Related Experiment Video
Updated: Jan 25, 2026

Ultrasensitive Detection of Biomarkers by Using a Molecular Imprinting Based Capacitive Biosensor
Published on: February 16, 2018
Exogenous coreactant-free integrated ECL biosensor based on P5AIn/Fe(II)-MOF for sensitive trimethylamine N-oxide
Xiaoyan Xu1, Xianhong Wang1, Aoze Wang1
1State Key Laboratory of Advanced Optical Polymer and Manufacturing Technology, Key Laboratory of Optic-Electric Sensing and Analytical Chemistry for Life Science, MOE, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China.
Background:
Trimethylamine N-oxide (TMAO) has attracted significant attention as a critical marker for seafood freshness. However, the development of integrated methods combining rapid sample pretreatment with highly sensitive detection for TMAO remains a significant gap. A novel exogenous coreactant-free integrated ECL immunosensor was constructed for sensitive TMAO detection using poly(5-aminoindole)/Iron-based metal-organic framework (P5AIn/Fe-MOF) as a dual-functional platform.
Results:
In the P5AIn/Fe-MOF composite, the Fe-MOF served as both a co-reaction promoter and an in-situ reduction matrix, exhibiting unique synergistic effects with P5AIn. P5AIn not only enhanced the structural stability of Fe-MOF but also significantly improved electron transfer efficiency. Meanwhile, the inherent conductivity and porous structure of Fe-MOF facilitated rapid electron transfer during the conversion of TMAO to trimethylamine (TMA), maximizing catalytic accessibility. The generated TMA serves as an endogenous 'coreactant' to amplify ECL signals, thereby achieving exogenous coreactant-free effects and simplifying operational procedures. An efficient ECL probe was designed by loading Ru(bpy)32+ onto Zn3(HHTP)2 and conjugating it with antibodies. The confined pore structure of Zn3(HHTP)2 effectively suppressed energy dissipation, significantly boosting the ECL response of Ru(bpy)32+. The constructed biosensor has a wide linear range of 0.1-100 ng/mL and a low detection limit of 0.033 ng/mL. Its successful application in frozen shrimp samples validated its practical detection capability.
Significance:
This study proposes a novel exogenous coreactant-free detection strategy, integrating sample pretreatment and signal generation into a single platform. It offers a new approach for simple, rapid and sensitive TMAO detection, holding promising application prospects in marine food safety monitoring.
Related Concept Videos
Oxidation Numbers
Pyruvate Oxidation
First, the enzyme pyruvate dehydrogenase removes the carboxyl group from pyruvate and releases it as carbon dioxide. The stripped molecule is then oxidized and releases electrons, which are then picked up by NAD+...
Oxidation-Reduction Reactions
Healthcare Associated Infections I: Iatrogenic, Exogenic and Endogenic
HAIs significantly increase the cost of health care. Extended stays in healthcare institutions, increased disability, increased costs of medications, including specialized antibiotics, and prolonged recovery times add to the patient's expenses and the healthcare institution and funding bodies.
Ions as Acids and Bases
Salts are ionic compounds composed of cations and anions, either of which may be capable of undergoing an acid or base ionization reaction with water. Aqueous salt solutions, therefore, may be acidic, basic, or neutral, depending on the relative acid-base strengths of the salt’s constituent ions. For example, dissolving the ammonium chloride in water results in its dissociation, as described by the equation:
Oxidation of Alcohols
The process of oxidation in a chemical reaction is observed in any of the three forms:

