Reactivity mapping of luminescence in space: Insights into heterogeneous electrochemiluminescence bioassays

Spatially resolved electrochemiluminescence through a chemical lens

“…[11][12][13][14][15][16][17][18][19][20][21][22] The heterogeneous ECL mechanism of the [Ru(bpy) 3 ] 2+ /TPrA system is an active area of investigation. 14,32,33,43,44 In such a conguration, the ECL luminophore is not free to diffuse and cannot be directly oxidised at the electrode. 45,46 In the current system under investigation, the [Ru(bpy) 3 ] 2+ label is covalently bound to the bead as in beadbased ECL immunoassays.…”

“…46 Many research groups, including ours, mapped the ECL reactivity and the emission spatial distribution in such a context. 14,15,33,43 The maximum of ECL emission occurs in the micrometric region where concentrations of TPrAc and TPrAc + radicals are locally the highest. 43,44 We also demonstrated, by analysing the side-view ECL image of the beads that only luminophores located within the 3 mm region close to the electrode contribute to the signal.…”

“…14,15,33,43 The maximum of ECL emission occurs in the micrometric region where concentrations of TPrAc and TPrAc + radicals are locally the highest. 43,44 We also demonstrated, by analysing the side-view ECL image of the beads that only luminophores located within the 3 mm region close to the electrode contribute to the signal. 33 The diffusion proles of TPrAc and TPrAc + radicals are determined by the lifetime of TPrAc + in turn imposing the space region where the ECL emission is obtained.…”

“…Herein, the distribution of the ECL-emitting layer has been investigated by ECLM at the level of single microbeads with different dimensions (8, 12 and 14 mm). The model ECL [Ru(bpy) 3 ] 2+ label was conjugated to the beads (named Ru@bead) resembling bead-based immunoassays 17,[41][42][43] (see the ESI for the details †). ECL emission was generated in a conguration named surface generation-bead emission.…”

Electrochemiluminescence Loss in Photobleaching

“…In order to measure quantitatively the effects of photobleaching on the ECL emission, it is essential that the ECL intensity does not vary due to other experimental parameters. Recently, we demonstrated that the ECL intensities of labeled cells and immunosensing beads decreased very significantly when recording consecutive ECL images [14c] . Indeed, the ECL intensity dropped by a factor 5 between the first and the second ECL image for the same labeled cell (or bead) [14c] .…”