Simulation-Assisted Self-Assembly of Multicomponent Polymers into Hierarchical Assemblies with Varied Morphologies

Archimedean Spirals with Controllable Chirality: Disk Substrate-Mediated Solution Assembly of Rod-Coil Block Copolymers

Spirals are common in nature; however, they are rarely observed in polymer self-assembly systems, and the formation mechanism is not well understood. Herein, we report the formation of two-dimensional (2D) spiral patterns via microdisk substrate-mediated solution self-assembly of polypeptide-based rod-coil block copolymers. The spiral pattern consists of multiple strands assembled from the block copolymers, and two central points are observed. The spirals fit well with the Archimedean spiral model, and their chirality is dependent on the chirality of the polypeptide blocks. As revealed by a combination of experiments and theoretical simulations, these spirals are induced by an interplay of the parallel ordering tendency of the strands and circular confinement of the microdisks. This work presents the first example regarding substrate-mediated self-assembly of block copolymers into spirals. The gained information could not only enhance our understanding of natural spirals but also assist in both the controllable preparations and applications of spiral nanostructures.

Synergetic Self-Assembly of Liquid Crystalline Block Copolymer with Amphiphiles for Fabrication of Hierarchical Assemblies

Novel functions and advanced structure, where each single component could not be produced individually, can exhibit from the collective and synergistic behavior of component systems. This synergetic strategy has been successfully demonstrated for co-assembly of polymer-polymer to construct hierarchical nanomaterials. However, differences in the natures of polymer and small molecules impose challenges in the construction of sophisticated co-assemblies with geometrical and compositional control. Herein, a synergetic self-assembly strategy is proposed to prepare organic-organic hybrid colloidal mesostructures by blending a liquid crystalline block copolymer (LC-BCP) with small molecular amphiphiles. Through a classic solvent-exchange process, amphiphiles embedded with LC-BCP realize multi-component nucleation and hierarchical assembly driven by anisotropic interaction from the LC ordering alignment of the core-forming block. 1D nanofibers with a periodic striped structure are formed by further LC component fusion and refinement. In addition, LC ordering effect of LC-BCP can be regulated by selecting appropriate solvents and leads to the formation of vesicular co-micelles. By means of the thermal-responsive behavior of amphiphiles, hexagonal pore arrays are finally generated on the surface of those vesicles.

Helical Self-Assembly of Amphiphilic Chiral Azobenzene Alternating Copolymers

Imposing chirality to supramolecular architectures is an important step forward toward understanding and utilization of chiral nanomaterials. This article reports the self-assembly of amphiphilic chiral alternating copolymers of poly(binaphthyl azobenzene-alt-hexaethylene glycol) (P(BNPAzo-alt-EG₆)) into helical supramolecular rods. Unlike conventional chiral assembly of copolymers largely through intermolecular organization, the intrachain stacking of chiral units along the main chain into single molecular micelles with amplified axial chirality of binaphthyl is key to the formation of helical supramolecular rods, which takes advantage of the particular chiral unit and soft unit alternating topological structure of the backbones. Moreover, the supramolecular self-assembly is light reversible because the azobenzene rings in the backbone scarcely execute trans- to cis-isomerization upon UV irradiation, and therefore the supramolecular rods keep their sublevel chirality even though the helical appearance was destroyed. This work paves an effective route to construct and regulate chiral supramolecular architectures and reveals an insight into natural and artificial chiral self-assembly.

Anchorage-Dependent Living Supramolecular Self-Assembly of Polymeric Micelles

Anchorage-dependent contact-inhibited growth usually refers to on-surface cell proliferation inhibited by the proximity of other cells. This phenomenon, prominent in nature, has yet to be achieved with polymeric micelles. Here, we report the control living supra-macromolecular self-assembly of elongated micelles with a liquid crystalline core onto a hydrophobic substrate via the synergetic interactions between the substrate and aggregates dispersed in solution. In this system, seed formation is a transient phenomenon induced by the adsorption and rearrangement of the core-swollen aggregates. The seeds then trigger the growth of elongated micelles onto the substrate in a living controllable manner until the contact with the substrate is disrupted. Brownian dynamic simulations show that this unique behavior is due to the fusion of the aggregates onto both ends of the anchored seeds. More important, the micelle length can be tuned by varying the substrate hydrophobicity, a key step toward the fabrication of intricate structures.

