Developing Safe Organohydrogel Sunscreens Using Polyelectrolyte-Betaine Surfactant Complexes.

Oil-in-water emulsions are extensively used in skincare products due to their improved texture, stability, and effectiveness. There is limited success in developing effective delivery systems that can selectively target the active sunscreen ingredients onto the skin surface. Herein, an organohydrogel was prepared by physical cross-linking of an oil-in-water nanoemulsion with chitosan under neutral pH conditions. In the presence of a small quantity of coconut oil, lauramidopropyl betaine and glycerol were able to emulsify the active sunscreen ingredients into nanoscale droplets with enhanced ultraviolet light absorption. A facile pH-triggered interfacial cross-linking approach was applied to transform the nanoemulsion into an organohydrogel sunscreen. Furthermore, the organohydrogel sunscreen displayed encouraging characteristics including efficient UV-blocking capacity, resistance to water, simple removal, and minimal skin penetration. This facile approach provides an effective pathway for scaling up the organohydrogels, which are highly suitable for the safe application of sunscreen.

Effect of lysophospholipids on the growth performance, nutrient digestibility, lipid metabolism and meat quality of fattening rabbits.

The present study aimed to investigate the effect of emulsifier lysophospholipids (LP), enzymatically modified from soy phospholipids, on the growth performance, nutrient digestibility, lipid metabolism and meat quality of fattening rabbits. The LP was added in control (CON), LP1, LP2 and LP3 at 0, 200, 400 and 600 mg/kg, respectively. A total of 240 rabbits at approximately 52 d of age were divided into 4 groups with 6 replicates of 10 rabbits each. The feeding trial lasted for 42 d. Results showed that compared to CON, LP1, LP2 and LP3 increased (p < 0.05) body weight gain, feed efficiency, the apparent faecal digestibility of gross energy, crude protein and ether extract, the percentages of dissectible fat and ether extract in the longissimus and legs, the serum contents of apolipoprotein B, free fatty acid and total phospholipids in the longissimus, but decreased (p < 0.05) serum total triglyceride and total cholesterol. Meanwhile, LP1, LP2 and LP3 had higher (p < 0.05) carcass weight, longissimus weight and percentages of foreleg and hindleg than the CON; and the three LP diets also increased (p < 0.05) the tenderness, lightness and redness of longissimus. It is concluded that soy LP as an emulsifier can improve the growth, digestibility and meat quality of fattening rabbits.

Multilayer-Stabilized Water-in-Water Emulsions.

Water-in-water (W/W) emulsions are of interest for various applications due to their inherent biocompatibility, ultralow interfacial tensions, and large interface thickness. However, it is still challenging to prepare stable W/W emulsions with tailored phase architectures compared to oil-in-water (O/W) and water-in-oil (W/O) emulsions. Here, we report a multilayer-stabilized W/W emulsion composed of poly(ethylene glycol)/dextran in the presence of DNA strands. The W/W emulsions present onion-ring-like structures, which are interpreted by a nanofluid film model. Emulsion behavior, e.g., stability, interface tension, etc., can be controlled by the type of DNA (single or double strands), DNA concentration, and volume fraction of dispersed phase. Our findings could broaden the preparation of novel emulsions for potential applications in emulsion polymerization, new media of homogeneous catalysis, and DNA transportation of water-in-water media.

Multistimuli-Responsive and Antifreeze Aggregation-Induced Emission-Active Gels Based on CuNCs.

Multistimuli-responsive fluorescent gelsbased small molecular gelator by supramolecular assembly, possessing excellent dynamic and reversible characteristic, have caused much concern. In this article, aggregation-induced emission-active fluorescence gels (AIE-gels) with chirality were developed by combining Cu nanoclusters (CuNCs) and natural amino acids, l-tryptophan (l-Trp) or d-Tryptophan (d-Trp). In DMSO/H2O mixed solvents, CuNCs can self-assemble to form intertwined fibersbased nanoparticles with numerous pores by introducing Zn2+. Fibers as second networks of heteronetwork structures are characterized with the participation of l-Trp or d-Trp for cross-linking to reinforce mechanical strength and chiral regulation of gel networks. Aggregation-induced emission enhancement (AIEE) of CuNCs endows the gels with excellent fluorescent properties by introducing solvents and gelation process. The fluorescent gels exhibit sufficient fluorescence intensity (FI) at -20 °C to -80 °C and possess sensitive responsibility including gel-sol transition and fluorescence behavior for stimuli of mechanical force, heating, pH, H2O2, and ethylene diamine tetraacetic acid (EDTA).

