Modification of Indium Tin Oxide with Dendrimer-Encapsulated Nanoparticles To Provide Enhanced Stable Electrochemiluminescence of Ru(bpy)₃²⁺/Tripropylamine While Preserving Optical Transparency of Indium Tin Oxide for Sensitive Electrochemiluminescence-Based Analyses

Abstract

Here, we report highly enhanced stable electrogenerated chemiluminescence (ECL) of Ru(bpy)3(2+) (bpy = 2,2'-bipyridyl) with tripropylamine (TPrA) coreactant on indium tin oxide (ITO) electrodes modified with amine-terminated dendrimers encapsulating catalytic nanoparticles while maintaining optical transparency of ITO and feasibility of the modified ITOs to sensitive ECL-based assays. As model systems, we prepared Pt and Au dendrimer-encapsulated nanoparticles (DENs) using amine-terminated sixth-generation poly(amido amine) dendrimers and subsequently immobilized the DENs onto ITO surfaces via electrooxidative grafting of the terminal amines of dendrimers to the surfaces. The resulting DEN-modified ITOs preserved good optical transparency of ITO and exhibited highly catalyzed electrochemical oxidation of Ru(bpy)3(2+)/TPrA, leading to significantly increased ECL emission. Especially, the Pt DEN-modified ITO electrode provides negligible transmittance drop, i.e., only ∼1.99% over the entire visible region, and exhibited not only much enhanced (i.e., ∼213-fold increase compared to ECL obtained from bare ITO) but also stable ECL emission under consecutive potential scans from 0.00 to 1.10 V for 10 cycles, which allowed ∼329 times more sensitive ECL-based analysis of nicotine using the Pt DEN-modified ITO compared with the use of bare ITO.

Gold Nanoclusters@Ru(bpy)32+-Layered Double Hydroxide Ultrathin Film as a Cathodic Electrochemiluminescence Resonance Energy Transfer Probe

“…Bovine serum albumin (BSA), Ru(bpy) 3 3 , NaNO 3 , formamide, ascorbic acid, Na 2 HPO 4 , and NaH 2 PO 4 were supplied by Beijing Chemical Reagent Company (Beijing, China). Phosphate buffer solution (PBS, pH = 7.5, 0.1 M) was prepared using 0.1 M Na 2 HPO 4 and 0.1 M NaH 2 PO 4 .…”

“…8 Alternately, considerable effort has been devoted to the development of the cathodic ECL of Ru(bpy) 3 2+ for avoiding the disadvantages of anodic reactions. 9−11 However, the cathodic ECL of Ru(bpy) 3 2+ is hardly happened in aqueous solutions owing to the high instability of reaction intermediates. 9 To solve these problems, scientists have aroused considerable interest in ECL resonance energy transfer (ERET) between suitable donors (e.g., luminol and quantum dots) and Ru(bpy) 3 2+ acceptors.…”

Novel gold nanocluster electrochemiluminescence immunosensors based on nanoporous NiGd–Ni2O3–Gd2O3 alloys

“…Organic or metallic organic compound luminescent materials, such as luminol, tris(2,2'-bipyridyl)ruthenium(II) chloride, have been applied in the fabrication of electrochemiluminescence (ECL) immunosensors (Zhao et al 2015;Cao et al 2012;Kim, Y., Kim, J. 2014;Chen et al 2013).…”

Enhanced Electrochemiluminescence of Luminol on Indium Tin Oxide Modified with Dendrimer‐Encapsulated Au Nanoparticles

“…Electrochemiluminescence (ECL) has been attractive as a versatile electroanalytical technique for detection of a variety of analytes such as DNA, antibodies, proteins, and small molecules 1–6. This is because ECL provides beneficial features over photoluminescence, including low background, good spatial and temporal controllability, and simple instrumentation, mainly due to its unique luminescence‐generating process in which electrogenerated species undergo electron transfer reactions to form excited states emitting light near electrode surfaces 7–10. Specifically, luminol has been widely used in ECL‐based analyses since the ECL of luminol was first reported by Harvey 11, 12.…”

“…The other one is attachment of pre‐synthesized Au nanoparticles on electrodes with adhesive layers formed by silanization, self‐assembled monolayer (SAM) of thiolates, or layer‐by‐layer (LbL) assembly techniques 19, 24, 25. Recently, our group also reported electrochemical modification of electrode surfaces with amine‐terminated dendrimers encapsulating Au nanoparticles 26–29, which can be utilized for sensitive ECL‐based analyses 10. For example, we modified indium tin oxide (ITO) surfaces with dendrimer‐encapsulated Au nanoparticles (Au DENs) via electrooxidative grafting of amine terminals of the dendrimers onto ITO, and showed that the Au DEN‐modified ITO electrodes exhibited enhanced ECL emission of Ru(bpy) 3 2+ (bpy=2,2′‐bipyridyl) with tripropylamine (TPrA) co‐reactant even at lower applied potentials compared to bare ITOs 10, 29.…”