Regulating the morphology and size of homopolypeptide self-assemblies via selective solvents

It remains a great challenge to control the morphology and size of self-assembled homopolypeptide aggregates. In this work, rod-like micelles including spindles and cylinders were prepared by a solution self-assembly of poly(γ-benzyl-l-glutamate) (PBLG) homopolypeptides with different degrees of polymerization, in which their size was controlled precisely by tuning the ratio of water/methanol in selective cosolvents. The length of the rod-like micelles increased with an increasing amount of methanol in the selective cosolvents, which was confirmed using the combination of SEM, TEM and AFM. The self-assembly mechanism of PBLG in selective cosolvents was investigated by using complementary Fourier transform infrared (FT-IR), circular dichroism (CD) and low-field NMR analyses. It was found that the shrinkage and swelling of PBLG chains play important roles in the self-assembly process. The obtained results may provide a guideline for the study of regulating the assembled aggregate sizes.

Adenine-Functionalized Supramolecular Micelles for Selective Cancer Chemotherapy

Functional supramolecular micelles containing self-complementary multiple hydrogen bonding adenine groups (A-PPG) can spontaneously self-assemble into stable nanosized micelles in aqueous solution. These micelles can be used to selectively deliver anticancer drugs to cancer cells and effectively promote tumor cell death via apoptosis, without harming normal cells. The drug-loaded micelles exhibit tunable drug-loading capacity and rapid pH-triggered drug release under acidic conditions, as well as a high drug-entrapment stability in serum-rich media due to the reversible hydrogen-bonded adenine-adenine interactions within the micellar interior; these properties are critical to achieving effective chemotherapeutic drug delivery and controlled drug release. In vitro assays show that the drug-loaded micelles exert significant cytotoxic effects on cancer cells, with minimal effects on normal cells under physiological conditions. Cytotoxicity assays using A-PPG micelles loaded with different anticancer drugs confirm these effects. Importantly, cellular internalization and flow cytometric analyses demonstrate that the adenine moieties within A-PPG micelles significantly increase selective endocytic uptake of the supramolecular micelles by cancer cells, which in turn induce apoptotic cell death and substantially enhance the response to chemotherapy. Thus, A-PPG micelles can improve the safety and efficacy of cancer chemotherapy.

2D Chiral Stripe Nanopatterns Self-Assembled from Rod-Coil Block Copolymers on Microstripes

Chiral nanoarchitectures usually possess unique and intriguing properties. However, the construction of 2D chiral nanopatterns through polymer self-assembly is a challenge. Reported herein is the formation of chiral stripe nanopatterns through surface self-assembly of polypeptide-based rod-coil block copolymers on microstripes. The nanostripes align oblique to the boundary of the microstripes, resulting in the chirality of the nanopatterns. The chirality of the nanopatterns is closely related to the width of the microstripes, i.e., a narrower width results in higher chirality. Besides, the chiral sense of the nanopatterns can be regulated by the chirality of the polypeptide blocks. This work demonstrates the transmission of chirality from polymer to nanoarchitecture on a confined surface, which can guide the preparation of nanopatterns with tuned chiral features.