Elastomeric Liquid-Free Conductor for Iontronic Devices.

For a long time, the potential application of gel-based ionic devices was limited by the problem of liquid leakage or evaporation. Here, we utilized amorphous, irreversible and reversible cross-linked polyTA (PTA) as a matrix and lithium bis(trifluoromethane sulfonamide) (LiTFSI) as an electrolyte to prepare a stretchable (495%) and self-healing (94%) solvent-free elastomeric ionic conductor. The liquid-free ionic elastomer can be used as a stable strain sensor to monitor human activities sensitively under extreme temperatures. Moreover, the prepared elastic conductor (TEOA0.10-PTA@LiTFSI) was also considered an electrode to assemble with self-designed repairable dielectric organosilicon layers (RD-PDMS) to develop a sustainable triboelectric nanogenerator (SU-TENG) with outstanding performance. SU-TENG maintained good working ability under extreme conditions (-20 °C, 60 °C, and 200% strain). This work provided a low-cost and simple idea for the development of reliable iontronic equipment for human-computer interaction, motion sensing, and sustainable energy.

Self-Assembly of Amphiphilic Copper Nanoclusters Driven by Cationic Surfactants.

Amphiphilicity is an excellent physicochemical property, which is yet to be explored from traditional surfactants to nanoparticles. This article shows that the amphiphilicity of copper nanoclusters (CuNCs) can be readily tuned by electrostatic interactions with cationic surfactants and cetyltrimethylammonium cations (CTA+) with counterions Br-, Cl-, and C7H8O3S-. Due to the role of surface ligands, the complexes of glutathione-capped CuNCs (GSH-CuNCs) and the surfactants exhibit good amphiphilicity, which enables them to self-assemble like a molecular amphiphile. This could significantly increase the utility of metal nanoclusters in basic and applied research. As the concentration of the surfactant changes, the aggregates change from nanoparticles to network-like structures. After the formation of supramolecular self-assemblies by hydrophobic interactions, the enhancement of fluorescence intensity was observed, which can be ascribed to the suppression of intramolecular vibrations based on aggregation-induced emission (AIE) and combined with the compactness of GSH-CuNCs in self-assemblies. Our study provides a facile way to generate solid fluorescent materials with excellent fluorescence performance, which may find applications in light-emitting diodes (LEDs).

Eu3+-Controlled Fluorescent Bilayer Vesicles.

By appropriate substitution, polyoxometalates (POMs) can be modified to be organic-inorganic supramolecules (OISMs) that are nonaqueous or water soluble and form aggregates in solution. Here, we report a new OISM, (TBA)3POM-PPCT, that can self-assemble to form bilayer vesicles controlled by Eu3+ in nonaqueous solution. Dynamic light scattering, transmission and scanning electron microscopy techniques, and atomic force microscopy clearly demonstrated the controllable formation of stable bilayer vesicles with an average hydrodynamic radius of about 510 nm. Because of the coordination between (TBA)3POM-PPCT and Eu3+, the stable vesicles possess fluorescence, determined by studying fluorescence spectra, and show highly selective response to Cu2+, allowing them to function as an ion-detecting platform to Cu2+.

Dual pH-Responsive Polymer Nanogels with a Core-Shell Structure for Improved Cell Association.

We report the fabrication of polymer nanogels with a pH-responsive core and a pH-sheddable shell and investigate the pH-dependent cell association of the pH-responsive polymer nanogels. The pH-responsive core composed of poly(2-diisopropylaminoethyl methacrylate) (PDPA) with a pKa ≈ 6.2 was synthesized by using polymerization in emulsion droplets. The pH-sheddable poly(ethylene glycol) (PEG) shell was coated on the amine-modified PDPA nanogels by an acid-degradable amide bond. The PEG shell is cleavable in response to the acidic tumor microenvironment, and subsequently, the surface charge of the nanogels can be reversed, which effectively enhances cellular association of these nanogels. The reported pH-responsive polymer nanogels provide a promising way for the better understanding of bio-nano interactions and potentially enrich the application of therapeutic delivery for cancer therapy.

