Vibrational Spectroscopy of Biomembranes

Abstract

Vibrational spectroscopy, commonly associated with IR absorption and Raman scattering, has provided a powerful approach for investigating interactions between biomolecules that make up cellular membranes. Because the IR and Raman signals arise from the intrinsic properties of these molecules, vibrational spectroscopy probes the delicate interactions that regulate biomembranes with minimal perturbation. Numerous innovative measurements, including nonlinear optical processes and confined bilayer assemblies, have provided new insights into membrane behavior. In this review, we highlight the use of vibrational spectroscopy to study lipid-lipid interactions. We also examine recent work in which vibrational measurements have been used to investigate the incorporation of peptides and proteins into lipid bilayers, and we discuss the interactions of small molecules and drugs with membrane structures. Emerging techniques and measurements on intact cellular membranes provide a prospective on the future of vibrational spectroscopic studies of biomembranes.

Near-Real-Time Analysis of the Phenotypic Responses of Escherichia coli to 1-Butanol Exposure Using Raman Spectroscopy

“…Membrane fluidity has long been used to assess the effects of solvents on microbial cell membranes (15,21,23,27), and membrane fluidity has been observed to increase in E. coli cells upon 1-butanol exposure (23). Previous research has also closely tied cell membrane fluidity with changes in fluorescence anisotropy (21,23,54). Experimental fluorescence anisotropy results obtained in this research are in agreement with this observation.…”

“…Time course Raman signal intensities (at assigned bands taken from the literature [42,45,46,[52][53][54]) were correlated with the corresponding changes in membrane-derived fatty acid levels and composition, as determined by GC-FID. Correlation coefficients (R values) between these two methods are presented in Table S1 in the supplemental material.…”

“…The molecular mechanisms behind this initial decrease and lag are unknown and remain a topic for further investigation. To assess membrane fluidity using Raman spectroscopy, three signal intensity ratios (I 2870 /I 2954 , I 2850 /I 2880 , and I 2852 / I 2924 ) were analyzed based on previously published results (53,54,57,58). The identification of Raman peaks corresponding to symmetric and asymmetric stretching of cell membranes was used to derive these ratios.…”

A mechanistic view of lipid membrane disrupting effect of PAMAM dendrimers

“…Differential scanning calorimetry (DSC), small-and wide-angle X-ray scattering (SWAXS), infrared spectroscopy (IR) and freeze-fracture electron microscopy (FFTEM) are prevalent methods to characterize liposomes and to monitor the changes in their structure caused by other molecules [30][31][32][33]. Still there are only a few papers in which these methods are used in order to investigate the interactions between dendrimers and liposomes [34][35][36].…”

“…[39,40] Infrared spectroscopy is used to study the structure and organization of lipid bilayers. Changes in the frequencies and widths of vibrational bands and/or splitting of the spectral features provide information on the interactions between functional groups of lipids and macromolecules [32,33]. Highly purified synthetic 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) was purchased from NOF Corporation.…”