Tannic Acid-Capped Gold Nanoparticles as a Novel Nanozyme for Colorimetric Determination of Pb2+ Ions

Abstract

In this study, tannic acid-modified gold nanoparticles were found to have superior nanozyme activity and catalyze the oxidation reaction of 3,3′,5,5′-tetramethylbenzidine in the presence of hydrogen peroxide. Enhancing the catalytic activity of the nanozyme by Pb2+ ions caused by selectively binding metal ions by the tannic acid-capped surface of gold nanoparticles makes them an ideal colorimetric probe for Pb2+. The parameters of the reaction, including pH, incubation time, and concentration of components, were optimized to reach maximal sensitivity of Pb2+ detection. The absorption change is directly proportional to the Pb2+ concentration and allows the determination of Pb2+ ions within 10 min. The colorimetric sensor is characterized by a wide linear range from 25 to 500 ng×mL−1 with a low limit of detection of 11.3 ng×mL−1. The highly sensitive and selective Pb2+ detection in tap, drinking, and spring water revealed the feasibility and applicability of the developed colorimetric sensor.

Coordination‐Driven One‐Step Rapid Self‐Assembly Synthesis of Dual‐Functional Ag@Pt Nanozyme

“…The lower free energy favors the proximity of FNA to nucleation seq and the surface of the nanozyme, which improves the electron transfer on the surface of the nanozyme and enzymatic activity. [ 40,41 ] However, when the two sequences are completely complementary, the increase in enzyme activity is not noticeable (ES‐15‐2 and NS15‐2). Combined with the downstream hybridization seq optimization results, it can be seen that the complementary sequence here is different from that of Figure 2a (orange background), and it is in the trade‐off state of promotion and inhibition.…”

The optimization of gold nanoparticles–horseradish peroxidase as peroxidase mimic using central composite design for the detection of hydrogen peroxide

“…Employing enzymatically active HRP-coated AuNPs, they catalyzed polymerization, resulting in thermoresponsive polymers, and fully recovered without significant loss of their catalytic activity [35]. Tannic acid-modified gold nanoparticles exhibit superior nanozyme activity and catalyze the oxidation reaction of TMB in the presence of H 2 O 2 [36]. Positively charged gold nanoparticles possess intrinsic peroxidase-like activity and can catalyze the oxidation of the peroxidase substrate, TMB, by H 2 O 2 , providing a straightforward approach to colorimetric detection [23].…”

Recent advances in colorimetric sensors based on nanozymes with peroxidase-like activity

“…2). Additionally, some materials, such as quantum dots (QDs), 68 β-cyclodextrin (β-CD), 69 polyoxometalates (POMs), 70 polyvinyl alcohol, 71 hydrogel, 72 cysteamine 73 and tannic acid 74 combined with Au NPs showed higher catalytic activity under neutral conditions, and were successfully utilized for colorimetric detection of metal ions and small biological molecules.…”