Study On Electrochemiluminescence Biosensors Constructed By Perylenetetracarboxylic Dianhydride And Nanomaterials

Electrochemiluminescence (ECL) is a light emision produced by an electrochemical reaction between electrochemically generated species under potential. It is the product of elelctrochemical and chemiluminescent methods. And ECL has not only the high sensitivity, wide linear ranges and simple operation of chemiluminescence assay but also easy control as well as excellent selectivity of elelctrochemical analysis. ECL biosensors apply ECL techniques to detect bioactive materies which have advantages of high sensitivity, low cost, low background signal and simple setup. Perylenetetracarboxylic dianhydride (PTCDA), asπ-stacking semiconducting material, owns superior ECL properies due to porous structure, finer electrical conductivity and good thermal stability. Moreover, nanomaterials play a pivotal role in developing ECL immunosensors for their large specific surface area, good biocompatibility and fast electron tranafer rate. Particularly, studies on ECL biosensors constructed by PTCDA and nanomaterials would have momentously theoretical significance and practical application prospect.Part 1 A novel solid-state electrochemiluminescence detector for capillary electrophoresis based on tris(2,2’-bipyridyl)ruthenium(Ⅱ) immobilized in Nafion/PTC-NH2 composite filmA new electrochemiluminescence (ECL) detector for capillary electrophoresis (CE) based on tris(2,2’-bipyridyl)ruthenium(Ⅱ) (Ru(bpy)32+) immobilized in Nafion/PTC-NH2 (an ammonolysis product of 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA)) composite film was presented for the first time. The Nafion/PTC-NH2 composite film could effectively immobilize tris(2,2’-bipyridyl)ruthenium(Ⅱ) via ion-exchange and electrostatic interaction. Cyclic voltammetric and ECL behavior of Nafion/PTC-NH2/Ru composite film was investigated compared to Nafion/Ru composite. The Nafion/PTC-NH2/Ru composite film exhibited good ECL stability and simple operability. Then the CE with solid-state ECL detector system was successfully used to detect sophora -a quinolizidine type-alkaloids as sophoridine (SR) and matrine (MT). The CE-ECL parameters that affected separation and detection were optimized. Under the optimized conditions, the linear range was from 2.5×10-8～2×10-6mol·L-1 for SR,1.0×10-8～1.0×10-6 mol·L-1 for MT. The detection limit (S/N=3) was estimated to be 5×10-9 and 10-9 mol·L-1 for SR and MT, respectively. It was shown that the CE coupling with solid-state ECL detector system exhibited satisfying sensitivity of analysis.Part 2 Electrochemiluminescent 3,4,9,10-peryIenetetracarboxylic dianhydride film for ultrasensitive immunoassayIn this paper, the electrochemiluminescence (ECL) of 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) film with the coreactant peroxydisulfate (S2O82-) was studied and employed for ultrasensitively immunosensing a-fetoprotein (AFP) originally. The CS-PTCDA composite film exhibited intense ECL signal as well as satisfactory stability in the presence of S2O82-, which holded significant promise for the construction of highly sensitive ECL biosensors. Here a new strategy, via the conjugation of multiwalled carbon nanotubes-polyaniline (MWCNT-PANI) nanocomposite and gold nanoparticles (GNPs) with the film, was developed to magnify the ECL intensity of PTCDA and thereby enhance the detection sensitivity. This PTCDA-based ECL immunosensor was low cost, simple operation, high sensitivity and low toxicity etc, showing a wide linear range from 0.0001 to 10 ng·mL-1 and a relatively low detection limit of 33 fg·mL-1 for AFP detection. The present work demonstrated that PTCDA film as an ECL probe was a promising candidate for immunoassays and has potential application prospect.Part 3 PTCGNPs composite as labels for a highly sensitive sandwich-type electrochemiluminesent immunosensorIn this work, PTCGNPs composite with strong electrochemiluminescent (ECL) response was synthesized and employed to establish a novel sandwich-type ECL immunosensor for quantitatively detection of protein. Herein, DpAu embedded graphene were used as the immobilization platform which could adsorb antibody, enhance the electrical conductivity and improve ECL signals. This highly sensitive sandwich-type ECL immunosensor, with a wide linear range from 0.001 to 50 ng·mL-1 and a low detection limit of 0.33 pg·mL-1 (S/N=3) for a-fetoprotein (AFP) detection, had great potential for protein detection in clinical medicine.