Study On The Combination Of New Carbon Nanomaterials And Pt-PMB Nanocomposites For PCSK9 Analysis

Cardiovascular disease has high morbidity,high mortality,a poor prognosis and high risk of recurrence.And it remains the leading cause of death worldwide.The proprotein convertase subtilisin/kexin type 9?PCSK9?reduces the clearance of low-density lipoprotein cholesterol?LDL-C?and increases plasma LDL-C levels,leading to the occurrence and development of atherosclerosis and promoting the occurrence of cardiovascular and cerebrovascular events.PCSK9 is the most promising lipid-lowering drug target after statins.The detection of PCSK9 is of great significance for the treatment of cardiovascular diseases and the screening of new drugs.Nano sensing technology provides the possibility for the sensitive detection of PCSK9,and provides a new technical strategy for the treatment of cardiovascular diseases and the evaluation of drug effects.The nitrogen-doped graphene nanoribbons?N-GNRs?synthesized in this experiment are a new type of carbon nanomaterials,which not only have fast electron transfer properties and high thermal conductivity,but also catalyze hydrogen peroxide?H₂O₂?.Palladium platinum alloy?PdPt?nanoparticles can catalyze the reduction of H₂O₂,improve biocompatibility and promote electron transfer.Amino functionalized fullerene(n-C₆₀)is a promising nanomaterial with large specific surface area,good biocompatibility and hydrophilicity.And it surface contains rich amino groups that can be used for further modification.In view of the above advantages,we used n-C₆₀ as a carrier to immobilize PdPt nanoparticles to obtainamino-functionalizedfullerenepalladium-platinumalloy.(n-C₆₀-PdPt)nanocomposites.n-C₆₀-PdPt can not only support biological molecules,but also catalyze H₂O₂ to generate electrochemical signals.The combination of N-GNRs and n-C₆₀-PdPt can not only improve electron transfer efficiency,but also synergistically catalyze H₂O₂.In order to verify the performance of nanomaterials,N-GNRs and n-C₆₀-PdPt were used to construct a label-free immunosensor for rapid detection of PCSK9 in serum through antigen-antibody immunoreaction.For the first time,we used a one-step method to synthesize Pt-poly?methylene blue??Pt-PMB?nanocomposite with uniform morphology and good electrical conductivity,which has redox properties and can be used as a new type of signal tag to generate electrochemical signals.Based on this,we combined Pt-PMB with antibodies to form bioconjugates,which were used as recognition elements.N-GNRs,n-C₆₀-PdPt and Pt-PMB nanocomposites were used to construct a sandwich-type immunosensor for ultrasensitive detection of PCSK9 in serum through antigen-antibody immunoreaction.Under the optimum conditions,the label-free immunosensor showed a linear range of 10 pg.mL^-1to 100 ng.mL^-11 with a detection limit of 3.33 pg.mL^-1?S/N=3?and the sandwich-type immunosensor exhibited a linear range of 100 fg.mL^-1 to 100ng.mL^-11 with a detection limit of 33 fg.mL^-1?S/N=3?for PCSK9 detection.This testing strategy provides a good technical platform for the treatment of cardiovascular diseases and the screening and evaluation of lipid-lowering drugs.