Study On The Fabrication Of Disease Marker Sensors Based On Carbon-rich Nanomaterials

Disease markers play a crucial role in the prevention,diagnosis,treatment and prognosis of diseases.Therefore,the development of highly sensitive and highly selective detection methods is of great significance for the diagnosis of related diseases.Electrochemiluminescence?ECL?sensor and electrochemical sensor are well applied in medical analysis,food security and environment monitoring.Employment the carbon-rich nanomaterials,with good biocompatibility,chemical stability,good electrical conductivity for the construction of sensors can shorten the response time,reduce background signal and improve the detection sensitivity.In this paper,we used various carbon-rich nanomaterials to develop a series of disease marker sensors.The main contents and results are as following:?1?Biomimetic polydopamine nanosphere?PDANS?was easily prepared and was firstly exploited as an ECL nanoquencher for the development of a sandwich type immunosensor.The PDANSs with abundant active functional groups can facilely label the detection antibody.Theamino-modifiedmultiwallcarbonnanotubes/Nafion?MWCNTs-NH₂@N?composite-film was adoptedas amatrixto incorporate the luminophor tris-?2,2'-bipyridine?ruthenium(Ru?bpy?₃²⁺)and immobilize the capture antibody.The quenching mechanism is believed that the excited states of Ru?bpy?₃²⁺can be annihilated by quinone units in PDANSs via energy transfer.The ECL quenching efficiency was logarithmically related to the concentration of the PSA in the range from 0.1 pg·mL^-1 to20·ng·mL^-1 with a detection limit of 35 fg·mL^-1.Furthermore,the proposed ECL immunosensor presented good stability,repeatability and selectivity.?2?A novel ECL signal-off aptasensor was proposed for the determination of thrombin?TB?based on carbon dots?C-dots?.Ag-decorated polydopamine nanospheres?PDANS@Ag?was firstly exploited as a matrix to carry C-dots and label probing DNA?pDNA?.The PDANS with the high specific surface area and unique adhesion ability could load a large number of C-dots.Ag nanoparticles?AgNPs?could enhance the ECL emission efficiency of C-dots and promote the signal response.The platinum functionalized graphene?Gr-Pt?nanocomposite was used to modify the electrode,which improved the electronic transmission rate.The ECL nanoprobe PDANS@Ag/C-dots was introduced into the electrode interface via the hybridization chain reaction between cDNA and pDNA,which generate a strong ECL signal.The target analytes TB can specifically recognize the cDNA,leading to the release of the signal probe from the electrode surface and the decrease of ECL intensity.A linear response range from 1.0×10^-6 to 5.0 nmol·L^-1 with a detection limit of 0.35 fmol·L^-1 was obtained under the optimized experimental conditions.Furthermore,the proposed ECL aptasensor presented good stability,repeatability and selectivity.?3?An efficient quenching ECL immunosensor for highly sensitive detection of insulin was constructed using carboxyl-functionalized g-C₃N₄?C-g-C₃N₄?as an ECL emitter and hollow NiPd nanoparticles loading with G-quadruplex/hemin DNAzyme?NiPd-DNAzyme?as the dual-quenching probe.In this protocol,the as-prepared C-g-C₃N₄ served as both a luminophore and the matrix to immobilize capture antibody?Ab₁?by amide linkage,which exhibiting strong ECL activity in the presence of the coreactant H₂O₂.The NiPd showed good peroxidase-activity and loading capacity for both G-quadruplex/hemin DNAzyme and detection antibody?Ab₂?.The dual-peroxidase nature of NiPd-DNAzyme composite highly promoted the reduction of H₂O₂,resulting in the consumption of the coreactant of C-g-C₃N₄and obvious ECL quenching.Using insulin as a model analyte,the change of ECL intensity was logarithmically related to the concentration of the insulin in the range from 0.1 pg mL^-1 to20.0 ng mL^-1 with a detection limit of 33 fg mL^-1.?4?A novel and ultrasensitive sandwich-type electrochemical immunosensor was designed for the quantitative detection of SCCA based on the?-cyclodextrin functionalized graphene nanosheet?CD-GN?and the ternary hollow Pt/PdCu nanocube anchored on three-dimensional graphene framework?Pt/PdCu-3DGF?.CD-GN exhibited high specific surface area and good dispersibility and stability in water,which were beneficial to fix captured antibodies?Ab₁?through the supramolecular host-guest interaction between CD and Ab₁.The specific surface area of Pt/PdCu-3DGF synthesized by solvothermal method is large,and more detection antibodies can be effectively captured.Furthermore,the ternary metal nanoparticles exhibited high electrocatalytic activity toward the reduction of hydrogen peroxide.Under optimal conditions,the fabricated immunosensor showed a sensitive response to SCCA with two linear ranges.The linear ranges are 0.0001 ng·mL^-1 to 1 ng·mL^-1 and 1ng·mL^-1 to 30 ng·mL^-1 with a detection limit of 25 fg·mL^-1.