Metal-Organic Gels of Catechol-Based Ligands with Ni(II) Acetate for Dye Adsorption.

Metal organic gels (MOGs) are a class of supramolecular complexes, which have attracted widespread interest because of the coupled advantages of inorganic and organic building blocks. A new compound terminated with catechol was synthesized. This new compound can be used to coordinate with Ni2+ to form MOGs. These MOGs show favorable viscoelasticity and wormhole-shaped porous structures, which were confirmed by transmission electron microscope and scanning electronic microscope images. Taking the benefits of porosity into account, the xerogel could serve as an adsorbent to adsorb dye molecules from the aqueous media. The experimental results indicate that xerogels possess good adsorption effect both on anionic and cationic dyes. Exhaustive research has been performed on the adsorption kinetics and isotherms, revealing that the adsorption process accords with the pseudo-second-order model and the Langmuir model.

Self-Assembled Magnetic Viruslike Particles for Encapsulation and Delivery of Deoxyribonucleic Acid.

Developing nontoxic artificial carriers for stimuli-responsive capture, transport, and delivery of biomolecules is of immense scientific interest. Herein, for the first time, we synthesize a double-tailed cationic surfactant, (C16H33)2(CH3)2N+[FeCl3Br]-, which possesses magnetic properties [magnetic surfactants (Mag-Surfs)]. The time-dependent formation of virus-shaped hybrid mixed assemblies of polyoxometalates (POMs) {Mo72Fe30}/Mag-Surf with hollow-shell structures is followed. These structures serve well as robust high-surface-area shuttles, which can be manipulated with applied magnetic fields. By using cationic Mag-Surfs, the anionic POMs and DNA can be complexed in these ternary mixtures. These virus-shaped complexes act as nanoanchors and nanomotors, which can be utilized for binding, anchoring, and delivery of biomolecules, such as DNA. It is found that they have a good absorption capacity for DNA and myoglobin over 24 h, after application of a magnetic field. The realization of magnetic virus-shaped {Mo72Fe30}/Mag-Surf spheres may open possibilities for designing other functional nanoparticles, allowing effective control over the delivery/separation of biomolecules.

Versatile Self-Assembly and Biosensing Applications of DNA and Carbon Quantum Dots Coordinated Cerium Ions.

Self-assembly exploits noncovalent interactions to offer a facile and effective method for the construction of soft materials with multifunctionalities and diversity. In this work, fluorescence carbon quantum dots coordinated by Ce3+ ions (CQDCe) have been synthesized and exploited as building blocks to generate a series of hierarchical structures through the ionic self-assembly of CQDCe and biomolecules, namely DNA, myoglobin (Mb), and hyaluronic acid (HA). In particular, vesicles can be constructed by the simple mixing of oppositely charged CQDCe and DNA in water. The formation of unusual vesicles can be explained by the self-assembly of CQDCe with a rearranged structure and the rigid DNA biomolecular scaffolds. This facile noncovalent self-assembly method has inspired the innovative use of virgin DNA as a building block to construct vesicles rather than resorting to a sophisticated synthesis. The self-assembly of CQDCe-biopolymers was accompanied by aggregation-induced photoluminescence (PL) quenching. The biosensing platform was designed to detect polypeptides and deoxyribonuclease I through competitive binding of CQDCe and enzymatic hydrolysis of the DNA backbone, respectively. We believe that the integrative self-assembly of CQDCe and DNA will enrich the theoretical study of vesicle formation by DNA molecules and extend the application of fluorescence carbon quantum dots in the biological field.

Surfactant-Modified Ultrafine Gold Nanoparticles with Magnetic Responsiveness for Reversible Convergence and Release of Biomacromolecules.