Self-Assembly-Assisted Kinetically Controlled Papain-Catalyzed Formation of mPEG-b-Phe(Leu)x

Self-assembling peptide materials are promising next-generation materials with applications that include tissue engineering scaffolds, drug delivery, bionanomedicine, and enviro-responsive materials. Despite these advances, synthetic methods to form peptides and peptide-polymer conjugates still largely rely on solid-phase peptide synthesis (SPPS) and N-carboxyanhydride ring-opening polymerization (NCA-ROP), while green methods remain largely undeveloped. This work demonstrates a protease-catalyzed peptide synthesis (PCPS) capable of directly grafting leucine ethyl ester (Leu-OEt) from the C-terminus of a methoxy poly(ethylene glycol)-phenylalanine ethyl ester macroinitiator in a one-pot, aqueous reaction. By using the natural tendency of the growing hydrophobic peptide segment to self-assemble, a large narrowing of the (Leu)_x distributions for both mPEG₄₅-b-Phe(Leu)_x and oligo(Leu)_x coproducts, relative to oligo(Leu)_x synthesized in the absence of a macroinitiator (mPEG₄₅-Phe-OEt), was achieved. A mechanism is described where in situ β-sheet coassembly of mPEG₄₅-b-Phe(Leu)_x and oligo(Leu)_x coproducts during polymerization prevents peptide hydrolysis, providing a means to control the degree of polymerization (DP) and dispersity of diblock (Leu)_x segments (matrix-assisted laser desorption time-of-flight (MALDI-TOF) x = 5.1, dispersity ≤ 1.02). The use of self-assembly to control the uniformity of peptides synthesized by PCPS paves the way for precise peptide block copolymer architectures with various polymer backbones and amino acid compositions synthesized by a green process.

Novel amphiphilic graft block azobenzene-containing copolymer with polypeptide block: synthesis, self-assembly and photo-responsive behavior

Well-defined amphiphilic graft block azobenzene-containing copolymer with polypeptide block was synthesized via a combination of copper-mediated atom transfer radical polymerization (ATRP), ring-opening polymerization and click reaction. The alkyne-terminated poly[6-(4-methoxy-azobenzene-4′-oxy)hexyl methacrylate] (PAzoMA) was synthesized by ATRP with a bromine-containing alkyne bifunctional initiator, and the azido-terminated poly(γ-2-chloroethyl-l-glutamate) (PCELG) was synthesized by ROP of γ-2-chloroethyl-l-glutamate-N-carboxyanhydride (CELG-NCA), then the two homopolymers were conjugated by click reaction to afford block azobenzene-containing copolymer PAzoMA-b-PCELG. The chloro groups in PCELG block were transformed into azido groups via azide reactions, and the alkyne-terminated MPEG was grafted to the polypeptide block to afford the final product PAzoMA-b-poly((l-glutamate)-graft-methoxy poly(ethylene glycol)) (PAzoMA-b-(PELG-g-MPEG)) by click reaction. Giant vesicles (micrometer size) were obtained from the amphiphilic graft block copolymer PAzoMA-b-(PELG-g-MPEG) through a solution self-assembly due to the rigid PAzoMA chains and polypeptide chains with the α-helical structure. The investigation of the photo-isomerization behavior of PAzoMA-b-(PELG-g-MPEG) in solution and in vesicular solution showed trans–cis isomerization in solution was quicker than that in vesicular solution and azobenzene J-aggregates in the vesicle solution were only observed. The formation mechanisms of the vesicles were also explored. The research results may provide guidelines for the study of complex copolymers containing different types of rigid chains.

Giant vesicles (micrometer size) were prepared from novel amphiphilic graft block azobenzene-containing copolymer with polypeptide block synthesized via a combination of ATRP, ROP and click reaction.

Self-assembly of rod-coil block copolymers on a substrate into micrometer-scale ordered stripe nanopatterns

Micrometer-scale ordered stripe nanopatterns are readily constructed through an adsorption-assembly of rod-coil block copolymers on the substrate.

Ordered Surface Nanostructures Self-Assembled from Rod-Coil Block Copolymers on Microspheres

An ordered surface nanostructure endows materials advanced functions. However, fabricating ordered surface-patterned particles via the polymer self-assembly approach is a challenge. Here we report that poly(γ-benzyl-l-glutamate)-block-poly(ethylene glycol) rod-coil block copolymers are able to form uniform-surface micelles on polystyrene microspheres through a solution self-assembly approach. The size of the surface micelles can be varied by the molecular weight of the block copolymers. These surface micelles are arranged in a manner consistent with the Euler theorem. Most of the micelles are six-fold coordinated, and the number difference between the five-fold and the seven-fold coordination is 12. Simulations on model systems qualitatively reproduced the experimental findings and provided direct observations for the surface-patterned particles, including the polymer chain packing manner in surface micelles at the molecular level and the array feature of the surface micelles through 2D projections of the surface patterns.

Cellular internalization of polypeptide-based nanoparticles: effects of size, shape and surface morphology

Nanoparticles (NPs) can be taken up by cells; however, the effects of the structural characteristics of NPs on their cellular internalization have not been well explored. In this work, cellular internalization performances of various NPs including rods with helical surface (helical rods), spheres with stripe-pattern surface (striped spheres), and spheres with smooth surface (smooth spheres) were investigated by a combination of experiments and theoretical simulations. This study focuses on the effects of the size, shape, and surface morphology on their cellular internalization behaviors. These NPs were self-assembled from mixtures of fluorescein isothiocyanate (FITC)-labelled poly(γ-benzyl-l-glutamate)-block-poly(ethylene glycol) (PBLG(FITC)-b-PEG) block copolymers and PBLG or polystyrene (PS) homopolymers. It was found that the NPs possessing smaller size, rod-like shape, and helical/striped surface morphology exhibit higher cellular internalization efficiency. Such differences in the internalization efficiency for the NPs can be attributed to the differences in both their surface areas and internalization pathways. This study could not only guide the design of nanocarriers with enhanced cellular internalization efficiency, but also deepen our understanding of the internalization behavior of natural NPs with similar structures (e.g., virus).

Supramolecular step-growth polymerization kinetics of pre-assembled triblock copolymer micelles

Pre-assembled copolymer micelles were found to “polymerize” into hierarchical nanowires, induced by the structural defects on the micelle surfaces.

Morphology Evolution of Stimuli-Responsive Triblock Copolymer Modulated by Polyoxometalates

Polyoxometalate (POM) H₃PMo₁₂O₄₀ was coassembled with stimuli-responsive triblock copolymer poly(ethylene oxide)- block-polystyrene- block-poly(2-(dimethylamino)ethyl methacrylate) (PEO- b-PS- b-PDMAEMA) by electrostatic interactions. Depending on the POM contents, the hybrid complexes can self-assemble into a series of morphologies: micelles, rods, toroids, and vesicles. Unlike traditional morphology transition of amphiphilic block copolymer derived from a broad range of hydrophobic volume fractions, POM-induced morphology transitions just occurred in a narrow range of volume fractions. The length of rod micelles exponentially decreased with solvent compositions (tetrahydrofuran/H₂O). The hybrid assemblies showed acid-base responsibility due to the PDMAEMA block. Rod micelles could further assemble and disassemble reversibly upon adding acid/base. Fluorescent polyoxometalate Na₉EuW₁₀O₃₆ was also complexed with PEO- b-PS- b-PDMAEMA to prepare fluorescent vesicles. The vesicles showed off-on switchable fluorescence behavior accompanied with reversible vesicle-to-micelle transformation in response to pH stimuli.

