Phytosynthesis of Palladium Nanoclusters: An Efficient Nanozyme for Ultrasensitive and Selective Detection of Reactive Oxygen Species

Abstract

Hydrogen peroxide is a low-reactivity reactive oxygen species (ROS); however, it can easily penetrate cell membranes and produce highly reactive hydroxyl radical species through Fenton’s reaction. Its presence in abnormal amounts can lead to serious diseases in humans. Although the development of a simple, ultrasensitive, and selective method for H2O2 detection is crucial, this remains a strategic challenge. The peroxidase mimetic activity of palladium nanoclusters (PdNCs) has not previously been evaluated. In this study, we developed an ultrasensitive and selective colorimetric detection method for H2O2 using PdNCs. An unprecedented eco-friendly, cost-effective, and facile biological method was developed for the synthesis of PdNCs. This is the first report of the biosynthesis of PdNCs. The synthesized nanoclusters had a significantly narrow size distribution profile and high stability. The nanoclusters were demonstrated to possess a peroxidase mimetic activity that could oxidize peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB). Various interfering substances in serum (100 μM phenylalanine, cysteine, tryptophan, arginine, glucose, urea, Na+, Fe2+, PO43−, Mn+2, Ca2+, Mg2+, Zn2+, NH4+, and K+) were included to evaluate the selectivity of the assay, and oxidation of TMB occurred only in the presence of H2O2. Therefore, PdNCs show an efficient nanozyme for the peroxidase mimetic activity. The assay produced a sufficient signal at the ultralow concentration of 0.0625 µM H2O2. This colorimetric assay provides a real-time, rapid, and easy-to-use platform for the detection of H2O2 for clinical purposes.

A Review on Metal- and Metal Oxide-Based Nanozymes: Properties, Mechanisms, and Applications

“…Among these assays, colorimetry and electrochemistry have gradually became main technologies for H 2 O 2 determination owing to low cost, high [341], C-dots/Fe 3 O 4 [130], and Rh [354,355]) have been developed to manufacture colorimetric sensors. To our knowledge, the currently lowest detection limit of H 2 O 2 based on colorimetry is 0.0625 µM reported by Tripathi et al [356], and the palladium nanoclusters (Pd NCs) were designed by biological methods firstly in their study, in which Pd NCs were served as POD mimics.…”

“…Diverse POD mimics (e.g., Cu 2 O–Au [ 350 ], Fe–N–C [ 351 ], Cu(II)-coated Fe 3 O 4 [ 352 ], PtCu [ 353 ], V 2 O 5 [ 341 ], C-dots/Fe 3 O 4 [ 130 ], and Rh [ 354 , 355 ]) have been developed to manufacture colorimetric sensors. To our knowledge, the currently lowest detection limit of H 2 O 2 based on colorimetry is 0.0625 µM reported by Tripathi et al [ 356 ], and the palladium nanoclusters (Pd NCs) were designed by biological methods firstly in their study, in which Pd NCs were served as POD mimics. Glucose Glucose is an indispensable nutrient for metabolism in organisms.…”

Recent Developments in Detoxification of Organic Pollutants Using CdS-based Nanocomposites

“…(a) the surface layer, (b) the shell layer, and (c) the core, which is the centre of the nanoparticle and is commonly referred as the nanoparticle itself [61]. It is because of these special properties that these materials became a topic of immense interest for scientists in various fields, also their mesoporous nature making them an exceptional choice in drug delivery [62,63], biological and chemical sensing [64,65], gas sensing [66], CO 2 http://www.nanobe.org capturing [67] and other related applications [68]. Properties like large fraction of atoms being present on the surface, high surface energy, receded structural demerits, that are a product of their size which is in nano range, are the ones that make them superior to their bulk counterparts.…”

Nanomaterial Based Biosensors for Detection of Viruses Including SARS-CoV-2: A Review

“…Similarly, an electrochemical immunesensor using gold nanoparticles (AuNPs) has been developed, which contains carbon electrodes to detect the human coronavirus [11]. The nanoparticles undergo a colorimetric change on interaction with the virus by (1) showing peroxidase-like activity [12,13], (2) aggregation of the nanomaterial or (3) destabilization of the nanomaterial structure [14]. Researchers have exploited these characteristic features of the nanomaterials for HIV-AIDS detection [15].…”