It is difficult to synthesize magnetic gold nanoparticles (AuNPs) with ultrafine sizes (<2 nm) based on a conventional method via coating AuNPs using magnetic particles, compounds, or ions. Here, magnetic cationic surfactants C16H33N+(CH3)3[CeCl3Br]- (CTACe) and C16H33N+(CH3)3[GdCl3Br]- (CTAGd) are prepared by a one-step coordination reaction, i.e., C16H33N+(CH3)3Br- (CTABr) + CeCl3 or GdCl3 → CTACe or CTAGd. A simple strategy for fabricate ultrafine (<2 nm) magnetic gold nanoparticles (AuNPs) via surface modification with weak oxidizing paramagnetic cationic surfactants, CTACe or CTAGd, is developed. The resulting AuNPs can highly concentrate the charges of cationic surfactants on their surfaces, thereby presenting strong electrostatic interaction with negatively charged biomacromolecules, DNA, and proteins. As a consequence, they can converge DNA and proteins over 90% at a lower dosage than magnetic surfactants or existing magnetic AuNPs. The surface modification with these cationic surfactants endows AuNPs with strong magnetism, which allows them to magnetize and migrate the attached biomacromolecules with a much higher efficiency. The native conformation of DNA and proteins can be protected during the migration. Besides, the captured DNA and proteins could be released after adding sufficient inorganic salts such as at cNaBr = 50 mmol·L-1. Our results could offer new guidance for a diverse range of systems including gene delivery, DNA transfection, and protein delivery and separation.

Magnetic Fullerene-DNA/Hyaluronic Acid Nanovehicles with Magnetism/Reduction Dual-Responsive Triggered Release.

We created the dual-responsive nanovehicle that can effectively combine and abundantly utilize magnetic and glutathione (GSH)-reductive triggers to control the drug delivery and achieve more intelligent and powerful targeting. In the nanovehicles, paramagnetic fullerene (C60@CTAF) was prepared via one-step modification of fullerene with magnetic surfactant CTAF by hydrophobic interaction for the first time. The perfect conjugation of C60 and CTAF increased the solubility or dispersity of fullerenes and qualified CTAF with more powerful assembly capability with DNA. DNA molecule in the nanovehicles acted as an electrostatic scaffold to load anticancer drug Dox as well as the important building block for assembly with C60@CTAF into C60@CTAF/DNA. The further combination of deshielding and targeting functions in reduction-responsive disulfide modified HA-SS-COOH coating on C60@CTAF/DNA complexes could reduce the agglomeration and regulate the morphology of C60@CTAF/DNA complexes from irregular microstructures to more uniform ones. More importantly, the introduction of HA-SS-COOH provided a response to a simulating reductive extra-tumoral environment by efficient cleavage of disulfide linkages by GSH and site-specific drug delivery to HepG2 cells. Amazingly, the final nanovehicles presented an increased magnetic susceptibility compared with paramagnetic CTAF, and they "walked" under an applied magnetic field. Because of their facile fabrication, rapid responsiveness to extra tumoral environment, and external automatic controllability by external magnet, the drug delivery nanovehicles constructed by magnetic fullerene-DNA/hyaluronic acid might be of great interest for making new functional nucleic-acid-based drug carriers.

Self-Organization and Vesicle Formation of Amphiphilic Fulleromonodendrons Bearing Oligo(poly(ethylene oxide)) Chains.

A new series of N-methylfulleropyrrolidines bearing oligo(poly(ethylene oxide))-appended Percec monodendrons (fulleromonodendrons, 4a-f) have been synthesized. The substituted position of the oligo(poly(ethylene oxide)) chain(s) on the phenyl group of the Percec monodendron for 4a-f was varied, which is at the 4-, 2,4-, 3,5-, 3,4,5-, 2,3,4- and 2,4,6- position, respectively. 4a-e are obtained as solids at 25 °C and can self-organize into lamellar phases as revealed by X-ray diffraction (XRD) and small-angle X-ray scattering (SAXS) measurements, while 4f appears as a viscous liquid. The substitution patterns of the oligo(poly(ethylene oxide)) chain(s) also significantly influence the solubility of 4a-f, especially in ethanol and water. Formation of self-organized supramolecular structures of 4d and 4e in water as well as 4d in ethanol is evidenced from UV-vis and dynamic light scattering (DLS) measurements. Further studies in water using various imaging techniques including transmission electron microscopy (TEM), freeze-fracture TEM (FF-TEM), cryo-TEM and atomic force microscopy (AFM) observations revealed the formation of well-defined vesicles for 4d and plate-like aggregates for 4e, indicating that the aggregation behavior of the fulleromonodendrons is highly dependent on their molecular structures. For 4d in ethanol, only irregular aggregates were noticed, indicating the solvent also plays a role on regulating the aggregation behavior. After functionalization with the Percec monodendrons, 4a-f can preserve the intriguing electrochemical properties of pristine C60 as revealed by cyclic voltammetries. The thermotropic properties of 4a-f have also been investigated. It was found that all of them show good thermal stability, but no mesophases were detected within the investigated temperature ranges.

