Bioactive material-based nanozymes with multifunctional attributes for biomedicine: Expanding antioxidant therapeutics for neuroprotection, cancer, and anti-inflammatory pathologies

Considering the biochemical rationale, the deployments of enzymes as therapeutic targets against several oxidative stress-related diseases have been hindered by the limitations of natural enzymes. Nanomaterials exhibiting catalytic activities have emerged as artificial nano-enzymes, so-called “nanozymes” with high structural stability, tunable catalytic activity, functional variety for various biomedical applications, including neuroprotection, cancer therapies, and several inflammatory pathologies. Owing to the current advancement, involvement of different bioactive materials, and the synergy of multifunctional materials, this newly emerged class of nanomaterial-based artificial enzymes is of high interest to deal with the disadvantages presented by the natural enzymes. Considering the above critiques, herein, we provide a biochemical rationale in the context of antioxidant nanozymes and present an overview of the recent advances in nanozymes as possible therapeutic agents. Following a brief introduction, the structural biochemistry of three representative natural enzymes that nanozymes mimic, mainly superoxide dismutase, catalase, and glutathione peroxidase are discussed with relevant key examples. Then, the second part of the review spotlights the properties of metal-based nanozymes with particular emphasis on cerium-, vanadium-, and Prussian blue-based nanozymes, their structure-activity relationship, and their adaptiveness to the biological micro-environment to act as robust therapeutic agents. Furthermore, current advances and applications of nanozymes in biomedicine in the context of neuroprotection, cancer therapies, and related inflammatory pathologies have also been discussed with relevant examples. Finally, the present challenges that nanozyme research is experiencing are discussed to propose possible research directions aimed at reaching its full potential in the near future.