Triblock Copolymer F127 Research Articles

Rational Synthesis of Spongy Fe3N@N-Doped Carbon Nanorods with Controlled Topography and Porosity for Enhanced Energy Storage Anodes in Lithium-Ion Batteries.

Iron nitrides with the merits of high theoretical capacities, cost-effectiveness, and good electronic/ionic conductivity have been recognized as attractive anode candidates for lithium-ion batteries (LIBs). Carbon compositing, pore engineering, and nanostructure construction have proved to be effective strategies to prepare high-performance metal nitride anodes for LIBs. Herein, we synthesized a series of Fe3N-embedded and N-doped carbon nanorods (Fe3N@NCNR) with a hierarchical porous system and controllable topography by metal-catalyzed graphitization-nitridization of the Fe(III)-triazole framework (Fe-MOF) and thermal evaporation of the triblock copolymer F127 template assembled in Fe-MOF via hydrogen bonding interaction, followed by the air oxidation and urea-assisted ammonolysis processes. The Fe3N@NCNR as anodes for LIBs display extraordinary lithium storage capabilities with a high reversible capacity of 830 mA h g-1 at 0.1 C, a good rate performance of 576 mAh g-1 at 5 C, and a long-term cycling stability of 742 mA h g-1 over 600 cycles at 1 C. Such outstanding performance benefits from the spongy carbon nanorods with rich macropores for rapid electronic/ionic transport and effective accommodation of electrode volume expansion, abundant N-doped meso-/microporous carbon for the additional storage of Li+ via capacitive effect, and the efficient utilization of Fe3N nanoparticles uniformly distributed through carbon nanorods. Importantly, this work introduces an effective strategy to construct superior performance nitride anodes from MOF surfactants based on hydrogen bonding-driven interface self-assembly and provides insight into the preparation of highly efficient nanoarchitectures for Li+ storage.

Evaporation-induced self-assembly of hierarchical zinc silicate hybrid scaffolds for bone tissue engineering: Meso and macro scale porosity design

In this study, zinc silicate hybrid scaffolds with hierarchical meso/macroporous structures were synthesized using evaporation-induced self-assembly and sacrificial foamy templates. F127 triblock copolymer and polyurethane (PU) foam served as templates for mesoporosity and macroporosity, respectively. The scaffolds were calcined at 550, 650, and 750 °C for 2 h to remove the templates and form the crystalline phase. Analytical techniques, including BET, XRD, SEM, FTIR, and STA, were used to study the impact of calcination temperature on the scaffolds' meso-texture and crystalline phase. Results showed that increasing the calcination temperature to 750 °C significantly enhanced the overall crystallinity. The crystallized ZnO content increased from 10.3 wt% to 32 wt%, and the willemite (Zn2SiO4) crystalline phase formed. Willemite content was approximately 3 wt% at 650 °C and 67 wt% at 750 °C, as determined by quantitative XRD analyses via Rietveld refinement. The emergence of the willemite phase adversely impacted the specific surface area, leading to a reduction from 123.18 m2/g to 2.18 m2/g, and compromised meso-texture-related characteristics, indicating a substantial disruption in mesoporosity. The pure willemite sample was also obtained by increasing the calcination temperature up to 1000 °C. Although the sample contained no secondary phase, the specific surface area and total mesopore volume were drastically reduced, indicating the negative effect of high calcination temperature on mesoporosity. In contrast to the mesostructure, the macrostructure of the scaffolds exhibited negligible sensitivity to calcination temperature, maintaining a mean macropore diameter of around 200 μm. Furthermore, the in vitro performance of the scaffolds was evaluated by assessing apatite formation ability, degradability, and cytocompatibility. It was demonstrated that the scaffolds calcined at 750 °C exhibited superior performance in terms of apatite formation and cytocompatibility when cultivated with MG-63 human osteosarcoma cells.

