Light-induced transformation of vesicles to micelles and vesicle-gels to sols

Abstract

Vesicles are self-assembled nanocontainers that are used for the controlled release of cosmetics, drugs, and proteins. Researchers have been seeking to create photoresponsive vesicles that could enable the triggered release of encapsulated molecules with accurate spatial resolution. While several photoresponsive vesicle formulations have been reported, these systems are rather complex as they rely on special light-sensitive amphiphiles that require synthesis. In this study, we report a new class of photoresponsive vesicles based on two inexpensive and commercially available amphiphiles. Specifically, we employ p-octyloxydiphenyliodonium hexafluoroantimonate (ODPI), a cationic amphiphile that finds use as a photoinitiator, and a common anionic surfactant, sodium dodecylbenzenesulfonate (SDBS). Mixtures of ODPI and SDBS form "catanionic" vesicles at certain molar ratios due to ionic interactions between the cationic and anionic headgroups. When irradiated with ultraviolet (UV) light, ODPI loses its charge and, in turn, the vesicles are converted into micelles due to the loss of ionic interactions. In addition, a mixture of these photoresponsive vesicles and a hydrophobically modified biopolymer gives a photoresponsive vesicle-gel. The vesicle-gel is formed because hydrophobes on the polymer insert into vesicle bilayers and thus induce a three-dimensional network of vesicles connected by polymer chains.Upon UV irradiation, the network is disrupted because of the conversion of vesicles to micelles, with the polymer hydrophobes getting sequestered within the micelles. As a result, the gel is converted to a sol, which manifests as a 40 000-fold light-induced drop in sample viscosity.

Insights into the Gelating Abilities of Ricinelaidic Acid and its Ammonium Salts: How do Stereochemistry, Charge, and Chain Lengths Control Gelation of a Long‐Chain Alkenoic Acid?

“…As the number of potential and realized applications for molecular gels (such as in the areas of sensors, cosmetic carriers, templates for materials synthesis, food additives, and lubricants) has increased, attaining the goal to design molecular gelators a priori and to predict their gelating abilities in specific liquids has become increasingly important. A logical method to advance our path to that goal is to perform systematic and targeted studies on structural analogues of gelators and to use those data to create correlations between molecular structures and the properties of their aggregates .…”

“…[5] The 1D objectsm ay bundle into objectsw ith larger cross-sections [1d] and interactf urther to form the 3D self-assembled fibrillarn etworks (SAFiNs) that immobilize the liquid by surface tension, capillary forces and related interfacial interactions. [1f, g, 6] As the number of potential and realized applications for molecular gels (such as in the areas of sensors, [7] cosmetic carri-ers, [8] templates for materials synthesis, [9] food additives, [10] and lubricants [3,11] )h as increased, attaining the goal to design molecular gelators ap riori and to predict their gelating abilities in specific liquids has become increasingly important.Alogical method to advance our path to that goal is to perform systematic and targeted studies on structurala nalogues of gelators and to use those data to create correlations between molecular structuresa nd the properties of their aggregates. [12] These studies are also expected to aid in severalaspects of crystal engineering, for which the objective is to create 2D and 3D crystalline objects.…”

Investigation on the aggregation behavior of photo-responsive system composed of 1-hexadecyl-3-methylimidazolium bromide and 2-methoxycinnamic acid

“…27,[43][44][45] Light-responsive wormlike micelles always take advantage of some light-induced trans-to-cis isomerization of additives containing certain functional groups or surfactants. 27,[43][44][45] Light-responsive wormlike micelles always take advantage of some light-induced trans-to-cis isomerization of additives containing certain functional groups or surfactants.…”

Loading of Vesicles into Soft Amphiphilic Nanotubes using Osmosis

“…[4] As well as the use of alarge variety of naturally-occurring amphiphiles, [5] major effort has been devoted to the synthesis of novel amphiphilic molecules which can self-assemble into nanotubes,v esicles,r ibbons,s heets,o rh elical structures. [10] Furthermore,p articular focus has been directed toward the development of multicomponent [11] and stimuli-responsive [12] self-assembled systems which adapt in response to light, [13] temperature, [14] magnetic, [15] and electric fields, [16] ionic strength, [17] pH changes, [18] and ultrasound. [10] Furthermore,p articular focus has been directed toward the development of multicomponent [11] and stimuli-responsive [12] self-assembled systems which adapt in response to light, [13] temperature, [14] magnetic, [15] and electric fields, [16] ionic strength, [17] pH changes, [18] and ultrasound.…”

“…[6] Prominent examples include amphiphilic polymers [7] and block copolymers, [8] amphiphilic peptides, [9] and photoresponsive amphiphiles. [10] Furthermore,p articular focus has been directed toward the development of multicomponent [11] and stimuli-responsive [12] self-assembled systems which adapt in response to light, [13] temperature, [14] magnetic, [15] and electric fields, [16] ionic strength, [17] pH changes, [18] and ultrasound. [19] These stimuli have been explored extensively to induce structural changes in nanostructures,s uch as nanoparticles, [20] polymers, [21] gels, [22] and porous materials.…”