Spider silk has been used to create a superlens for a microscope, allowing scientists to view objects previously deemed "invisible".
Physical laws of light make it impossible to view structures smaller than 200 nanometers - the smallest size of bacteria - using a normal microscope alone.
But scientists from Bangor and Oxford universities found the silk lets them see beyond the current magnification.
The discovery was hailed as "exciting".
Bangor University said extending the limit of the classical microscope's resolution had been the "Holy Grail" of microscopy for over a century and superlenses had been the goal since the turn of the millennium.
Manufactured superlenses have previously been used but this is believed to be the first time a naturally occurring biological material had been used to create one.
The team found applying the dragline silk of a golden silk orb-weaver spider to the material being viewed provided an additional two to three times magnification.
This allowed them to view structures previously classed as "invisible", including some germs and viruses.
The findings have been published in a paper in the nanoscience research journal Nano Letters.
Dr Zengbo Wang, who led Bangor's team, said producing manufactured superlenses involved some complex engineering processes and finding a natural superlens was important "so that everyone can access superlenses".
Prof Fritz Vollrath, whose silk group at Oxford University's department of zoology collaborated on the project, said it was "very exciting".
"These lenses could be used for seeing and viewing previously 'invisible' structures, including engineered nano-structures and biological micro-structures as well as, potentially, native germs and viruses," he said.
"In much the same was as when you look through a cylindrical glass or bottle, the clearest image only runs along the narrow strip directly opposite your line of vision, or resting on the surface being viewed, the single filament provides a one-dimensional viewing image along its length."
The golden silk orb-weaver spider - often called Nephila or banana spiders - are known for the impressive webs they weave and are found in warmer regions around the world.