Dynamic and programmable morphology and size evolution via a living hierarchical self-assembly strategy

Recent advances in the preparation of shape-shifting and size-growing nanostructures are hot topics in development of nanoscience, because many intelligent functions are always relied on their shape and dimension. Here we report a tunable manipulation of sequential self-assembled transformation in situ via a hierarchical assembly strategy based on a living thiol-disulfide exchange reaction. By tailoring the external stimuli, the reactive points can be generated at the ends of initially unimolecular micelles, which subsequently drive the pre-assemblies to periodically proceed into the hierarchically micellar connection, axial growth, bending, and cyclization processes from nanoscopic assemblies to macroscopic particles. Of particular interest would be systems that acquired the shape control and size adjustment of self-assemblies after termination or reactivation of disulfide reshuffling reaction by regulating external stimuli whenever needed. Such a hierarchical strategy for self-assembled evolution is universally applicable not only for other disulfide-linked dendritic polymers but also for exploitation of biological applications.

Multicomponent peptide assemblies

Self-assembled peptide nanostructures have been increasingly exploited as functional materials for applications in biomedicine and energy. The emergent properties of these nanomaterials determine the applications for which they can be exploited. It has recently been appreciated that nanomaterials composed of multicomponent coassembled peptides often display unique emergent properties that have the potential to dramatically expand the functional utility of peptide-based materials. This review presents recent efforts in the development of multicomponent peptide assemblies. The discussion includes multicomponent assemblies derived from short low molecular weight peptides, peptide amphiphiles, coiled coil peptides, collagen, and β-sheet peptides. The design, structure, emergent properties, and applications for these multicomponent assemblies are presented in order to illustrate the potential of these formulations as sophisticated next-generation bio-inspired materials.

Self-Assembly of Rod-Coil Block Copolymers on Carbon Nanotubes: A Route toward Diverse Surface Nanostructures

In this work, it is reported that poly(γ-benzyl-l-glutamate)-block-poly(ethylene glycol) (PBLG-b-PEG) rod-coil block copolymers (BCPs) can disperse carbon nanotubes (CNTs) in solution and form various surface nanostructures on the CNTs via solution self-assembly. In an organic solvent that dissolves the BCPs, the PBLG rod blocks adsorb on CNT surfaces, and the BCPs form conformal coatings. Then, by the introduction of water, a selective solvent for PEG blocks, the BCPs in the coatings further self-assemble into diverse surface nanostructures, such as helices (left-handed or right-handed), gyros, spheres, and rings. The morphology of the surface nanostructure can be tailored by initial organic solvent composition, preparation temperature, feeding ratio of BCPs to CNTs, degree of polymerization of PBLG blocks, and diameter of the CNTs.

Polypeptide self-assemblies: nanostructures and bioapplications

Polypeptide copolymers can self-assemble into diverse aggregates. The morphology and structure of aggregates can be varied by changing molecular architectures, self-assembling conditions, and introducing secondary components such as polymers and nanoparticles. Polypeptide self-assemblies have gained significant attention because of their potential applications as delivery vehicles for therapeutic payloads and as additives in the biomimetic mineralization of inorganics. This review article provides an overview of recent advances in nanostructures and bioapplications related to polypeptide self-assemblies. We highlight recent contributions to developing strategies for the construction of polypeptide assemblies with increasing complexity and novel functionality that are suitable for bioapplications. The relationship between the structure and properties of the polypeptide aggregates is emphasized. Finally, we briefly outline our perspectives and discuss the challenges in the field.

pH-Induced evolution of surface patterns in micelles assembled from dirhamnolipids: dissipative particle dynamics simulation

Dissipative particle dynamics (DPD) simulation is used to study the effect of pH on the morphological transition in micelles assembled from dirhamnolipids (diRLs), and analyze the pH-driven mechanism and influence factors of micellar surface patterns.