Thermo-reversible capture and release of DNA by zwitterionic surfactants.

The thermo-reversible capture and release of DNA were studied by the protonation and deprotonation of alkyldimethylamine oxide (CnDMAO, n = 10, 12 and 14) in Tris-HCl buffer solution. DNA/C14DMAO in Tris-HCl buffer solution with pH = 7.2 is transparent at 25 °C, indicating that DNA molecules exist mainly in individuals and the binding of C14DMAO is weak. With the increase of temperature, the pH of the buffer solution continuously decreases, which leads to protonation of C14DMAO (C14DMAO + H(+)→ C14DMAOH(+)) and an obvious increase of the turbidity of the samples. This indicates a stronger binding of the protonated C14DMAOH(+) to DNA. Further investigations demonstrated the formation of DNA/C14DMAOH(+) complexes, in which the stretched DNA molecules are effectively compacted as evidenced from UV-vis absorptions, circular dichroism (CD) measurements, atomic force microscopy (AFM) observations, dynamic light scattering (DLS) measurements and agarose gel electrophoresis (AGE). Interestingly, when the temperature is turned back to 25 °C, the compacted DNA molecules can fully recover to the stretched conformation. This cycle can be repeated several times without obvious loss of efficiency. The effect of the chain length of CnDMAO has also been investigated. When C14DMAO was replaced by C12DMAO, similar phenomena can be observed with a slightly higher critical surfactant concentration for DNA compaction and a slightly lower pH of Tris-HCl buffer solution with pH = 6.8. For the DNA/C10DMAO system, however, no DNA compaction was observed even in Tris-HCl buffer solution with a much lower pH and a much higher C10DMAO concentration. The negative charges of DNA molecules can easily be neutralized by positive charges of cationic CnDMAOH(+) (n = 12 and 14) micelles. DNA was compacted and then insoluble DNA/CnDMAOH(+) complexes were formed. Because of the much higher critical micelle concentration (cmc) of the shorter chain length C10DMAOH(+), cationic C10DMAOH(+) micelles cannot form under the studied condition to compact DNA. The strategy may provide an efficient and alternative approach for stimuli-responsive gene therapy and drug release.

Colloidal Wormlike Micelles with Highly Ferromagnetic Properties.

For the first time, a new fabrication method for manipulating the ferromagnetic property of molecular magnets by forming wormlike micelles in magnetic-ionic-liquid (mag-IL) complexes is reported. The ferromagnetism of the mag-IL complexes was enhanced 4-fold because of the formation of wormlike micelles, presenting new evidence for the essence of magnetism generation at a molecular level. Characteristics such as morphology and magnetic properties of the wormlike micelle gel were investigated in detail by cryogenic transmission electron microscopy (Cryo-TEM), rheological measurements, circular dichroism (CD), FT-IR spectra, and the superconducting quantum interference device method (SQUID). An explanation of ferromagnetism elevation from the view of the molecular (ionic) distribution is also given. For the changes of magnetic properties (ferromagnetism elevation) in the wormlike micelle systems, the ability of CTAFe in magnetizing AzoNa4 (or AzoH4) can be ascribed to an interplay of the magnetic [FeCl3Br](-) ions both in the Stern layer and in the cores of the wormlike micelles. Formation of colloidal aggregates, i.e., wormlike micelles, provides a new strategy to tune the magnetic properties of novel molecular magnets.

Self-assembled switching gels with multiresponsivity and chirality.

