Access to 2,4-Disubstituted Pyrrole-Based Polymer with Long-Wavelength and Stimuli-Responsive Properties via Copper-Catalyzed [3+2] Polycycloaddition.

Pyrrole-based polymers (PBPs), a type of fascinating functional polymers, play a crucial role in materials science. However, efficient synthetic strategies of PBPs with diverse structures are mainly focused on conjugated polypyrroles and still remain challenging. Herein, an atom and step economy protocol is described to access various 2,4-disubstituted PBPs by in situ formation of pyrrole core structure via copper-catalyzed [3+2] polycycloaddition of dialkynones and diisocyanoacetates. A series of PBPs is prepared with high molecular weight (Mw up to 18 200 Da) and moderate to good yield (up to 87%), which possesses a fluorescent emission located in the green to yellow light region. Blending the PBPs with polyvinyl alcohol, the stretchable composite films exhibit a significant strengthening of the mechanical properties (tensile stress up to 59 MPa, elongation at break >400%) and an unprecedented stress-responsive luminescence enhancement that over fourfold fluorescent emission intensity is maintained upon stretching up to 100%. On the basis of computational studies, the unique photophysical and mechanical properties are attributed to the substitution of carbonyl chromophores on the pyrrole unit.

An Opto- and Thermal-Rewrite PCM/CNF-IR 780 Energy Storage Nanopaper with Mechanical Regulated Performance.

In spite of efforts to fabricate self-assembled energy storage nanopaper with potential applications in displays, greenhouses, and sensors, few studies have investigated their multiple stimuli-sensitivities. Here, an opto- and thermal-rewrite phase change material/cellulose nanofibril (PCM/CNF) energy storage nanopaper with mechanical regulated performance is facilely fabricated, through 5 min sonication of PCMs and CNFs in an aqueous system. The combination of PCM and CNF not only guarantees the recyclability of PCM without leakage, but also offers nanopaper adaptive properties by leveraging the mobility and optical variation accompanying solid-to-liquid transition of PCM. Besides, trace near-infrared (NIR) dye (IR 780) in it imparts a PCM-embedded nanopaper photothermal effect to modulate the local transparency via time- and position-controlled laser exposure, leading to a reusable opto-writing nanopaper. Furthermore, since the synergistic effect of stick-and-slip function attributes from PCMs and pore structures are produced by calcium ions, the PCM/CNF energy storage nanopaper exhibits excellent mechanically regulated performance from rigid to flexible, which greatly enriches their application in energy-efficient smart buildings and displays.

All-Organic Superhydrophobic Coating Comprising Raspberry-Like Particles and Fluorinated Polyurethane Prepared via Thiol-Click Reaction.

Mechanically robust superhydrophobic coatings have been extensively reported using chemically susceptible inorganic fillers like slica, titanium dioxide, and zinc oxide for constructing micro-nano structures. Organic particles are good candidates for improving chemical resistance, whereas the synthesis of organic particles with well-defined and stable micro-nano structures remains exclusive. Here, an all-organic, cross-linked superhydrophobic coating comprising raspberry-like fluorinated micro particles (RLFMP) and fluorinated polyurethane (FPU) is prepared via thiol-click reaction. Benefiting from the robust micro-nano structure of RLFMP and the excellent flexibility of FPU, the coating can maintain superhydrophobicity after severe alkali corrosion or mechanical damage, while the superhydrophobicity can be repaired readily by the fast recovery of micro-nano roughness and migration of branched fluoroalkyl chains to the coating surface. This design strategy is expected to provide a good application of thiol-click chemistry.

Preparation of Poly(thiol-urethane) Covalent Adaptable Networks Based on Multiple-Types Dynamic Motifs.

