Study On The Application Of Novel Carbon Nanocomposties For The Detection Of Biomarkers In Cardiovascular Diseases

Owing to the small size,nanomaterials have the unique optical,electronical and mechanical properties which are be widely used in nano-drug carrier,diagnosis,treatment and so on.Cardiovascular diseases have serious effect on people’s life and even threaten human health.It is a major contributor to global morbility and motality.The detection of cardiovascular disease related biomarkers plays an important role in its development.For example,the detection of the single nucleotide polymorphisms in cardiovascular diseases-related gene can be used for the prevention,diagnosis and treatment.In addition,the detection of therapic target for cardivocascular diseases is of great benefit to the drug development and targeted therapy.In our work,the merits of carbon nanocomposites were employed to the construction of electrochemical biosensor for the quantitative detection of cardiovascular diseases-related biomarkers.It set a firm foundation for the diagnosis,treatment and prevention of cardiovascular diseases.Also,it provided usful information for the drug development for the cardiovascular diseases.Our work mainly focuses on the two aspects:1.Study on the nitrogen-doped graphene nanocomposties for the high-fidelity detection of LPL gene SNP（rs1801177）.The nanocomposites of Fullerene/polyamidoamine/gold nanoparticles(C₆₀/PAMAM/AuNPs)were prepared as the modified film.It can be used to combine with the thiol-based capture probe.The bioconjugates served as therecognizationsubstance.Additionally,nitrogen-doped graphene/palladium platinum bimetallic nanoparticles/polyaniline（N-G/PdPt/PANI）nanohybrids were synthesized for the first time,which acted as the novel redox probe and catalyst.N-G holds the advantages of better electrical conductivity for the acceleration of electrons and more surface-active groups which enables immobilize countless PdPt bimetal nanoparticles.Moreover,PANI can be served as the redox probe by spontaneous redox reation.So the additional electroactive substances are unneccessary.The construction process was simplified.With the catalysis of H₂O₂ by nanohybrids,the electron transfer rate was increased.As a result,the electrochemical signal of N-G/PdPt/PANI itself could be significantly enhanced,inducing the improvement of the sensitivity.Under the optimal condition,the electrochemical DNA biosensor exhibited satisfying performance for the detection of LPL gene SNP（rs1801177）with a wide linearity ranging from 0.00001 nM to 10 nM and a relatively low detection limit of 3 fM.The proposed biosensor showed excellent selectivity and specificity.The results suggested that this method has provided a new method for the detetion of the LPL gene SNP（rs1801177）.Also,our work can provid some useful imformation for the diagnosis,treatment and prevention in cardiovascular diseases.2.Study on the c-MWCNTs nanocomposites for the detection of soluble CD40 ligand.In this work,the nanocomposites of carboxylated multiwalled carbon nanotubes/branched polyethylenimine/gold nanoparticles（c-MWCNTs/b-PEI/Au NPs）were synthetized to serve as the modified materials on the electrode to construct the electrochemical immunosensor for the detection of sCD40L.Owing to the properties of large specific surface area and excellent conductivity,the c-MWCNTs can be employed as the good modified materials.However,practical application was limited by the short-coming of weak dispersity.To address the problems,the b-PEI was selected to functionalize the c-MWCNTs because of its ability to disperse the c-MWCNTs.In addition,the b-PEI could provide a large content of amino groups.A great number of amino modified sites were supplied,which can load many AuNPs.The AuNPs can immobilize the antibodies.As a result,the amount of antibodies immobilization was greatly increased.Finally,the sensitivity of immunosensor was strongly increased.The c-MWCNTs/b-PEI/AuNPs was used to combine with the anti-sCD40L,which can serve as the recognization substance of sCD40L to achieve the sensitive detection of sCD40L.Under the optimal condition,the immunosensor displays a good linear response range from 0.1 pg mL^-1 to100 pg mL^-11 sCD40L and a relatively low detection limit of 3 fg mL^-1.Importantly,the immunosensor displayed specific,rapid and portable detection of sCD40L,thereby providing a new platform for the potential application in clinic bioanalysis.The sCD40L was the therapied target for cardiovascular diseases.Our work can provid some important imformation to the drug development for cardiovascular diseases.