Enhanced electrochemiluminescence of Ru(bpy)₃²⁺‐doped silica nanoparticles by chitosan/Nafion shell@carbon nanotube core‐modified electrode

Abstract

Although Ru(bpy)32+‐doped silica nanoparticles have been widely explored as the labelling tags for electrochemiluminescence (ECL) sensing different targets, the poor electrical conductive properties of the silica nano‐matrix greatly limit their ECL sensitivity. Therefore, a novel scheme to overcome this drawback on Ru(bpy)32+‐doped silica nanoparticles ECL is desirable. Here, a new scheme for this purpose was developed based on electrochemically depositing a nanoscale chitosan hydrogel layer on the carbon nanotube (CNT) surface to form chitosan hydrogel shell@CNT core nanocomposites. In this case, the nanoscale chitosan hydrogel layer only formed on the CNT surface due to the superior electrocatalytic effect of CNT on H+ reduction compared with the basic glass carbon electrode. Due to both the superhydrophilic properties and polyelectrolyte features of nanoscale chitosan hydrogel on the CNT surface, chemical affinity as well as the electric conductivity between Ru(bpy)32+‐doped silica nanoparticles and CNT were obviously enhanced, and then the ECL effectivity of Ru(bpy)32+ inside silica nanoparticles was improved. Furthermore, based on the discriminative interaction of these Ru(bpy)32+‐doped silica nanoparticles towards both the ssDNA probes and the ssDNA probe/miRNA complex, as well as the specific adsorption effect of these nanoparticles on the nanoscale chitosan shell@Nafion/CNT core‐modified glass carbon electrode, a highly sensitive ECL method for miRNA determination was developed and successfully used to detect miRNA in human serum samples.

Novel dual‐sensitization electrochemiluminescence immunosensor using photopermeable Ru(bpy)32+‐doped chitosan/SiO2 nanoparticles as labels and chitosan‐decorated Nafion/MWNTs composites as enhancer

“…From the CV curves of the chitosan/Nafion/MWNTs-modified electrode (Figure S3c), the redox peak current of the Fe(CN strengthening the affinities with each other. [33] Therefore, the elec- corresponding CV responses of different modified electrodes were also improved (Figure 4). The above experimental results showed that the chitosan/Nafion/MWNTs-modified electrode was an excellent ECL immunosensing platform, while the Ru(bpy) 3 2+ /chitosan/SiO 2 NPs were suitable as electroactive labels for high sensitivity detection of PSA in the proposed ECL immunosensor.…”

Critical review of polymer and hydrogel deposition methods for optical and electrochemical bioanalytical sensors correlated to the sensor’s applicability in real samples

“…It is best suited for coating of a small and defined area, because for larger areas, controlling thickness, porosity, and uniformity of the film is more difficult [34]. The general process includes the mixing of recognition elements such as enzymes [8,9,35,36], DNA derivatives [10,37], or probes such as fluorescent dyes, luminophores [38], or nanoparticles [39,40] with an evaporable solvent and a binder (e.g., hydrogels, polymers, or cross-linkers like glutaraldehyde), followed by application of this cocktail to the desired surface. In addition to the cocktail composition and surface conditions, drying time, annealing temperature, and the applied volume are contributing factors toward the final homogeneity and morphology of the deposited material.…”

Formation of miRNA Nanoprobes—Conjugation Approaches Leading to the Functionalization

“…Carbon nanomaterials for miRNA detection can be in the form of carbon nanoparticles [ 31 ], carbon nanotubes [ 32 ], nanofibers [ 33 ], quantum dots [ 34 ], fullerenes [ 35 ], graphene nanosheets [ 36 ], and graphene oxide [ 37 ].…”