To solve the issue of polymeric materials recycling, developing intrinsic self-healing materials containing dynamic bonds has attracted many researchers' highly concerning. However, the tradeoff between their mechanical strength and stretchability always does not avoid. Herein, to surmount the above tradeoff, metal-ligand (Cu2+ -S) interactions are introduced into the cross-linking polythiourethane covalent adaptable networks (PTU CANs) with three kinds of dynamic motifs (thiourethane, disulfide, and hydrogen bonds). When the molar ratio of Cu2+ to S is 6.37%, the break strength (9.41 ± 0.34 MPa) and Young's modulus (26.02 ± 0.55 MPa) of the metal-ligand coordination complex PTU (Cu2+ -PTU-3) dramatically increase, whereas the peak strain almost does not decline (454.44 ± 3.95%). To conduct the repairing, Cu2+ -PTU-3 is further confirmed excellent repairing capability. Therefore, these new PTU CANs have significant potential for the new self-healing materials.

A Three-Armed Polymer with Tunable Self-Assembly and Self-Healing Properties Based on Benzene-1,3,5-tricarboxamide and Metal-Ligand Interactions.

The dynamic nature of supramolecules makes them useful in the fields of smart devices. The combination of multiple dynamic interactions in one material may bring some enhanced properties in mechanical property, self-healing property, or recyclability. Thus, it is significantly meaningful to design new materials with multi-dynamic bonds and clarify their bonding mechanisms. Here, a novel three-armed polymer based on benzene-1,3,5-tricarboxamide (BTA) is developed and the polymer could be further complexed by metal ions to form dynamic zinc-imidazole interactions. In this system, BTA is located in the center, and the ligand-functionalized monomer is copolymerized with n-butyl acrylate to form three chains. This is the first time BTA is introduced to a self-healing system to endow the polymer with assembly and self-healing properties. The composition, chemical structure, assembly behavior, mechanical properties, and self-healing properties of the polymer are investigated. It is revealed that the assembly behavior of the polymer depends on the BTA contents and time. The mechanical property can be easily tuned by ligand/metal ratio and is significantly adjusted by the polymer chain length and environment humidity. Long polymer chains not only contribute to good mechanical property but also promote the self-healing process due to the effective physical entanglement.

Highly Thermally Conductive Polyimide Composites via Constructing 3D Networks.

Easy and high efficient methods are in great demand to obtain polyimide (PI) composites with high thermal conductivity in the electronic packaging field. In this work, PI/boron nitride (BN) composites with high thermal conductivity are easily fabricated. Tightly connected and well-arranged BN platelets construct effective 3D thermally conductive networks in the PI matrix upon hot pressing, after BN platelets are coated on the surface of PI granules by the help of a kind of PI adhesive. The thermal conductivity of the PI/BN composites reaches as high as 4.47 W mK-1 at a low BN loading of 20 vol%, showing an enhancement of 2099%, compared to pure PI. Such enhancement of the thermal conductivity is the highest compared with the results in the open literature. Our work is a good example that utilized the sufficient physical connection (aggregates) of thermally conductive fillers to significantly promote the thermal conductivity of polymer composites.

Synthesis of Negative-Charged Metal-Containing Cyclomatrix Polyphosphazene Microspheres Based on Polyoxometalates and Application in Charge-Selective Dye Adsorption.

A negative-charged, metal-containing cyclomatrix polyphosphazene microsphere (MCPM) is synthesized using the strategy of precipitation polymerization of di-functionalized polyoxometalates (POMs) and hexachlorocyclotriphosphazene. The chemical structure of these MCPMs is well characterized by 13 C MAS NMR and 31 P MAS NMR, as well as FT-IR, electron microscopy, and X-ray photoelectron spectroscopy. The covalent grafting of the rigid POMs clusters into the framework of these microspheres prevents the collapsing of the pores, making these MCPMs porous materials. Taking advantage of the porous structure and the negative charges in the frameworks, these materials show interesting charge-selective adsorption properties, as demonstrated by the selective adsorption of positive-charged dyes in comparison with negative-charged dyes.

A Novel Reprocessable and Recyclable Acrylonitrile-Butadiene Rubber Based on Dynamic Oxime-Carbamate Bond.

