Enhanced Peroxidase-Mimic Catalytic Activity via Cerium Doping of Strontium-Based Metal–Organic Frameworks with Design of a Smartphone-Based Sensor for On-Site Salivary Total Antioxidant Capacity Detection in Lung Cancer Patients

Abstract

The development of artificial nanozymes with superior catalytic performance and excellent stability has been a long-standing objective for chemists. The total antioxidant capacity (TAC) is one of the most important bioanalytical measures of oxidative stress in the body. The present work aims to develop a smartphone-assisted visual detection sensor using cerium-doped strontium-based metal–organic frameworks (Ce-SrMOFs) as peroxidase-like nanozymes for the rapid, low-cost, on-site detection of TAC. The pristine SrMOF functioned as a peroxidase nanozyme, and its enzymatic activity was enhanced after doping it with Ce(IV) ions because of the multivalent nature and synergistic impact of the heteroatoms. The Ce-SrMOFs were sensitive to the single electron transfer and hydrogen atom transfer processes, which implies that the Ce-SrMOFs can serve as an ideal nanozyme candidate for TAC analysis. The investigated mechanism revealed that •OH is the most active oxygen species for the peroxidase-like activity. The Ce-SrMOFs exhibited a strong affinity for 3,3′,5,5′-tetramethylbenzidine (TMB) and H2O2, with K m values of 0.082 and 0.427 mM, which are 5.29- and 8.67-fold lower than those of horseradish peroxidase (HRP), respectively. The Ce-SrMOFs were used for the detection of ascorbic acid, cysteine, and glutathione, with limits of detection of 44, 53, and 512 nM, respectively. The proposed method proved effective in measuring the TAC in saliva samples from lung cancer patients, thereby yielding results with satisfactory precision and accuracy.

Accuracy improvement via novel ratiometry design in distance-based microfluidic paper based analytical device: instrument-free point of care testing

“…Currently, numerous analytical techniques developed for the determination of various biological molecules, such as electrochemistry, 5,6 high-performance liquid chromatography, 7 uorescence, [8][9][10][11][12] colorimetry, [13][14][15][16][17] chemiluminescence, 18 capillary electrophoresis, 19 and the enzyme-linked immunosorbent assay (ELISA). 20,21 However, most of these methods and techniques suffer from obstacles such as the need for costly and sophisticated instruments, skilled personnel, complicated pretreatments, or costly biological reagents.…”

Red-Emissive Carbon Dots Combined with Ferric Ions for Detection of Total Antioxidant Capacity in Food

“…However, excess reactive oxygen species (ROS) would impair the intracellular redox homeostasis and would contribute to injury of the bio-macromolecules and serious diseases, such as cancer, cardiovascular disease, Alzheimer’s disease, and various inflammations. − The human’s antioxidant system is based on the endogenously generated antioxidant enzymes and have to be supplemented with various exogeneous antioxidants [ascorbic acid (AA) and vitamins E] obtained from diet and fruit. , Several small-molecular antioxidants are usually utilized as nutritive additives in the food and beverage industries. Therefore, a precise and sensitive strategy to monitor the antioxidant content in food is urgently required …”

“…GSH) and single electron transfer (SET) functioning species (etc. AA) . Due to the various antioxidants existing in the human body, the actual number cannot be determined by analyzing a single type of antioxidants.…”

“…In general, the cellular redox homeostasis highly relies on the intake of antioxidants, notably cystine (Cys), glutathione (GSH), and AA . However, effective detection of individual antioxidants is challenging, due to the potential interaction . Herein, the total antioxidant capacity (TAC) is proposed to indicate the antioxidant capacity and implies the content of ROS that a test solution can scavenge from samples of various natural sources .…”

“…Herein, the total antioxidant capacity (TAC) is proposed to indicate the antioxidant capacity and implies the content of ROS that a test solution can scavenge from samples of various natural sources . Besides the techniques of analyzing the TAC by chromatography and Fourier transform infrared spectroscopy, which require sophisticated apparatus and skilled operators, the standard strategies for accessing the TAC are mainly centered in colorimetric methods. ,− In general, these assays are usually based on the following strategies: (1) reduction of the Fe­(III) complex by antioxidants to generate the Fe­(II) complex (593 nm), (2) analysis of the typical absorption of the 2,2′-azinobis­(3- ethylbenzthiazolin-6-sulfonic acid) radical cation (ABTS •+ ) at 734 nm, and (3) [2,2-di­(4-tert-octylphenyl)-1-picrylhydrazyl] radical (DPPH • ) at 517 nm, which can be scavenged by the antioxidants . Among various TAC assays, the ferric reducing antioxidant power (FRAP) is the standard, most simple, and cost-effective strategy.…”