A multiresponsive hydrogel material consisting of a commercial cationic surfactant and an azobenzene derivative functionalized with four carboxylic acid groups was constructed. The achiral azobenzene molecule as a gelator produces chirality at the supramolecular level in the presence of H(+). The acid-induced gelation and morphology change of supramolecular gels were investigated in detail by cryogenic transmission electron microscopy (cryo-TEM), rheological measurements, circular dichroism (CD), and (1)H NMR spectra. Based on the results, a mechanism of the intermolecular H-bond-directed gelation and supramolecular chirality was proposed. Other than the pH sensitivity, the microstructure and the chirality of the hydrogel demonstrate reversible switching behavior in response to photoirradiation, on account of the photoisomerization of the azobenzene derivative. Accordingly, a chiroptical switch comprising four different states in response to pH and light stimuli is strategically constructed. Not only does the present system provide a good opportunity for investigating the gelation-induced supramolecular chirality by symmetry breaking totally based on achiral molecules, but it also proposes a new strategy to build multiresponsive supramolecular switches as particularly attractive for the future development of functional materials.

Ordered DNA-Surfactant Hybrid Nanospheres Triggered by Magnetic Cationic Surfactants for Photon- and Magneto-Manipulated Drug Delivery and Release.

Here we construct for the first time ordered surfactant-DNA hybrid nanospheres of double-strand (ds) DNA and cationic surfactants with magnetic counterion, [FeCl3Br](-). The specificity of the magnetic cationic surfactants that can compact DNA at high concentrations makes it possible for building ordered nanospheres through aggregation, fusion, and coagulation. Cationic surfactants with conventional Br(-) cannot produce spheres under the same condition because they lose the DNA compaction ability. When a light-responsive magnetic cationic surfactant is used to produce nanospheres, a dual-controllable drug-delivery platform can be built simply by the applications of external magnetic force and alternative UV and visible light. These nanospheres obtain high drug absorption efficiency, slow release property, and good biocompatibility. There is potential for effective magnetic-field-based targeted drug delivery, followed by photocontrollable drug release. We deduce that our results might be of great interest for making new functional nucleic-acid-based nanomachines and be envisioned to find applications in nanotechnology and biochemistry.

Sponge phase producing porous CeO2 for catalytic oxidation of CO.

The aggregation behavior of mixtures of the alkaline amino acid L-Arginine (L-Arg) and bis(2-ethylhexyl)phosphoric acid (DEHPA) in water was studied in detail. At a fixed L-Arg concentration, a phase sequence of micellar phase (L1 phase), vesicle phase (Lαv phase), planar lamellar phase (Lαl phase), and sponge phase (L3 phase) was obtained with increasing DEHPA concentration due to changes in the packing parameter. The phase transition of the lamellar structures was determined by freeze-fracture TEM and (2)H NMR spectroscopy. Rheological measurements reflected the phase transition through significant variations of both the elastic modulus and the viscous modulus. Porous CeO2 materials were produced by utilizing the L3 phase as template, and the porous CeO2 exhibited excellent catalytic oxidation activity toward CO due to its high surface area, which provides more active sites for CO conversion.

Magnetic-field-induced orientational phase structure transition.

Magnetic field effect on the phase transition at high temperature (from 50 °C) inside the magnetic field has been found in C14G2 (N-tetradecyllactobionamide)/C12EO4 (tetraethylene glycol monododecyl ether)/D2O system. The phase was transited quickly from lamellar phase to isotropic phases [bottom, micellar phase (L1 phase) and top, sponge phase (L3 phase)] induced by a magnetic field, which was demonstrated by (2)H NMR and FF-TEM measurements. The isotropic phases induced by magnetic field were not stable, and the upper L3 phase can recover to lamellar phase after being restored in a 55 °C thermostat outside the magnetic field for about one month. During the mechanism study, the C12EO4 molecule was proved to be the dominant component for the phase transition induced by the magnetic field, while the C14G2 molecule was the auxiliary and just affected the transition speed. The breaking and rebuilding of hydrogen bonds could play an important role in the phase transition and recovering. Moreover, the surfactant concentration had an effect on the speed of phase transiting and phase recovering. These observations could provide an understanding of the phase transition and also the applications for the controlled drug delivery system of bilayer membranes driving, induced by the magnetic field.