Scientists who understand the nature of a stabilizing force between molecules, or between parts of the same molecule, can incorporate this force systematically into the design of new materials. This molecular engineering can result in unique and beneficial stability or functionality. The McCurdy group at CSULA strives to generate new knowledge about a specific stabilizing force in protein-like molecules that will guide the development of materials with useful properties. Specifically, PREM-funded MS student Alicia Mullaley is attempting to understand interactions of the cation-pi type using synthetic peptides. Alicia has determined the strength of the interaction for a number of helical peptidic molecules and is currently analyzing this data to determine the relative importance of various structural features on the strength of the interaction. These fundamental studies on the cation-pi interaction will have future impact on the molecular design of new materials.

Figure 1. Circular dichroism spectra of Y/K peptides.

Certain antibiotics bind to specific receptors on bacterial cell walls blocking further growth and eventually leading to the bacterial death. Dr. Menake Piyasena (PREM Post-doc fellow) at CSULA has demonstrated a bead-based technique on a microfluidic format that can be used to monitor bacteria-antibiotic interactions. Proof of concept studies utilized a fluorescent dye labeled peptide that resembled the bacterial cell wall and the antibiotic teicoplanin which was covalently immobilized onto magnetic beads. In a microfluidic channel made of polydimethylsiloxane (PDMS), teicoplanin-coated magnetic beads were packed and the binding of injected fluorescent peptide was monitored via fluorescent microscopy. The antibiotic-peptide interaction was further confirmed by flow cytometry and fluorometry. The concept we have developed can be used to monitor bacterial interactions with other drugs and also as a device for pathogen detection.