A perylene diimide probe for NIR-II fluorescence imaging guided photothermal and type I/type II photodynamic synergistic therapy

Phototherapy has garnered significant attention in the past decade. Photothermal and photodynamic synergistic therapy combined with NIR fluorescence imaging has been one of the most attractive treatment options because of the deep tissue penetration, high selectivity and excellent therapeutic effect. Benefiting from the superb photometrics and ease of modification, perylene diimide (PDI) and its derivatives have been employed as sensing probes and therapeutic agents in the biological and biomedical research fields, and exhibiting excellent potential. Herein, we reported the development of a novel organic small-molecule phototherapeutic agent, PDI-TN. The absorption of PDI-TN extends into the NIR region, which provides feasibility for NIR phototherapy. PDI-TN overcomes the traditional Aggregation-Caused Quenching (ACQ) effect and exhibits typical characteristics of Aggregation-Induced Emission (AIE). Subsequently, PDI-TN NPs were obtained by using an amphiphilic triblock copolymer F127 to encapsulate PDI-TN. Interestingly, the PDI-TN NPs not only exhibit satisfactory photothermal effects, but also can generate O2•- and 1O2 through type I and type II pathways, respectively. Additionally, the PDI-TN NPs emit strong fluorescence in the NIR-II region, and show outstanding therapeutic potential for in vivo NIR-II fluorescence imaging. To our knowledge, PDI-TN is the first PDI derivative used for NIR-II fluorescence imaging-guided photodynamic and photothermal synergistic therapy, which suggests excellent potential for future biological/biomedical applications.

Efficient green Cr(VI) adsorbent from sorghum waste: Eco-designed functionalized mesoporous silica FDU-12

This paper presents an eco-design approach to the synthesis of a highly efficient Cr(VI) adsorbent, utilizing a positively charged surface mesoporous FDU-12 material (designated as MI-Cl-FDU-12) for the first time. The MI-Cl-FDU-12 anion-exchange adsorbent was synthesized via a facile one-pot synthesis approach using sodium silicate extracted from sorghum waste as a green silica source, 1-methyl-3-(triethoxysilylpropyl) imidazolium chloride as a functionalization agent, triblock copolymer F127 as a templating or pore-directing agent, trimethyl benzene as a swelling agent, KCl as an additive, and water as a solvent. The synthesis method offers a sustainable and environmentally friendly approach to the production of a so-called “green” adsorbent with a bimodal micro-/mesoporous structure and a high surface area comparable with the previous reports regarding FDU-12 synthesis. MI-Cl-FDU-12 was applied as an anion exchanger for the adsorption of toxic Cr(VI) oxyanions from aqueous media and various kinetic and isotherm models were fitted to experimental data to propose the adsorption behavior of Cr(VI) on the adsorbent. Langmuir model revealed the best fit to the experimental data at four different temperatures, indicating a homogeneous surface site affinity. The theoretical maximum adsorption capacities of the adsorbent were found to be 363.5, 385.5, 409.0, and 416.9 mg g−1 at 298, 303, 308, and 313 K, respectively; at optimal conditions (pH=2, adsorbent dose=3.0 mg, and contact time of 30 min), surpassing that of most previously reported Cr(VI) adsorbents in the literature. A regeneration study revealed that this adsorbent possesses outstanding performance even after six consecutive recycling.

ROS-producing nanomaterial engineered from Cu(I) complexes with P2N2-ligands for cancer cells treating

