A peptide with a dual mechanism of action – it dissolves the bacterial membrane and activates the immune system – could be an effective weapon against microorganisms that have evolved ways to evade antibiotics, as superbugs do. Scientists at the University of Pennsylvania (UPenn) have designed stable synthetic peptides that activate mast cell receptors, which are cells involved in the innate and adaptive immune response. This dual approach eliminates bacteria and recruits neutrophils to finish the job.