Investigating the Effects of Commercial Antimicrobial Agents on Human Corneal Epithelial Cell Membranes
Poster Feb 27, 2015
Ian J. Horner, Jerod J. Hurst, Nadine D. Kraut, Alyssa A. Rook, Crystal M. Collado, G Ekin-Atilla Gokcumen, and Frank V. Bright
Multi-purpose solutions (MPS) are a single solution that functions to simultaneously rinse, disinfect, clean and store soft contact lenses. Several commercial MPS products contain polyhexamethylene biguanide (PHMB) and/or polyquaternium-1 (PQ-1) as antimicrobial agents. In this proster we report the effects of PHMB and PQ-1 on small unilamellar vesicles (SUV) that we have designed to mimic the average human corneal epithelial cell membrane. Specifically, we assessed the interactions of PHMB and PQ-1 on the biomembrane by using fluorescence spectroscopy, dynamic light scattering (DLS), and liquid chromatography/mass spectrometry (LC-MS). Fluorescence assessed the membrane surface polarity and stability through the temperature-dependent generalized polarization (GP), the gel-to-liquid transition temperature (Tm) and the associated van’t Hoff enthalpy (ΔHVH) as a function of PHMB and PQ-1 concentration. DLS evaluated SUV aggregation as a function of PHMB and PQ-1 concentration and SUV composition. LC-MS determined the composition of any precipitates that formed. PHMB association with the mimic SUV bilayer leads to: (i) a decrease in surface polarity, (ii) an increase in (Tm), (iii) an increase in phospholipid-phospholipid cooperativity, and (iv) an increase in SUV size on a nanometer scale. PQ-1 association with the mimic SUV bilayer leads to: (i) an increase in surface polarity (ii) no change in (Tm), (iii) no change in phospholipid-phospholipid cooperativity, and (iv) an increase in SUV size on a micron scale due to SUV aggregate formation. The aggregates exhibited a phospholipid composition equivalent to the SUV prior to the addition of PQ-1. These results are consistent with PHMB adsorbing onto and PQ-1 intercalating into the mimic SUV bilayer structures.
Proteomics and Substrate Based MS Imaging of Xenobiotic Metabolising Enzymes in Ex Vivo Human Skin and a Human Living Skin Equivalent ModelPoster
Untargeted proteomics analysis showed that human skin and a commercially available living skin equivalent model exhibit a similar distribution of xenobiotic metabolising enzymes. A new technique, substrate based mass spectrometry imaging (SB-MSI) was developed during this study.READ MORE
Development and Assessment of Non-Infected and Infected Skin Models Using MALDI-MSIPoster
Infections have detrimental effects on wound healing leading to chronic wound formation. The use of labskin,a living skin model, in combination with mass spectrometry imaging, provides a good model for assessing wound healing factors.READ MORE
Overcoming the Challenges of Analysing Ionic Polar Pesticides in FoodPoster
Here, the novel application of the Waters’ Torus DEA column is presented, showing the improved performance of a UPLC-MS/MS method for the underivatised
analysis of glyphosate and a selection of other anionic pesticides.