Conelike Janus Composite Particles

Conelike cross-linked PS particles are polymerized at a patchy emulsion interface. The PS particles synthesized in the dispersed paraffin phase immigrate toward the interface due to the Pickering effect. At the triple phase contact line, the particles are squeezed into cone shape under an outward convex interfacial tension mismatch. The conelike PS particles are adhered to paraffin sphere surface and synchronously protected, which allows selective modifications of the two sides. The Janus particles can self-organize into superstructures in dispersions. Robust coatings are easily fabricated from the Janus particles, whose wettability is tunable from highly adhesive for water to superhydrophobic by simply changing the size distribution of the Janus particles

Robust Reactive Janus Composite Particles of Snowman Shape

We present a facile approach toward snowman-like silica@PDVB/PS Janus particles by seed emulsion polymerization using a gelable monomer MPS against a PDVB/PS hollow particle. Individual silica bulge is protruded from the seed particle surface, whose size is tunable. The silica@PDVB Janus particles are derived after dissolution of PS, which are robust to tolerate against organic solvents. Both sides are reactive for selective modifications to grow desired materials with tunable wettability and functionality. As solid emulsifiers, the Janus balance of the particles is tunable from more hydrophobic to more hydrophilic by changing either aspect size ratio or composition of the two sides

Janus Nanocage toward Platelet Delivery

The platelet-shaped Janus nanocages with a mesoporous silica shell are prepared. PEG moiety onto the exterior surface is responsible for good dispersity in water. The graphene sheet inside the cavity is responsible for hydrophobic performance to selectively capture hydrophobic species, and photothermal effect by NIR irradiation. As a biocompatible DOX-loaded Janus platelet delivery, HeLa cell cytotoxicity is greatly enhanced under NIR irradiation. There exists a synergetic effect between the chemotherapy and photothermal therapy

Claw Amphiphiles with a Dendrimer Core: Nanoparticle Stability and Drug Encapsulation Are Directly Proportional to the Number of Digits

There are numerous pharmaceutical, food, and consumer product applications requiring the incorporation of hydrophobic solutes within aqueous media. Often amphiphiles and/or polymers are used to produce encapsulating nanostructures. Because the encapsulation efficiencies of these nanostructures directly impact on the process or product, it is often desirable to optimize this parameter. To produce these advanced functional materials, we hypothesized that an amphiphile with a claw shape would favor polymer aggregation into nanoparticles and hydrophobic compound encapsulation. Claw amphiphiles were prepared by attaching one end of comb-shaped chitosan amphiphile chains [<i>N</i>,<i>N</i>,<i>N</i>-trimethyl,<i> N</i>,<i>N</i>-dimethyl,<i> N</i>-monomethyl,<i> N</i>-palmitoyl,<i> N</i>-acetyl, 6-<i>O</i>-glycol chitosan (GCPQA)] to a central dendrimer core [generation 3 diaminobutane poly­(propylenimine) dendrimer (DAB)] to give DAB-GCPQA. The linear chitosan amphiphile (GCPQA) forms the digits of the claw. These claw amphiphiles were very stable and had a high encapsulating efficiency. DAB-GCPQAs (<i>M</i>_n = 30 and 70 kDa) had extremely low critical micelle concentrations [CMCs = 0.43 μg mL^–1 (13 nM) and 0.093 μg mL^–1 (0.9 nM), respectively], and their CMCs were lower than that of linear GCPQA [<i>M</i>_n = 14 kDa, CMC = 0.77 μg mL^–1 (38 nM)]. The claw amphiphile CMCs decreased linearly with the number of digits (<i>r</i>² = 0.98), and drug encapsulation (hydrophobic drug propofol) in 4 mg mL^–1 dispersions of the amphiphiles increased linearly (<i>r</i>² = 0.94) with the number of digits. DAB-GCPQA70 (4 mg mL^–1, 0.058 mM) encapsulated propofol (7.3 mg mL^–1, 40 mM). Finally, despite their stability, claw amphiphile nanoparticles are able to release the encapsulated drug <i>in vivo</i>, as shown with the claw amphiphile–propofol formulations in a murine loss of righting reflex model

Janus Cages of Bilayered Polymer–Inorganic Composites

Janus cages with a bilayer polymer–inorganic composite shell are synthesized by an emulsion interfacial self-organized sol–gel process followed by a polymer grafting onto the interior surface containing a vinyl group. Binary surfactants experience a phase separation to create transverse channels across the shell. The Janus cages can be functionalized by either growing responsive polymers or integrating with functional nanoparticles. They are promising in controlled loading and triggered release of desired materials under guidance

