Sum-frequency spectroscopy
Equipment: Sum-frequency generation spectrometer (SFG)
Sum-frequency spectroscopy is a powerful second-order non-linear optical technique with submonolayer sensitivity and high surface selectivity, that has been widely used as an in situ surface analytical method for probing buried interfaces. In a sum-frequency experiment the temporal and spatial overlap of two beams on the sample surface leads to the generation of a third light beam with frequency corresponding to the sum of the frequencies of the exciting beams. In our spectrometer one of the beams is tunable in the infrared region, and by scanning the IR frequency the vibrational spectra of interfacial molecules can be obtained. The analysis of sum-frequency spectra makes it possible to characterize the ordering, orientation and conformation of molecular species in the interfacial region, as well as the changes in these properties.
Research project: Charecterization of the membrane affinity of peptide conjugated polymer nanoparticles as delivery agents using sum-frequency vibrational spectroscopy
Within this project we are investigating the membrane affinity of peptide conjugated polymer nanoparticles using model membranes.
Szilvia Bősze and her coworkers design and synthesize therapeutic agent – peptide conjugates. The tasks of Gergő Gyulai are to synthesize biocompatible and biodegradable polymer based, peptide conjugated nanocarriers and to study their surface properties. Additionally he is performing the quantitative characterization of their interactions with model membrane systems using tensiometry, atomic force microscopy (AFM) and quartz crystal microbalance (QCM). Tamás Keszthelyi performs investigations of the effect of polymer nanoparticles and peptide conjugated nanocarriers on the structure of model biomembranes by sum-frequency vibrational spectroscopy. These investigations will hopefully lead to the molecular level understanding of nanocarrier – biomembrane interactions. During the sum-frequency vibrational spectroscopy investigations both phospholipid Langmuir monolayers on liquid subphase and solid-supported bilayers will be applied as biomembrane models.
Tamás Keszthelyi - Gergő Gyulai - Szilvia Bősze