Sensitive Electrochemiluminescence Biosensor Based on Au-ITO Hybrid Bipolar Electrode Amplification System for Cell Surface Protein Detection

Abstract

Here we developed a novel hybrid bipolar electrode (BPE)-electrochemiluminescence (ECL) biosensor based on hybrid bipolar electrode (BPE) for the measurement of cancer cell surface protein using ferrocence (Fc) labeled aptamer as signal recognition and amplification probe. According to the electric neutrality of BPE, the cathode of U-shaped ITO BPE was electrochemically deposited by Au nanoparticles (NPs) to enhance its conductivity and surface area, decrease the overpotential of O2 reduction, which would correspondingly increase the oxidation current of Ru(bpy)3(2+)/tripropylamine (TPA) on the anode of BPE and resulting a ∼4-fold enhancement of ECL intensity. Then a signal amplification strategy was designed by introducing Fc modified aptamer on the anode surface of BPE through hybridization for detecting the amount of mucin-1 on MCF-7 cells. The presence of Fc could not only inhibit the oxidation of Ru(bpy)3(2+) because of its lower oxidation potential, its oxidation product Fc(+) could also quench the ECL of Ru(bpy)3(2+)/TPA by efficient energy-transfer from the excited-state Ru(bpy)3(2+)* to Fc(+), making the ECL intensity greatly quenched. On the basis of the cathodic Au NPs induced ECL enhancing coupled with anodic Fc induced signal quenching amplification, the approach allowed detection of mucin-1 aptamer at a concentration down to 0.5 fM and was capable of detecting a minimum of 20 MCF-7 cells. Besides, the amount of mucin-1 on MCF-7 cells was calculated to be 9041 ± 388 molecules/cell. This approach therefore shows great promise in bioanalysis.

Propulsion of copper microswimmers in folded fluid channels by bipolar electrochemistry

“…On the basis of this concept, bipolar electrochemistry has been used for materials preparation and fabrication, 55 sensing, 56 screening, 57 microswimmers. 58 Based upon the splitting of water, Kuhn and co-workers have designed and fabricated a lot of bipolar micromotors and channels.…”

Towards Nanostructured ITO-Based Electrochemical Sensors: Fabrication, Characterization and Functionalization

“…In particular, indium tin oxide (ITO) has recently been used as thin film electrodes in electrochemical biosensors [3] owing to its good electrical conductivity and high transparency to optical wavelengths, resulting in a good candidate for either electrochemical and/or optical biosensors. Few studies on the utilization of thin ITO films as biosensing electrodes can be found in the literature.…”

“…Same authors reported later an improved system to determine the dynamic cellular attachment, spreading and proliferation of endothelial cells [5]. Indium tin oxide has been used recently in combination with gold for the development of an electrochemiluminescent biosensor for detecting cancer cell surface proteins [6].…”

Electrochemiluminescence immunosensing strategy based on the use of Au@Ag nanorods as a peroxidase mimic and NH4CoPO4 as a supercapacitive supporter: Application to the determination of carcinoembryonic antigen

“…Electrochemiluminescence (ECL) is a powerful analytical technique due to its high sensitivity, wide linear range, low background and simple instrumentation [1][2][3][4][5][6]. One of the mostly used ECL systems is luminol-H 2 O 2 system because of its low oxidation potential, inexpensive reagent consumption and the high emission yields [7][8][9][10].…”