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The innate cartilage extracellular matrix is avascular and plays a vital role in innate chondrocytes. Recapping the crucial components of the extracellular matrix in engineered organs via polymeric gels and bioinspired approaches is promising for improving the regenerative aptitude of encapsulated cartilage/chondrocytes. Conventional gel formation techniques for polymeric materials rely on employing oxidative crosslinking, which is constrained in this avascular environment. Further, poor mechanical properties limit the practical applications of polymeric gels and reduce their therapeutic efficacy. Herein, the purpose of this study was to develop a bioadhesive gel possessing dual crosslinking for engineering cartilage. Tyramine (TYR) was first chemically conjugated to the alginate (ALG) backbone to form an ALG-TYR precursor, followed by the addition of calcium peroxide (CaO

Carbohydrates are key building blocks for advanced functional materials owing to their biological functions and unique material properties. Here, we propose a star-shaped discrete block co-oligomer (BCO) platform to access carbohydrate nanostructures in bulk and thin-film states via the microphase separation of immiscible carbohydrate and hydrophobic blocks (maltooligosaccharides with 1-4 glucose units and solanesol, respectively). BCOs with various star-shaped architectures and saccharide volume fractions were synthesized using a modular approach. In the bulk, the BCOs self-assembled into common lamellar, cylindrical, and spherical carbohydrate microdomains as well as double gyroid, hexagonally perforated lamellar, and

Using the electrostatic complex of G4 poly(amidoamine) (PAMAM) dendrimer with an amphiphilic surfactant as a model system, contrast variation small angle neutron scattering (SANS) is implemented to resolve the key structural characteristics of dendrimer-based guest–host system. Quantifications of the radial distributions of the scattering length density and the hydration level within the complex molecule reveal that the surfactant is embedded in the peripheral region of dendrimer and the steric crowding in this region increases the backfolding of the dendritic segments, thereby reducing the hydration level throughout the complex molecule. The insights into the spatial location of the guest molecules as well as the perturbations of dendrimer conformation and hydration level deduced here are crucial for the delicate design of dendrimer-based guest–host system for biomedical applications.

We outline a machine learning strategy for quantitively determining the conformation of AB-type diblock copolymers with excluded volume effects using small angle scattering. Complemented by computer simulations, a correlation matrix connecting conformations of different copolymers according to their scattering features is established on the mathematical framework of a Gaussian process, a multivariate extension of the familiar univariate Gaussian distribution. We show that the relevant conformational characteristics of copolymers can be probabilistically inferred from their coherent scattering cross sections without any restriction imposed by model assumptions. This work not only facilitates the quantitative structural analysis of copolymer solutions but also provides the reliable benchmarking for the related theoretical development of scattering functions.

The self-consistent field theory (SCFT) predicted the existence of a close-packed sphere phase over a narrow window in the phase diagram of a block copolymer (bcp). It however remains unclear wheth...

Patients with irregular, huge burn wounds require time-consuming healing. The skin has an epithelial barrier mechanism. Hence, the penetration and retention of therapeutics across the skin to deep lesion is generally quite difficult and these usually constrain the delivery/therapeutic efficacies for wound healing. Effective burn wound healing also necessitates proper circulation. Conventional polymeric dressing usually exhibits weak mechanical behaviors, obstructing their load-bearing applications. Cold atmospheric plasma (CAP) was used as an efficient, environmentally friendly, and biocompatible process to crosslink methylcellulose (MC) designed for topical administration such as therapeutic substances of platelets (SP) and polyethyleneimine-polypyrrole nanoparticle (PEI-PPy NP)-laden MC hydrogel carriers, and wound dressings. The roles of framework parameters for CAP-treated SP-PEI-PPy NP-MC polymeric complex system; chemical, physical, and photothermal effects; morphological, spectroscopical, mechanical, rheological, and surface properties; in vitro drug release; and hydrophobicity are discussed. Furthermore, CAP-treated SP-PEI-PPy NP-MC polymeric complex possessed augmented mechanical properties, biocompatibility, sustainable drug release, drug-retention effects, and near-infrared (NIR)-induced hyperthermia effects that drove heat-shock protein (HSP) expression with drug permeation to deep lesions. This work sheds light on the CAP crosslinking polymeric technology and the efficacy of combining sustained drug release with photothermal therapy in burn wound bioengineering carrier designs.

Electrostatic compaction of double stranded DNA induced by a positively charged poly(amidoamine) (PAMAM) dendrimer of generation four (G4) was found to produce two unique types of DNA mesophases, in which the DNA bent into superhelices packed in a tetragonal or hexagonal lattice. The structure formed at a lower dendrimer charge density was three-dimensionally (3D) ordered, as characterized by the P41212 space group with a 41 screw axis in a tetragonal arrangement, showing that the weakly bent DNA superhelices with a pitch length of ca. 5.0 nm possessed both identical handedness and phase conservation. The 3D ordered structure transformed into a 2D mesophase at a higher dendrimer charge density, wherein the strongly bent superhelices with a pitch length of ca. 4.0 nm organized in a hexagonal lattice without lateral coherence of helical trajectory. The counterion valency of the protonic acid that is used to charge the dendrimer was found to influence the phase diagram. Under a given dendrimer charge density, the complex with a multivalent acid-protonated dendrimer tended to form structures with less curved DNA, attesting that the driving force of charge matching was reduced by increasing the counterion valency of the dendrimer.

The cylindrical micelles formed by amphiphilic surfactants in aqueous media generally organize in two-dimensional (2D) hexagonal lattice because of their largely circular cross section. Here we demonstrate that the packing habit of the cylindrical micelles of anionic sodium dodecyl sulfate (SDS) was perturbed by the electrostatic binding with a positively charged poly(amidoamine) (PAMAM) G4 dendrimer via cooperative deformation for charge matching, leading to the ribbon phase with nonhexagonal 2D lattices. The cylindrical micelles with elliptic cross section packed in the centered rectangular lattice with orthorhombic cmm symmetry over a broad range of surfactant-to-dendrimer amine group molar ratio. The packing structure transformed to the oblique lattice with monoclinic p2 symmetry at the stoichiometric composition. Detailed analysis of the geometry of the dendrimers accommodated in the interstitial tunnels surrounded by the SDS cylinders revealed that the dendrimer molecules were elongated into prolate...

X-ray photon correlation spectroscopy and small-angle X-ray scattering were used to study the thermally driven motion and hierarchical structure of palladium (Pd) nanoparticles (NPs) in the concentrated solutions composed of polymers with different molecular weights. The Pd NPs were formed by in situ reduction of palladium(II) acetylacetonate (Pd(acac)2) in the solution of poly(2-vinylpyridine) (P2VP) and benzyl alcohol which acted as the reduction agent and solvent. Below the entanglement molecular weight (Me) of P2VP, a diffusion mode was found together with a fractal structure built up by the primary particles spanning over a broad range of length scales. Above Me, a subdiffusive motion was identified along with diffusive motion, and the hybrids formed a fractal structure built by the local clusters assembled by primary particles. The structural differences were attributed to different kinetic pathways of NP organization mediated by attractive interaction between P2VP and Pd NPs as well as the viscosit...

Spherical micelles formed by block copolymers (bcps) are soft colloids capable of packing into three-dimensionally ordered lattice. Although close-packed sphere structure has been predicted to exist over a narrow region in the phase diagram, it remains unclear whether face-centered cubic (FCC) or hexagonal close packed (HCP) lattice is the stable close packing symmetry for the crystallographically equivalent bcp micelles, as they are essentially degenerated. The present study explores the lattice structure organized by the spherical micelles in bcp/homopolymer blends after erasing the solvent history involved in the blend preparation. The facts that the FCC structure developed in the solvent-cast blend transformed into HCP on heating and HCP phase was formed upon cooling from the disordered micelle phase attest that HCP was the favored close-packed lattice over FCC. The better thermodynamic stability of HCP phase was attributed to the more extensive connectivity of the octahedron voids in the lattice, which prescribed a higher overall translational entropy of the homopolymer chains localized in the voids for space filling.

A heterocyclic polyamide 6 (i.e. caprolactam (CPL; 90 mol%)/sebacic acid (SBA; 5 mol%)/1,3-cyclohexanebis (methylamine)(CHM; 5 mol%) copolyamide) with superior transparency, haze, hygroscopicity and crystallinity to an ordinary polyamide 6 (PA 6) based on CPL (100 mol%) have prepared by the design of appropriate prescriptions. The transparency, haze, hygroscopicity, and crystallinity of lab-made heterocyclic PA 6 are 86.5%, 13.2%, 1.36% (24hr)/1.89% (48hr), and 11.5%, respectively, while those of PA 6 are 26.0%, 94.2%, 1.80% (24hr)/2.45% (48hr), and 24.0%, respectively. Experimental results demonstrate that physical properties of lab-made heterocyclic PA 6 deeply depend on its heterocyclic structure and introduction of SBA and CHM into PA 6 can effectively improves optical, hygroscopic, thermal decomposition, and crystalline characteristics of PA 6, revealing that it is a highly potential polymeric material for optical films, electrical encapsulation, and food packages.

A photosensitive polyimide (PSPI) with high glass transition temperature (Tg; 259 ℃), good inherent viscosity (I.V.; 0.31 dL/g), and superb decomposition temperature (Td; 368 ℃) has been manufactured by the appropriate prescription of diamine monomer (i.e. 2,2-bis (3-amino-4- hydroxyphenyl)-hexafluoropropane; APAF), dianhydride monomer (i.e. 4,4′-(4,4′- isopropylidenediphenoxy)bis(phthalic anhydride); BPADA), cyclodehydating agent (i.e. p-xylene), base (i.e. N,N,N-triethylamine; TEA), and photosensitive monomer (i.e. acryloyl chloride; AOC). In order to explore the applying feasibility, we have prepared lithographic insulation pattern resin (LIPR) of integrated circuit (IC) with PSPI (i.e. APAF/BPADA/AOC polyimide), solvent (i.e. N-methyl-2-pyrrolidone; NMP), photoinitiator (i.e. I-305), crosslinking agent (i.e. CLA-1), co-photoinitiator (i.e. I-309) as well as coupling agent (i.e. vinyltrimethoxysilane; VTES) and utilized it without negative photoreist by silicon wafer, i-line (wavelength: 365 nm; optical density: 1200 mW/cm2), and photomask. Experimental results reveal that lab-made LIPR of IC based on PSPI is a promising IC package material with high tensile strength of 106 MPa, excellent adhesion on silicon wafer (i.e. eligible of cross-cut examination), great coefficient of thermal expansion (CTE) of 17.9 ppm/℃, low dielectric constant (Dk) of 3.5, high surface electric resistance of 8.3 × 1011 Ω/sq., low dielectric loss (Df) of 0.01, moderate hygroscopicity of 2.9% (23 ℃, 24 h), and low residual stress of 32.0 MPa.

The discovery of Frank-Kasper (FK) phase in block copolymer (bcp) has prompted the progress of the field of soft quasicrystals. In principle, the formation of FK phase from the supercooled liquid phase of the bcp micelles should involve the mass transport of constituent molecules to transform the unimodal distribution of micelle size into the multimodal distribution prescribed by the volume asymmetry of the Voronoi cells in the FK phase. Here we present a new regime in which the Laves C14 phase of bcp developed below the glass transition temperature of the micelle core, where the mass transport was inhibited by the immobile block chains forming the core. The bcp micelle comprising a glassy core and a soft corona resembles the fuzzy colloid and the strong van der Waals attraction between the cores directs their organization into C14 phase to minimize the interparticle interaction energy under the metastable condition.

The columnar mesophase, in which the molecular or supramolecular building blocks with rod-like geometry pack into two-dimensional (2D) lattices, is an important class of mesomorphic structure having been found in various liquid crystalline materials for practical applications. The cylindrical micelles assembled by amphiphilic surfactants may also form columnar mesophases with the micelle packing symmetry being tunable by the molecular characteristics of the surfactants. In this study, we demonstrate that a positively charged tree-like polymer, poly(amidoamine) (PAMAM) G4 dendrimer, acted as an effective structure-directing agent for the columnar mesophase of a common anionic surfactant, sodium dodecyl sulfate (SDS), via their electrostatic interaction. By adjusting the dendrimer charge density and the nominal binding ratio (Xn) of SDS to dendrimer, the electrostatic complexes self-assembled to form a body-centered cubic (BCC) sphere phase, wherein the dendrimers were staggered between the interspaces of the SDS spherical micelles packed in the BCC lattice. Four types of 2D columnar mesophase composed of SDS cylindrical micelles and dendrimers were accommodated within the interstitial tunnels, including the hexagonal columnar phase (Colhex), simple rectangular columnar phase (Colsr), oblique columnar phase (Colob) and centered rectangular columnar phase (Colcr). A detailed analysis of the geometry of the dendrimer in the columnar mesophases revealed that the structural transition was governed by the interplay among the lateral and axial deformations of the dendrimer, and the deformation of the SDS micelle cross section for achieving effective charge matching and accommodation of the dendrimer. The present study demonstrated the power of the dendrimer in directing the long-range ordered packing of oppositely charged cylinders to yield a rich structural polymorphism of the columnar mesophase that may be exploited for the development of functional materials.

A series of novel photo-switchable [2]rotaxanes (i.e., Rot-A-SP and Rot-B-SP before and after shuttling controlled by acid-base, respectively) containing one spiropyran (SP) unit (as a photochromic stopper) on the axle and two tetraphenylethylene (TPE) units on the macrocycle were synthesized via click reaction. Upon UV/visible light exposure, both mono-fluorophoric rotaxanes Rot-A-SP and Rot-B-SP with the closed form (i.e., non-emissive SP unit) could be transformed into the open form (i.e., red-emissive merocyanine (MC) unit) to acquire their respective bi-fluorophoric Rot-A-MC and Rot-B-MC reversibly. The aggregation-induced emission (AIE) properties of bi-fluorophoric TPE combined with MC AIEgens of these designed rotaxanes and mixtures in semi-aqueous solutions induced interesting ratiometric photoluminescence (PL) and Forster resonance energy transfer (FRET) behaviors, which were further investigated and verified by dynamic light scattering (DLS), X-ray diffraction (XRD), and time-resolved photoluminescence (TRPL) measurements along with theoretical studies. Accordingly, in contrast to the model axle (Axle-MC) and the analogous mixture (Mixture-MC, containing the axle and macrocycle components in a 1:1 molar ratio), more efficient FRET behaviors and stronger red PL emissions were obtained from dual-AIEgens between a blue-emissive TPE donor (PL emission at 468 nm) and a red-emissive MC acceptor (PL emission at 668 nm) in both novel photo-switchable [2]rotaxanes Rot-A-MC and Rot-B-MC under various external modulations, including water content, UV/Vis irradiation, pH value, and temperature. Furthermore, the reversible fluorescent photo-patterning applications of Rot-A-SP in a powder form and a solid film with excellent photochromic and fluorescent behaviors are first investigated in this report.

Gene therapy is one of the most important developments for modern medicine. As such methods for the compaction and delivery of nucleic acids bearing therapeutic sequences is essential. The quest for non-viral carriers of nucleic acids has produced a number of possible candidates with dendrimer being among the most promising. Their hyper-branched structure and well-defined size together with low cytotoxicity has found success in both ex-vivo and in-vivo studies. The compaction of DNA with dendrimer has produced a rich array of different structures depending on the physiochemical conditions. Mechanisms that drive the compaction have been shown to be a number of physical interactions that reduce the large polymeric entity from 100s of nanometers to some tens of nanometers to fit into the cell nucleus. The mechanisms driving the compaction of DNA will be discussed in detail while the focus will be directed to tuning the structural properties of the complexes and their structural characterization using small-angle scattering techniques.

Nitric oxide (NO) is a potent tumor-cell radiosensitizer but it can be readily scavenged by hemoglobin (Hb) in vivo. A biomimetic incubator that can generate and deliver NO in a scavenger (Hb)-free environment to enhance its radiosensitizing effect to maximize its efficacy in radiotherapy is proposed. This NO incubator comprises a poly(lactic-co-glycolic acid) (PLGA) hollow microsphere (HM) that contains an NO donor (NONOate) and a surfactant molecule (sodium caprate, SC) in its aqueous core. In acidic tumorous environments, the PLGA shell of the HM allows the penetration of protons from the outside, activating the hydrolytic cleavage of NONOate, spontaneously generating NO bubbles, which are immediately trapped/stabilized by SC. The SC-stabilized NO bubbles in the HM are then squeezed through the spaces of its PLGA matrices by the elevated internal pressure. Upon leaving the HM, the entrapped NO molecules may passively diffuse through their SC-stabilized/protected layer gradually to the tumor site, having a long-lasting radiosensitizing effect and inhibiting tumor growth. The entire process of NO generation and delivery is conducted in a scavenger (Hb)-free environment, mimicking the development of young ovoviviparous fish inside their mothers' bodies in the absence of predators before birth.

Our previous works have disclosed a thermodynamically stable ordered bicontinuous double diamond (OBDD) structure and the order–order transition (OOT) between OBDD and ordered bicontinuous double gyroid (OBDG) phases in a stereoregular diblock copolymer, syndiotactic polypropylene-block-polystyrene (sPP-b-PS). Here we investigate the effect of blending with a small amount of sPP homopolymer (h-sPP) on the stability of the OBDD phase, where h-sPP formed the dry-brush mixture with the minority sPP block chains in the network microdomains due to their comparable molecular weights. The OBDD structure developed in the blend was found to exist over a broader temperature window than that formed in the neat sPP-b-PS. Nevertheless, the OBDD–OBDG transition displayed by the neat diblock was no longer observed in the blends; instead, the OBDD phase transformed into the hexagonally packed cylinder (HEX) structure on heating, indicating that HEX superseded OBDG upon blending with h-sPP. According to the experimentally...

We investigate the formation of the ordered bicontinuous structures in a stereoregular diblock copolymer, isotactic polypropylene-block-polystyrene (iPP-b-PS), in which the minority PP block possessed isotactic configuration. This diblock displayed the conventional ordered bicontinuous double gyroid (OBDG) morphology upon heating above the crystal melting point of the iPP block from the as-cast state. The OBDG phase remained stable in the heating process up to the order–disorder transition. In the subsequent cooling process from the nearly disordered state, the OBDG phase first developed, but when the temperature was sufficiently low, an order–order transition from OBDG to the ordered bicontinuous double diamond (OBDD) phase occurred, and OBDD eventually became the dominant structure. The results attested that OBDD and OBDG represented the thermodynamically stable structure at the lower and the higher temperature, respectively, and the OBDG morphology formed in the as-cast state was metastable. The presen...

Films of ethylene vinyl alcohol copolymer (EVOH) and EVOH containing poly(oxypropylene)diamine intercalated montmorrilonite were prepared by solution casting. The nanostructures and viscosity were ...

Chromium(III) sulfate is extensively used in leather processing to stabilize the collagen molecules in hides and skins. Although its excess usage causes severe environmental pollution and health concerns, the role of chromium in stabilizing collagen still remains poorly understood. For the first time, by integrating a number of techniques, including real-time small-angle X-ray scattering, differential scanning calorimetry and natural cross-link analysis, we reveal crucial molecular-level indicators of collagen stability. The results indicate that collagen molecules achieve maximum molecular stability at concentrations as low as 1.8 wt % even if excess chromium (>3.7%) is introduced into the collagen matrix. At low concentrations (1.8% to 3.7%), the active amino acid residues are saturated via covalent bonding with chromium. Any excess chromium interacts purely non-covalently with the collagen molecule and, we propose, can be substituted by environment-friendly alternatives. Further, important natural cros...

Biomaterial-based devices have demonstrated versatility in various applications and have drawn recent considerable attention. In this study, we present non-volatile resistive switching memory devices based on a natural-derived DNA biomaterial. The structure consists of a DNA-based biomaterial layer sandwiched between two electrodes, where the DNA-based biomaterial is solution-processed without sequence control or external doping of nanoparticles. The fabricated device was tested at room temperature without encapsulation and exhibited a reliable resistive switching behavior and multi-level operation with low switching voltages, 10 4 s retention time, and more than 200 cycles in memory endurance testing. Our demonstration shows that reliable memory devices can be realized using only one layer of natural DNA biomaterial, without the need for composite layers. Our characterization also provides underlying physics that may be exploited for the design and fabrication of natural DNA-based optoelectronics.

