Li Zhang,Hetong Qi,Jie Hao,Lifen Yang,Ping Yu,Lanqun Mao
Developing water-stable and adaptive supramolecular materials is of great importance in various research fields. Here, we demonstrate a new kind of water-stable, adaptive, and electroactive supramolecular ionic materials (SIM) that is formed from the aqueous solutions of imidazolium-based dication and dianionic dye (i.e., 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), ABTS) through ionic self-assembly. The formed SIM not only shows good thermostability and unique optical and electrochemical properties that are raised from precursors of the SIM, but also exhibits good water-stability, salt-stability, and adaptive encapsulation properties toward some heterocyclic cationic dye molecules. UV–vis and FT-IR results demonstrate that this encapsulation property is essentially based on the electrostatic interactions between the guest dye molecules and ABTS in the SIM. The application of the SIM prepared here is illustrated by the development of a new electrochemical sensor for NADH sensing at a low potential. This study not only opens a new avenue to the preparation of the supramolecular materials, but also provides a versatile platform for electrochemical (bio)sensing.
Minling Ding,Huizhe Niu,Nan Zhang,Tongtong Hou,Ping Guan,Xiaoling Hu
Here we report on a facile, rapid, selective, and stable electrochemical sensing platform for nicotinamide adenine dinucleotide (NADH) based on polythionine-methylene blue/electrochemically reduced graphene oxide modified glassy carbon electrode (PTH-MB DES -ERG/GCE). The ERG was directly formed on a glassy carbon electrode (ERG/GCE) through one-step electrochemical reduction of GO in PBS solution (10 mM, pH 7.4). In a PBS electrolyte, respectively, containing 50% (v/v) three different deep eutectic solvents (DES), thionine and methylene blue were polymerized on the surface of ERG/GCE. The electrochemical properties of the polymers polymerized in different electrolytes were investigated. The PTH-MB DES -ERG composite has a higher performance in the electrocatalytic oxidation of NADH than that of PTH-MB DES . The as-prepared PTH-MB DES -ERG/GCE demonstrated excellent direct electrocatalytic oxidation toward NADH, providing a favorable platform for electron transfer from NADH to the electrode. The sensor displayed a wide linear range from 1.52 μM to 3333.33 μM with a limit of detection of 0.51 nM. The interference from the ascorbic acid and uric acid was negligible. The prepared sensor was further tested for the determination of NADH in artificial urine samples, showing the PTH-MB DES -ERG/GCE formed by electropolymerization have promising biomedical applications.
Nicotinamide adenine dinucleotide (NADH) is a crucial biomolecule that serves as an essential cofactor in numerous biocatalytic reactions and a pivotal regulator of mitochondrial function and cellular physiology. This study developed a SECM platform utilizing a double-mediator system for the real-time, in situ, and non-invasive detection of intracellular NADH at the single living cell level. The system employs 1-methoxy-5-methylphenazinium methyl sulfate (mPMS), which permeates the cell membrane to oxidize intracellular NADH, and ferricyanide ([Fe(CN)₆]³⁻), which shuttles electrons from the reduced mPMS to the SECM tip. This methodology was applied to investigate mitochondrial impairment in human hepatoma (HepG2) cells induced by polycyclic aromatic sulfur heterocycles (PASHs). The metabolic response was corroborated by analyzing poly(ADP-ribose) polymerase (PARP) activity, adenosine triphosphate (ATP) content, and mitochondrial membrane potential (MMP). Results demonstrated that exposure to dibenzothiophene (DBT) activated PARP, leading to severe depletion of NADH and ATP and a significant decline in MMP, thereby confirming comprehensive mitochondrial dysfunction. Comparative analysis with its non-sulfur analog fluorene (Flu) revealed that the sulfur atom in DBT's structure is a critical determinant of its enhanced cytotoxicity. This work establishes a reliable and innovative analytical approach for assessing the subcellular metabolic effects of environmental pollutants, providing a new platform for in-depth cytotoxicity mechanistic studies.
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