Na Li,Yaoguang Wang,Wei Cao,Yunhui Zhang,Tao Yan,Bin Du,Qin Wei
The excellent catalytic activity of a novel nanomaterial was introduced to ultrasensitive sandwich-type electrochemical immunosensor applications for detection of carcinoembryonic antigen (CEA). Amino-functionalized multi-walled carbon nanotube (MWCNT-NH2) supported PdPt nanocages were used as catalytic labels of secondary anti-CEA. PdPt nanocages with hollow interiors and porous walls could efficiently enhance electrocatalysis for reduction of H2O2. Meanwhile, with good dispersion, large specific surface area and amino groups, MWCNT-NH2 can immobilize a large amount of PdPt nanocages to improve the sensitivity and amplify the signal of the immunosensor. For the immobilization of primary antibodies, 3-aminopropyltriethoxysilane functionalized graphene sheets were used as transducing materials to modify glassy carbon electrodes and to enhance the electron transfer efficiently. Under the optimal conditions, the electrochemical immunosensor exhibited a wide linear range of 0.001–20 ng mL−1 with a low detection limit of 0.2 pg mL−1 for CEA. The proposed sensing strategy enriches electrochemical immunoassays and may have a promising application in bioassay analysis.
Qixia Guan,Hao Guo,Rui Xue,Mingyue Wang,Xin Zhao,Tian Fan,Wenhu Yang,Mengni Xu,Wu Yang
An electrochemical sensing platform for simultaneous determination of dopamine (DA) and uric acid (UA) is constructed based on covalent organic framework materials (IL COF-1), aminofunctionalized carbon nanotubes (MWCNT-NH 2 ), and gold nanoparticles (AuNPs). The prepared sensor shows a good performance in detection of DA and UA due to porosity, large specific surface area, high conductivity and more active sites of the composite modified material. Under optimized experimental conditions, the constructed electrochemical sensor has sensitive response and good linearity to both DA and UA. Their wide linear ranges are 0.7–108 μM and 0.97–200 μM, and the detection limits are 0.21 μM and 0.29 μM (S/N = 3), respectively. The developed method has been successfully employed to determine the contents of DA and UA in dopamine injection and human urine samples. It has a satisfactory recovery rate, and the relative standard deviations (RSD) of three parallel determinations are all below 5.0%. In comparison, the constructed sensor platform has superior performance including low cost, simple structure, wide linear range and high sensitivity than some traditional methods, which is expected to be widely used in real sample analysis.
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