Mechanism and Application Research of Electrochemiluminescence Immunoassay
Chapter 1 Overview of Electrochemiluminescence Immunoassay Technology
Electrochemiluminescence immunoassay (ECLIA) is one of the most promising immunodetection technologies in the 21st century. Its technical principles integrate cutting-edge achievements from multiple disciplines, including electrochemical excitation, nanomaterial science, molecular biology, and immunology. This technology system constructs a complete automated labeled immune analysis platform by systematically integrating electronic luminescent technology, nanoparticle carrier technology, high-specificity biotin-avidin amplification systems, antigen-antibody immune reactions, and electromagnetic field separation techniques.
In terms of specific technical implementation, ECLIA systems typically use surface-functionalized magnetic microspheres as solid-phase carriers. This design not only increases the specific surface area of the reaction system but also facilitates rapid separation through a magnetic field. As the core luminescent label, tris(bipyridyl)ruthenium [Ru(bpy)3]2+ complex undergoes a cascade redox reaction with electron donor tripropylamine (TPA) under electrode excitation to produce stable light signals at a wavelength of 620 nm. This unique luminescent mechanism allows ECLIA to combine the high sensitivity (detection limit reaching 10^-15-10^-18 mol/L) characteristic of chemiluminescent technology with the specificity (cross-reactivity rate <0.01%) inherent in immunological analysis.
Compared to traditional enzyme-linked immunosorbent assays (ELISA), ECLIA demonstrates significant advantages. The reaction process is completed within an entirely automated closed system that effectively avoids human operational errors; its detection linear range can be expanded by 4-6 orders of magnitude; labeling stability is excellent with preservation exceeding 18 months at 4°C; more importantly, it completely eliminates risks associated with radioactive isotopes usage. These characteristics present broad application prospects for clinical testing, biomedical research, and drug development fields.
Chapter 2 Mechanism of Electrochemiluminescence Action
2.1 Stage of Electrochemical Reaction The luminescent process in ECLIA begins with electrochemical oxidation reactions on the electrode surface. When a specific working voltage (usually between 1.5-2.8V) is applied,u200b [Ru(bpy)_3]^{2+} loses electrons at the anode becoming [Ru(bpy)_3]^{3+}, which possesses strong oxidizing capabilities while TPA undergoes oxidation simultaneously forming cationic free radical TPA^+. Subsequently through spontaneous deprotonation reactions reducing free radicals TPA· are generated as well—these two parallel electrochemical reactions constitute initiation steps for entire luminescent processes. 2.2 Stage Of Chemiluminescent Reactions Oxidized state [Ru(bpy)_3]^{3+} encounters reduced state TPA· after diffusion layer interaction leading to electron transfer reactions transforming ruthenium complexes into excited states [Ru(bpy)_3]^{2+}*. Upon returning back towards ground states via radiative transitions releasing photons corresponding wavelengths occurs without any involvement from external excitation sources—this unique energy conversion method effectively reduces background noise crucially contributing towards achieving high signal-to-noise ratios. 2.. Signal Amplification Mechanisms One prominent technological advantage exhibited by ECLIA lies within its signal amplification mechanisms where unconsumed species such as [Ru(bpy)_3]^{2+}u200b & TPA continue participating next rounds during cycles thereby allowing single labeled molecules generating multiple photon signals over time—a theoretical calculation indicates optimized conditions yield >106 photons per minute per molecule resulting exponential signaling amplifications improving sensitivities surpassing conventional ELISAs up-to several orders magnitudes higher!
Chapter Three Clinical Detection Applications Progression...
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