Scientists develop enzyme mimetic with potential applications in wastewater treatment, healthcare

The nanozyme can degrade pollutants in wastewater by oxidising them in the presence of sunlight, thereby reducing the toxicity of wastewater.

Scientists at the Materials Research Centre (MRC), Indian Institute of Science (IISc), have developed a new type of enzyme mimetic that can degrade toxic chemicals in industrial wastewater effectively in the presence of sunlight. 

Enzymes are proteins that catalyse a majority of biological reactions in living systems. However, the practical use of natural enzymes is hindered by inherent limitations such as sensitivity to denaturation (breakdown/damage), complex production procedures, high costs, and difficulties in recycling, says Subinoy Rana, Assistant Professor at MRC and corresponding author of the paper published in Nanoscale. 

Mass producing these enzymes is an expensive and time-consuming process. Another problem is storage – most of the natural enzymes are temperature-sensitive and require storage at cooler temperatures, often as low as -20°C. 

Nano-sized enzyme mimetics or “nanozymes” manufactured in the lab can mimic such natural enzymes and overcome these practical challenges.  

In the current study, the IISc team synthesised a platinum-containing nanozyme called NanoPtA, which can be converted into powder form for industrial use. 

When the NanoPtA comes in contact with wastewater, the benzene rings and long alkyl chains present in the molecule form multiple non-covalent interactions. Individual NanoPtA molecules connect together to form tape-like structures that start emitting light, which is the origin of its oxidising capacity. The nanozyme can then degrade pollutants present in wastewater by oxidising them in the presence of sunlight, thereby reducing the toxicity of wastewater. 

The team found that the nanozyme could degrade even small (micromolar) quantities of common effluents like phenols and dyes within ten minutes when placed under sunlight. The researchers also found that the NanoPtA complex was quite stable, lasting for up to 75 days at room temperature.