An artificial "virus" that destroys bacteria on contact could help turn the tide in the superbug war, say scientists.
The microscopic molecule, which has a polyhedral structure similar to that of natural viruses, acts like a guided missile to blast through the cell walls of germs.
Unlike a traditional antibiotic, it uses brute force to disrupt the most vulnerable part of a bacterial cell - its outer membrane.
As a result it is less likely to become ineffective as bacteria mutate into new resistant forms.
The synthetic virus measures 20 nanometres across, or 20 millionths of a millimetre.
It is said to cause no damage to human cells, while being capable of penetrating them.
In future such lab-made viral molecules could be used to deliver therapeutic genes or attack bacteria hiding within cells, the scientists claim.
The research, carried out at the National Physical Laboratory and University College London (UCL), is reported in the journal Nature Communications.
Professor Bart Hoogenboom, from UCL, said: "When we exposed bacterial model membranes to these synthetic viruses in our experiments, the results were devastating: within a few minutes, the membranes were completely destroyed."
The scientists hope the virus will lead to a whole new "army" of molecules with the potential to halt the march of antimicrobial resistance (AMR).
Bacteria resistant to existing antibiotics already kill at least 700,000 people worldwide each year.
Some experts fear the world is heading for a terrifying post-antibiotic era in which minor cuts and grazes could prove lethal if they became infected.
Dr Max Ryadnov, biometrology science leader at NPL, said: "This research ... offers long-term and creative solutions for alternative treatments to infectious diseases that are urgently needed."