The work presents core–shell nanoparticles (NPs) built from the novel Cu(I) complexes with cyclic P2N2-ligands (1,5-diaza-3,7-diphosphacyclooctanes) that can visualize their entry into cancer and normal cells using a luminescent signal and treat cells by self-enhancing generation of reactive oxygen species (ROS). Variation of P- and N-substituents in the series of P2N2-ligands allows structure optimization of the Cu(I) complexes for the formation of the luminescent NPs with high chemical stability. The non-covalent modification of the NPs with triblock copolymer F-127 provides their high colloidal stability, followed by efficient cell internalization of the NPs visualized by their blue (⁓450 nm) luminescence. The cytotoxic effects of the NPs toward the normal and some of cancer cells are significantly lower than those of the corresponding molecular complexes, which correlates with the chemical stability of the NPs in the solutions. The ability of the NPs to self-enhanced and H2O2-induced ROS generation is demonstrated in solutions and intracellular space by means of the standard electron spin resonance (ESR) and fluorescence techniques correspondingly. The anticancer specificity of the NPs toward HuTu 80 cancer cells and the apoptotic cell death pathway correlate with the intracellular level of ROS, which agrees well with the self-enhancing ROS generation of the NPs. The enhanced level of ROS revealed in HuTu 80 cells incubated with the NPs can be associated with the significant level of their mitochondrial localization.

Multifunctional Hydrogel Eye Drops for Synergistic Treatment of Ocular Inflammatory Disease.

Uveitis is a complex ocular inflammatory disease with a multifactorial etiology that can result in blindness. Although corticosteroid eye drops are the primary treatment for anterior uveitis, their efficacy is limited by low bioavailability, adverse effects, and a narrow focus on inflammation. In this study, the multifunctional hydrogel eye drops (designated as DCFH) were developed by incorporating the anti-inflammatory agent dexamethasone (DSP) and reactive oxygen species (ROS) scavenger cerium-based metal-organic frameworks (Ce-MOFs) into thermosensitive triblock copolymer F127 for the synergistic treatment against uveitis. The resulting F127 eye drops offer a favorable alternative to ophthalmic solution due to its thermosensitivity, thixotropy, light transmittance, improved ocular bioavailability, and unexpected anti-inflammatory efficacy. Notably, the participation of nanoporous Ce-MOFs, functional drug carriers, not only reduces ROS level but also boosts the anti-inflammatory activity of DSP in vitro. Therapeutically, the multifunctional DCFH exhibits superior efficacy in treating endotoxin-induced uveitis by mitigating the ophthalmic inflammatory reaction, suppressing inflammatory cytokines (e.g., TNF-α, IL-6, and IL-17) and downregulating the expression of iNOS and NLPR3. This synergistic treatment provides a valuable and promising approach for the management of uveitis and other ocular inflammatory conditions.

Bioinspired synthesis of micelle-templated ultrathin silica-layered mesoporous nanoparticles with enhanced mass transfer and stability for biocatalysis

Bioinspired enzyme encapsulation technologies have received increasing attention in sustainable development owing to the enzyme protection from external stressors while mimicking the cellular environment and structure. In this study, we developed a diatom-inspired synthesis of ultrathin silica-layered nanoparticles directed by silica-forming R5 peptide- and carbonic anhydrase (CA)-functionalized micelles. Each CA and R5 peptide was covalently conjugated with N-hydroxysuccinimide (NHS)-ester-modified hydrophilic ends of the triblock copolymer F127 (F127–CA and F127–R5). F127–CA/R5 micelles were prepared by controlling the molar ratio of F127–CA and F127–R5. F127–CA/R5 micelle@silica nanoparticles (SiNPs) were synthesized through R5 peptide-catalyzed silicification of the F127–CA/R5 micelle in a two-phase system. F127–CA/R5 micelle@SiNPs exhibited uniform and monodisperse particles with a size of 17 nm, indicating the formation of a ∼1.5-nm ultrathin and mesoporous silica layer compared with F127–CA/R5 micelle. F127–CA/R5 micelle@SiNPs exhibited almost identical KM and kcat values in CO2 hydration activity compared with the free enzyme. In addition, F127–CA/R5 micelle@SiNPs also showed enhanced stability compared to free ngCA under the operation condition of CO2 capture and sequestration with good storage stability. These results indicated that an ultrathin and mesoporous silica layer on the micelle could protect enzymes from external environments while minimizing limited mass transfer. Thus, our strategy could offer a new direction for enzyme-based green chemistry in practical applications, providing enhanced mass transfer and stability.

