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Lipid-headgroup dehydration by DMSO, which should increase friction, is offset by both higher areal head-group density and by rigidity-enhancement of the lipid bilayers, both of which act to reduce frictional dissipation.

Ordered mesoporous silica materials gain high interest because of their potential applications in catalysis, selective adsorption, separation, and controlled drug release. Due to their morphological characteristics, mainly the tunable, ordered nanometric pores, they can be utilized as supporting hosts for confined chemical reactions. Applications of these materials, however, are limited by structural design. Here, we present a new approach for the 3D printing of complex geometry silica objects with an ordered mesoporous structure by stereolithography. The process uses photocurable liquid compositions that contain a structure-directing agent, silica precursors, and elastomer-forming monomers that, after printing and calcination, form porous silica monoliths. The objects have extremely high surface area, 1900 m2/g, and very low density and are thermally and chemically stable. This work enables the formation of ordered porous objects having complex geometries that can be utilized in applications in both the industry and academia, overcoming the structural limitations associated with traditional processing methods.

Background In Doxil®, PEGylated nanoliposomes are created by hydration of the lipids in ammonium sulfate, and are remotely loaded with doxorubicin by a transmembrane ammonium gradient. The ammonium sulfate is then removed from the external aqueous phase, surrounding the liposomes, and replaced by an isoosmotic sucrose solution in 10 mM histidine buffer at pH 6.5. Methods We prepared PEGylated liposomal doxorubicin (PLD) with a series of ammonium monovalent salts that after remote loading became the intraliposome doxorubicin counteranions. We analyzed the liposomes by solution X-ray scattering, differential scanning calorimetry, and electron micropscopy. Results PLDs prepared with sulfonic acid derivatives as counteranion exhibited chemical and physical stabilities. We determined the effect of these ammonium salt counteranions on the structure, morphology, and thermotropic behavior of the PEGylated nanoliposomes, formed before and after doxorubicin loading, and the bulk properties of the doxorubicin-counteranion complexes. By comparing the structure of the doxorubicin complexes in the bulk and inside the nanoliposomes, we revealed the effect of confinement on the structure and doxorubicin release rate for each of the derivatives of the ammonium sulfonic acid counteranions. Conclusions We found that the extent and direction of the doxorubicin confinement effect and its release rate were strongly dependent on the type of counteranion. The counteranions, however, neither affected the structure and thermotropic behavior of the liposome membrane, nor the thickness and density of the liposome PEG layers. In an additional study, it was demonstrated that PLD made with ammonium-methane sulfonate exhibit a much lower Hand and Foot syndrome. General significance The structure, physical state, and pharmacokinetics of doxorubicin in PEGylated nanoliposomes, prepared by transmembrane remote loading using gradients of ammonium salts, strongly depend on the counteranions.

The advancement of tissue engineering and regenerative medicine has generated a growing demand for collagen fibers that both resemble native collagen fibers as closely as possible in terms of structure and function, and can be produced in large quantities and processed by current textile technologies. However, the collagen spinning methodologies reported thus far have not matured sufficiently to provide a spinning rate suitable for large-scale production and also generate fibers with insufficient mechanical properties. In the current study, we introduce three new elements into existing collagen fiber spinning technologies: the use of recombinant human collagen, high concentration dope, and spin drawing. At the optimal draw ratio, mechanically strong, aligned, thin fibers, with diameters similar to those of cotton or polyester fibers, are obtained at rates exceeding 1,000 m/h. The resulting fibers display an ultimate tensile strength (UTS) of 150 MPa and a strain of 0.21 after being hydrated in PBS, values which are comparable to and even surpass those reported for human patellar and Achilles tendons. The production technology is simple, based entirely on existing fiber production machinery, and suitable for scale-up and rapid production of large fiber quantities.

