Revealing the mechanisms of vesicle formation with multiple spectral methods

Abstract

Kinetics in the self-assembly of amphiphilic molecules and the formation of micelles/vesicles may be clearly revealed by spectroscopic methods including second harmonic generation, two-photon fluorescence and Rayleigh scattering.

Combined Second Harmonic Generation and Fluorescence Analyses of the Structures and Dynamics of Molecules on Lipids Using Dual-Probes: A Review

“…By inserting a 490 nm long pass dichroic mirror in the light pass, the SHG and TPF signals at different wavelength positions were separated and detected by two photomultiplier tubes. In the reports reviewed in this manuscript [47,57,58,61,62] the SHG signal was recorded at a relatively large spatial angle range (approximately ± 40 • ) centered at the forward direction of the laser because of the following reason. The vesicles involved in these reports were prepared using hydration method with sonication (referred as mixed unilamellar vesicles, MUVs).…”

“…The combined SHG and TPF analyses were also performed with the aid of Rayleigh scattering in studying the self-assembly of DOX and surfactant, sodium bis (2-ethylhexyl) sulfosuccinate (AOT) and the formation of binary complex vesicles in solution [47]. In this report, the time evolution of the SHG, TPF, and Rayleigh scattering signals plotted in Figure 12 were used to propose a formation mechanism of the DOX/AOT vesicles illustrated in Figure 13.…”

“…As aforementioned, SHG signal reflects the asymmetry of the interfaces, including the interfaces of the possible structures in the mixed solutions including the micelles, aggregated micelles and vesicles. At the same time, the size of these structures is crucial for their SHG efficiency [47,63,64]. For this reason, the increase in the SHG signal was used as an indicator of the formation of aggregated micelles and the transformation from As aforementioned, SHG signal reflects the asymmetry of the interfaces, including the interfaces of the possible structures in the mixed solutions including the micelles, aggregated micelles and vesicles.…”

“…For this reason, the increase in the SHG signal was used as an indicator of the formation of aggregated micelles and the transformation from As aforementioned, SHG signal reflects the asymmetry of the interfaces, including the interfaces of the possible structures in the mixed solutions including the micelles, aggregated micelles and vesicles. At the same time, the size of these structures is crucial for their SHG efficiency [47,63,64]. For this reason, the increase in the SHG signal was used as an indicator of the formation of aggregated micelles and the transformation from aggregated micelles to vesicles.…”

“…Then, we showed that the combined SHG and TPF methods were used to investigate the interactions between DOPG lipid membrane and anthracyclines with Be noted that the vesicle as a whole is symmetric with an inversion center. However, because of the different speeds for the excitation laser and generated SHG signal in the vesicles, the scattered SHG signal from different part of the vesicles interference with each other and emit detectable SHG for relatively large sized vesicles [22,47].…”