Nanostructure Formation in the Lecithin/Isooctane/Water System

Abstract

We present here for the first time a study of the self-assembled nanostructures in the lecithin/isooctane/water system by direct-imaging techniques, namely, cryogenic transmission electron microscopy (cryo-TEM) and cryogenic scanning electron microscopy (cryo-SEM). Along the dilution line [water]/[lecithin] = 5, we identified a nanostructural development with the increase of lecithin concentration. The system changes from a single reverse micellar phase, through a reverse micellar phase coexisting with a lamellar phase, and finally to a reverse liquid crystalline cubic phase and a lamellar phase. We compared the nanostructures formed when phosphatidylcholine rather than naturally occurring lecithin is used and found that both phase behavior and nanostructure are significantly different. The use of the two complementary cryo-EM techniques proved very efficient in the nanostructural characterization of the system. We also performed small-angle X-ray scattering to confirm our findings. Since the system is very sensitive to changes in composition, the cryo-EM specimens were prepared in a Controlled Environment Vitrification System (CEVS) that has been modified for our specimen preparation needs. We were able to overcome the challenges involved in directly imaging this nonaqueous (oil-rich), concentrated complex liquid systems, thus extending the usefulness of those characterization techniques.

Development of pharmaceutical clear gel based on Peceol®, lecithin, ethanol and water: Physicochemical characterization and stability study

“…As demonstrated by several studies, lecithin microemulsion was formed without alcohol by substituting triglyceride by mineral oil (e.g. alkane and cycloalkane) [17][18][19][20]. A transition from spherical to flexible cylindrical reverse micelles was observed upon addition of small amount of water to the lecithin microemulsion [21][22][23][24][25].…”

Nonvolatile molecular memory with the multilevel states based on MoS2 nanochannel field effect transistor through tuning gate voltage to control molecular configurations

“…Although slush nitrogen has a cooling rate lower than organic cryogens, the rate necessary for vitrification of organic liquids is less than that of aqueous solutions 53,56 . As a result, we have found that organic electrolytes up to at least microns thick on the surface of large samples such as coin cell battery electrodes can be vitrified by plunge freezing in slush nitrogen.…”

Exploring the water/oil/water interface of phospholipid stabilized double emulsions by micro-focusing synchrotron SAXS

“…1 In particular, phospholipids 2,3 constitute an important class of molecules to build membrane models, and have been extensively used in the study of signal transduction and transport phenomena. 4 Moreover, so self-organized structures not only serve as synthetic models to mimic biological cells, 5 but also play a key role for developing carriers in drug delivery [6][7][8] or serve as encapsulating agents in the food industry. [1][2][3]9 Such versatile applications have motivated researchers to develop different methodologies for controlling their architecture.…”

“…[18][19][20][21] From a molecular point of view, though it is established that in dispersed systems amphiphiles are mainly localized at the interface between polar and nonpolar domains, the detailed representation of their arrangement is a difficult task, especially when the interfacial region extends over lengths that are hundreds of times larger than the molecular size. 5 Highresolution techniques, such as small angle scattering, are valuable tools for probing the organization of amphiphiles at the o/w interface of emulsions [6][7][8][9] and can be used to unravel the interfacial structure.…”