Based On The Study Of The Interaction Between Graphene Oxide-silver Nanoparticle Composites And Biological Macromolecules

Graphene Oxide(GO)is a new type of carbon nanomaterial,which has a wide range of applications in biomedical,environmental protection,energy storage and other fields.GO as graphene important derivatives,its good physical and chemical properties promotes the GO has become the support platform for composite materials.In recent years,nanocomposite materials in biological imaging,biological sensing and detection and treatment of cancer based on the GO has been widely to explore.Researchers are currently considering its application in clinical diagnosis and treatment.The nanoparticles are embedded in graphene oxide to form a hybrid material with special properties.The specific synergy of the two materials can not only improve the efficiency of the treatment process,but also provide key ideas for the pathological analysis process.However,due to the unique properties of composite materials,it exhibits a complex mechanism of action in the process of interacting with biological macromolecules,which brings some difficulties to clinical practical applications.Therefore,based on the study of the mechanism between GO-based nanocomposite materials and biomacromolecules,exploring the biological effects of composite materials in the process of action has instructive significance for solving practical problems in clinical applications.This paper was based on the GO in situ synthesis of silver nanoparticles(AgNPs).The composite materials interacted with biological macromolecules(DNA and trypsin).Systematic research on biological macromolecules in the fluorescence properties,adsorption behavior,conformation and enzyme activity changes were explored.We also theoretically explain the mechanism of interaction or intermolecular forces.The main contents and results are as follows:(1)The effect of GO-AgNPs on the fluorescence characteristics of DNA labeled with methylene blueGraphene-silver nanoparticles(GO-AgNPs)are becoming increasingly important in the field of bioanalysis due to its special affinity for DNA.Meanwhile,GO-AgNPs nanocomposites are commonly used as quenching agents.We synthesized different proportions of GO-AgNPs nanocomposites(1:1,1:3,1:5,1:10)as fluorescence quenching agents to interact with methylene blue(MB)labeled DNA.The results showed that the fluorescence intensity of DNA-MB system decreased gradually with the increase of the concentration of GO-AgNPs nanocomposites.The quenching of DNA-MB by AgNPs and GO was not a simple additive effect,but a synergistic effect.The DNA-MB quenching efficiency was increased with the decrease of GO/AgNPs ratio at different ratios(1:1,1:3,1:5,1:10)of GO-AgNPs.The interaction between GO-AgNPs and DNA-MB was studied by thermodynamic analysis,and it was concluded that the intermolecular force between GO-AgNPs and DNA-MB was hydrogen bond.Our work will provide an important theoretical and experimental basis for fluorescence sensing of DNA.(2)Interaction between GO-AgNPs and trypsin:studies on adsorption behavior,conformational structure and enzyme activity.Since there are relatively few reports on whether GO-AgNPs bind and alter the structure and function of trypsin,multiple methods have been used to systematically characterize the molecular interaction between GO-AgNPs and trypsin.The results showed that GO-AgNPs combined with trypsin to form a ground state complex.The adsorption capacity of GO-AgNPs on trypsin was higher than that of GO alone.Langmuir-Blodgett assembly confirmed that AgNPs did not interfere with absorption of GO to trypsin.After interacting with GO-AgNPs,the secondary structure and microenvironment of trypsin were altered.In addition,GO-AgNPs also enhanced the activity of trypsin and promoted the hydrolysis of bovine serum protein(BSA)by trypsin.These findings provide important support for the application of GO based nanocomposites in highly efficient immobilized enzymes.