Photoassisted synthesis of high-crystallinity TS-1 with triblock copolymer F127 and its application for photodegradation of erythromycin

As a successful industrial catalyst, titanium silicalite-1 zeolite (TS-1) is limited as a photocatalyst in wastewater treatment due to the complexity and high energy consumption of its synthesis. Here, a novel synthesis hierarchical TS-1 was developed using triblock copolymer F127 and a phototreatment synthesis method. This method resulted in a super high crystallinity of the synthesized TS-1. A synthesis mechanism was proposed, and some reactions between Si and Ti species were studied by density functional theory (DFT) calculations. Compared to TS-1 synthesized using the conventional method, the catalyst in this study exhibited superior performance in the interfacial charge transport efficiency. In the removal of the antibiotic erythromycin from water, the synthesized catalyst demonstrated exceptional performance in terms of adsorption, photoactivity, stability and anti-interference ability against pH, anions, and cations. These findings suggested that the synthesis method used in this work is feasible, and the TS-1 products have great potential in pollutant degradation.

Glucose-derived zirconium-containing mesoporous composite for efficient catalytic transfer hydrogenation of furfural to furfuryl alcohol

Meerwein-Ponndorf-Verley (MPV) reaction has been widely acknowledged to be a mild catalytic transfer hydrogenation method for selective reduction of biomass-derived furfural to furfuryl alcohol. Herein zirconium-containing mesoporous composite catalyst was developed through the combination of sol-gel process and soft templating method, in which naturally abundant glucose and F127 triblock copolymer were used as the ligand and pore-forming agent, respectively. The hydroxyl groups in glucose molecules were demonstrated to be coordinated with zirconium ion during hydrolysis-condensation of zirconium precursor, leading to the even dispersion of zirconia nanoparticles in the composite catalyst. The composite catalyst was proven to be highly efficient for catalyzing MPV reduction of furfural with the maximum furfuryl alcohol yield of 93.4% at 180 °C within 180 min in 2-propanol, which served as both solvent and reductant. The composite also showed a good reusability. After five consecutive reaction cycles, furfuryl alcohol yield was slightly reduced from 93.4% to 77.7%, but it could be recovered to 92.8% after the reused composite was regenerated with dilute alkali solution. Batch experiments and systematic characterizations demonstrated that the excellent catalytic performance of composite catalyst was determined by multiple factors mainly including the stronger Lewis acidity, a considerable amount of basic site and the rich mesoporous structure. This study provides a facile strategy to prepare multifunctional composite catalysts using naturally abundant carbohydrates as the feedstocks for lignocellulosic biorefinery.

Effect of salt addition on a triblock copolymer-zwitterionic surfactant assembly: insight from excited-state proton transfer.

Copolymer-surfactant assemblies are frequently utilized across various fields, from medicine to nanotechnology. Understanding the organization of the mixed assemblies in a saline environment will further expand their application horizons, especially under physiological conditions. Excited-state proton transfer (ESPT) can provide insight into the hydration nature and organization of the non-toxic assembly of a triblock copolymer F127 (poly-(ethylene oxide)101 (PEO101)-poly(propylene oxide)56 (PPO56)-PEO101)) and a zwitterionic sulfobetaine surfactant N-dodecyl-N,N-dimethyl-3-ammoniopropane sulfonate (SB12). Here, we present a comprehensive investigation of the compactness and hydration nature of the F127-SB12 mixed assemblies at different salt concentrations using the ESPT of 8-hydroxy pyrene-1,3,6-trisulfonate (HPTS). In the absence of salts, gradual SB12 addition to a premicellar (0.4 mM) or a post-micellar (4 mM) F127 solution leads to an anomalous modulation of the protonated and deprotonated emission bands. The emission intensity ratio (protonated/deprotonated) first increases to a maximum at a particular SB12 concentration (6 mM and 35 mM for the premicellar and post-micellar F127 assemblies, respectively), and then the ratio decreases with a further increase in the surfactant concentration. Since the intensity ratio is an indicator of the retardation of the ESPT process, the mixed micellar configuration displaying a maximum intensity ratio represents the most compact and least hydrated state. Salt addition to this configuration lowers the intensity ratio, signifying an enhanced ESPT process. Dynamic light scattering (DLS) results indicate that the size of the mixed assembly remains almost unaltered with the addition of salts. Thus, salinity enhances the ESPT process inside the F127-SB12 mixed assemblies without significantly altering the hydrodynamic radius.

