A photoelectrochemical biosensor using ruthenium complex-reduced graphene oxide hybrid as the photocurrent signal reporter assembled on rhombic TiO2 nanocrystals driven by visible light.
An ultrasensitive photoelectrochemical (PEC) immunoassay of cancer biomarker carcinoembryonie antigen (CEA) is proposed that uses rhombic titanium dioxide nanocrystals (TiO2 NCs) coupled with Ab2-RGO-Ru bioconjugate, which featured CEA signal antibody (Ab2) and ruthenium tris(bipyridine) (Ru complex) labels linked to reduced graphene oxide (RGO) for signal amplification. Herein, the Ru complex acts as an electron donor, while RGO serves as an electron acceptor which facilitates charge separation and suppresses recombination of photoexcited electron-hole pairs in the hybridized species. The rhombic TiO2 NCs were fabricated through a solvothermal technique in anhydrous ethanol, followed by spin-coating process and calcination, an ITO/TiO2 electrode was obtained. Chitosan (CS) and glutaraldehyde (GLD) were used to modify the prepared ITO/TiO2 electrode to covalently immobilize antibodies. With a sandwich-type immunoreaction, CEA and Ab2-RGO-Ru were conjugated successively to form a sandwich-type immunocomplex. Thus, a sandwich-type PEC immunosensor was fabricated for the detection of CEA was developed by monitoring the changes in the photocurrent signals of the electrode resulting from the immunoreaction. The proposed PEC immunosensor showed high sensitivity, selectivity, excellent stability, and good reproducibility, and thus has great potential to be used for other biological assays.
School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, PR China.
Lei
L
Ge
School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, PR China.
Yanhu
Y
Wang
School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, PR China.
Hongmei
H
Yang
School of Material Science and Engineering, University of Jinan, 250022, Jinan, PR China; State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, PR China.
Ping
P
Yang
School of Material Science and Engineering, University of Jinan, 250022, Jinan, PR China.
Xin
X
Cheng
School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, PR China.
Mei
M
Yan
School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, PR China. Electronic address: ujn.yujh@gmail.com.
Jinghua
J
Yu
D015374:Biosensing Techniques; D055664:Electrochemical Techniques; D006108:Graphite / Q000737:chemistry*; D008027:Light; D053758:Nanoparticles / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D055668:Photochemical Processes; D012428:Ruthenium / Q000737:chemistry; D014025:Titanium / Q000737:chemistry
D009942:Organometallic Compounds; D010087:Oxides; C009495:titanium dioxide; D006108:Graphite; D012428:Ruthenium; D014025:Titanium
Immunoassays; Photoelectrochemistry; Reduced graphene oxide; Rhombic TiO(2) nanocrystals; Ru complex