Infectious diseases remain some of the most common causes of death worldwide. Treatment options are endangered by the growing problem of antibiotic resistance. New antimicrobial agents must be developed to counter the threat. Antimicrobial peptides are an emerging alternative to conventional antibiotics. Unlike most antibiotics that interrupt some aspect of the biochemical life cycle of bacteria (e.g. inhibiting synthesis of a key protein), antimicrobial peptides can take a somewhat more direct approach by disrupting the physical integrity of bacterial cell walls.
Atomic Force Microscopy (AFM) is a powerful tool for visualizing membranes, including both model membranes (e.g. lipid bilayers) and the cell walls of intact cells. AFM can visualize these membranes with nanometer-scale resolution in physiologically relevant conditions. Recent advances have improved the temporal resolution of AFMs too, so it is now possible to monitor dynamic processes with AFM at frame rates exceeding 10 frames/second. This application note presents an example where the effect of an antimicrobial peptide is measured on a model lipid membrane. The AFM clearly reveals time-dependent pore formation in the membrane due to its interactions with the peptide.
The application note describes: