Multifunctional homopolymer vesicles for facile immobilization of gold nanoparticles and effective water remediation

A glycopolymersome strategy for 'drug-free' treatment of diabetic nephropathy

Diabetic nephropathy is a severe complication of diabetes. Treatment of diabetic nephropathy is an important challenge due to persistent hyperglycemia and elevated levels of reactive oxygen species (ROS) in the kidney. Herein, we designed a glycopolymersome that can treat type 2 diabetic nephropathy by effectively inhibiting hyperglycemia and ROS-associated diabetic nephropathy pathogenesis. The glycopolymersome is self-assembled from phenylboronic acid derivative-containing copolymer, poly(ethylene oxide)45-block-poly[(aspartic acid)13-stat-glucosamine24-stat-(phenylboronic acid)18-stat-(phenylboronic acid pinacol ester)3] [PEO45-b-P(Asp13-stat-GA24-stat-PBA18-stat-PAPE3)]. PBA segment can reversibly bind blood glucose or GA segment for long-term regulation of blood glucose levels; PAPE segment can scavenge excessive ROS for renoprotection. In vitro studies confirmed that the glycopolymersomes exhibit efficient blood glucose responsiveness within 2 h and satisfactory ROS-scavenging ability with 500 μM H2O2. Moreover, the glycopolymersomes display long-acting regulation of blood glucose levels in type 2 diabetic nephropathy mice within 32 h. Dihydroethidium staining revealed that these glycopolymersomes reduced ROS to normal levels in the kidney, which led to 61.7% and 76.6% reduction in creatinine and urea levels, respectively, along with suppressing renal apoptosis, collagen accumulation, and glycogen deposition in type 2 diabetic nephropathy mice. Notably, the polypeptide-based glycopolymersome was synthesized by ring-opening polymerization (ROP) of N-carboxyanhydrides (NCAs), thereby exhibiting favorable biodegradability. Overall, we proposed a new glycopolymersome strategy for 'drug-free' treatment of diabetic nephropathy, which could be extended to encompass the design of various multifunctional nanoparticles targeting diabetes and its associated complications.

pH-Modulated 1D Hierarchical Self-Assembly of a Brush-Like Poly-Para-Phenylene Homopolymer

The controllable self-assembly of conjugated homopolymers, especially homopolymers without other segments (a prerequisite for phase separation), which can afford chances to achieve tunable optical/electronic properties, remains a great challenge due to their poor solubility and has remained rarely documented. Herein, a conjugated homopolymer (DPPP-COOH) is synthesized, which has a unique brush-like structure with a conjugated dendritic poly-para-phenylene (DPPP) backbone and alkyl-carboxyl side chains at both edges of the backbone. The introduction of carboxyl makes the brush-like homopolymer exhibit pH-modulated 1D hierarchical self-assembly behavior in dilute solution, and allows for flexible morphological regulation of the assemblies, forming some uncommon superstructures including ultralong nanowires (at pH 7), superhelices (at pH 10) and "single-wall" nanotubes (at pH 13), respectively. Furthermore, the good aqueous dispersibility and 1D feature endow the superstructures formed in a high-concentration neutral solution with high broad-spectrum antibacterial performance superior to that of many conventional 1D materials.

A Potentially Versatile Enzyme Sensor Platform: Enzyme-Loaded, Tagged, Porous Polymeric Nanocapsules

Enzymes are essential to life and indispensable in a wide range of industries (food, pharmaceutical, medical, biosensing, etc.); however, a significant shortcoming of these fragile biological catalysts is their poor stability. To address this challenge, a variety of immobilization methods have been described to enhance the enzyme's stability. These immobilization methods generally are specific to an individual enzyme or optimal for a particular application. The aim of this study is to explore the utility of porous, indicator moiety-tagged, polymeric nanocapsules (NCs) for the encapsulation of enzymes and measurement of the enzyme's substrate. As a model enzyme, glucose oxidase (GOx) is used. The GOx enzyme-loaded, fluorophore-tagged NCs were synthesized by using self-assembled surfactant vesicle templates. To show that the biological activity of GOx is preserved during entrapment, the rate of the GOx enzyme catalyzed reaction was measured. To evaluate the protective features of the porous NCs, the encapsulated GOx enzyme activity was followed in the presence of hydrolytic enzymes. During the encapsulation of GOx and the purification of the GOx-loaded NCs, the GOx activity decayed less than 10%, and up to 30% of the encapsulated GOx activity could be retained for 3-5 days in the presence of hydrolytic enzymes. In support of the potentially unique advantages of the enzyme-loaded NCs, as a proof-of-concept example, the fluorophore-tagged, GOx-loaded NCs were used for the determination of glucose in the concentration range between 18 and 162 mg/dL and for imaging the distribution of glucose concentration in imaging experiments.

Colloidal Polymer-Templated Formation of Inorganic Nanocrystals and their Emerging Applications

Inorganic nanocrystals possess unique physicochemical properties compared to their bulk counterparts. Stabilizing agents are commonly used for the preparation of inorganic nanocrystals with controllable properties. Particularly, colloidal polymers have emerged as general and robust templates for in situ formation and confinement of inorganic nanocrystals. In addition to templating and stabilizing inorganic nanocrystals, colloidal polymers can tailor their physicochemical properties such as size, shape, structure, composition, surface chemistry, and so on. By incorporating functional groups into colloidal polymers, desired functions can be integrated with inorganic nanocrystals, advancing their potential applications. Here, recent advances in the colloidal polymer-templated formation of inorganic nanocrystals are reviewed. Seven types of colloidal polymers, including dendrimer, polymer micelle, stare-like block polymer, bottlebrush polymer, spherical polyelectrolyte brush, microgel, and single-chain nanoparticle, have been extensively applied for the synthesis of inorganic nanocrystals. Different strategies for the development of these colloidal polymer-templated inorganic nanocrystals are summarized. Then, their emerging applications in the fields of catalysis, biomedicine, solar cells, sensing, light-emitting diodes, and lithium-ion batteries are highlighted. Last, the remaining issues and future directions are discussed. This review will stimulate the development and application of colloidal polymer-templated inorganic nanocrystals.

Poly(ionic liquid) nanovesicles via polymerization induced self-assembly and their stabilization of Cu nanoparticles for tailored CO2 electroreduction

Herein, we report a straightforward, scalable synthetic route towards poly(ionic liquid) (PIL) homopolymer nanovesicles (NVs) with a tunable particle size of 50 to 120 nm and a shell thickness of 15 to 60 nm via one-step free radical polymerization induced self-assembly. By increasing monomer concentration for polymerization, their nanoscopic morphology can evolve from hollow NVs to dense spheres, and finally to directional worms, in which a multilamellar packing of PIL chains occurred in all samples. The transformation mechanism of NVs' internal morphology is studied in detail by coarse-grained simulations, revealing a correlation between the PIL chain length and the shell thickness of NVs. To explore their potential applications, PIL NVs with varied shell thickness are in situ functionalized with ultra-small (1 ∼ 3 nm in size) copper nanoparticles (CuNPs) and employed as electrocatalysts for CO₂ electroreduction. The composite electrocatalysts exhibit a 2.5-fold enhancement in selectivity towards C₁ products (e.g., CH₄), compared to the pristine CuNPs. This enhancement is attributed to the strong electronic interactions between the CuNPs and the surface functionalities of PIL NVs. This study casts new aspects on using nanostructured PILs as new electrocatalyst supports in CO₂ conversion to C₁ products.

Generation of sub-5 nm AuNPs in the special space of the loop-cluster corona of a polymer vesicle: preparation and its unique catalytic performance in the reduction of 4-nitrophenol

The hybrid vesicle AuNP@LCCV, in which a large number of AuNPs with an average size of about 2.8 nm were densely and uniformly distributed in an isolated state throughout the corona of the unusual polymer vesicle, was prepared via in situ reduction of Au³⁺ ions, which were encapsulated in advance in the unique polymer vesicle (LCCV) consisting of a hydrophobic membrane of poly(2-phenyl-2-oxazoline) and a hydrophilic loop-cluster corona of polyethyleneimine. The vesicle was formed via self-assembly from a comb-like block copolymer in which a polystyrenic main chain was grafted densely with diblock polyethyleneimine-b-poly(2-phenyl-2-oxazoline) and acted as a reactor for the reduction of Au³⁺. The hybrid vesicle AuNP@LCCV showed powerful catalytic ability in the reduction of nitrophenols (NPs). Interestingly, the reduction reactions of NPs showed a remarkably long induction time, which could be shortened dramatically from 60 min to 1-2 min by greatly increasing the concentration of NaBH₄. It is revealed that the oxygen adsorbed on the AuNPs significantly inhibited the reduction, causing the induction time. Once the oxygen is chemically cleaned from the surface of the AuNPs, the reduction of 4-NP proceeds gradually for a while and then completes suddenly. The reduction mechanism accompanying the oxygen-dependent induction time is proposed from the view of the strong oxygen affinity of the catalyst AuNP@LCCV.

Efficient Removal of Pb(Ⅱ) by Highly Porous Polymeric Sponges Self-Assembled from a Poly(Amic Acid)

Lead (II) (Pb(II)) is widespread in water and very harmful to creatures, and the efficient removal of it is still challenging. Therefore, we prepared a novel sponge-like polymer-based absorbent (poly(amic acid), PAA sponge) with a highly porous structure using a straightforward polymer self-assembly strategy for the efficient removal of Pb(II). In this study, the effects of the pH, dosage, adsorption time and concentration of Pb(II) on the adsorption behavior of the PAA sponge are investigated, revealing a rapid adsorption process with a removal efficiency up to 89.0% in 2 min. Based on the adsorption thermodynamics, the adsorption capacity increases with the concentration of Pb(II), reaching a maximum adsorption capacity of 609.7 mg g^-1 according to the Langmuir simulation fitting. Furthermore, the PAA sponge can be efficiently recycled and the removal efficiency of Pb(II) is still as high as 93% after five adsorption-desorption cycles. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses reveal that the efficient adsorption of Pb(II) by the PAA sponge is mainly due to the strong interaction between nitrogen-containing functional groups and Pb(II), and the coordination of oxygen atoms is also involved. Overall, we propose a polymer self-assembly strategy to easily prepare a PAA sponge for the efficient removal of Pb(II) from water.

A self-crosslinking nanogel scaffold for enhanced catalytic efficiency and stability

We report a facile and efficient approach to prepare multifunctional bioinspired platforms under mild conditions that offer increased catalytic efficiency and stability.

Oxygen-generating polymer vesicles for enhanced sonodynamic tumor therapy

The efficacy of sonodynamic therapy (SDT) is often limited by the insolubility of sonosensitizers and unfavorable hypoxia tumor microenvironment. To meet this challenge, an oxygen-generating polymer vesicle is developed to achieve enhanced SDT. The hydrophilic coronas and the hydrophobic membrane of polymer vesicles can function as different modules for the simultaneous delivery of manganese dioxide and chlorine e6 (designated as Ce6-MnO₂-PVs). These Ce6-MnO₂-PVs exhibited high catalase mimetic activity and could efficiently generate reactive oxygen species upon ultrasound activation. In vivo results showed that Ce6-MnO₂-PVs almost completely eradicated the subcutaneous tumors (94% volume reduction) without any obvious systemic toxicity. Moreover, these Ce6-MnO₂-PVs showed effective behavior for the attenuation of crucial tumor progression-releated factors. Specially, the expression levels of both hypoxia-inducible factor-1α and vascular endothelial growth factor at 4 h post-injection detected by immunofluorescence were reduced by 66% and 52%, respectively. These findings suggest that Ce6-MnO₂-PVs may serve as an effective and safe platform for enahnced SDT in hypoxic tumors.

Tuning Morphologies and Reactivities of Hybrid Organic-Inorganic Nanoparticles

Hybrid nanoparticles (hNPs), or nanoparticles composed of both organic and inorganic components, hold promise for diverse energy and environmental applications due to their ability to stabilize reactive nanomaterials against aggregation, enhancing their ability to pervade tortuous spaces and travel long distances to degrade contaminants in situ. Past studies have investigated the use of polymer or surfactant coatings to stabilize nanomaterials against aggregation. However, fabrication of these materials often requires multiple steps and lacks specificity in the control of their morphologies and reactivities. Here, we demonstrated a method of producing stable hNPs with tunable morphologies by incubating polystyrene nanoparticles formed via Flash NanoPrecipitation with citrate-stabilized gold nanocatalysts. Using this simple fabrication technique, we found that gold adsorption to polystyrene nanoparticles was enabled by the presence of a good solvent for polystyrene. Furthermore, changing process parameters, such as gold incubation time, and molecular parameters, such as polymer molecular weight and end-group functionality, provided control over the resultant nanocatalyst loading and dispersal atop hNPs. We classified these morphologies into three distinct regimes─aggregated, dispersed, or internalized─and we showed that the emergence of these regimes has key implications for controlling reaction rates in applications such as heterogeneous catalysis or groundwater remediation. Specifically, we found that hNPs with gold nanocatalysts embedded below the surfaces of polystyrene nanoparticles exhibited slower bulk catalytic reduction capacity than their disperse, surface-decorated counterparts. Taken together, our work demonstrates a simple way by which hNPs can be fabricated and presents a method to control catalytic reactions using reactive nanomaterials.

Polythionoester Vesicle: An Efficient Polymeric Platform for Tuning H2S Release

Hydrogen sulfide (H₂S) serves as a key gaseous regulator that not only directs many physiological activities, but also manifests therapeutic benefits to many diseases. Developing H₂S vehicle platforms for its local delivery and long-acting release is important to achieve target gas therapy. Most of the known H₂S-donating polymers contain labile thioester scaffolds within their structures that suffer from the issue of low gas releasing efficiency. Here we present the use of thionoester, a constitutional isomer of thioester, as the functional unit to build a structural platform of cysteine-triggered H₂S donor polymer, polythionoester. Simple exchange of the sulfur and oxygen positions in the carbonyl sulfide scaffold makes the polythionoesters undergo a distinct mechanism of H₂S production, which can largely improve the gas-releasing efficiency (>80%). Moreover, the thionoester-containing block copolymers can self-assemble into vesicles in an aqueous media. We discover that control over the size effect can adjust the vesicle disassembly rate and gas-releasing kinetics. A tunable half-life of H₂S generation (2.6-9.8 h) can be accessed by tailoring the vesicle dimension. This allows such polymersomes to be potential as a gas nanodelivery system for long-lasting gas therapeutics.

Functional Nanohybrids and Nanocomposites Development for the Removal of Environmental Pollutants and Bioremediation

World population growth, with the consequent consumption of primary resources and production of waste, is progressively and seriously increasing the impact of anthropic activities on the environment and ecosystems. Environmental pollution deriving from anthropogenic activities is nowadays a serious problem that afflicts our planet and that cannot be neglected. In this regard, one of the most challenging tasks of the 21st century is to develop new eco-friendly, sustainable and economically-sound technologies to remediate the environment from pollutants. Nanotechnologies and new performing nanomaterials, thanks to their unique features, such as high surface area (surface/volume ratio), catalytic capacity, reactivity and easy functionalization to chemically modulate their properties, represent potential for the development of sustainable, advanced and innovative products/techniques for environmental (bio)remediation. This review discusses the most recent innovations of environmental recovery strategies of polluted areas based on different nanocomposites and nanohybrids with some examples of their use in combination with bioremediation techniques. In particular, attention is focused on eco-friendly and regenerable nano-solutions and their safe-by-design properties to support the latest research and innovation on sustainable strategies in the field of environmental (bio)remediation.

Mesoporous ferrihydrite-supported Pd nanoparticles for enhanced catalytic dehalogenation of chlorinated environmental pollutant

Organic chlorides are a group of ubiquitous environmental pollutants that have attracted wide attention because of their carcinogenetic effect on human. Catalytic hydrodechlorination represents one of the most promising methods for the removal of these contaminants, but it suffers from drawbacks such as catalytic inefficiency and/or instability, and the danger of using H₂ as hydrogen source. The relationship between the catalyst structure and its dehalogenation activity has not been completely understood. By combining the advantages of Pd nanocatalyst and mesoporous ferrihydrite (Fh) with its distinctive structure, here we present a new composite material with Pd nanoparticles (NPs) supported onto the Fh (Pd/Fh), which has excellent catalytic dehalogenation performance with a rapid, complete dechlorination of chlorophenol (turnover frequency 25.2 min^-1) and the ability to perform well over a wide range of pH and temperature. The superior catalytic property of Pd/Fh can be attributed to the three unique functions of Fh, including: 1) having abundant hydroxyl groups that provide interaction sites with metals for incorporating highly dispersed small Pd NPs; 2) facilitating the fast adsorption of chlorophenol onto the catalyst surface via hydrogen bonding and importantly, 3) working as an electron mediator to greatly enhance the electron transfer from iron or chemicals (e.g., NaBH₄) to the catalyst, thereby achieving a synergistic effect between Pd catalyst and support, and an enhanced dechlorination activity. In essence, this work presents a promising catalyst for the efficient dehalogenation of chlorinated environmental pollutants and provides an insight into the relationship between catalyst structure and dehalogenation activity.

Homopolymer nanobowls with controlled size and denting degree

Homopolymer nanobowls hold promising potential applications in many fields because of their designability, large specific surface area and high packing density. However, it is still challenging to prepare nanobowls with...

Supramolecular-micelle-directed preparation of uniform magnetic nanofibers with length tunability, colloidal stability and capacity for surface functionalization

We report a versatile and efficient platform to prepare uniform magnetic nanofibers with length tunability, colloidal and morphological stability, capacity for surface functionalization and enhanced T₂ contrast.

Accelerated Reaction Rates within Self-Assembled Polymer Nanoreactors with Tunable Hydrophobic Microenvironments

Performing reactions in the presence of self-assembled hierarchical structures of amphiphilic macromolecules can accelerate reactions while using water as the bulk solvent due to the hydrophobic effect. We leveraged non-covalent interactions to self-assemble filled-polymer micelle nanoreactors (NR) incorporating gold nanoparticle catalysts into various amphiphilic polymer nanostructures with comparable hydrodynamic nanoreactor size and gold concentration in the nanoreactor dispersion. We systematically studied the effect of the hydrophobic co-precipitant on self-assembly and catalytic performance. We observed that co-precipitants that interact with gold are beneficial for improving incorporation efficiency of the gold nanoparticles into the nanocomposite nanoreactor during self-assembly but decrease catalytic performance. Hierarchical assemblies with co-precipitants that leverage noncovalent interactions could enhance catalytic performance. For the co-precipitants that do not interact strongly with gold, the catalytic performance was strongly affected by the hydrophobic microenvironment of the co-precipitant. Specifically, the apparent reaction rate per surface area using castor oil (CO) was over 8-fold greater than polystyrene (750 g/mol, PS 750); the turnover frequency was higher than previously reported self-assembled polymer systems. The increase in apparent catalytic performance could be attributed to differences in reactant solubility rather than differences in mass transfer or intrinsic kinetics; higher reactant solubility enhances apparent reaction rates. Full conversion of 4-nitrophenol was achieved within three minutes for at least 10 sequential reactions demonstrating that the nanoreactors could be used for multiple reactions.

Coupled photocatalytic-bacterial degradation of pyrene: Removal enhancement and bacterial community responses

Polycyclic aromatic hydrocarbons (PAHs) are a class of pollutants that ubiquitously present in environment and hard to be degraded by microorganisms. Herein, we reported a novel photocatalytic-bacterial coupled removal system to treat PAH-polluted water. Using pyrene as the model pollutant, we demonstrated that the removal percentage of different groups was in order: 63.89% ± 1.03% (Vis-Biological) > 61.27% ± 1.08% (UV-Biological) > 59.58% ± 1.15% (UV) > 57.41% ± 1.13% (Vis) > 6.65% ± 0.72% (Biological) > 1.70% ± 0.34% (Control), showing the coupled system significantly improved the removal percentage of pyrene. Additionally, we observed that the coupled system driven by visible light showed higher removal percentage than UV light, exhibiting a good potential for future application. Sequencing analysis of 16S rRNA genes showed that alpha diversity (richness, evenness and diversity) got promoted and data of the relative abundance showed that Pseudomonadaceae was substituted as the dominant bacteria for Planococcaceae, with some other functional bacteria quickly acclimatizing in the bacterial community. Difference analysis indicated that over half of top fifteen genera were generally different significantly (p < 0.001) among two different samples, and UV light altered structure and composition of bacterial community more than visible light. Functional features' change suggested that the bacterial community not only protected itself but also participated in degrading pyrene. Overall, our study offered a new method for PAH degradation and contributed to further understanding of coupled catalytic-bacterial degradation processes.

Phenanthrene removal and response of bacterial community in the combined system of photocatalysis and PAH-degrading microbial consortium in laboratory system

This work aimed to study the removal of phenanthrene, change of bacterial community and microbial functions through combined photocatalysis and biodegradation under ultraviolet (UV) and visible light illumination. Results showed that phenanthrene removal was enhanced in combined system irradiated by UV and visible light. High-throughput sequencing of 16S rRNA gene manifested that alpha diversity (richness, evenness and diversity) got promoted and data of relative abundance reported that Planococcaceae as the dominant bacteriawas replaced by Pseudomonadaceae, with some other functional bacteria quickly acclimatizing. Difference analysis indicated that top fifteen genera were generally different significantly (p < 0.001) among two distinct samples, particularly for Pseudomonas on relative abundance. Functional features' regulation suggested that the bacterial community not only protected itself well but also participated in degrading phenanthrene. Selecting suitable degrading microbial consortium from natural environment and understanding deeply on performance of bacterial community contribute to assemble effective and directional combined system.

Dual Corona Vesicles with Intrinsic Antibacterial and Enhanced Antibiotic Delivery Capabilities for Effective Treatment of Biofilm-Induced Periodontitis

Periodontitis is a common disease caused by plaque biofilms, which are important pathogenic factors of many diseases and may be eradicated by antibiotic therapy. However, low-dose antibiotic therapy is a complicated challenge for eradicating biofilms as hundreds (even thousands) of times higher concentrations of antibiotics are needed than killing planktonic bacteria. Polymer vesicles may solve these problems via effective antibiotic delivery into biofilms, but traditional single corona vesicles lack the multifunctionalities essential for biofilm eradication. In this paper, we aim to effectively treat biofilm-induced periodontitis using much lower concentrations of antibiotics than traditional antibiotic therapy by designing a multifunctional dual corona vesicle with intrinsic antibacterial and enhanced antibiotic delivery capabilities. This vesicle is co-assembled from two block copolymers, poly(ε-caprolactone)-block-poly(lysine-stat-phenylalanine) [PCL-b-P(Lys-stat-Phe)] and poly(ethylene oxide)-block-poly(ε-caprolactone) [PEO-b-PCL]. Both PEO and P(Lys-stat-Phe) coronas have their specific functions: PEO endows vesicles with protein repelling ability to penetrate extracellular polymeric substances in biofilms ("stealthy" coronas), whereas P(Lys-stat-Phe) provides vesicles with positive charges and broad spectrum intrinsic antibacterial activity. As a result, the dosage of antibiotics can be reduced by 50% when encapsulated in the dual corona vesicles to eradicate Escherichia coli or Staphylococcus aureus biofilms. Furthermore, effective in vivo treatment has been achieved from a rat periodontitis model, as confirmed by significantly reduced dental plaque, and alleviated inflammation. Overall, this "stealthy" and antibacterial dual corona vesicle demonstrates a fresh insight for improving the antibiofilm efficiency of antibiotics and combating the serious threat of biofilm-associated diseases.

Lamellae and parking garage structures in amphiphilic homopolymer brushes with different grafting densities

This article is devoted to the study of polymer layers of amphiphilic homopolymers tightly grafted to a flat surface at the nodes of a square lattice. It was shown that, due to the amphiphilicity of monomer units containing groups with different affinities, in a selective solvent, such layers form lamellae perpendicular to the grafting surface. The period of the lamellae depends on the grafting density and the quality of the solvent. The results are presented in the form of a state diagram in variables "the energy of attraction of the side groups" (effective solvent quality) and "the distance between the grafting points" (inversely proportional to the square root of the grafting density). The diagram contains the regions of stability of lamellae with significantly different periods, and a transitional area with a parking garage structure. The diagram is constructed by calculating the layer-by-layer structure factor and the angle of inclination of the lamellae in the slice. The calculations were performed for different sizes of the simulation box, and the most commensurate size was determined by a special procedure for each grafting density. The results may be interesting not only to specialists in polymer science but also to all those who investigate the processes of self-organization and rearrangement in dense systems.

Ring-Opening Polymerization of N-Carboxyanhydride-Induced Self-Assembly for Fabricating Biodegradable Polymer Vesicles

Polymerization-induced self-assembly (PISA) is regarded as one of the most important strategies in macromolecular nanotechnology, as it can create a wide range of nanoparticles at high concentrations and on a large scale. However, open-to-air PISA with biodegradable product is still a complicated challenge, as traditional PISA is usually carried out under oxygen-free conditions to afford nonbiodegradable polymers. To meet the above challenges, we propose a convenient one-pot open-to-air ring-opening polymerization (ROP) of N-carboxyanhydride (NCA)-induced self-assembly (NCA-PISA) at 10 °C, without the need for degassing, heating, catalysts, or chain transfer agents. The morphologies of nanoparticles depend on the ratio of the initiator to the monomer and the solid content. Polymer vesicles can be fabricated when the ratio and the solid content are 1:20 and 20%, respectively. Overall, this versatile one-pot NCA-PISA provides an insight into facilely fabricating biodegradable nanoparticles in air.

Enantioselective cytotoxicity of chiral polymer vesicles with linear and hyperbranched structures

Herein, we study the enantioselective cytotoxicity of vesicles self-assembled by optically active linear polymers (LNPs) and hyperbranched polymers (HBPs). Compared to HBP vesicles, LNP vesicles exhibit properties such as a higher surface charge density and more violent interaction with simulated biomembranes which results in larger cytotoxicity against HeLa cells. Specifically, racemic-LNP vesicles exhibit the largest cytotoxicity of all. More interestingly, there is no significant enantioselective dependence of HBP vesicles on the abovementioned properties. Overall, we proved that the cytotoxicity of vesicles is deeply related to chirality and topological-structures. This research is of great fundamental value for the design of novel bio-interface materials.

The construction of thiol-functionalized DNAsomes with small molecules response and protein release

In this work, a poly(N-isopropylacrylamide) polymer (PNIPAAm) was prepared via the photoinduced reversible addition-fragmentation chain transfer (RAFT) polymerization using Ru(bpy)₃Cl₂·6H₂O as photoinitiator. The design and spontaneous assembly of thiol-functionalized DNA-Thiol/PNIPAAm polymeric capsule (DNAsomes) by water-in-oil Pickering emulsion method and effective response with small molecules (Sybr green and phenanthrene) were described. The intermediate product, DNA-Thiol/PNIPAAm conjugates and DNAsomes were characterized by using ¹H NMR, dynamic light scattering (DLS), SEM, TEM and UV-vis methods. The obtained results indicated that DNA-Thiol/PNIPAAm constructs assembled in a Pickering emulsion could produce DNA-based spherical DNAsomes with typically 3.3-267.7 μm in diameter. The DNAsomes showed a vesicle formation approximately 2 μm in diameter, resulting in phenanthrene molecule intercalating with DNAsomes. The phenomenon indicated that the DNA-Thiol/PNIPAAm conjugates may have potential applications in recognition polycyclic aromatic hydrocarbon molecules. The membrane of the DNAsomes could effective response toward small molecules such as Sybr green or phenanthrene, and DNAsomes has release capability of protein (BSA) under reductive agent glutathione (GSH). Our results highlight the potential of integrating aspects of supramolecular and polymer chemistry into the design and construction of DNA-polymeric capsule, guest molecule encapsulation, control delivery of drugs, recognition organic polycyclic aromatic hydrocarbon molecules and gene-directed capsule synthesis.

Nanobowls with controlled openings and interior holes driven by the synergy of hydrogen bonding and π-π interaction

Asymmetric nanoparticles such as nanobowls have promising potential in many fields due to their interior asymmetric cavities and specific concave structure. However, the fabrication of nanobowls and control over their openings and interior holes are still challenging. Herein we demonstrate a versatile strategy for preparing nanobowls with precisely controlled openings and interior holes based on the synergy of hydrogen bonding and π-π interaction of homopolymers. We designed and synthesized a series of amphiphilic homopolymers with an amino alcohol moiety and azobenzene pendant (poly(2-hydroxy-3-((4-(phenyldiazenyl)phenyl)amino)propyl methacrylate) (PHAzoMA)). The homopolymers can self-assemble into nanobowls due to the heterogeneous shrinkage of the preformed spheres. Upon increasing the molecular weight of the homopolymers from 10.1 to 76.9 kg mol-1, the sizes of the openings of nanobowls can be precisely controlled from 242 to 423 nm with a linear relationship as a result of the enhancement of the hydrogen bonding and π-π interaction between homopolymer chains. Overall, we have prepared finely controlled nanobowls by the synergy of non-covalent interactions such as hydrogen bonding and π-π interaction of polymers, which opens a new avenue for the preparation of asymmetric nanoparticles.

Synthesis and scale-up of water-soluble quaternary cationic monomers in a continuous flow system

A novel, simple, power-saving and effective method for the synthesis and scale-up of cationic water-soluble polyelectrolytes represented by dimethyldiallylammonium chloride (DMDAAC) with commercially available reagents in a two-step continuous flow system has been developed.

Evolution of diverse higher-order membrane structures of block copolymer vesicles

An evolutionary route to polymer vesicles with diverse higher-order membrane structures has been discovered.

Plasmonic vesicles with tailored collective properties

Plasmonic nanoparticle assemblies have been exhibiting unique collective properties absent in their individual counterparts. However, it is an important challenge to manipulate those properties due to the difficulty in controlling the arrangement and distance between plasmonic nanoparticles. Herein, we propose an alternative strategy for manipulating the distance between gold nanoparticles on the plasmonic vesicles to afford tunable collective properties by changing the temperature. To reach this goal, a thermally responsive vesicle is self-assembled from an azobenzene-terminated homopolymer, poly(2-(2-ethoxyethoxy)ethyl acrylate) (Azo-PEEA). Gold nanoparticles are then decorated on its membrane to afford plasmonic vesicles, which can be grouped and fused into larger plasmonic vesicles when heated. Consequently, the gold nanoparticles come closer, creating local hot spots in the gap between adjacent gold nanoparticles, leading to the red shift of local surface plasmon resonance (LSPR) peaks and better surface-enhanced Raman scattering (SERS). Besides, the structure and the collective optical properties of the plasmonic vesicles can be reserved under various conditions, e.g., different pH values, high salt concentration and relatively high temperature once they are heated up to 35 °C.

Novel core-shell-like nanocomposites xCu@Cu2O/MgAlO-rGO through an in situ self-reduction strategy for highly efficient reduction of 4-nitrophenol

A series of novel hierarchical nanocomposite catalysts xCu@Cu₂O/MgAlO-rGO were fabricated by calcination of Cu_xMg_3-xAl-LDH/rGO precursors (LDH: layered double hydroxide, rGO: reduced graphene oxide, and x = 0.5, 1.0, and 1.5), obtained by a facile citric acid-assisted coprecipitation route, under a N₂ flow upon in situ self-reduction of lattice atomic-dispersed Cu²⁺ by rGO. Systematic characterization reveals highly dispersed core-shell-like Cu@Cu₂O nanoparticles near the border between vertically interconnected mixed oxide MgAlO nanoplates and rGO layers. All the obtained catalysts show extraordinary catalytic performances for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) at room temperature. The 1.0Cu@Cu₂O/MgAlO-rGO shows the highest activity for complete conversion of 4-NP with an apparent rate constant (k_app) of 55.3 × 10^-3 s^-1, a normalized rate constant (k_nor) of 14 497 s^-1 g^-1 on an active Cu content, and an unprecedented recycling stability for 25 successive cycles, which are superior to those of the recently reported Cu- and Co-based metal nanoparticles and even compared favourably with those of the most active noble metal catalysts. The superior activity of 1.0Cu@Cu₂O/MgAlO-rGO can be attributed to the highly dispersed core-shell-like Cu@Cu₂O nanoparticles and the greatly enhanced four-phase synergistic effect among Cu, Cu₂O, MgAlO and rGO upon calcination. Moreover, 1.0Cu@Cu₂O/MgAlO-rGO shows an excellent efficiency in the fixed bed system for the treatment of simulated industrial effluents containing nitrophenols and organic dyes. The present cost-effective, highly efficient and reusable non-noble metal nanocatalyst would open a new pathway for future water remediation.

An Innovative Approach to Control Steel Reinforcement Corrosion by Self-Healing

The corrosion of reinforced steel, and subsequent reinforced concrete degradation, is a major concern for infrastructure durability. New materials with specific, tailor-made properties or the establishment of optimum construction regimes are among the many approaches to improving civil structure performance. Ideally, novel materials would carry self-repairing or self-healing capacities, triggered in the event of detrimental influence and/or damage. Controlling or altering a material's behavior at the nano-level would result in traditional materials with radically enhanced properties. Nevertheless, nanotechnology applications are still rare in construction, and would break new ground in engineering practice. An approach to controlling the corrosion-related degradation of reinforced concrete was designed as a synergetic action of electrochemistry, cement chemistry and nanotechnology. This contribution presents the concept of the approach, namely to simultaneously achieve steel corrosion resistance and improved bulk matrix properties. The technical background and challenges for the application of polymeric nanomaterials in the field are briefly outlined in view of this concept, which has the added value of self-healing. The credibility of the approach is discussed with reference to previously reported outcomes, and is illustrated via the results of the steel electrochemical responses and microscopic evaluations of the discussed materials.

Efficient Removal of Polycyclic Aromatic Hydrocarbons, Dyes, and Heavy Metal Ions by a Homopolymer Vesicle

It is an important challenge to effectively remove environmental pollutants such as polycyclic aromatic hydrocarbons (PAHs), dyes, and heavy metal ions at a low cost. Herein, we present a multifunctional homopolymer vesicle self-assembled from a scalable homopolymer, poly(amic acid) (PAA), at room temperature. The vesicle can efficiently eliminate PAHs, cationic dyes, and heavy metal ions from water based on π-π stacking, hydrophobic effect, and electrostatic interactions with the pollutants. The residual concentrations of PAHs, cationic dyes, and heavy metal ions (such as Ni²⁺) in water are lower than 0.60 and 0.30 parts per billion (ppb) and 0.095 parts per million (ppm), respectively, representing a promising adsorbent for water remediation. Furthermore, precious metal ions such as Ag⁺ can be recovered into silver nanoparticles by in situ reduction on the membrane of PAA vesicles to form a silver nanoparticle/vesicle composite (Ag@vesicle) that can effectively catalyze the reduction of toxic pollutants such as aromatic nitro-compounds and be recycled for more than ten times.

Formation of non-spherical polymersomes driven by hydrophobic directional aromatic perylene interactions

Polymersomes, made up of amphiphilic block copolymers, are emerging as a powerful tool in drug delivery and synthetic biology due to their high stability, chemical versatility, and surface modifiability. The full potential of polymersomes, however, has been hindered by a lack of versatile methods for shape control. Here we show that a range of non-spherical polymersome morphologies with anisotropic membranes can be obtained by exploiting hydrophobic directional aromatic interactions between perylene polymer units within the membrane structure. By controlling the extent of solvation/desolvation of the aromatic side chains through changes in solvent quality, we demonstrate facile access to polymersomes that are either ellipsoidal or tubular-shaped. Our results indicate that perylene aromatic interactions have a great potential in the design of non-spherical polymersomes and other structurally complex self-assembled polymer structures.

Controlling the generation of bilayer and multilayer vesicles in block copolymer/epoxy blends by a slow photopolymerization process

Vesicles are a highly attractive morphology to achieve in micellar dispersions of block copolymers (BCP) in epoxy thermosets due to the fact that small amounts can affect a large volume fraction of the matrix, a fact that is important for toughening purposes. However, generating vesicles in epoxy matrices requires operating in a narrow range of formulations and processing conditions. In this report, we show that block-copolymer vesicles dispersed in an epoxy matrix could be obtained through a sphere-to-cylinder-to-vesicle micellar transition induced by visible-light photopolymerization at room temperature. A 10 wt% colloidal solution of poly(ethylene-co-butene)-block-poly(ethylene oxide) (PEB-b-PEO) block copolymer (BCP) in an epoxy monomer (DGEBA) self-assembled into spherical micelles as shown by small-angle X-ray scattering (SAXS). During a slow photopolymerization of the epoxy monomer carried out at room temperature, a sphere-to-cylinder-to-vesicle transition took place as revealed by in situ SAXS and TEM images. This was driven by the tendency of the system to reduce the local interfacial curvature as a response to a decrease in the miscibility of PEO blocks in the polymerizing epoxy matrix. When the BCP concentration was increased from 10 to 20 and 40 wt%, the final structure evolved from bilayer vesicles to multilayer vesicles and to lamellae, respectively. In particular, for 20 wt% PEB-b-PEO, transient structures such as partially fused multilayered vesicles were observed by TEM, giving insight into the growth mechanism of multilayer vesicles. On the contrary, when a relatively fast thermal polymerization was performed at 80 °C, the final morphology consisted of kinetically trapped spherical and cylindrical micelles. Hopefully, this study will lead to new protocols for the preparation of vesicles dispersed in epoxy matrices in a controlled way.