Table 2.

Advantages and disadvantages of the biomarker detection ECL systems.

Sensing System	Advantages	Limitations
Systems based on the chemical reactions of the luminophore and co-reactant	Simple design and operation; Rapid detection; Multiplexing capability using dual or multiple ECL emitters.	Limited sensitivity; Possibility of cross-interference between the luminophore and co-reactant; Possibility of a low stability and reproducibility of the electrode immobilised co-reactant.
Systems that incorporate co-reaction accelerator-involved reactions	High sensitivity by using dual or multiple co-reaction accelerators; Easy selection of luminophore regardless of the luminescent intensity.	Need for an additional synthesis and conjugation process of the co-reaction accelerator.
Systems that incorporate resonance energy transfer reactions	High sensitivity, Extension of the dynamic range of the modulation in the ECL intensity by introducing a quencher.	Potential of varying the energy transfer efficiency depending on the position and distance of the acceptor and donor; Complex operation; Additional costs for materials and processing.
Systems that incorporate an enzyme reaction-based signal amplification	Superior sensitivity.	Complex operation; Additional costs for materials and processing; Potential variations in assay time depending on the catalytic ability of enzymes and nanozymes; Potential cross-reactivity in the hybridisation-based method.