Nanozymes for Environmental Pollutant Monitoring and Remediation

Abstract

Nanozymes are advanced nanomaterials which mimic natural enzymes by exhibiting enzyme-like properties. As nanozymes offer better structural stability over their respective natural enzymes, they are ideal candidates for real-time and/or remote environmental pollutant monitoring and remediation. In this review, we classify nanozymes into four types depending on their enzyme-mimicking behaviour (active metal centre mimic, functional mimic, nanocomposite or 3D structural mimic) and offer mechanistic insights into the nature of their catalytic activity. Following this, we discuss the current environmental translation of nanozymes into a powerful sensing or remediation tool through inventive nano-architectural design of nanozymes and their transduction methodologies. Here, we focus on recent developments in nanozymes for the detection of heavy metal ions, pesticides and other organic pollutants, emphasising optical methods and a few electrochemical techniques. Strategies to remediate persistent organic pollutants such as pesticides, phenols, antibiotics and textile dyes are included. We conclude with a discussion on the practical deployment of these nanozymes in terms of their effectiveness, reusability, real-time in-field application, commercial production and regulatory considerations.

Nanozyme Catalytic Turnover and Self-Limited Reactions

“…Nanozymes might replace enzymes for biomedical, 11−14 bioanalytical, 15−18 and environmental applications. 19,20 One type of nanozyme immobilizes small molecular catalysts on nanoparticles (NPs), where the nanoparticle core serves only as a support. 21 A representative example was reported by Manea et al, where they functionalized AuNPs with thiolated azacrown and loaded it with Zn 2+ ions to mimic RNase activity.…”

Enzyme (Single and Multiple) and Nanozyme Biosensors: Recent Developments and Their Novel Applications in the Water-Food-Health Nexus

“…Therefore, the study of alternatives to solve the weaknesses of natural enzymes has increased [ 86 ]. Nanozymes are nanomaterials that possess unique physicochemical properties and mimic natural enzymes properties ( Figure 5 ) [ 87 ]. Significant progress has been made since the report of Zn 2+− triazacyclonane-functionalized gold nanoparticles with intrinsic peroxidase-like activity due to the rapid development of nanomaterials [ 88 ].…”

Nanozymes—Hitting the Biosensing “Target”

“…Metal ions, especially heavy metals, are not easily metabolized and, therefore, accumulate in organs resulting in tissue damage and increasing disease vulnerability over time [ 129 , 130 ]. As a result, the accurate detection of metal ions in the environment or tissues is urgently needed as a prelude to environmental remediation [ 131 ] or clinical intervention strategies [ 28 , 132 ]. Here we give two examples linked to mercury (Hg) and Cu ions to illustrate the critical characteristics of the materials and the proposed mechanism of action for target ion detection.…”