Molecular organization of antifungal antibiotic amphotericin B in lipid monolayers studied by means of Fluorescence Lifetime Imaging Microscopy

Abstract

Amphotericin B (AmB) is a life-saving polyene antibiotic used to treat deep-seated mycotic infections. Both the mode of therapeutic action as well as toxic side effects are directly dependent on molecular organization of the drug. Binding of AmB to lipid monolayers formed with dipalmitoylphosphatidylcholine, pure and containing 40 mol% cholesterol or ergosterol, the sterols of human and fungi respectively, has been examined by means of

Interactions of bioactive molecules & nanomaterials with Langmuir monolayers as cell membrane models

“…Further studies employing BAM, ATR-FTIR and fluorescence-lifetime imaging microscopy (FLIM) confirmed the enhanced incorporation of AmB into ergosterol-containing model membranes [132,142,143]. In particular, other factors, such as membrane fluidity [132,142] (dependent on DPPC-sterol proportion in a model membrane and type of sterol) and the aggregation state of drug molecules [144,145], were also found to be important.…”

Interaction of Amphotericin B with Ergosterol/Cholesterol‐Containing POPG Liposomes Studied by Absorption, Fluorescence and Second Harmonic Spectroscopy

“…Figure (a & b) shows the absorption spectra of AmB at two extreme A/L values for all three liposome systems prepared at pH 7.4. When A/L value is 0.14, (Figure , a) there is a clear difference in the spectra between the three liposomes in the region of 410–416 nm which corresponds to the S 0 → S 2 transition . As the A/L value is increased to 8.55, the spectra of AmB in the presence of POPG‐Ergo liposomes is distinctly red‐shifted compared to that of POPG‐Chol and POPG liposomes.…”

Biomembrane models

“…Lipid monomolecular layers deposited onto solid supports using LB fi lms can easily be subjected to numerous microscopic and spectroscopic studies. For example, modifi ed lipid LB fi lms, deposited onto mica, have been studied by AFM (see Figure 2.8) 112,[115][116][117] and FLIM, 118 when deposited onto quartz have been studied by ultraviolet-visible (UV-vis) absorption and fl uorescence spectroscopic techniques 106,110,118 and when deposited onto ZnSe or Ge monocrystals have been studied with FTIR. 106,110,111 For the FTIR analysis, a polarized IR measuring beam is used to calculate the order parameters of different segments of the membrane-forming lipid molecules and therefore provides information on the structural and dynamic properties of the system.…”