Spectroscopic Properties of Hydrophobic Dyes Incorporated into Phospholipid Bilayers. An Application to the Study of Membrane-Surfactant Interactions

✍ Scribed by Peter Kaschny; Félix M. Goñ

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 337 KB
• Volume: 161
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1993.1435

✦ Synopsis

The spectral characteristics of three dyes (merocyanine 540, pinacyanol chloride, and nile red) incorporated into model membranes have been examined and the effects of increasing concentrations of the non-ionic surfactant Triton X-100 have been recorded. When required, absorption spectra have been decomposed to reveal partially overlapping bands, using curvefitting teehnifues. The main conclusion is that all three dyes show eharacteristic speetral changes, each at specific lipid/detergent ratios, suggesting that they are reporting on different aspects of membrane-surfactant interaction. The maximum absorption wavelength ( (\lambda_{\max }) ) of each dye is blue-shifted in the presence of detergent. In the case of pinacyanol chloride and nile red, this occurs at sublytic phospholipid/detergent ratios. The (\lambda_{\text {max }}) blue shift of the merocyanine 540 monomer peak, however, runs in parallel with the membrane solubilization process. Moreover, merocyanine 540 dimerization is enhanced before membrane disruption occurs. These findings are compared with other techniques employed on membrane-surfactant interactions, indicating that lipophilic dyes may be useful tools sensitively monitoring sublytic and lytic detergent effects. 1993 Academic Press, Inc.