Amphiphilic interaction-mediated ordering of nanoparticles in Pickering emulsion droplets.

For various industrial processes, the stabilization of an oil phase is crucial and demands a proper balance of complex interactions in an emulsion system. In Pickering emulsions, this is achieved by introducing nanoparticles, which become organized at the oil-water interface. The influence of interparticle interactions towards the formation of a stable emulsion and the ordering of the stabilizing nanoparticles is intriguing and needs attention. In this work, the role of amphiphilic interactions between hydrophilic silica nanoparticles and the Pluronic F127 tri-block co-polymer towards the spontaneous formation of a fairly stable Pickering emulsion has been studied using small-angle X-ray scattering. Unlike the usual random arrangements of the nanoparticles in a conventional Pickering emulsion, we observed highly organized silica nanoparticles at the oil-water interface. The established standard raspberry structural model of the Pickering emulsion fails to explain such strong ordering as observed in the present case. A plausible formation mechanism of the present Pickering emulsion with a high on-surface silica correlation is elucidated on the basis of the combined interactions of the block co-polymer and silica particles. A computer model is developed to elucidate the effects of size and distribution of the surface-decorating nanoparticles and their positional correlation.

Preparation and Application of a Magnetic Oxidized Micro/Mesoporous Carbon with Efficient Adsorption for Cu(II) and Pb(II).

Water pollution is a worldwide problem that requires urgent attention and prevention and exceeding use of heavy-metal ions is one of the most harmful factors, which poses a serious threat to human health and the ecological environment. In this work, a magnetic oxidized micro/mesoporous carbon (MOMMC) was prepared for the easy separation of Cu(II) and Pb(II) from water. The dual-template method was used to prepare micro/mesoporous carbon using sucrose as the carbon source, silica nanoparticles formed by tetraethyl orthosilicate as the microporous templates, and triblock copolymer F127 as the mesoporous template. MOMMC was obtained by oxidation using potassium persulfate and then magnetized through in situ synthesis of Fe3O4 nanoparticles. FTIR, TG-DSC, XRD, TEM, SEM, nitrogen adsorption-desorption isotherms, zeta potential, and VSM were used to confirm the synthetic process, structure, and basic properties of MOMMC. The high-saturation magnetization (59.6 emu·g-1) of MOMMC indicated its easy and fast separation from water by an external magnetic field. Kinetics studies showed that the adsorption of Cu(II) and Pb(II) on MOMMC fit the pseudo-second-order model well. Isotherm studies showed that the adsorption behavior of Cu(II) was better described by the Langmuir model, and the adsorption behavior of Pb(II) was better described by both Langmuir and Redlich-Peterson models. MOMMC obtained efficient adsorption for Cu(II) and Pb(II) with the large adsorption capacity of 877.19 and 943.40 mg·g-1 according to the Langmuir adsorption isotherm equation, and a better selectivity for Pb(II) was observed in competitive adsorption. MOMMC still possessed a large adsorption capacity for Cu(II) and Pb(II) after three adsorption-desorption cycles. These findings show that MOMMC represents an excellent adsorption material for the efficient removal of heavy-metal ions.

Conquering Cancer Multi-Drug Resistance Using Curcumin and Cisplatin Prodrug-Encapsulated Mesoporous Silica Nanoparticles for Synergistic Chemo- and Photodynamic Therapies.

