Mass Spectrometry Imaging of Chlorhexidine and Bacteria in a Model Wound

The ability to generate two-dimensional images of a wound that contains information about the distribution of bacteria overlaid with the distribution of drugs and metabolites could enhance our understanding of wound healing processes. Advances in technology are leading to a rapid expansion in mass spectrometry-based imaging. When combined with the ability of matrix assisted laser desorption ionization to ionize a wide range of molecules, imaging mass spectrometry is a powerful biomedical research tool. However, this technique has yet to be used to investigate bacterial colonization of wounds or the distribution of antimicrobial agents on tissue. To address this, distribution and persistence of the antimicrobial agent chlorhexidine on a model human tissue was investigated. The ability to detect and localize Staphylococcus aureus on the same tissue model was also addressed. Sub-millimeter resolution ion images from these experiments show the promise of using mass spectrometry imaging to investigate the growth and treatment of bacteria on skin. This methodology will be of value in the development of wound dressings with improved antimicrobial properties and a more careful analysis of the concentration of antimicrobial agents required to prevent biofilm formation and persistence.