TY - JOUR T1 - Physicochemical properties of mucus gel in CF and healthy controls assessed by Raman spectroscopy and force-distance atomic force microscopy JF - European Respiratory Journal JO - Eur Respir J VL - 42 IS - Suppl 57 SP - P2110 AU - Andrey Malkovskiy AU - Jacquelyn Zirbes AU - Jayakumar Rajadas AU - Carlos Milla Y1 - 2013/09/01 UR - http://erj.ersjournals.com/content/42/Suppl_57/P2110.abstract N2 - Current models of the basic defect in CF propose a dehydration of mucosal surfaces affecting the properties of secretions. Most studies of CF secretions have utilized sputum, which is a mix of mucus and other components. We attempted to define the properties of secreted CF mucus by studying Sub-mandibular salivary gland secretions, which have similar mucin composition to bronchial glands. Saliva was collected in 2 CF patients (DF508 homozygotes) and 4 healthy controls (HC). Mucus gel was separated by centrifugation and its properties analyzed by Raman spectroscopy and force-distance atomic force microscopy (AFM) elasticity measurements. All experiments were conducted blinded to the sample identity. Raman spectra of CF mucus showed a sharp distinct peak at 2080 cm-1, which was absent in HC. No particular signatures were found in the 400-800 cm-1 region, where disulfide bonds occur. By AFM, when small clusters of the mucus gel were probed the CF specimens exhibited higher stiffness than the HC samples. We are conducting further experiments with sharper cantilevers in order to determine if larger differences in stiffness can be detected. In addition, AFM imaging of highly-dilute mucus revealed that HC samples separated in small clusters and separate chains, in contrast to CF samples where no separate chains were observed. In conclusion, significant abnormalities in the measurable properties of gland secreted mucus from CF patients have been detected. Current work is directed at fully characterizing the peak detected by Raman spectroscopy. The Raman signature of CF mucus can be potentially used as a biomarker of the basic defect of this disease. ER -