The covalent cross-linked rubber has outstanding mechanical properties and chemical resistance, making it possible for a wide range of applications. Towards efforts to resource waste and environmental pollution, rubber recycling is a concerning problem. However, it is a big challenge to endow the most widely used commercial rubber systems with recyclability. In this paper, a novel reprocessable and recyclable acrylonitrile-butadiene rubber (NBR) is developed by introducing oxime-carbamate bonds into the raw NBR. Amidoxime NBR is prepared by a nucleophilic addition reaction of hydroxylamine hydrochloride and raw NBR, and then cross-linked amidoxime NBR using different amounts of toluene diisocynate (TDI). Results show that the obtained material exhibits good reprocessable property; the repairing efficiency exceeds 90% after two remoldings. In addition, it also has better mechanical properties: A tensile strength reaching a maximum value of 4.85 MPa when TDI cross-linker is 15.36 wt%, which is superior to vulcanized NBR (3.18 MPa).

Surface Microstructure Regulation of Porous Polymer Microspheres by Volume Contraction of Phase Separation Process in Traditional Suspension Polymerization System.

In the present work, the suspension polymerization method is used for the preparation of porous polymer microspheres with different surface morphology, and the preparation mechanism is systematically expounded. The morphology results show that the smooth, convex, and wrinkled microspheres could be controlled by adjusting the ratio of monomer to porogens. The micelles forming the framework support the "Eggshell," and its size and shape directly affect the morphology of "Eggshell." The addition of monomers (GMA), whose polymer has low glass transition temperature (Tg ), is important for the formation of wrinkled morphology. The amount of toluene and polydimethylsiloxane also affects the surface morphology of microspheres. In addition, the effect of polydimethylsiloxane is also more significant. The preparation process of the wrinkled P(GMA-St-EGDA) microspheres with abundant epoxy groups can be amplified. The morphology of the material prepared in the 100 L reactor is well maintained, and the yield in the size range of 80-160 µm is more than 80%. The surface wrinkled porous polymer microspheres have potential applications in the fields of enzyme carrier, separation and purification, and light scattering.

Bovine serum albumin surface imprinted polymer fabricated by surface grafting copolymerization on zinc oxide rods and its application for protein recognition.

A novel bovine serum albumin (BSA) surface imprinted polymer based on ZnO rods was synthesized by surface grafting copolymerization. It exhibited an excellent recognition performance to bovine serum albumin. The adsorption capacity and imprinting factor of bovine serum albumin could reach 89.27 mg/g and 2.35, respectively. Furthermore, the fluorescence property of ZnO was used for tracing the process of protein imprinting and it implied the excellent optical sensing property of this material. More importantly, the hypothesis that the surface charge of carrier could affect the imprinting process was confirmed. That is, ZnO with positive surface charge could not only improve the recognition specificity of binding sites to template proteins (pI < 7), but also deteriorate the bindings between sites and non-template proteins (pI > 7). It was also important that the reusability of ZnO@BSA molecularly imprinted polymers was satisfactory. This implied that the poor mechanical/chemical stability of traditional zinc oxide sensors could be solved by the introduction of surface grafting copolymerization. These results revealed that the ZnO@BSA molecularly imprinted polymers are a promising optical/electrochemical sensor element.

Functional thiolactone assisted imprinting cavities with abundant amines for strong binding of protein imprinted nanospheres.

In order to develop new protein imprinting polymerization methods and to prepare protein imprinted nanomaterials with high recognition, a novel protein imprinted strategy is developed in this study by using polyethyleneimine (PEI) for aminolysis of tailor-made thiolactone-based functional monomers and crosslinkers on amine-modified magnetic nanospheres in an aqueous medium. The prepared protein imprinted nanospheres can seize BSA templates in the imprinting polymerization process through multiple hydrogen bonds, and hydrophobic and electrostatic interactions. In addition, the aminolysis reaction also generates abundant amide bonds in the imprinting polymer network, which not only enhances the hydrogen bonding interactions between the imprinted nanospheres and BSA but also improves the stability of the imprinting cavities by increasing the rigidity of the polymer chains. Based on the above advantages, the protein imprinted nanospheres show excellent rebinding specificity for BSA, for which the rebinding capacity is up to 505 ± 15 mg g-1 and the imprinting factor is 4.09. The protein imprinted nanospheres exhibit fast adsorption kinetics, outstanding reusability, and can selectively separate BSA from a protein mixture and actual biological samples. The generality of this imprinted method is also verified. Thus, this study will provide a new idea for the design of protein imprinted materials with high recognition.

