Graphene-Ruthenium(II) complex composites for sensitive ECL immunosensors.
Non-covalent modiﬁcation method has been proven as an effective strategy for enhancing the chemical properties of graphene while the structure and electronic properties of graphene can be retained. This work describes a novel strategy to fabricate a solid-state electrochemiluminescent (ECL) immunosensor based on ruthenium(II) complex/3,4,9,10-perylenetetracarboxylic acid (PTCA)/graphene nanocomposites (Ru-PTCA/G) for sensitive detection of α-fetoprotein (AFP). It is found that immobilization of PTCA and reduction of GO can be simultaneously achieved in one-pot synthesis method under alkaline condition and moderate temperature, forming PTCA/G nanocomposites. Further covalent attachment of ruthenium(II) complex to the PTCA assembled on graphene sheets produces the functional Ru-PTCA/G nanocomposites which show good electrochemical activity and ca. 21 times higher luminescence quantum efficiency than the adsorbed derivative ruthenium(II) complex. The Ru-PTCA/G nanocomposites based solid-state ECL sensor exhibits high stability toward the determination of tripropylamine (TPA) coreactant. In addition, a new ECL immunosensor based on steric hindrance effect is fabricated by cross-linking α-fetoprotein antibody (anti-AFP) with chitosan covered on Ru-PTCA/G composites modiﬁed electrode for detection of cancer biomarker AFP. This ECL immunosensor shows an extremely sensitive response to AFP in a linear range of 5 pg·mL(-1) -10 ng·mL(-1) with a detection limit of 0.2 pg·mL(-1) . The present approach is effective for various molecules immobilization and may become a promising technique for biomolecular detection.
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China.
Fang-Nan
FN
Xiao
Min
M
Wang
Feng-Bin
FB
Wang
Xing-Hua
XH
Xia
D015374:Biosensing Techniques / Q000295:instrumentation*; D058266:Dielectric Spectroscopy; D004566:Electrodes; D006108:Graphite / Q000737:chemistry*; D007118:Immunoassay / Q000295:instrumentation*; D008163:Luminescent Measurements / Q000295:instrumentation*; D018625:Microscopy, Atomic Force; D053761:Nanocomposites / Q000737:chemistry*; D010569:Perylene / Q000737:chemistry; D056951:Photoelectron Spectroscopy; D012428:Ruthenium / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013059:Spectrum Analysis, Raman; D000509:alpha-Fetoproteins / Q000378:metabolism
D000509:alpha-Fetoproteins; D010569:Perylene; D006108:Graphite; D012428:Ruthenium
ECL immunosensor; PTCA; graphene; nanocomposites; ruthenium(II) complex