Controlled Hydrogel Formation in the Internal Compartment of Giant Unilamellar Vesicles

Abstract

The introduction of poly(ethylene dioxythiophene) (PEDOT)/poly(styrene sulfonate) (PSS) polyelectrolyte into giant unilamellar phospholipid vesicles (GUVs) and cross-linking with Ca2+ ions to generate a hydrogel within the internal compartment are reported. The aqueous colloidal suspension of PEDOT with excess PSS was microinjected into the internal compartment of liposomes as well as networks of GUVs and lipid nanotubes. The subsequent introduction of calcium ions as cross-linking agent in order to induce hydrogel formation was achieved by three different methods: vesicle fusion, electroporation, and direct microinjection. Gel formation was probed by coinjection of fluorescent nanoparticles and tracking of Brownian motion. Particle mobility was shown to be distinctly reduced in the gel-filled vesicles. Diffusion constants for the particles were calculated from the projected movement of the particles and compared to particles in reference gels and solutions.

Preparation of PVP hydrogel nanoparticles using lecithin vesicles

“…Fluctuation of crosslinking density, known to influence hydrogel particle morphology, may also account for the lack of defined shape. 13 Non spherical particles have also been reported with other nanogels prepared using vesicles. 17,37 Particle swelling was estimated directly and the swelling ratio (Q) was 10, i.e., particles absorb only 10 times their mass in water.…”

“…Larger nanogels (about 450 nm) are obtained from encapsulation of 20% dextran hydroyethylmethacrylate solution ( -Mn= 19000) inside vesicles obtained by phospholipids film hydration, followed by extru- sion. 37 Poly(ethylenedioxythiophene)/poly(styrenesulfonate) 13 and poly(N-isopropylacrylamide) 12,16 microgels, in conjunction with lipid bilayers, are obtained by injecting a polymer solution inside GUVs, followed by freeze-thaw cycles and electroporation. The vesicle diameters, in these latter cases, vary from 5 to 100 µm.…”

“…9 Alternatively, nanogels can be prepared by inclusion in reverse micelles of pre-formed polymers, followed by crosslinking. 10 Vesicles also can be used to obtain hydrogels nanoparticles, by monomer encapsulation followed by polymerization 11 or gelation of encapsulated polymers, generally induced by sol-gel temperature transitions 12 or ionic crosslinking, 13 typically without removal of the lipid bilayer. 14 These gel-like vesicles work as cell models, since they have elastic modulus comparable to that of cell cytoplasm 14 and are considered artificial cytoskeletons.…”

Chemical Analysis in Nanoscale Surfactant Networks

“…The internal and external solution composition as well as different lipid compositions (which can also include membrane proteins) can be used to tailor a reactor. Furthermore, polymers can be included to create crowded environments (32,33). Network topology can be controlled, too, and it is possible to use either static-or dynamic-shell networks (where the network geometry is changed during the course of a reaction).…”

Nanoparticle Synthesis in Vesicle Microreactors

“…On the contrary, performing inorganic synthesis reactions in GUVs should be expected to shed light on cell-based nanoparticle synthesis and the corresponding mechanism, since GUVs have dimensions in the cell-size scale (micrometer). Until now, the investigations on various biological activities using GUVs as prototypes of cells have been widely performed covering many aspects: preparation (Angelova et al, 1986;Larsen et al, 2003;Takakura et al, 2003;Mohanty et al, 2003;Pautot et al, 2003), membrane related processes like fusion, fission, budding (Walde et al, 2010;Wang et al, 2010;Hanczyc et al, 2004), cellular processes and mechanisms like adhesion, communication, endocytosis, exocytosis (Marrink et al, 2003;Haque et al, 2001;Chen et al, 2005;Rustom et al, 2004;Menger et al, 1992Menger et al, , 1997Menger et al, and 2002Hanczyc et al, 2003;Espinoza et al, 1999;Ichikawa et al, 2004;Davidson et al, 2003), structure and shape transformation (Suezaki, 2002;Sasaki et al, 2004;Boon et al, 2002;Lee et al, 2005;Hamada et al, 2005;Tomšiè et al, 2005;Brückner et al, 2001), drug release Barragan et al, 2001;Park et al, 2000;Sun et al, 2003;Vandenburg et al, 2002), micromanipulation (Karlsson et al, 2001;Marmottant et al, 2003), compartmentation (Jesorka et al, 2005;Bucher et al, 1998;) and microreactors (Vriezema et ...…”