A Review of Electrogenerated Chemiluminescent Biosensors for Assays in Biological Matrices

Abstract

Electrogenerated chemiluminescence (ECL) is the production of light via electron transfer reactions between electrochemically produced reagents. ECL-based biosensors use specific biological interactions to recognize an analyte and produce a luminescent signal. Biosensors fabricated with novel biorecognition species have increased the number of analytes detected. Some of these analytes include peptides, cells, enzymes and nucleic acids. ECL biosensors are selective, simple, sensitive and have low detection limits. Traditional methods use ruthenium complexes or luminol to generate ECL. Nanomaterials can be incorporated into ECL biosensors to improve efficiency, but also represent a new class of ECL emitters. This article reviews the application of ruthenium complex, luminol and nanomaterial-based ECL biosensors to making measurements in biological matrices over the past 4 years.

Cyclometalated Iridium‐Complex‐Based Label‐Free Supersandwich Electrogenerated Chemiluminescence Biosensor for the Detection of Micro‐RNA

“…The ECL intensitypotential profile of [(bt) 2 Ir(dmphen)](PF 6 ) in ion annihilation process in MeCN containing 0.1 M TBAPF 6 showed a moderately intense ECL emission (I = 2,799) in the anodic regions during dynamic backward potential scanning and a weak ECL emission (I = 81) in the cathodic regions during dynamic forward potential scanning (Figure S-3). This observation is attributed to the fact that the radical anions formed at reduction potential are more stable than the radical cations formed at the oxidation potential.…”

“…[42] This suggests that there exists triplet state emissive characteristics in PL of [(bt) 2 Ir(dmphen)](PF 6 ). [43] Figure 1B shows a cyclic voltammogram of [(bt) 2 Ir(dmphen)](PF 6 ) at a platinum electrode in MeCN containing 0.1 M TBAPF 6 . The electrochemical data are summarized in Table 2.…”

“…[36] We observed that at a gold electrode in Ru(phen) 3 2 + and TPA aqueous solution the ECL peak of Ru(phen) 3 2 + at + 0.8 V was close to that of TPA at + 0.6 V. This indicated that a high background arising from TPA would interfere the ECL peak arising from Ru(phen) 3 2 + . Thus, a new cyclometalated iridium(III) complex, [(bt) 2 Ir(dmphen)](PF 6 ) was designed as an ECL DNA intercalator in this work. Bt was chosen as the C^N main ligand because it is a typical cyclometalating ligand framework to construct heteroleptic iridium complexes which exhibit high luminescent efficiencies.…”

“…[1] In the past decades, a variety of biosensing systems for the detection of DNA have been developed by taking various sensing technologies such as fluorescence, [2] electrochemical, [3] surface plasmon resonance, [4] surface enhanced Raman [5] and electrogenerated chemiluminescence [6] . In recent years, development of highly sensitive and accurate methods for the detection of micro-RNAs (mi-RNAs) has attracted much attention since specific mi-RNAs may serve as biomarkers for some cancers.…”

“…[30] Zhang and co-workers [31] employed a cyclometalated Iridium(III) complex [(ppy) 2 Ir(dcbpy)](PF 6 ) as an ECL labeling reagent to construct an ultrasensitive biosensor, which was successfully applied in cancer cell detection. Recently, Tang and co-workers [32] demonstrated a novel cyclometalated Iridium(III) complex [(ppy) 2 Ir(dppz)](PF 6 ) as an intercalator to develop a highly sensitive photoelectrochemical biosensor for the detection of DNA.…”