An amphiphile based on polyethylene glycol (PEG) polymer and two molecular moieties (perylene diimide and C7 fluoroalkyl, PDI and C7 F) attached to its termini assembles into crystalline films with long-range order. The films reversibly switch from crystalline to amorphous above the PEG melting temperature. The adaptive behavior stems from the responsiveness of the PEG domain and the robustness of the PDI and C7 F assemblies. The hydrophobicity of the film can be controlled by heating, resulting in switching from highly hydrophobic to superhydrophilic. The long-range order, reversible crystallinity switching, and the temperature-controlled wettability demonstrate the potential of block copolymer analogues based on simple polymeric/molecular hybrids.

A new approach for doping of Cu2S nanocrystal arrays using thermal treatment at moderate temperatures (T < 400 K) is presented. This thermal doping process yields conductance enhancement by 6 orders of magnitude. Local probe measurements prove this doping is an intraparticle effect and, moreover, tunneling spectroscopy data signify p-type doping. The doping mechanism is attributed to Cu vacancy formation, resulting in free holes. Thermal-doping temperature dependence exhibits an Arrhenius-like behavior, providing the vacancy formation energy of 1.6 eV. The moderate temperature conditions for thermal doping unique to these nanocrystals allow patterned doping of nanocrystal films through local heating by a focused laser beam, toward fabrication of nanocrystal-based electronic devices.

Background Among nanodrugs, PEGylated nanoliposomes loaded with an active agent are of major importance. In this paper we studied the structures and morphology of PEGylated nanoliposomes before and after remote loading with doxorubicin. Methods High-resolution structures were obtained by solution X-ray scattering combined with our advanced analysis tools. We studied the PEGylated liposomal doxorubicin (PLD) product Doxil ® , and its generics, where remote doxorubicin loading is performed by a gradient of ammonium sulfate, and LC100, a novel PLD under development, where remote loading was done by a gradient of ammonium methanesulfonate. The PLD structures were compared with drug-free nanoliposomes having identical composition. Results We determined the membrane electron density profiles of the empty and loaded PLDs, the thickness and density of the PEG layers, and the structure of the drug inside the liposomes. Conclusions The liposomal membranes had the same structure for both ammonium salts. We found that the drug formed crystals inside PLDs loaded by ammonium sulfate, whereas it had an amorphous morphology in the PLD loaded by ammonium methanesulfonate. The variations of the drug's structural parameters between the generics of Doxil ® are similar to the variations between batches of the same product, suggesting that all these products were structurally similar. General significance This paper demonstrates that solution X-ray scattering, when combined with our powerful analysis tools, can determine the high-resolution structure of complex non-crystallized nanoparticle dispersions used in nanomedicine, thereby providing useful physical insights into their functions.

Ionic liquids have a variety of unique controllable structures and properties. These properties may be used to tailor the self-assembly of charged and dipolar biomolecules. Using solution X-ray scattering, we measured the structure of Dilauryl(C12:0)-sn-glycero-3-phospho-l-choline (DLPC), a dipolar (or zwitterionic) lipid, in the water-soluble room temperature ionic liquid Ethyl Methyl Imidazolium Ethyl Sulfate (EMIES) and mixtures of EMIES and water. We find that the interaction between the lipid bilayers is dominated by the balance between the charging of the polar headgroups by the ionic liquid, softening of the bilayer, and the osmotic pressure induced by the solvent. This balance leads to the following changes with increasing ionic liquid concentration: an incomplete unbinding transition from an attractive regime to a swollen regime of the lamellar phase formed by the bilayers. The swollen phase is followed by a collapse of the bilayers into a highly desolvated lamellar phase at some critical EMIES concentration, and eventually formation of lipid-crystalline phase, at very high EMIES concentrations. The latter phase is revealed by wide-angle X-ray scattering (WAXS) from the lipid solutions, showing multiple Bragg peaks, consistent with highly ordered structures. These structures were not observed in any other type of aqueous solutions containing monovalent or multivalent ions. The kinetics and temperature dependence of these transitions were also determined.