Pyrrolidinyl ligand motif-assisted bovine serum albumin molecularly imprinted polymers with high specificity.

Ideal binding ligands for anchoring proteins are essential for the design and assembly of desirable molecularly imprinted polymers (MIPs). In this study, bovine serum albumin-MIPs (BSA-MIPs) were successfully prepared by orchestrating the involvement of orientation-controllable binding ligands via sequential thiol-ene click and thiol-ene-amine conjugation. We showed that the optimal thiol-ene-amine conjugates and binding ligands were decisive in determining the rebinding capacity and selectivity. The pyrrolidinyl MIPs exhibited the best adsorption capacity of 352 ± 22 mg/g and a superior imprinting factor of 4.72 among MIPs with various binding ligands. These favourable results were further studied by computational simulation and isothermal titration calorimetry (ITC). Molecular docking revealed the preferential binding free energy and H-bonds between BSA residues and the thiol-ene-amine conjugates. Meanwhile, the pyrrolidinyl ligand motif enabled entropy-favourable affinity to be achieved via hydrophobic effects with the BSA template by ITC thermodynamics. Because of these favourable bindings, the MIPs exhibited excellent adsorption specificity to BSA over competing proteins. The proof-of-concept of MIPs with orientation-controllable conjugates and proven binding ligands for target proteins demonstrates that this material is promising for use with a real biological sample.

Ring -opening of polythiolactones to construct protein-imprinted nanospheres with high recognition and regulation capabilities.

Developing and preparing novel protein-imprinted nanomaterials with high recognition ability remains challenging because it is difficult to controllably and orderly design and arrange functional groups on the imprinted polymer layers of protein-imprinted nanomaterials to improve their protein identification. Herein, we present a new technology using rationally designed polythiolactone-decorated magnetic nanospheres as the precursor of multifunctionalized imprinted materials. Moreover, the strategy of ring-opening the polythiolactione layers using primary amines with terminal alcohols, acids and pyrrolidines introduces abundant recognition sites, which enhance the recognition for template proteins through multiple hydrogen-bonding and hydrophobic interactions. Thiols generated in situ by the ring-opening reaction provide sufficient crosslinking sites proximate to each recognition site for the formation of imprinting cavities, endowing the imprinted nanospheres with promising regulation capabilities. Based on the rational design, the imprinted nanospheres can be prepared conveniently and present tunable rebinding capacity and specificity for bovine serum albumin (BSA). The maximum saturated rebinding capacity of imprinted materials for BSA is up to 285 ± 15 mg g-1 and the highest imprinting factor reaches 5.79. The simple and versatile strategy demonstrated in this study shows promise for the design of other protein-imprinted materials with high recognition ability.

Cobalt-Iron Double Ion-Bovine Serum Albumin Chelation-Assisted Thermo-Sensitive Surface-Imprinted Nanocage with High Specificity.

To develop multifunctional protein imprinted materials, a cobalt-iron double ion-BSA directional chelation-assisted thermo-sensitive surface-imprinted hollow nanocage (Co-Fe@CBMA-MIPs) with excellent specificity is developed on the surface of ZIF-67@Co-Fe in this study by synergizing the advantages of surface imprinting, metal ion chelation, anti-protein adsorption segments, and thermo-sensitive components. Beyond previous research, well-designed multifunctional protein-imprinted materials possess high binding capacity, fast adsorption kinetics, and outstanding selectivity. When the adsorption is carried out at 32 °C, the adsorption capacity of Co-Fe@CBMA-MIPs for BSA reaches 520.35 mg/g within 50 min. The imprinting factor is 8.55. The selectivity factors of Co-Fe@CBMA-MIPs for HSA, Bhb, OVA, and Lyz are 3.72, 6.09, 4.10, and 8.41, respectively. More significantly, Co-Fe@CBMA-MIPs could specifically recognize BSA from mixed proteins and actual samples and exhibit excellent repeated use stability. Based on the above advantages, the development of this research provides an effective means to improve the recognition specificity of molecularly imprinted polymers.

