Fe-MOGs-based enzyme mimetic and its mediated electrochemiluminescence for in situ detection of H2O2 released from Hela cells

Abstract

Enzyme mimetics have attracted wide interest due to their inherent enzyme-like activity and unique physicochemical properties, as well as promising applications in disease diagnosis, treatment and monitoring. Inspired by the attributes of nonheme iron enzymes, synthetic models were designed to mimic their capability and investigate the catalytic mechanisms. Herein, metal-organic gels (Fe-MOGs) with horseradish peroxidase (HRP) like Fe-NX structure were successfully synthesized though the coordination between iron and 1,10-phenanthroline-2,9-dicarboxylic acid (PDA) and exhibited excellent peroxidase-like activity. Its structure-activity relationship and the in-situ electrochemiluminescence (ECL) detection of H2O2 secreted by Hela cells were further investigated. The highly dispersed Fe-NX active sites inside Fe-MOGs were able to catalyze the decomposition of H2O2 into large amounts of reactive oxygen species (ROS) via a Fenton-like reaction under a low overpotential. Due to the accumulation of ROS free radicals, the luminol ECL emission was significantly amplified. A proof-ofconcept biosensor was constructed with a detection limit as low as 2.2 nM and a wide linear range from 0.01 to 40 μM. As a novel metal organic gels based enzyme mimetic, Fe-MOGs show great promises in early cancer detection and pathological process monitoring.

Peroxidase-Like N-Doped Carbon Nanotubes Loaded with NiCo-Layered Double-Hydroxide Nanoflowers for Dual-Mode Ultrasensitive and Real-Time Detection of H2O2 Secreted from Cancer Cells

“…According to the calibration equations obtained from the fabricated ECL biosensor, the amount of H 2 O 2 released from HeLa cells at a density of 3.55 × 10 4 cells/mL was calculated to be 18.47 nM. Therefore, according to the Avogadro equation ( n = N 0 / N A , N A = 6.02 × 10 23 mol –1 ), the average number of extracellular H 2 O 2 molecules released per HeLa cell ( N 0 ) was calculated to be 0.125 × 10 11 , which was lower than that of the proposed method. ,, …”

“…H 2 O 2 , as the most stable reactive oxygen species (ROS), is an essential metabolite byproduct and an intermediate of several oxidases in cells, which has long been associated with immune responses, signal transduction, and cancer. − Growing evidence suggests that the levels of H 2 O 2 in normal cells maintain a balance between production and catabolism. In general, cancer cells with abnormal physiological H 2 O 2 levels increase dramatically owing to the rapid proliferation, invasion, and metastasis of cells. − Compared to normal cells, H 2 O 2 in cancer cells can rapidly diffuse across the living cell membrane (within 5 s) under the stimulation of ultraviolet (UV) light and drugs. − For example, the amount of H 2 O 2 released from 10 5 cell/mL of lung cancer cells A549 is approximately 0.109 ± 0.005 μM. In addition, barely H 2 O 2 was released from healthy human umbilical vein endothelial cells (−0.006 ± 0.004 μM) .…”

A novel nanosponge–hydrogel system‐based electrochemiluminescence biosensor for uric acid detection

“…[ 11 ] Shan's group synthesized metal–organic gels using horseradish peroxidase. [ 12 ] Metal–organic gels based on the EC platform were used for i n situ detection of H 2 O 2 generated from HeLa cells. However, the gel was just used as a simple carrier in the ECL sensing application.…”

4,6-O-Phenylethylidene Acetal Protected D-Glucosamine Carbamate-Based Gelators and Their Applications for Multi-Component Gels

“…A few recent reports have demonstrated the use of metal–organic gels (MOG) or metal–organic frameworks as enzyme mimics for CL systems [ 36 , 38 , 39 , 40 ]. An iron-based metal–organic gel showed enzyme-mimicking activities and was able to detect H 2 O 2 released from Hela cells using luminol chemiluminescence [ 41 ].…”