A dissipative particle dynamics simulation study on phase diagrams for the self-assembly of amphiphilic hyperbranched multiarm copolymers in various solvents

Self-assembly of amphiphilic hyperbranched multiarm copolymers (HMCs) has shown great potential for preparing all kinds of delicate supramolecular structures in all scales and dimensions in solution. However, theoretical studies on the influencing factors for the self-assembly of HMCs have been greatly lagging behind. The phase diagram of HMCs in selective solvents is very necessary but has not been disclosed up to now. Here, the self-assembly of HMCs with different hydrophilic fractions in various solvents was studied systematically by using dissipative particle dynamics (DPD) simulations. Three morphological phase diagrams are constructed and a rich variety of morphologies, ranging from spherical micelles, worm-like micelles, membranes, vesicles, vesosomes, small micellar aggregates (SMAs), and aggregates of spherical and worm-like micelles to helical micelles, are obtained. In addition, both the self-assembly mechanisms and the dynamic processes for the formation of these self-assemblies have been systematically investigated. The simulation results are consistent with available experimental observations. Besides, several novel structures, like aggregates of spherical and worm-like micelles, vesosomes and helical micelles, are firstly discovered for HMC self-assembly. We believe the current work will extend the knowledge on the self-assembly of HMCs, especially on the control of supramolecular structures and on fabricating novel self-assemblies.

Controllable multicompartment morphologies from cooperative self-assembly of copolymer-copolymer blends

Multicompartment nanostructures, such as microcapsules with clearly separated shell and core, are not easily accessible by conventional block copolymer self-assembly. We assess a versatile computational strategy through cooperative assembly of diblock copolymer blends to generate spherical and cylindrical compartmentalized micelles with intricate structures and morphologies. The co-assembly strategy combines the advantages of polymer blending and incompatibility-induced phase separation. Following this strategy, various nanoassemblies of pure AB, binary AB/AC and ternary AB/AC/AD systems such as compartmentalized micelles with sponge-like, Janus, capsule-like and onion-like morphologies can be obtained. The formation and structural adjustment of microcapsule micelles, in which the shell or core can be occupied by either pure or mixed diblock copolymers, were explored. The mechanism involving the separation of shell and core copolymers is attributed to the stretching force differences of copolymers which drive the arrangement of different copolymers in a pathway to minimize the total interfacial energy. Moreover, by adjusting block interactions, an efficient approach is exhibited for regulating the shell or core composition and morphology in microcapsule micelles, such as the transition from the "pure shell/mixed core" morphology to the "mixed shell/pure core" morphology in the AB/AC/AD micelle. This mesoscale simulation study identifies the key factors governing co-assembly of diblock copolymer blends and provides bottom-up insights towards the design and optimization of new multicompartment micelles.

Cellular Internalization of Rod-Like Nanoparticles with Various Surface Patterns: Novel Entry Pathway and Controllable Uptake Capacity

The cellular internalization of rod-like nanoparticles (NPs) is investigated in a combined experimental and simulation study. These rod-like nanoparticles with smooth, abacus-like (i.e., beads-on-wires), and helical surface patterns are prepared by the cooperative self-assembly of poly(γ-benzyl-l-glutamate)-block-poly(ethylene glycol) (PBLG-b-PEG) block copolymers and PBLG homopolymers. All three types of NPs can be internalized via endocytosis. Helical NPs exhibit the best endocytic efficacy, followed by smooth NPs and abacus-like NPs. Coarse-grained molecular dynamics simulations are used to examine the endocytic efficiency of these NPs. The NPs with helical and abacus-like surfaces can be endocytosed via novel "standing up" (tip entry) and "gyroscope-like" (precession) pathways, respectively, which are distinct from the pathway of traditional NPs with smooth surfaces. This finding indicates that the cellular internalization capacity and pathways can be regulated by introducing stripe patterns (helical and abacus-like) onto the surface of rod-like NPs. The results of this study may lead to novel applications of biomaterials, such as advanced drug delivery systems.

Toroid Formation through a Supramolecular "Cyclization Reaction" of Rodlike Micelles

Constructing polymeric toroids with a uniform, tunable size is challenging. Reported herein is the formation of uniform toroids from poly(γ-benzyl-l-glutamate)-graft-poly(ethylene glycol) (PBLG-g-PEG) graft copolymers by a two-step self-assembly process. In the first step, uniform rodlike micelles are prepared by dialyzing the polymer dissolved in tetrahydrofuran (THF)/N,N'-dimethylformamide (DMF) against water. With the addition of THF in the second step, the rodlike micelles curve and then close end-to-end to form uniform toroids, which resemble a cyclization reaction.

Hierarchical Colloidal Polymeric Structure from Surfactant-Like Amphiphiles in Selective Solvents

We investigated the self-assembly of surfactant-like amphiphiles consisting of a hydrophilic head and a hydrophobic tail using the dissipative particle dynamics method. By controlling the interaction parameter between the hydrophilic head and the solvent, the length of the hydrophobic tail, the size of the hydrophilic head, and the polymer concentration, we found seven self-assembled morphologies, including spherelike micelles, pomegranate-like micelles, hierarchical colloidal polymeric (HCP) structures, pomegranate-like columnar structures, branched hybrid structures, disklike micelles, and vesicles. Importantly, the HCP structure widely existing in this system has a regular two-component alternating structure and prospective application in soft-matter nanotechnology. The formation process and the structural properties of the HCP structure are intensively studied. The dimension of the HCP structure is largely controlled by the hydrophobic tail and the polymer concentration.

Polymerization-Induced Cooperative Assembly of Block Copolymer and Homopolymer via RAFT Dispersion Polymerization

Polymerization-induced cooperative assembly (PICA) is developed to promote morphological transitions at high solids via RAFT dispersion polymerization, using both a macromolecular chain transfer agent (macro-CTA) and a small molecule chain transfer agent (CTA) to generate nano-objects consisting of well-defined block copolymer and homopolymer. PICA is demonstrated to promote morphological transitions under various conditions. Elemental mapping provides unambiguous evidence for the uniform distribution of the homopolymer within the core of the nano-objects. It is proposed that the growing homopolymer first reaches its solubility limit and forms aggregates, which induce the adsorption of the growing block copolymer. This effective and robust PICA approach significantly expands the capability to promote morphological transitions in RAFT dispersion polymerization and will facilitate the efficient synthesis of various higher-order morphologies at high solids.

In situ synthesis of a self-assembled AB/B blend of poly(ethylene glycol)-b-polystyrene/polystyrene by dispersion RAFT polymerization

A diblock-copolymer/homopolymer self-assembled blend was synthesized through dispersion RAFT polymerization, and its morphology changed with a decreasing ratio of diblock-copolymer/homopolymer.

Directed assembly of functionalized nanoparticles with amphiphilic diblock copolymers

We theoretically propose a simple approach to achieve soft nanoparticles with a self-patchiness nature, which are further directed to assemble into a rich variety of highly ordered superstructures.

Versatile multicompartment nanoparticles constructed with two thermo-responsive, pH-responsive and hydrolytic diblock copolymers

Multicompartment block copolymer nanoparticles constructed with two smart diblock copolymers are prepared and their versatile morphology upon stimuli is demonstrated.

Strong Bioinspired Polymer Hydrogel with Tunable Stiffness and Toughness for Mimicking the Extracellular Matrix

Inspired by the delicate architecture of hyaline articular cartilage, we report on a biomimetic polymer hydrogel that incorporates strong intermolecular hydrogen bonding between urethane-urethane linkages as well as urethane-ester linkages. The resultant hydrogel, containing ≈75% water, can endure a compressive stress up to 56 MPa with a strain of 98%, and exhibit tunable compressive modulus (0.19-1.38 MPa), as well as toughness (3629-28290 J m^-2) within a wide range. The tensile strength and elastic modulus reach as high as 0.56 and 5.5 MPa, respectively. The high stiffness and toughness enable the gel to withstand cyclic compressive loadings without fracturing. Moreover, our hydrogel mimics the extracellular matrices of cartilage and bone tissues and provides biochemical and physical cues that support the three-dimensional proliferation of chondrocytes and osteogenic differentiation of preosteoblasts.