Binding interaction of differently charged fluorescent probes with egg yolk phosphatidylcholine and the effect of β-cyclodextrin on the lipid–probe complexes: A fluorometric investigation

• Interaction of egg yolk phosphatidylcholine with three fluorescent probes has been investigated.
• All the probes form 1:1 inclusion complexes with β-cyclodextrin.
• Addition of β-cyclodextrin leads to release of probes from the lipid environment.

Interaction of cationic phenosafranin (PSF), anionic 8-anilino-1-naphthalene sulfonate (ANS) and non-ionic nile red (NR) have been studied with the zwitterionic phospholipid, egg yolk L-α-phosphatidylcholine (EYPC). The study reveals discernible binding interactions of the three fluorescent probes with the EYPC lipid vesicle. Once the binding of the probes with the lipid is established, the effect of cyclic oligosaccharide, β-cyclodextrin (β-CD), on these lipid bound probes has been investigated. Different fluorometric techniques suggest that addition of β-CD to the probe–lipid complexes leads to the release of the probes from the lipid medium through the formation of probe–β-CD inclusion complexes. A competitive binding of the probes between β-cyclodextrin and the lipid is ascribed to be responsible for the effect. This provides an easy avenue for the removal of the probe molecules from the lipid environment. Extension of this work with drug molecules in cell membranes is expected to give rise to a strategy for the removal of adsorbed drugs from the cell membranes by the use of non-toxic β-cyclodextrin.

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