highly cross-linked protein fibers,presenting a three-dimensional layered porous network structure,which is conducive to molecular exchange,and has good air permeability and biocompatibility.ESM has a variety of natural active ingredients,such as amino acids(mainly glutamic acid,glycine and proline),as well as glucosamine,chondroitin and hyaluronic acid.It is an important potential biological tissue repair material.In addition,its unique structure is used as a template to prepare new nanomaterials.Accordingly,this thesis used ESM as the additive and template to synthesize copper-based nanocomposites using a green,safe and environmentally friendly method.And discussed its application in the treatment of organic pollutants,as well as antibacterial and promotion of skin wound healing properties and related mechanisms.First,the effects of different synthesis methods(coprecipitation,template and sol-gel methods)on the properties of Cu Fe₂O₄nanomaterials were explored.The material prepared by the co-precipitation method has poor dispersibility,and because of the use of strong alkali,it does not conform to the concept of ecological protection.The composite prepared by the template method had good dispersibility,more excellent antibacterial and catalytic performance,and the preparation method was simple and bio-environmental,but the yield was low.The composite prepared by the sol-gel method showed excellent performance in both catalytic and antibacterial activity,and had a high yield.It is the best experimental method in comprehensive consideration.Using ESM as the template,and the sol-gel method was used to successfully prepared the layered multi-channel nanocomposite ESM/Cu Fe₂O₄ with a unique coral-like structure under the optimal experimental conditions.Compared with the preparation of pure Cu Fe₂O₄ by ordinary chemical methods,this new structural material possessed powerful adsorption,high efficiency catalysis and long-term antibacterial functions.Using Congo Red as a model molecule to evaluate the adsorption performance of ESM/Cu Fe₂O₄,the maximum adsorption capacity was 199.23 mg/g.The 4-NP reduction experiment confirmed that the composite exhibited excellent catalytic activity at room temperature,and it only took about 5 min to reach a degradation rate of 98.9%.Reactive oxygen species(ROS)analysis showed that ESM/Cu Fe₂O₄ nanomaterial stimulated bacteria to produce a large amount of ROS,and the ROS levels of Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)were 2.1 and1.7 times of the control group,respectively.After 30 min co-culture with E.coli and 90 min co-culture with S.aureus,the bactericide rate almost reached 100%.The above experiment used ESM as a hard template.In order to further develop the function,it was dissolved as a soft template to synthesize nanoparticles(ESM/Cu S NPs)with good biocompatibility and near-infrared light(NIR)photothermal effect.Under the irradiation of the NIR laser,the temperature of the material rose from 25 to 56?in only 10 min.Experiments had proved that the excellent photothermal effect of ESM/Cu S NPs can be used for photothermal sterilization.Under natural conditions,the bactericidal rates of ESM/Cu S NPs to E.coli and S.aureus were 70%and 81%,respectively.After adding the NIR irradiation,the sterilization rate of the two bacteria was almost 100%,which proved that it had excellent photothermal sterilization performance.In addition,ESM/Cu S NPs was mixed with polyvinylpyrrolidone(PVP)solution and the appropriate ratio of carbon dots(CDs)was added to prepare an electrospinning solution.The wound dressing was prepared in situ on the surface of the wound model by electrospinning method to heal the skin wound of mice.In about 8 days,the wound healing area reached more than 90%.In addition,the rat tail hemostasis experiment showed that the amount of bleeding was reduced by 69.4%,and the hemostasis time was shortened by about 2 min,which proved that the dressing has excellent effects of rapid hemostasis,promotion of wound healing,and anti-infection.