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Recently we explained how some microbes keep us healthy. Unfortunately, not all microorganisms are helpful, and some cause illness. Recent discoveries could help keep nasties at bay.

A number of diseases are caused by bacteria. They range in severity from mild, irritating infections or a bit of diarrhoea, to life-threatening illnesses such as bacterial meningitis. Killing harmful bacteria is important in both preventing and treating disease.

There are ways to stop bacteria before they even enter the body. Bacteria are mostly water, so boiling temperatures can cause enough damage to kill most types of bacterial cells. Boiling contaminated water is one way to make it safe for drinking. Some pieces of medical equipment are also treated with high-pressure steam to eliminate any nasties present. However, some bacteria can survive high temperatures.

Another way to kill bacteria is by chemical means. Examples include antibacterial hand soap, and cleaners such as bleach. Sometimes antibiotics – chemicals to treat bacterial disease or infection – are prescribed. However, an increasing problem is antibiotic resistance, where bacteria evolve that cannot be controlled or killed by conventional antibiotics.

Recent research indicates that some surfaces also have bacteria slaying abilities. Inspired by the surface of some insect wings with antibacterial properties, scientists studied a material called black silicon. While it feels smooth to human touch, the surface of black silicon consists of tiny spikes at the nanoscale. The antibacterial insect wings have a similar structure.

Black silicon’s spikes are able to kill bacteria, not through heat or a chemical process, but by impaling them. One advantage of black silicon is that it killed a range of bacteria in the study, while many antibiotics are only effective against particular types of bacteria. The discovery of black silicon’s properties could lead to new antibacterial surfaces, suitable for medical devices.

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