Recently, the development of anti-cancer approaches using different physical or chemical pathways has shifted from monotherapy to synergistic therapy, which can enhance therapeutic effects. As a result, enormous efforts have been devoted to developing various delivery systems encapsulated with dual agents for synergistic effects and to combat cancer cells acquired drug resistance. In this study, we show how to make Institute of Bioengineering and Nanotechnology (IBN)-1-based mesoporous silica nanoparticles (MSNs) for multifunctional drug delivery to overcome drug resistance cancer therapy. Initially, curcumin (Cur)-embedded IBN-1 nanocomposites (IBN-1-Cur) are synthesized in a simple one-pot co-condensation and then immobilized with the prodrug of Cisplatin (CP) on the carboxylate-modified surface (IBN-1-Cur-CP) to achieve photodynamic therapy (PDT) and chemotherapy in one platform, respectively, in the fight against multidrug resistance (MDR) of MES-SA/DX5 cancer cells. The Pluronic F127 triblock copolymer, as the structure-directing agent, in nanoparticles acts as a p-glycoprotein (p-gp) inhibitor. These designed hybrid nanocomposites with excellent structural properties are efficiently internalized by the endocytosis and successfully deliver Cur and CP molecules into the cytosol. Furthermore, the presence of Cur photosensitizer in the nanochannels of MSNs resulted in increased levels of cellular reactive oxygen species (ROS) under light irradiation. Thus, IBN-1-Cur-CP showed excellent anti-cancer therapy in the face of MES-SA/DX5 resistance cancer cells, owing to the synergistic effects of chemo- and photodynamic treatment.

Hierarchically Annular Mesoporous Carbon Derived from Phenolic Resin for Efficient Removal of Antibiotics in Wastewater.

Antibiotics have become a new type of environmental pollutant due to their extensive use. High-performance adsorbents are of paramount significance for a cost-effective and environmentally friendly strategy to remove antibiotics from water environments. Herein, we report a novel annular mesoporous carbon (MCN), prepared by phenolic resin and triblock copolymer F127, as a high-performance adsorbent to remove penicillin, streptomycin, and tetracycline hydrochloride from wastewater. The MCNs have high purity, rich annular mesoporosity, a high surface area (605.53 m2/g), and large pore volume (0.58 cm3/g), improving the adsorption capacity and facilitating the efficient removal of penicillin, streptomycin, and tetracycline hydrochloride from water. In the application of MCNs to treat these three kinds of residual antibiotics, the adsorption amounts of tetracycline hydrochloride were higher than penicillin and streptomycin, and the adsorption capacity was up to 880.6 mg/g. Moreover, high removal efficiency (99.6%) and excellent recyclability were achieved. The results demonstrate that MCN adsorbents have significant potential in the treatment of water contaminated with antibiotics.

A Facile Fabrication of Ordered Mesoporous Carbons Derived from Phenolic Resin and Mesophase Pitch via a Self-Assembly Method

Ordered and disordered mesoporous structures were synthesized by a self-assembly method using a mixture of phenolic resin and petroleum-based mesophase pitch as the starting materials, amphiphilic triblock copolymer F127 as a soft template, hydrochloric acid as a catalyst, and distilled water as a solvent. Then, mesoporous carbons were obtained via autoclave method at low temperature (60 °C) and then carbonization at a relatively low temperature (600 °C), respectively. X-ray diffraction (XRD), small-angle X-ray scattering (SAXS), and transmission electron microscopy (TEM) analyses revealed that the porous carbons with a mesophase pitch content of approximately 10 wt% showed a highly ordered hexagonal mesostructure with a highly uniform pore size of ca. 5.0 nm. In addition, the mesoporous carbons prepared by self-assembly and low-temperature autoclave methods exhibited the amorphous or crystalline carbon structures with higher specific surface area (SSA) of 756 m2/s and pore volume of 0.63 cm3/g, depending on the synthesis method. As a result, mesoporous carbons having a high SSA were successfully prepared by changing the mixing ratio of mesophase pitch and phenolic resin. The electrochemical properties of as-obtained mesoporous carbon materials were investigated. Further, the OMC-meso-10 electrode delivered the maximum SC of about 241 F/g at an applied current density of 1 A/g, which was higher than those of the MC-10 (~104 F/g) and OMC-20 (~115 F/g).

