Study On The Function Of Cellulose/Fish Swim Bladder Gelatin Composites

Microcrystalline cellulose(MCC),which degrades the crystalline cellulose by enzymatic/chemical method,is hydrophilic,reproducible,biocompatible,high mechanical strength,and functional adjustable due to the presence of a large number of hydrogen bonds.MCC is widely used as a reinforcement material for polymers.Fish swim bladder gelatin(FG)is a biodegradable macromolecule produced by collagen hydrolysis,which is hydrophilic,low antigenicity,gel and biocompatibility.FG surface is rich in amino,carboxyl and hydroxyl functional groups,which is easy to functionalize modification,but FG has defects such as easy corrosion and mildew,poor thermal stability and mechanical properties.In this paper,MCC and its modified products were introduced into FG,and the microstructure,swelling degree,porosity and water absorption properties of the MCC/FG composite were optimized by adjusting the material ratio,drying conditions and crosslinking agents prepared by MCC/FG composite.Based on the high hydrophilicity,hygerability swelling and adsorption properties of the MCC/FG composite.To investigate its water actuation,slow drug release and adsorption functions,and explore its potential applications in environmental response,wound dressing and adsorption materials.The main research contents of this paper are as follows:(1)Preparation of anti-fungal FG by enzyme extraction method.Using fish swim bladder as raw material,the optimum technology of enzyme extraction FG was studied.The results showed that compared with the traditional process,the extraction yield of FG was significantly increased by enzymatic extraction and ultrasonic pretreatment.The extraction rates of papain and alkaline protease were 1.2 and 1.6 times of the traditional process,respectively.The FG extracted by alcalase protease had very low viscosity and no gel property.The FG extracted by traditional process and papain had good mechanical properties,and when the solid content was25%,the adhesive strength of conventional FG was slightly greater than that of enzymolysis FG.Through the isolation,culture and identification of FG-susceptible molds,and the performance evaluation of antibacterial agents,it was shown that hingusspora was one of the FG-susceptible molds,and the growth of hingusspora was inhibited by sodium tetraborate,sodium diacetate and andimede AL-D.Andimede AL-D had the best inhibitory effect on the susceptible mold.The growth of crossstreptosporus in FG was inhibited by adding only 0.3%andimede AL-D.The addition of antibacterial agents had little effect on the adhesive strength of FG.This part of research provides the raw material basis for the subsequent functionalization research.(2)Study on MCC/FG response to water drive.Using MCC and FG as raw materials,MCC was modified with silane coupling agent(KMCC for short)and glutaraldehyde was used as cross-linking agent to prepare KMCC/FG composite gel.A water-driven response actuator was constructed by filling the composite gel into a 3D-printed polylactic acid(PLA)double layer scaffold.By changing the material ratio of the composite gel,the swelling degree and swelling rate of the composite gel were regulated.By adjusting the structure of the active layer,different deformation styles of bending and twisting were realized.The results shown that the maximum curvature of KMCC/FG 10 was 0.083,which was about 2.0 times of FG(0.041).The larger the angle between active and passive layers was,the smaller the distortion was.KMCC/FG had the largest distortion at 20°,and the deflection and torsion angles were66.93 mm and 2.04π,respectively.The results shown that the actuator could effectively simulate bending deformation of ferns and twisting deformation of pea pods,and the deformation behavior was reversible and reproducible.The prepared water-driven response actuator had potential application in the field of environmental response.(3)Study on MCC/FG drug-loaded composite film.MCC/FG drug-loaded composite films were prepared using amoxicillin as sustained-release drug and genipin as cross-linking agent.The addition of MCC to FG could improve the mechanical properties of MCC/FG composite film,and the addition of MCC could reduce the swelling rate and swelling rate of composite film.Ultrasonic treatment had positive effect on the mechanical properties and swelling rate of the composite films.After ultrasonic treatment,the tensile strength and elastic modulus of son-MCC/FG 6 were increased by 115% and 227%,respectively,compared with FG.The composite film could achieve slow release of amoxicillin,with a cumulative release rate of 89%.NIH 3T3 cells grew well in the composite membrane extract,and the survival rate of cells was more than 85%,with no inhibitory effect on cell activity.Drug-loaded composite film had good antibacterial performance against Escherichia coli and Staphylococcus aureus,which could effectively prevent wound infection and avoid frequent dressing change.MCC/FG drug loaded composite film had the potential as wound dressing.(4)Study on the adsorption function of CNC/FG composite sponge.Cellulose nanocrystalline(CNC)was prepared by acid hydrolysis with MCC as raw material,and CNC/FG composite sponge was prepared by freeze-drying with glutaraldehyde as crosslinking agent.CNC and FG were mainly bonded by hydrogen bonds,and CNC was used as the reinforcing phase to compound into the FG matrix,which made the internal structure of the composite sponge orderly and stable,and thus improved the swelling performance.Appropriate amount of CNC could improve the porosity of the composite sponge,and the CNC/ FG 1composite sponge had the largest porosity,which was 93.76%.High porosity and strong water absorption could increase the adsorption and separation of active sites,and improved the swelling properties,mechanical properties and thermal stability of the composite sponge.CNC/FG composite sponge had good ability to absorb tannic acid.Under the optimal adsorption conditions,when the amount of CNC was 1%,the removal rate of tannic acid could reach about 80%.50% ethanol had good desorption effect on tannic.The sponge could be reused after analysis,indicating that it had application prospects in the field of adsorption materials.In conclusion,MCC and FG,two natural polymers from nature,can be used as the main raw materials to successfully prepare functional materials with high water absorption,hygroscopic swelling and adsorption properties,which is expected to be applied in the field of environmental response and biomedicine.