IISc team synthesises artificial enzyme

“The new nanozyme was produced using vanadium pentoxide nanocrystals of just 150-200 nm size,” explains Sourav Ghosh (right)

“The new nanozyme was produced using vanadium pentoxide nanocrystals of just 150-200 nm size,” explains Sourav Ghosh (right)  

Nanozyme mimics the antioxidant enzyme glutathione peroxidase

Nanomaterials that can behave like human enzymes have now been successfully synthesized by a team of researchers from Indian Institute of Science (IISc), Bengaluru. They produced the new nanozyme — nanomaterial with enzyme-like activity — by using vanadium pentoxide nanocrystals of just 150-200 nm size.

The nanozyme was able to act like the natural antioxidant enzyme glutathione peroxidase in our body and help maintain the hydrogen peroxide levels within the threshold. They synthesised the nanozyme with four different morphologies — nanowires, nanosheets, nanoflowers and nanospheres.

“All four morphologies are basically made of the vanadium and oxygen in the same ratio. The methods of production is slightly different giving each type a different shape, size and crystal facet or plane,” explains Sourav Ghosh, Ph.D. student at the institute and first author of the paper published in Angewandte Chemie.

The team then studied the ability of the nanozyme to catalytically reduce hydrogen peroxide, as high levels have been reported to generate reactive oxygen species and subsequently induce oxidative stress, which can damage the DNA, proteins and lipids.

The enzyme glutathione peroxidase maintains the levels of hydrogen peroxide in our body and prevents cell damage. But under oxidative stress condition, the amount of enzyme is not sufficient to maintain the hydrogen peroxide level. “Under these circumstances, the nanozyme that precisely functions as the natural enzyme can be used,” explains Prof. G. Mugesh from the Department of Inorganic and Physical Chemistry at the institute and corresponding author of the paper.

Kinetics and spectroscopy studies showed that the nanozyme was able to bring down the level of hydrogen peroxide. The nanozyme uses the same pathway as the natural enzyme but without generating any free radicals.

The team then studied if the change in morphology affected the catalytic ability and found that the nanospheres showed the highest activity among the four types, indicating that the surface-exposed crystal facets play crucial roles in the catalysis.

The study was primarily aimed at understanding the effect of different crystal facets of nanozymes on their enzyme mimetic activity. The team plans to carry out studies on mice models to understand more about the four nanozyme forms and their potential as therapeutic agents.

Nanozymes with tunable catalytic properties are emerging as the next generation of artificial enzymes that find applications in neuroprotection, cardioprotection and cancer therapy.

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