Evaluating The Interaction Of Nanomaterials/protein And Morpholino/protein Based On Atomic Force Microscopy

Understanding the interaction between nanoparticles,nucleic acid analogues and proteins is helpful to provide valuable information for the diagnosis and treatment of diseases,so it has become a research hotspot in the fields of chemistry,biology and medicine.As an important tool for the study of biological samples,atomic force microscope(AFM),can not only measure the surface of biomaterials at the atomic scale in the atmosphere or in the liquid environment,but also analyze the dynamic recognition process of biomolecules at single molecule level.It is one of the powerful means for the study of biomolecule interaction.Therefore,AFM was used to investigate the interaction of nanomaterials/proteins and morpholine nucleic acids/proteins.The details are as follows:1.The contradictory effect of AuNP-Mo S₂ on A?aggregation based on AFMDifferent concentrations of gold decorated molybdenum disulfide nanocomposite(AuNP-Mo S₂)were added to incubate with amyloid protein?(A?₄₀),and then AFM and Th T fluorescence spectrum were used to analyze the difference of A?₄₀ fibrillation process with or without AuNP-Mo S₂.The results showed that low concentration of AuNP-Mo S₂ can promote the formation of A?₄₀ fibrils,while high concentration of AuNP-Mo S₂ can inhibit the formation of A?₄₀ fibrils.In addition,it was found that both low and high concentrations of AuNP-Mo S₂ could reduce the lag period of A?₄₀ fibrillation.Finally,the mechanism was analyzed.The reason may be that AuNP-Mo S₂ plays a"nuclear"role in the process of A?₄₀fibrillation.At the same time,the ratio of A?₄₀ monomer adsorbed on AuNP-Mo S₂ against free A?₄₀ monomer in solution is also the reason why different concentrations of AuNP-Mo S₂ have different effects on the process of A?₄₀ fibrillation.This work is expected to develop a new inhibitor on amyloid fibrillation.2.The effect of AuNPs on the interaction of A?₄₀ monomer/A?₄₀ monomer by AFMGold nanoparticles(AuNPs)were modified on the surface of slide by silanization reagent,and then A?₄₀ monomers were fixed on both AFM tip and substrate respectively.Next,AFM was used to investigate the effect of AuNPs on the interaction of A?₄₀monomer/A?₄₀ monomer with the presence of Cu²⁺.The results show that Cu²⁺could improve the interaction of A?₄₀ monomer/A?₄₀ monomer.However,AuNPs could weaken the promotion effect of Cu²⁺on the interaction of A?₄₀ monomer/A?₄₀ monomer.This may be due to the fact that AuNPs plays the role of H₂O₂ catalase,which makes the concentration of H₂O₂ produced by reduction of Cu²⁺by A?₄₀ decrease.This work provides a new method for the study of enzymatic reaction.3.The interaction between MO probe/VEGF and aptamer/VEGF based on AFMCompared with the natural nucleic acid,MO showed superior hybrid efficiency,anti-enzymolysis capability and base mismatch discrimination even under low ionic strength.But there are few studies on the interaction between MO and protein.In order to further analyze the performance of MO,the interaction of MO probe with its targets VEGF was investigated at the single molecule level by AFM and SPR in this work.The results showed that MO could not interact with VEGF specifically,which may be due to the rigidity of the main chain and the neutrality of MO.This work provides new information for the study of the interaction between MO and biomolecules.