Subcategory: Biomedical Engineering
Shannon Mitchell - Xavier University of Louisiana
Co-Author(s): Nsoki Phambu, University of Tennessee, TN Anderson Sunda-Meya, Xavier University of Louisiana, LA
An increasing problem in pharmaceuticals today is that bacterial infections are gradually becoming more resistant to conventional antibiotics. Antimicrobial peptides or AMPs are a promising solution to this problem. The small antimicrobial peptide DDDDDDD-OH (D7) in zinc saline solution was found to be bactericidal for both Gram-positive and Gram-negative bacteria. This study investigates the binding of D7 with model membranes using atomic force microscopy (AFM). The model membranes considered were the saturated Dipalmitoyl Phosphatidylcholine (DPPC), the unsaturated Palmitoyloleoyl phosphatidylcholine (POPC), and the anionic Dipalmitoyl Glycero Phosphoglycerol (DPPG). AFM data shows that mixed (DMPC/DMPG) and (DMPC/DMPA) form large vesicular shapes. In the presence of D7, open vesicles in coexistence with flat discs are observed. The AFM provided unique information on the topography of peptide-treated membranes suggesting membrane changes as a result of peptide structuring and pore formation. In addition, structure and density of fibril formation are also compared on positively and negatively charged as well as hydrophobic chemically-modified surfaces at physiologically relevant conditions. The present study gives a critical view of the AFM technique, which can be useful for other studies concerning peptide–membrane interactions.
Funder Acknowledgement(s): This research was funded, in part, under the grant # HRD 1411209 a grant from the National Science Foundation awarded to Anderson Sunda-Meya.
Faculty Advisor: Anderson Sunda-Meya, email@example.com
Role: The AFM imagining, processing, and analysis.