Research Highlights

Semiconductor-coated nanoparticles kill bacteria, cancer cells

doi:10.1038/nindia.2019.29 Published online 12 March 2019

Researchers have synthesised nanocomposites that can inhibit the growth of two disease-causing bacteria, and kill breast and liver cancer cells, making them potentially useful for developing therapies for bacterial infections and cancers1.

Magnetic nanoparticles possess antibacterial and anticancer properties. However, they tend to aggregate, and this reduces their antibacterial and anticancer efficiency.

To overcome this drawback of magnetic nanoparticles, scientists from the Bose Institute in Kolkata, the Vidyasagar University in Midnapore and the North Bengal University in Darjeeling, all in India, prepared the nanocomposites by coating iron oxide nanoparticles, a type of magnetic nanoparticle, with zinc oxide, a semiconductor material.

The zinc-oxide coating formed disk-, spindle-, rod- and sphere-shaped nanocomposites. The researchers then tested the antibacterial and anticancer potential of the nanocomposites by exposing these particles to two disease-causing bacteria (Staphylococcus aureus and Vibrio cholerae), and to cultured human breast and liver cancer cells. 

The sphere- and rod-shaped nanocomposites significantly reduced the number of colonies formed by the bacteria. The nanocomposites generated reactive oxygen species that broke down DNA strands and destroyed lipids in the membrane, causing the death of the bacteria. 

All the nanocomposites exhibited toxic effects on the cancer cells at a low concentration. However, the sphere-shaped ones showed the highest toxicity against the cancer cells. The nanocomposites selectively killed the cancer cells, sparing normal cells. Increasing the concentration of the nanocomposites enhanced their anticancer efficiency.

The nanocomposites entered the cancer cells by rupturing the cell membrane and then generated reactive oxygen species that eventually killed the cells.


References

1. Jana, T. K. et al. The antibacterial and anticancer properties of zinc oxide coated iron oxide nanotextured composites. Colloids. Surf. B: Biointerfaces. 177, 512-519 (2019)