Preparation And Structural Properties Of Bacterial Cellulose-Based Cuprous Oxide Composite Membrane

Bacterial cellulose（BC）membrane is a natural polymer material with a three-dimensional network structure,which has great application potential in the fields of food,packaging,and biomedicine.However,BC film has limitations in application due to its lack of antibacterial properties.And cuprous oxide（Cu₂O）has good antibacterial activity and biocompatibility.In this paper,bacterial cellulose-based cuprous oxide composite membrane（BC/Cu₂O-SA）were prepared by in-situ growth of cuprous oxide quasi spherical aggregates（Cu₂O-SA）in BC membrane.The main research contents are as follows:（1）Cu₂O-SA was synthesized by liquid phase reduction using waste grape pulp extract（WGPE）as a reducing agent.The effects of changing reductant concentration and reaction temperature on the morphology,particle size,and particle size distribution of Cu₂O-SA were investigated.The microscopic growth process of Cu₂O-SA was also investigated by SEM.The main results are as follows:Increasing the concentration of reducing agent and reaction temperature can reduce the particle size of Cu₂O-SA,narrow its particle size distribution,and increase its specific surface area;Cu₂O-SA is formed by the aggregation and fusion of grains.With the increase of growth time,Cu₂O-SA will undergo aggregation and surface reconstruction.（2）Using mixed carbon source WGPE to produce BC,the effects of carbon source type,fermentation time,and WGPE volume fraction on the yield of BC were investigated.The effects of WGPE volume fraction on the thermal stability of BC membrane were also investigated.The main results are as follows:Mixed carbon source WGPE can improve the production efficiency of BC;With the increase of WGPE volume fraction,BC membrane exhibit better thermal stability.（3）BC/Cu₂O-SA was prepared by in-situ synthesis.The effects of changing reductant concentration and reaction temperature on the in-situ growth process of Cu₂O-SA and the thermal stability of BC/Cu₂O-SA were investigated.The main results are as follows:Cu₂O-SA grows slowly and is difficult to form in BC membrane at low temperatures;At high temperatures and high reducing agent concentrations,in-situ grown Cu₂O-SA exhibits good dispersion and particle size distribution.Further more,Cu₂O-SA and BC are entangled,enhancing the cross-linking effect between bacterial cellulose,BC/Cu₂O-SA exhibits good thermal stability.（4）The antibacterial performance of Cu₂O-SA was evaluated by minimum inhibitory concentration（MIC）,and the qualitative and quantitative analysis of the antibacterial performance of BC/Cu₂O-SA was conducted by bacteriostatic ring and contact method.The main results were as follows:Both Cu₂O-SA and BC/Cu₂O-SA had excellent antibacterial performance,and their antibacterial effect against Staphylococcus aureus was superior to that of Escherichia coli.The minimum inhibitory concentration of Cu₂O-SA against both bacteria was 3.125～6.25 mg/m L,The antibacterial rates of BC/Cu₂O-SA against both bacteria exceeded 99.9%.