Next-Generation Enzyme-inspired Engineering of Nanomaterials (Nanozymes) and their Challenges

Nanozymes are a class of nanomaterials that possess enzyme-like properties. Enzymes are natural catalysts that accelerate chemical reactions in living organisms. Similarly, nanozymes can mimic the functions of enzymes, but they are artificial nanomaterials with catalytic activity. Unlike natural enzymes, nanozymes are typically composed of inorganic materials such as metals, metal oxides, or carbon-based materials. Their catalytic activity arises from their specific surface structures, compositions, and unique properties at the nanoscale. Nanozymes have several advantages over natural enzymes. Firstly, they are generally more stable and robust, making them suitable for various applications in harsh environments. They can withstand high temperatures, extreme pH conditions, and organic solvents better than biological enzymes. Secondly, nanozymes can be easily synthesized, modified, and scaled up for large-scale production, whereas obtaining large quantities of natural enzymes can be challenging and costly.

While nanozymes have promising applications, they also have certain limitations that need to be considered. Here are some of the key limitations of nanozymes:

• Limited substrate specificity

• The complexity of catalytic mechanisms

• Limited regulation and control

• Biocompatibility and toxicity

• Scalability and cost

Our research group are trying to address these challenges by appropriate engineering of materials to produce next-generation enzyme mimetic nanomaterials that mimic antioxidant, oxidative and hydrolytic enzymes. By overcoming these challenges, nanozymes can be further optimized and tailored for specific applications, expanding their potential impact in various fields. 

Chemical Hydrogen Storage, Hydrogen Release, and Regeneration of Hydrogen Storage Systems

Hydrogen, a clean and environmentally friendly fuel, produces energy and water upon combustion. Storing hydrogen as a gas for onboard applications can be burdensome and potentially hazardous. Conversely, storing hydrogen in chemical forms offers advantages such as convenience, reduced volume occupancy, and ease of handling. However, the challenge lies in releasing hydrogen from chemical hydrogen storage sources like metal hydrides, mixed-metal hydrides, water, and small organic molecules.

In our laboratory, we focus on studying dehydrogenases and applying the principles of bioinorganic chemistry to efficiently facilitate the dehydrogenation of chemical hydrogen sources. To achieve this, we explore nanocatalysis, merging homogeneous and heterogeneous catalysis. Specifically, we investigate the dehydrogenation of chemical hydrogen storage sources such as ammonia borane and substituted amino-boranes.

Within our research, we have developed a range of next-generation nanocatalysts and supported nanocatalysts. These catalysts exhibit high turnover numbers and demonstrate remarkable catalytic efficiencies. To gain a comprehensive understanding of the underlying mechanisms, we delve into the chemical interactions occurring at the heterojunctions. This exploration allows us to probe and unravel the intricate details of the dehydrogenation process (Fig. 5).

Enzyme Models for Plastic Deconstruction 

Enzyme models for plastic deconstruction are gaining attention as a potential solution to address the environmental impact of accumulating plastic waste. Plastics, widely used for their advantageous properties, pose a significant threat to the environment and living organisms. Recycling plastic waste is one approach to mitigate this issue, but it often results in compromised product quality.

Various methods, including catalytic pyrolysis and conversion of plastic into fuel and carbon nanomaterials, have been explored as alternatives. Additionally, engineered enzymes with tailored active sites have shown promise in deconstructing plastics. Leveraging this knowledge, we aim to apply the principles of bioorganic, bioinorganic, and enzyme mimetics to develop innovative approaches for plastic waste deconstruction.

By designing enzyme models inspired by nature, we seek to unlock efficient and sustainable strategies for breaking down plastic waste. This interdisciplinary approach combines principles from bioorganic and bioinorganic chemistry, along with insights from enzyme mimetics. Through our research, we aspire to contribute to the development of effective methods for the deconstruction of plastic waste, mitigating its detrimental impact on the environment.