Fabrication of Raspberry-like Cytochrome C Surface-Imprinted Nanoparticles Based on MOF Composites for High-Performance Protein Separation.

The development of high-performance protein-imprinted materials is vital to meet the requirements of proteomics research but remains a challenge. Herein, a new type of raspberry-like cytochrome C-imprinted nanoparticle was first designed and fabricated via surface imprinting technology combined with a template immobilization strategy. In particular, the state-of-the-art metal-organic framework (MOF)/carbon nanoparticle (CN) composites were selected as protein immobilization carriers for two advantages: (1) the composites reflected the intrinsic characteristics of MOFs including flexible design, facile preparation, and extensive interactions with proteins and (2) the utilization of composites also overcame the issue associated with the severe agglomeration of individual MOFs during the post-use process. Therefore, the as-prepared composites exhibited a regular raspberry-like shape with good dispersion (polydispersity index (PDI) < 0.25), high specific surface area (551.4 m2 g-1), and outstanding cytochrome C immobilization capacity (900 mg g-1). Furthermore, a zwitterionic monomer was chosen to participate in the synthesis of an imprinting layer to reduce the nonspecific binding with proteins. As a result, the unique design presented here in both the protein immobilization carrier and the selected polymer composition endowed the imprinted material (noted as CN@UIO-66@MIPs) with the excellent ability for cytochrome C enrichment with extremely high recognition ability (imprinting factor (IF) = 6.1), rapid adsorption equilibrium time (40 min), and large adsorption capacity (815 mg g-1). Furthermore, encouraged by the experimental results, we successfully used CN@UIO-66@MIPs to specifically capture cytochrome C in mixed protein solutions and biological samples, which proved them to be a potential candidate for protein separation and purification.

Preparation of BSA surface imprinted manganese dioxide-loaded tubular carbon fibers with excellent specific rebinding to target protein.

Along with the wide development of protein imprinted polymers, the researchers still face many challenges, such as difficult template elution, slow adsorption rate and low adsorption capacity. In order to promote the progress of protein separation and purification, the surface imprinted manganese dioxide-loaded tubular carbon fibers (FTCFs@MnO2@MIPs) are prepared in this work. FTCFs@MnO2@MIPs are based on tubular carbon fibers (TCFs) coated with flaky MnO2. Dopamine (DA) and bovine serum albumin (BSA) are utilized as functional monomers and templates. The MnO2 nanosheets are grown and loaded on the surface of carboxyl-modified tubular carbon fibers (CMTCFs) to form a MnO2 shell, which provides more imprinting sites for protein imprinting. Meanwhile, this shell enhances the interaction between the imprinting sites and BSA. The content of MnO2 loaded on the surface of CMTCFs is 9.42%. The obtained materials are systematically characterized and the adsorption performances of FTCFs@MnO2@MIPs for BSA are investigated. The adsorption process of FTCFs@MnO2@MIPs exhibits significant self-driven characteristics. The adsorption capacity reaches 816.44 mg/g in 60 min and the imprinting factor (IF) is 3.31. FTCFs@MnO2@MIPs can selectively separate BSA from the mixed proteins and fetal bovine serum. Excellent reusability and practical application ability make MnO2-loaded tubular carbon fibers (FTCFs@MnO2) become a promising carrier in the field of protein imprinting.

Biodegradable conductive multifunctional branched poly(glycerol-amino acid)-based scaffolds for tumor/infection-impaired skin multimodal therapy.

