Electrogenerated Chemiluminescence for Immunoassay Applications

Abstract

Electrogenerated chemiluminescence (ECL) has recently become one of the most prominent and well-established transducers for immunoassay techniques. ECL relates a luminophore concentration in solution with the emission of light triggered by an electrochemical stimulus. ECL immunoassay (ECLIA) performance depends on the parameters of its light generation, including the luminophore, the species that emit light called labels in ECLIA; co-reactants, which are added reagents that support the luminophore to undergo the excited state; electrodes, which are the place for the ECL reactions to take place; and the format of the immunoassay. This review discusses the behaviour of ECLIA parameters, the required instrumentations, and some important examples of detections based on ECLIA.

Electrogenerated chemiluminescence of luminol at a boron-doped diamond electrode for the detection of hypochlorite

“…Luminol (5-amino-2,3-dihydro-1,4phthalazinedione), Ru(bpy) 3 2+ and quantum dots are generally used as luminophores in the presence of co-reactants, such as H 2 O 2 , TPrA, S 2 O 8 2− , etc. [9][10][11][12][13] These co-reactants must be electroactive substances, which can be oxidized or reduced on the electrode surface when a potential is applied, producing intermediate species that can react with the luminophore to promote it to an excited state. 9,10 Recently, our group studied the ECL of luminol on the surface of the boron-doped diamond (BDD) electrode, 11 since BDD has been reported as a unique electrode due to its very wide working potential and significantly low capacitive currents, which are highly required for sensor development.…”

“…[9][10][11][12][13] These co-reactants must be electroactive substances, which can be oxidized or reduced on the electrode surface when a potential is applied, producing intermediate species that can react with the luminophore to promote it to an excited state. 9,10 Recently, our group studied the ECL of luminol on the surface of the boron-doped diamond (BDD) electrode, 11 since BDD has been reported as a unique electrode due to its very wide working potential and significantly low capacitive currents, which are highly required for sensor development. [14][15][16][17][18][19] In addition, BDD also provides high resistance for application at extreme potentials, usually required to promote co-reactants to form the intermediate species.…”

“…[14][15][16][17][18][19] In addition, BDD also provides high resistance for application at extreme potentials, usually required to promote co-reactants to form the intermediate species. 9,11,[19][20][21] On the other hand, free chlorine, defined as dissolved gas (Cl 2 ), hypochlorous acid (HClO) and hypochlorite (ClO − ), has been widely used as a disinfecting agent in various applications such as in clinical practice, food industry, and drinking water treatment. A high concentration of free chlorine may induce the reaction of organic compounds, e.g.…”

“…Luminol (5-amino-2,3-dihydro-1,4-phthalazinedione), Ru(bpy) 3 2+ and quantum dots are generally used as luminophores in the presence of co-reactants, such as H 2 O 2 , TPrA, S 2 O 8 2− , etc . 9–13 These co-reactants must be electroactive substances, which can be oxidized or reduced on the electrode surface when a potential is applied, producing intermediate species that can react with the luminophore to promote it to an excited state. 9,10…”

“…9–13 These co-reactants must be electroactive substances, which can be oxidized or reduced on the electrode surface when a potential is applied, producing intermediate species that can react with the luminophore to promote it to an excited state. 9,10…”