Dually Responsive Janus Composite Nanosheets

Janus composite nanosheets of PNIPAM/silica/PDEAEMA are synthesized by sequential ATRP grafting two polymers from the corresponding sides of the Janus silica nanosheets. They are dually responsive to pH and temperature since wettability of the two sides is tunable accordingly. The nanosheets can serve as a responsive solid emulsifier. Type and stability of the emulsions are triggered by simply changing pH and temperature

Construction of Injectable Double-Network Hydrogels for Cell Delivery

Herein we present a unique method of using dynamic cross-links, which are dynamic covalent bonding and ionic interaction, for the construction of injectable double-network (DN) hydrogels, with the objective of cell delivery for cartilage repair. Glycol chitosan and dibenzaldhyde capped poly­(ethylene oxide) formed the first network, while calcium alginate formed the second one, and in the resultant DN hydrogel, either of the networks could be selectively removed. The moduli of the DN hydrogel were significantly improved compared to that of the parent single-network hydrogels and were tunable by changing the chemical components. In situ 3D cell encapsulation could be easily performed by mixing cell suspension to the polymer solutions and transferred through a syringe needle before sol–gel transition. Cell proliferation and mediated differentiation of mouse chondrogenic cells were achieved in the DN hydrogel extracellular matrix

Janus Nanoparticles of Block Copolymers by Emulsion Solvent Evaporation Induced Assembly

We present a facile approach toward straightforward synthesis of Janus nanoparticles (NPs) of poly­(4-vinylpyridine)-based block copolymers by solvent evaporation induced assembly within emulsion droplets. Formation of the Janus NPs is arisen from the synergistic effect between solvent selectivity and interfacial selectivity. This method is robust without the requisites of narrow molecular weight distribution and specific range of block fraction of the copolymers. Janus NPs can also be achieved from mixtures of copolymers, whose aspect size ratio and thus Janus balance are finely tunable. The Janus NPs are capable to self-assemble into ordered superstructures either onto substrates or in dispersions, whose morphology relies on Janus balance

Robust Anisotropic Composite Particles with Tunable Janus Balance

We report a general emulsion approach to protrude a lobe by swelling the polymer core from a core–shell structure, achieving anisotropic Janus composite particles with tunable chemistry, shape, size, and size ratio of the two parts thus Janus balance. Oil-in-water emulsion is employed to swell a polymer core through the crack open hole within the shell, and the core protrusion is restricted in the particle/oil confined compartments enveloped with surfactant. When monomers are used as the oil solvents, cross-linking can strengthen the polymer lobe to tolerate against organic solvents. By tuning polymerization time and monomer/particle weight ratio, the size ratio of the polymer/inorganic parts thus Janus balance of the composite particles is continuously tunable across from more hydrophilic to more lipophilic. The robust anisotropic particles with tunable Janus balance can be further used as solid surfactants to tune microstructure of emulsions

Construction of an Injectable Composite Double-Network Hydrogel as a Liquid Embolic Agent

Conventional embolists disreputably tend to recanalization arising from the low filling ratio due to their rigidity or instability. As a result, intelligent hydrogels with a tunable modulus may meaningfully improve the therapeutic efficacy. Herein, an injectable composite double-network (CDN) hydrogel with high shear responsibility was prepared as a liquid embolic agent by cross-linking poly(vinyl alcohol) (PVA) and carboxymethyl chitosan (CMC) via dynamic covalent bonding of borate ester and benzoic-imine. A two-dimensional nanosheet, i.e., layered double hydroxide (LDH), was incorporated into the network through physical interactions which led to serious reduction of yield stress for the injection of the hydrogel and the capacity for loading therapeutic agents like indocyanine green (ICG) and doxorubicin (DOX) for the functions of photothermal therapy (PTT) and chemotherapy. The CDN hydrogel could thus be transported through a thin catheter and further in situ strengthened under physiological conditions, like in blood, by secondarily cross-linking with phosphate ions for longer degradation duration and better mechanical property. These characteristics met the requirements of arterial interventional embolization, which was demonstrated by renal embolism operation on rabbits, and meanwhile favored the inhibition of subcutaneous tumor growth on an animal model. Therefore, this work makes a breakthrough in the case of largely reducing the embolism risks, thus affording a novel generation for interventional embolization