Preparation Of Metal-organic Framework Nanozyme/Polycaprolactone Composite Fibrous Membrane For Antibacterial Application

Bacterial-infected wound is one of the important reasons for the increase of human morbidity and mortality.Antibiotics are often used for antimicrobial treatment,but it may cause bacterial resistance and even produce super bacteria because of long-term use,which has a huge potential risk on human health.It is of great significance to reduce the use of antibiotics and to find suitable antimicrobial materials to replace antibiotic therapy.NH₂-Fe-MIL-88B(Fe-MOF)is a metal-organic framework nanozyme with large specific surface area,easily modified functional groups and POD-like activity.Fe-MOF can react with H₂O₂ to produce·OH through Fenton mechanism.·OH has strong oxidation ability and can destroy bacterial or cancer cell structure,which has great potential application value in the biological field.Fe-MOF used alone does not have significant antimicrobial properties and often requires an external supply of H₂O₂to have antimicrobial properties.However,giving H₂O₂ directly will cause certain toxic and side effects on the surrounding tissues because of H₂O₂rapid diffusion.In order to avoid the above problems,based on the cascade reaction characteristics between glucose oxidase(GOx)modified Fe-MOF hybrid enzyme and glucose,we prepared the composite fibrous membrane with self-activated cascade reaction and studied its antibacterial properties in this paper.The specific contents are as follows:(1)GOx-Fe-MOF(GF)nanozyme was successfully prepared by EDC/NHS coupling method.The effective cascade reactivity between GF nanozyme and glucose was verified by means of methyl orange indicating pH change of solution and terephthalic acid(PTA)detecting·OH method.GF nanozyme could decompose glucose to produce gluconic acid and H₂O₂.Gluconic acid can reduce pH value to 4.4,and then promote Fe-MOF catalysis of H₂O₂to produce·OH.The effect of mass ratio of GOx/Fe-MOF(1:1?1:8)on enzyme loading and antibacterial activity was further studied.The results showed that when GOx/Fe-MOF was 1:2,the maximum GOx loading of GF nanozyme was 289.1?g/mg,and the minimum inhibitory concentration was 0.015625 mg/m L.When the glucose concentration was greater than 1 m M,GF nanozyme had obvious bacteriostatic effect.(2)The hydrophobic polycaprolactone(PCL)fibrous membrane was prepared by electrospinning,and the water contact angle of PCL fibrous membrane was about 130.3°.After alkali hydrolysis,the water contact angle of PCL fibrous membrane was reduced to 55.6°.GF/PCL(GF/PCL-2,GF/PCL-4,GF/PCL-8)composite fibrous membranes were prepared by simple physical adsorption method and their antibacterial properties in LB agar and broth containing glucose(5 m M)were studied.The results showed that the antibacterial effect of GF/PCL-8 composite fibrous membrane was the best,and the bactericide rate of GF/PCL-2,GF/PCL-4,GF/PCL-8 composite fibrous membrane could reach 100%after being co-cultured with MRSA and E.coli for 5 h,suggesting excellent antibacterial performance.(3)The hydrophilic PCL/GE/D-glucose(PGD)fibrous membrane loaded with glucose was prepared by electrospinning.The water contact angle of PGD fibrous membrane was about 52.1°and the d=10 mm of PGD fibrous membrane could release glucose up to 3.2 m M.In this study,GF/PGD-2,GF/PGD-4 and GF/PGD-8 composite fibrous membranes with different GF loading were prepared by simple physical adsorption.The antibacterial properties of these membranes in nutrient broth or agar were studied.The results showed that without external glucose supply,the fibrous membrane could self-activate the antibacterial properties to produce·OH under wet environment.GF/PGD-8 composite fibrous membrane had the best antibacterial effect.Bactericidal efficiency of GF/PGD-4 composite fibrous membrane was up to100%against MRSA,while GF/PGD-8 composite fibrous membrane had 100%bactericidal efficiency against E.coli.In vivo antibacterial experiments indicated that GF/PGD-8 composite fibrous membrane had better healing effect than commercial Ag⁺dressing,and had good biological safety.