Herein, we propose a novel concept of adding PDI–PC61BM as a non-volatile morphology regulator to the active layer, with the low bandgap polymer PBDB-T as a donor and IT-DM as a nonfullerene molecule acceptor, to promote the molecular order of both the donor and acceptor. The power conversion efficiency (PCE) of the device based on PBDB-T:IT-DM system is promoted by 1.39% from 10.63% to 12.23%.

In eukaryotes, the compaction of chromatin fibers composed of nucleosome core particles (NCPs) connected by a linker DNA into chromosomes is highly efficient; however, the underlying folding mechanisms remain elusive. We used small angle X-ray scattering (SAXS) to investigate the influence of linker DNA length on the local structure and the interparticle interactions of the NCPs. In the presence of the linker DNA of 30 bp or less in length, the results suggest partial unwrapping of nucleosomal DNA on the NCP irrespective of the linker DNA length. Moreover, the presence of 15 bp linker DNA alleviated the electrostatic repulsion between the NCPs and prevented the formation of an ordered columnar hexagonal phase, demonstrating that the linker DNA plays an active role in chromatin folding. MOE (Min. of Education, S’pore) Accepted version

A long-chain branched copolyester (i.e. p-hydroxybenzoic acid (HBA)/2-hydroxy-6-naphthoic acid (HNA)/1,1,1-tris(4-hydroxyphenyl)ethane (THPE) copolyester) and its extrusion film with superior physical properties to commercial Ticona A950 and Vecstar CTZ have been manufactured by the design of appropriate prescriptions, T-Die extrusion, and thermal treatment of crystal transformation. In order to investigate the fabricating feasibility for flexible copper clad laminate (FCCL) of fourth/fifth generation long-term evolution (4G/5G LTE), we have also agglutinated lab-made copolyester extrusion film with the copper foil by hot compression. Experimental results manifest that lab-made copolyester extrusion film is a highly potential FCCL substrate of 4G/5G LTE because its thickness, dielectric constant (Dk), dielectric loss (Df), hygroscopicity, yellowness index (YI), antistatic capability, flammability, melting temperature (Tm), coefficient of thermal expansion (CTE), and peel strength to copper foil are 50 μm, 2.90, 0.00140, 0.04%, 2.7, 6.5 × 109 Ω/□, UL-94 V0, 305 °C, 24.8 ppm/°C, and 29.9 lb/in, respectively.

Hydrogen gas can reduce cytotoxic reactive oxygen species (ROS) that are produced in inflamed tissues. Inspired by natural photosynthesis, this work proposes a multicomponent nanoreactor (NR) that comprises chlorophyll a, l-ascorbic acid, and gold nanoparticles that are encapsulated in a liposomal (Lip) system that can produce H2 gas in situ upon photon absorption to mitigate inflammatory responses. Unlike a bulk system that contains free reacting molecules, this Lip NR system provides an optimal reaction environment, facilitating rapid activation of the photosynthesis of H2 gas, locally providing a high therapeutic concentration thereof. The photodriven NR system reduces the degrees of overproduction of ROS and pro-inflammatory cytokines both in vitro in RAW264.7 cells and in vivo in mice with paw inflammation that is induced by lipopolysaccharide (LPS). Histological examinations of tissue sections confirm the ability of the NR system to reduce LPS-induced inflammation. Experimental results indicate that...

Self-assembly of the supramolecules formed by the complexation between poly(amidoamine) (PAMAM) generation four (G4) dendrimer and the surfactant, dodecylbenzenesulfonic acid (DBSA), generated a hexagonal columnar phase and a typical flat lamellar phase at low and high surfactant binding ratio, respectively, due to the dominance of the dendrimer to attain its natural curvature and the surfactant alkyl tails to reduce their hydrophobic interaction energy and packing frustration. Most strikingly, the delicate balance between these two free energy components at the intermediate binding ratios resulted in an undulated lamellar structure characterized by the centered rectangular unit cell. The finding demonstrates the power of dendrimer as a building block for expanding the morphological window of polymeric assemblies by modulating the interfacial curvature of microphase-separated structure.