Porous cobaltate: Structure, active sites, thermocatalytic properties for ammonium perchlorate decomposition

Co3O4 is an excellent catalyst for the thermal decomposition of ammonium perchlorate (AP) due to its spinel structure and more Co3+ as catalytically active sites. In this work, MCo2O4 (M=Fe, Cu, Ni and Zn) with different Co species substituted with transition metal ion were prepared using triblock copolymer F127 as soft template by simple solvothermal and subsequent heat treatment. The porous MCo2O4 samples have higher Co3+ / Co2+ ratio than Co3O4, and exhibits better catalytic performance for thermal decomposition of AP. Especially with the addition of FeCo2O4, the high decomposition temperature (HDT) of AP decreases by an amazing 196.25 °C, showing the most excellent catalytic performance. The activation energy (Ea) decreases from 290.19 kJ·mol−1 for pure AP to 203.05 kJ·mol−1, while the reaction rate (k) increases from 0.499 s−1 to 1.699 s−1. Based on the electron transfer theory, the catalytic mechanism and active site of porous MCo2O4 series cobaltate materials are discussed. The results show that the porous FeCo2O4 not only has highest specific surface, but also has the highest Co3+/ Co2+ ratio, which suggest that the Co3+ on octahedral coordination sites is known as the catalytic active site for AP thermal decomposition.

Comparison of interaction patterns of a triblock copolymer micelle with zwitterionic vs. cationic surfactant: An excited-state proton transfer dynamics investigation

This investigation explored the interaction between a triblock copolymer F127 (poly-(ethylene oxide)101 (PEO101)–poly(propylene oxide)56 (PPO56)–PEO101)) micelle and a zwitterionic sulfobetaine surfactant N-dodecyl-N, N-dimethyl-3-ammoniopropane sulfonate (SB3–12 or SB12), primarily utilizing the excited-state proton transfer (ESPT) dynamics of a photoacid, 8-hydroxy pyrene-1,3,6-trisulfonate (HPTS). We compared the obtained interaction pattern to that of the cationic surfactant, dodecyl trimethylammonium bromide (DTAB or C12TAB), with the same alkyl chains. The two surfactants, irrespective of charge differences, grossly follow the same pattern as manifested by the change in the intensity ratio of the protonated and deprotonated emission bands. For both cases, the ratio first increases above a specific surfactant concentration, attaining a maximum at a particular concentration. The ratio decreases at a high concentration and finally levels off at a very high concentration. Interestingly, the ratio attains maximum for a post-micellar (30–35 mM) concentration (~ 10 times higher than critical micellar concentration or CMC) for SB12 whereas, the maximum occurs at a sub-micellar (6–8 mM) concentration (significantly lower than its CMC) for DTAB. Detailed analysis of the time-dependent emission intensity ratio reveals that ESPT dynamics is slower in the optimum F127-SB12 assembly than in the case of the cationic surfactant. The fluorescence anisotropy decay of 8-methoxypyrene-1,3,6-trisulfonate (MPTS), a methoxy analog of HPTS, also corroborates well with the anomalous pattern; the rotational dynamics become more retarded inside the F127-SB12 assembly than in the case of the cationic surfactant. Thus, although SB12 requires a higher surfactant concentration to acquire the optimum state, it results in a more organized and less hydrated state than the cationic surfactant.

Preparation of biocompatible hydrogels reinforced by different nanosheets.

