The filter that helps keeps out the germs

A new kind of filter has been developed that could act as a surgical seal to allow operations to be performed in non-sterile conditions.

“The membrane filter could potentially prevent germs, dust or allergens from reaching an open wound, while still allowing a doctor to perform surgery safely,” said Dr Tak-Sing Wong, from Pennsylvania State University, US.

The filter works in the opposite way from most other filters.

It blocks small particles while allowing larger objects to pass through. The “reverse filter” consists of a liquid membrane a bit like film that stretches across a toy bubble dispenser. Owing to its surface tension, small objects bounce off it, while larger ones puncture the seal – which then instantly heals.

The filter could also be used to keep odours trapped inside waterless toilets too.