Sodium dodecyl sulfate (SDS) is generally regarded as a potent permeability enhancer in oral formulations; however, one concern related to the use of any permeation enhancer is its possible absorption of unwanted toxins during the period of epithelial permeability enhancement. In this work, the safety and efficacy of an SDS-containing bubble carrier system that is developed from an orally administered enteric-coated capsule are evaluated. The bubble carriers comprise diethylene triamine pentaacetic acid (DTPA) dianhydride, sodium bicarbonate (SBC), SDS, and insulin. Upon exposure to the intestinal fluid, DTPA dianhydride hydrolyzes to yield acids, and SBC rapidly reacts with these acids to generate CO2, producing bubble carriers, each containing a self-assembling water film. The hydrophilic insulin is entrapped in the self-assembled water film, which is stabilized by SDS. The SDS in the bubble carrier system can act as a dissolution enhancer in the dispersion of insulin molecules, as a surfactant that stabilizes the bubble carriers, as a protease inhibitor that protects the protein drug, and as a permeation enhancer that augments its oral bioavailability. Hence, a significant increase in the plasma insulin level and an excellent blood glucose-lowering response in diabetic rats are effectively achieved. Moreover, the enhancement of epithelial permeation by this SDS-containing formulation does not promote the absorption of intestinal endotoxins. The above facts indicate that the bubble carrier system that is stabilized by SDS can be used as a safe and potent carrier in the oral delivery of therapeutic proteins.

The block copolymers of poly(acrylic acid)-b-poly(vinyl alcohol) (PAA-b-PVA) were obtained from the hydrolysis of poly(methyl acrylate)-b-poly(vinyl acetate) (PMA-b-PVAc), which was synthesized by cobalt-mediated radical polymerization (CMRP) using the cobalt(II) porphyrin complex (CoII(TMP)) as the mediator. The mechanical properties of the PAA-b-PVA free-standing films could be tuned by the pH of the aqueous solution used to cast the films. The block copolymer films showed a much higher tensile strain and fractural tensile strength than the films prepared from the blends of PAA and PVA homopolymers. FTIR and morphological characterizations suggested that the tensile properties of the films were governed by both the hydrogen bonding between PVA and PAA that led to interpolymer complexation and the phase-separated morphology. For a given type of material, the greater extent of interpolymer complexation attained at lower solution pH led to the film with better tensile properties. The difference in the leng...

The use of nanoscale templates to confine the crystallization process is an effective approach for creating large-scale crystal orientation. Here we incorporated poly(ethylene oxide) (PEO) into anodic aluminum oxide (AAO) nanochannels by a solution infiltration process to generate PEO nanotubes confined in the channels. The preferred crystal orientation of the PEO crystallites developed in the tubular space was then studied as a function of crystallization temperature (Tc), PEO molecular weight (MPEO), and AAO channel diameter (DAAO = 23 and 89 nm). Two distinct types of crystal orientation, i.e., perpendicular and tilt orientation with the (120) plane aligning along and tilting 45° away from the channel axis, respectively, were identified. Crystallization in the nanotubes templated by the AAO with DAAO of 23 nm led predominantly to perpendicularly oriented crystallites except for the high molecular weight PEO (MPEO = 95 000 g/mol), where a significant fraction of the crystallites showed tilt orientation....

The organo-soluble and extremely stable polynorbornene PHNB-HPB with a hexaphenylbenzene (HPB) moiety was prepared by ring-opening metathesis polymerization (ROMP) followed by hydrogenation. The hexa-peri-hexabenzocoronene (HBC)-containing PHNB-HBC, which is insoluble in commercial organic solvents, was prepared by the cyclodehydrogenation of PHNB-HPB. The glass transition temperature of PHNB-HPB was 205 °C. The temperatures required for a 10% weight loss (Td10) for PHNB-HPB and PHNB-HBC were 428 °C and 456 °C under a nitrogen flow, respectively. The PHNB-HBC exhibited an ordered self-assembly in the solid state. The exfoliation of PHNB-HBC aggregates was tested by ultrasonication in various solvents. The PHNB-HBC dispersion solutions showed an intensive emission of the 0–0 transition (465 nm) due to the lower D6h symmetrical structure and alkoxy substituents. Between different solvents, the dispersion in N-cyclohexyl-2-pyrrolidone (CHP) showed the highest individual metric and the strongest 0–0 transition (465 nm), indicating higher dispersibility.