The tumor/infection-impaired skin regeneration is still a challenge and the single modal therapy strategy is usually inefficient. Herein, a multimodal tumor therapy and antiinfection method based on the conductive multifunctional poly(glycerol-amino acid)-based scaffolds is reported. The multifunctional conductive scaffolds were formed through the crosslinking between branched poly(glycerol-amino acid), polypyrrole@polydopamine (PPy@PDA) nanoparticles and aldehyde F127 (PGFP scaffolds). PGFP scaffolds possessed controlled electrical conductivity, skin-adhesive behavior, broad-spectrum antibacterial activity, photothermal-responsive drug release and good cytocompatibility. Thus, PGFP scaffolds demonstrated the significant photothermo-chemo tumor and multidrug resistant infection therapy in vitro and in vivo, while promoting granulation tissue formation, collagen deposition, vascular endothelial differentiation and accelerated skin regeneration. This work also firstly demonstrated the important role of multifunctional conductive PPy@PDA nanoparticles in tumor/infection-impaired skin multimodal therapy. This study suggests that efficient multimodal therapy on diseased-impaired skin could be achieved through optimizing the structure and multifunctional properties of biomaterials.

[Preparation of warangalone-loaded liposomes and its inhibitory effect on breast cancer cells].

OBJECTIVE: To prepare warangalone-loaded thermosensitive liposomes (WLTSL) and evaluate its inhibitory effect on breast cancer cells in vitro. METHODS: MTT assay was used to assess the changes in proliferation of 3 breast cancer cell lines (MDA-MB-231, MCF7, and SKBR3) following treatment with warangalone, soy isoflavone and genistein. Colony-forming assay and wound healing assay was used to assess colony forming activity and migration of MDA-MB-231 cells treated with warangalone. The effect of warangalone on the expression of MMP2 and MMP9 in MDA-MB-231 cells was examined with Western blotting. The thermosensitive liposomes (TSL) and WLTSL were prepared using a thin film hydration method, and the morphology, size, encapsulation efficiency and stability of the prepared liposomes were characterized using transmission electron microscopy, dynamic light scattering scanning and UV spectrophotometry. MTT assay was used to examine the inhibitory effect of WLTSL on mouse breast cancer cells (4T1) in vitro. RESULTS: Warangalone showed stronger anti-proliferation effects than soy isoflavones and genistein in the 3 human breast cancer cell lines and significantly inhibited colony formation by MDA-MB-231 cells. Treatment with warangalone significantly inhibited migration of the breast cancer cells and down-regulated the cellular expressions of MMP2 and MMP9. The prepared TSL and WLTSL presented with a homogeneous, irregular spherical morphology, with a mean particle size of 56.23±0.61 nm, a polymer dispersity index of 0.241±0.014, a Zeta potential of -40.40±0.46 mV, and an encapsulation efficiency was 87.68±2.41%. WLTSL showed a good stability at 4 ℃ and 37 ℃ and a stronger inhibitory effect than warangalone in 4T1 cells. CONCLUSIONS: Warangalone inhibits the proliferation, migration and invasion of breast cancer cells, and the prepared WLTSL possesses good physical properties and strong anti-breast cancer activity.

Preparation of surface protein imprinted thermosensitive polymer monolithic column and its specific adsorption for BSA.

In this work, a novel thermosensitive surface protein imprinted polymer monolithic column (TsIPMC) was synthesized by combining high internal phase emulsion with 1,1-diphenylethene (DPE) controlled polymerization. Innovatively, DPE and acrylic acid (AA) monomers were introduced in high internal oil and water phases respectively. The research showed that DPE could not only initiate the polymerization of monomers, but also improve the pore performance of monolithic columns. The elution efficiency of template or target protein could be significantly improved by the thermoresponse characteristics of TsIPMC. The effects of DPE and AA on adsorption capacity and imprinting factor (IF) were studied. The optimization results presented that the optimal addition amounts were 55 mg and 50 mg. Under such conditions, the IF of as-prepared TsIPMC was 1.61 and the saturated adsorption capacity was 66 mg/mL. The influences of the flow rate and target protein concentration on the adsorption equilibrium time and effluent volume were revealed. TsIPMC showed higher selectivity for different competing proteins. The reuse stability result showed that the adsorption of TsIPMC to BSA decreased by 3.69% after 12 times of reuse, and the IF remained basically unchanged. TsIPMC would demonstrate the potential applications in the field of protein purification and separation.