Researches And Application Of Electrochemiluminescent Biosensors Based On Carbon Nanomaterials

The determination of tumor markers, DNA and cancer cells, not only plays an important role in diagnosing a disease, but also offers opportunities for understanding fundamental biological processes involved in disease progression. To achieve an accurate and rapid detection of biomolecules relevant to cancer, countries researchers are paying more attention on developing more effective methods and have made some marked achievements. However, it is difficult to realize expensive equipment and professional operation for remote regions with limited resource. Therefore, it is of considerable interest to the further research for rapid, simple, sensitive and accurate alternative methodology for determination of tumor markers.In this paper, we focus on establishing electrochemiluminescences(ECL) detection means for biosenser, and carbon dots with excellent ECL property was prepared. In order to further enhance the intensity of ECL signal, they were immobilized onto nanoporous silver, nanoporous PtNi alloy nanomaterials, combined with the rolling circle amplification(RCA) technique. Our biosensors based on the specific binding of antibody to antigen and cells to aptamers showed wide linear range, good specificity and stability. And paper chips were combined with biosensor technique to develop low-cost, high-throughput real-time detection system. The main research is as follows:(1) The three-dimensional(3D) graphene conjugated with gold nanoparticles(AuNPs)(3D-GR@AuNPs) was synthesised used to modify glassy carbon electrode, the 3D-GR has been decorated with a large amount of Au nanoparticles about several nanometres. The effective surface area can be easily produced after 3D-GR@AuNPs was used as modifier. The carbon dots(CDs) simply prepared by electrooxidation of graphite was used as ECL reagent. The nanoporous sliver(NPS) with controllable 3D structure could provide a good platform for high loading of CDs, which formed the NPS@CDs composites as good ECL label. The new biosensor displayed good analytical performance for the detection ofprostate protein antigen high specificity and good sensitivity.(2) The 3D macroporous Au-paper electrode was fabricated and employed as the working electrode for specific and efficient antibodies capture. We developed a cascade signal amplification strategy for detection of IgG antigen by combining the rolling circle amplification(RCA) technique with oligonucleotide functionalized CDs, based on a paper-based ECL origami device. The RCA product containing tandem-repeat sequences could serve as an excellent template for periodic assembly of CDs, which presented per protein recognition event to numerous CDs tags for ECL readout. The proposed strategy showed remarkable amplification efficiency and good stability.(3) Au@Pd nanoparticles were grown on cellulose to fabricate Au@Pd paper-based working electrodes with 3D incompact macroporous architecture for aptamers capture. The CDs with good water-solubility prepared by electrooxidation of graphite. PtNi alloy with bicontinuous and controllable network architecture can act as a support for loading with CDs The PtNi@CDs thereby formed are good ECL labels. Aptamer-based ECL method was utilized for MCF-7 cells sensing, which possesses the advantages of rapid response, high sensitivity, ease of use, low cost and small-sized commercial detectors.