Dynamic Mapping of Electrochemiluminescence Reactivity in Space: Application to Bead-Based Assays

Abstract

As an electrochemical technique offering an optical readout, electrochemiluminescence (ECL) evolved recently into a powerful microscopy technique with the visualization of a wide range of microscopic entities. However, the dynamic imaging of transient ECL events did not receive intensive attention due to the limited number of electrogenerated photons. Here, the reaction kinetics of the model ECL bioassay system was revealed by dynamic imaging of single [Ru­(bpy)3]2+-functionalized beads in the presence of the efficient tripropylamine coreactant. The time profile behavior of ECL emission, the variations of the ECL layer thickness, and the position of maximum ECL intensity over time were investigated, which were not achieved by static imaging in previous studies. Moreover, the dynamics of the ECL emission were confronted with the simulation. The reported dynamic ECL imaging allows the investigation of the ECL kinetics and mechanisms operating in bioassays and cell microscopy.

Redox-mediated electrochemiluminescence enhancement for bead-based immunoassay

“…, only the luminophores located in the ECL reactive layer, where both TPrA˙ + and TPrA˙ coexist, are involved in the ECL process; see Scheme S1†). 37–44…”

“…10,35,36 The short half-life of TPrAc + represents an intrinsic limitation to the signal intensity since the radical cations diffuse only within a limited region from the electrode surface, conning the ECL emitting layer to ∼3 mm (i.e., only the luminophores located in the ECL reactive layer, where both TPrAc + and TPrAc coexist, are involved in the ECL process; see Scheme S1 †). [37][38][39][40][41][42][43][44] We repeated CV-ECL measurements to test the effects of the addition in solution of each freely diffusing Ir(III) complex on the ECL signals of the Ru@Beads: hereaer, these systems will be denoted as Ru@Beads/[Ir(sppy) 3 ] 3− , Ru@Beads/[Ir(dfppy) 2 (pt-TEG)] + , and Ru@Beads/[Ir(bt) 2 (pt-TEG)] + indicating the addition of the corresponding Ir(III) complex (see Fig. 3a, S3, S4 and ESI Video 2 †).…”

Through-Space Electrochemiluminescence Reveals Bubble Forces at Remote Phase Boundaries

“…We also show that this is a general phenomenon (see Supporting Information Figure S7). The same technique could also be used for other through-space ECL studies, such as imaging single cells, phase boundaries within cells, and bead-based assays . The presented technique yields unique information regarding interfacial chemistry and offers new spectroelectrochemical tools to study the curious chemistry of phase boundary reactivity.…”

Nanoscale Luminescence Imaging/Detection of Single Particles: State-of-the-Art and Future Prospects

“…The change in the concentration of the phosphate buffer (buffer capacity) could alter both the thickness of the ECL-producing area and the rate of ECL reactions. The authors precisely controlled the distribution of the ECL emission through single micrometric bead-based mapping of the ECL reactivity, which allowed mechanistic insights and holds strong potential in ECL microscopy-based bioassays. , …”

“…The authors precisely controlled the distribution of the ECL emission through single micrometric bead-based mapping of the ECL reactivity, which allowed mechanistic insights and holds strong potential in ECL microscopy-based bioassays. 144,145 To enhance the performance of bioassays, diverse types of functional materials have been utilized as immunoassays labels. Particularly, NPs with luminescence characteristics allow the direct visualization (optical readout) of the target analyte at a single molecule level.…”