Identification of Lipid Aggregate Structures on TiO₂ Surface Using Headgroup IR Bands

Abstract

Attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy was used to study the nature of the dipalmitoylphosphatidylcholine (DPPC) aggregated structures adsorbed on TiO(2). DPPC molecules were assembled on TiO(2) using Langmuir-Blodgett (LB) deposition methods or by directly flowing the DPPC liposome solution across the TiO(2)-coated ATR crystal. We found that there is a direct correlation between the intensity and frequency position of the zwitterionic headgroup IR bands and the nature of LB films. Specifically, we have shown that the bands due to PO(2)(-) modes are sensitive to changes in the degree of hydration of the LB films and that the symmetric deformation vibrational mode (delta(s) (+)N-CH(3)) is sensitive to interaction with oppositely charged surface sites. Using this information, we found that the liposomes adsorbed on TiO(2) remain intact as vesicles and that the vesicles are stable and not removed in flowing water. We have also shown that the antisymmetric deformation vibrational (delta(as) (+)N-CH(3)) modes are sensitive to changes in lateral-lateral DPPC interactions. This information was used to show that there is a lateral interaction between each positively charged (+)N(CH(3))(3) headgroup and negatively charged PO(2)(-) headgroup of the adjacent DPPC molecule in the adsorbed vesicles and LB films. This study provides a framework for the use of this IR technique in studies of adsorption and transport of molecules across membrane interfaces.

Influence of cholesterol on liposome stability and on in vitro drug release

“…The strongest bands at 2920 and 2850 cm −1 represent the CH 2 symmetric and antisymmetric stretch modes [43], and the peak at around 1740 cm −1 characterizes the C=O stretch of the ester bond, where the fatty acid chain meets the head group [44]. FTIR spectra have been compared considering the increase of cholesterol amount which changes the detected signal.…”

Coating liposomes with yttrium basic carbonate: Making hybrid nanocapsules

“…3) demonstrates that the liposome templates are enclosed within the Y(OH)CO 3 ·xH 2 O shells. Indeed, it depicts all the spectral characteristics of phospholipid vesicles [25], except for those that are masked by the two strong absorption bands at In the absence of the liposome templates, but otherwise identical synthesis conditions, the initial solution evolves through a homogeneous nucleation and growth mechanism to yield ca. 900 nm size spherical Y(OH)CO 3 ·xH 2 O particles (see Supplementary material), in line with previous reports [22].…”

Biocompatible phosphatidylcholine bilayer coated on magnetic nanoparticles and their application in the extraction of several polycyclic aromatic hydrocarbons from environmental water and milk samples

“…The spectra of Fe 3 O 4 /PC consisted of bands at 2940 and 2850 cm −1 , which were attributed to symmetric and asymmetric methylene ( CH 2 ) and methyl ( CH 3 ) vibrations. The peaks at 1070 and 1244 cm −1 were resulted from vibrational modes of PO 2 − headgroups [28,36]. Carbonyl (C O) vibrations around 1740 cm −1 and quaternary ammonium (CN + (CH 3 ) 3 ) asymmetric vibrations at 970 cm −1 were observed for Fe 3 O 4 /PC [31].…”

“…including nanomaterials [27][28][29][30][31][32][33], to form supported lipid bilayers. Magnetoliposomes are magnetic nanoparticles coated with lipid bilayer, and have been prepared for medical applications such as targeted drug delivery, hyperthermia, and attachment of antibody molecules [34][35][36][37].…”