The impact of inorganic nanosheets with various chemical compositions and properties at different concentrations on the rheological properties and the gelation formation of a thermo-responsive hydrogel was investigated. F127 Pluronic triblock copolymers, with the structure (EO)99(PO)65(EO)99 (EO: ethylene oxide and PO propylene oxide respectively), functionalized by dimethacrylate (F127-DMA) at a concentration of 25% was used in this study. After careful characterization by complementary techniques: transmission electron microscopy (TEM), atomic force microscopy (AFM), and X-ray diffraction of nanosheets derived from the peeling of layered materials (montmorillonite, organoclays and hexaniobate), the nanosheets were seen to be suitably dispersed in the hydrogels. The inclusion of hydrophobic nanosheets (i.e. those treated with the grafting of surfactants onto their surface: organoclays and hexaniobate) leads to a depression of the gelation temperature while the nanocomposites exhibit an enhancement of their elastic properties, as determined by rheological measurements. In contrast, the inclusion of hydrophilic nanosheet derived from raw montmorillonite engenders an opposite trend. The whole nanocomposites whose gelation temperature can be tuned by both the nature and concentration of the nanosheets were successfully photopolymerized allowing the formation of a 3D structure containing a large content of water. The results obtained in this study open new perspectives for possible uses of hydrogel-based nanocomposites as embedding matrixes for bio-organisms.

A Sequential Therapeutic Hydrogel With Injectability and Antibacterial Activity for Deep Burn Wounds' Cleaning and Healing.

As a severe clinical challenge, escharotomy and infection are always the core concerns of deep burn injuries. However, a usual dressing without multifunctionality leads to intractable treatment on deep burn wounds. Herein, we fabricated a sequential therapeutic hydrogel to solve this problem. Cross-linked by modified polyvinyl alcohol (PVA-SH/ε-PL) and benzaldehyde-terminated F127 triblock copolymers (PF127-CHO), the hydrogel demonstrated excellent mechanical properties, injectability, tissue adhesiveness, antibacterial activity, biocompatibility, and satisfactory wound cleaning through both in vitro and in vivo assays. Additionally, based on the conception of “sequential therapy,” we proposed for the first time to load bromelain and EGF into the same hydrogel in stages for wound cleaning and healing. This work provides a strategy to fabricate a promising wound dressing for the treatment of deep burn wounds with injectability and improved patients’ compliance as it simplified the process of treatment due to its “three in one” characteristic (antibacterial activity, wound cleaning, and healing effects); therefore, it has great potential in wound dressing development and clinical application.

Templated synthesis of CuCo2O4-modified g-C3N4 heterojunctions for enhanced photoreduction of Hg2+ under visible light

BackgroundThe accumulation of mercury (II) ions (Hg2+) in wastewater causes critical impacts on human health and the whole environment. MethodsThis study report an efficient synthesis of CuCo2O4/g-C3N4 p-n heterojunction by templated growth via triblock copolymer F-127 and mesoporous silica MCM-41 for enhanced photoreduction of Hg2+. Significant FindingsThe 22.6 nm CuCo2O4 nanoparticles were anchored on g-C3N4 at minor content (0.5−2.0 wt. %) as observed by TEM analysis. The formed heterojunctions exhibited mesoporous surface textures with high specific surface areas. In addition, the visible-light harvesting of g-C3N4 was improved by adding CuCo2O4 due to the reduction of the bandgap energy from 2.77 to 2.17 eV. The complete visible-light photocatalytic reduction of Hg2+ utilizing 1.5 wt.% CuCo2O4-modified g-C3N4 was realized with a tremendous rate of 286.5 µmol min−1 after dose tuning at 1.5 gL−1. The enhanced catalytic presentation of this innovative CuCo2O4/g-C3N4 is denoted to the significant separation of photoinduced carriers through the p-n heterojunction's interface. The bearable photocatalytic reduction of Hg2+ for five cycles was also established for the regenerated photocatalyst.