Preparation Of Chiral Nanoprobes And The Analysis Of Disease Markers

Parkinson’s disease has been severely impaired the life quality and health of the patient,and increased the social burden.At present,the global prevalence of Parkinson’s disease among people over 65 years old is about 2%to 3%,and gradually increased in young adults.The formation and development of venous thrombosis with fibrin as the supporting structure is a key event in a variety of pathological processes and easily leads to a poor prognosis of surgery.Therefore,it will play a positive role in the prevention and treatment of related diseases by hindering the abnormal interaction between proteins,or destroying their pathological form.The environmental and food samples have a complex matrix and contain a wide variety of exogenous pollutants.Therefore,constructing a simple and reliable pre-screening platform for toxic exogenous chemicals can protect the organism from irreversible damage.Herein,we explore the interaction between chiral nanomaterials and two disease-related proteins based on two chiral nanoprobes.These two proteins are fibrin andα-synuclein,which are closely related to the pathological process of venous thrombosis and Parkinson’s disease,respectively.By exploring the physical and chemical changes during the interaction between chiral nanomaterials and proteins,as well as the role of chirality in these changes,the potential interaction mechanism has been specifically investigated.Moreover,the biological effects of chiral nanomaterials are verified by in vivo experiments.In addition,the gold-silver heterodimer is fabricated by the DNA self-assembly method.It can realize the highly sensitive and specific detection of 8-hydroxydeoxyguanylic acid（a biomarker of DNA oxidative damage）in cells and exhibit versatility for the evaluation of the DNA oxidative damage effects of exogenous compounds.Firstly,Co₃O₄ supraparticles（SPs）covering the platelet membrane on the surface are prepared.In vitro experiments show that Co₃O₄SPs can destroy the structure of fibrin and thrombus under electromagnetic field condition.Co₃O₄SPs are injected into venous thrombosis model mice through the tail vein.They can target the thrombus site with via platelet membranes.The results of in vivo experiments suggested that Co₃O₄SPs with the assistance of electromagnetic field displayed thrombolysis efficacy without significant side effects,such as bleeding.Secondly,experiment results reveal that Co₃O₄SPs can produce a large amount of ROS under electromagnetic field condition.The conpatison of the changes in the thrombolytic effect ofSPs with and without ROS inhibitor demonstrates the generation of ROS is the main reason for the collapse of fibrin and thrombus clot structure.Further analysis suggsts that the main kind of ROS is singlet oxygen,and the amount of singlet oxygen produced by D-Co₃O₄SPs is1.5 times higher than that of L-Co₃O₄SPs,leading to its better thrombolytic effect.Thirdly,we synthesize L-/D-tartaric acid modified Mn₂O₃ NPs（L-/D-Mn₂O₃ NPs）and compare the interaction results between Mn₂O₃ NPs with different chirality andα-synuclein.The spectral signals and TEM results jointly reveal that D-Mn₂O₃ NPs perform better than L-Mn₂O₃ NPs in inhibiting the aggregation ofα-synuclein monomers and disaggregatingα-synuclein aggregates.In addition,an external electromagnetic field can enhance the interaction between chiral Mn₂O₃ NPs andα-synuclein.D-Mn₂O₃ NPs combined with the electromagnetic field,being selected for the treatment of mice Parkinson’s model,and effectively improve the symptoms of Parkinson’s mice.Fourthly,the different affinity between NPs and proteins are revealed to explain the different interaction results of Mn₂O₃ NPs with different chirality towardsα-synuclein.ITC assay reveals that the affinity constants betweenα-synuclein monomers and L-Mn₂O₃ NPs,D-Mn₂O₃ NPs are 8.34×10⁵ M^-1 and 2.92×10⁶M^-1,respectively.The affinity constants betweenα-synuclein fibril and L-Mn₂O₃ NPs,D-Mn₂O₃ NPs are 2.61×10⁶ M^-1 and 1.35×10⁷ M^-1,respectively.In contrast,the affinity constants betweenα-synuclein and Mn₂O₃ NPs synthesized by using tyrosine and penicillamine as chiral ligands are 1-2 orders of magnitude less than that of L-/D-Mn₂O₃ NPs.Moreover,the magnetic force exerted on Mn₂O₃ NPs by the applied electromagnetic field explained the underlying mechanism of the enhanced interaction between chiral Mn₂O₃ NPs andα-synuclein under an electromagnetic field.Finally,the gold-silver heterodimer to specifically recognize the 8-OHd G was prepared by the DNA self-assembly method.The dihedral angle between the dimers and the plasmonic effect endow the assemblies of strong circular dichroism（CD）signal in the visible light region.In the presence of 8-OHd G,the dimer disassembled into individual nanoparticles,and therefore,the CD signal changed.At the same time,the fluorescence signal,which is previously quenched by the energy resonance transfer effect,can gradually recover.Based on this principle,the high sensitivity and dual-signal detection of 8-OHd G was achieved.The limit of detection（LOD）of the CD and fluorescence signal are 0.032 nmol/L and 0.064 nmol/L,respectively.Moreover,based on this heterodimer probe,the oxidative damage effects of fipronil,nonylphenol,and alternol on the DNA of NG108 cells were evaluated.The above-mentioned studies effectively achieve the treatment of venous thrombus and Parkinson’s disease by applying chiral nanomaterials with the assistance of a non-invasive external electromagnetic field.It provides a theory and experimental foundation for subsequent study on using external energy fields to manipulate the biological effects of chiral nanomaterials.The chiral heterodimer probes synthesized by the DNA self-assembly method provide a flexible design application platform for detecting other biomarkers and evaluating the potential toxicity of exogenous compounds.