We reported a type of strong and highly directional non-covalent interactions based on the dimerization of single-stranded helix to double-stranded helix that can achieve supramolecular polymerization, giving rise to the formation of linear supramolecular polymers.

The self-assembly of block copolymer in solution has proven to be an effective strategy for building up a wide range of nanomaterials with diverse structures and applications. This paper reports a facile self-assembly approach towards two-dimensional (2D) sandwich-like mesoporous nitrogen-doped carbon/reduced graphene oxide nanocomposites (denoted as mNC/rGO) with well-defined large mesopores. The strategy involves the synergistic self-assembly of polystyrene-block-poly(ethylene oxide) (PS-b-PEO) spherical micelles, m-phenylenediamine (mPD) monomers and GO in solution and the subsequent carbonization at 900℃. The resultant mNC/rGO nanosheets have an average pore size of 19 nm, a high specific surface of 812 m²·g^-1 and a nitrogen content of 2.2 wt%. As an oxygen reduction reaction (ORR) catalyst, the unique structural features render the metal-free nanosheets excellent electrocatalytic performance. In a 0.1 mol·L^-1 KOH alkaline medium, mNC/rGO exhibits a four-electron transfer pathway with a high half-wave-potential (E_1/2) of +0.77 V versus reversible hydrogen electrode (RHE) and a limiting current density (J_L) of 5.2 mA·cm^-2, which are well comparable with those of the commercial Pt/C catalysts.

The excellent drug encapsulation, prolonged in vivo circulation time, enhanced pharmacokinetics, and reduced adverse effects make the polymeric assemblies ideal carriers in nanomedicine, and become an emerging research field with rapid development. In vivo, the polymer nanoassemblies will experience five steps, including circulation in the blood, accumulation in the tumoral site, penetration into the deep tumor tissue to reach cancer cells, internalization into cancer cells, and intracellular drug release. However, although tremendous efforts have been made to the material design, currently available carriers still have difficulties in fulfilling all of the requirements. Moreover, the long-standing dilemma of the synchronized stability and permeability of vesicles is still a big challenge, which confused researchers for a long time. This feature article focuses on the recent progress of single-or multi-stimuli triggered theranostic platforms, and the extracellularly reengineered shell-sheddable polymeric nanocarriers are systematically discussed. The perspectives for future developments in the nanocarriers functioned with artificial helical polymers (the potential cell-penetrating peptides mimics) are also proposed. We speculate that this feature article can fit the interesting of diverse readers and a guideline for the design of next generation of drug nanocarriers.

Complex emulsions, such as double emulsions and high-internal-phase emulsions, have shown great applications in the fields of drug delivery, sensing, catalysis, oil-water separation and self-healing materials. Their controllable preparation is at the forefront of interface and material science. Surfactants and polymers have been widely used as emulsifiers for building complex emulsions. Yet some inherent disadvantages exist including multi-step emulsifications and low production efficiency. Alternatively, supramolecular polymer emulsifier for complex emulsions via one-step emulsification is rising as a new strategy due to the ease of preparation. In this feature article, we review our recent progresses in using supramolecular polymer emulsifiers for the preparation of complex emulsions. Double emulsions and high-internal-phase emulsions are successfully prepared via one-step emulsification with the help of different supramolecular interactions including electrostatic, hydrogen bond, coordination interaction and dynamic covalent bond, which will be particularly emphasized in detail. In the end, a comprehensive prospect is given for the future development of this field. This article is expected to provide new inspirations for preparing complex emulsions via supramolecular routes.

Highly intricate surface architectures derived from patterned polymer microstructures have received increasing concern in recent years. Directional photo-manipulation (DPM) of azopolymers is one of the effective strategies to tune the patterned polymer microstructures through directional mass migration (DMM) upon polarized light illumination. In this feature article, we emphasize the latest advances of DPM on azopatterns created by self-assembly. The mechanism of DMM, the photo-manipulation performance, and functions of manipulated patterns are introduced in sequence. As presented, DPM can manipulate the as-prepared microstructures feasibly by taking the advantages of non-contacting and nondestructive characters. Moreover, the challenges and opportunities of DPM strategy are discussed in conclusion.

Macroscopic supramolecular assembly (MSA) has been a recent progress in supramolecular chemistry. MSA mainly focuses on studies of the building blocks with a size beyond ten micrometers and the non-covalent interactions between these interactive building blocks to form ordered structures. MSA is essential to realize the concept of "self-assembly at all scales" by bridging most supramolecular researches at molecular level and at macroscopic scale. This review summaries the development of MSA, the basic design principle and related strategies to achieve MSA and potential applications. Correspondingly, we try to elucidate the correlations and differences between "macroscopic assembly" and MSA based on intermolecular interactions; the design principle and the underlying assembly mechanism of MSA are proposed to understand the reported MSA behaviors; to demonstrate further applications of MSA, we introduce some methods to improve the ordered degree of the assembled structures from the point of precise assembly and thus envision some possible fields for the use of MSA.

The applications of nanotechnology in biomedicine have gained considerable attentions in recent years owing to the great enhancement of therapeutic efficiency. Integration of self-assembly into nanotechnology has brought tremendous convenience during the formation of nano-carriers. Based on distinctive methods of self-assembly, nano-therapeutics have been developed to an impressive stage with the ability to perform site-specific delivery with temporal and spatial control. This review focuses on the recent advances in the preparing methods for nano-therapeutics, and their applications in the treatments of diseases.

Biological stimuli-responsive polymers have increasingly attracted attention in recent years because it can satisfy many requirements of applications related with human body while traditional systems do not meet. Due to the importance of this burgeoning field, great efforts have been devoted and, up to now, polymer chemists have made a remarkable success in this prospective research topic. In this review, we systematically generalize the present state of biological stimuli-responsive polymer systems. We highlight several representative examples to specify the current problems and look ahead a clear sense of direction in this area.

Peptide hydrogels have been widely used for diverse biomedical applications. However, our current understanding of the physical principles underlying the self-assembly process is still limited. In this review, we summarize our current understanding on the physical chemistry principles from the basic interactions that drive the self-assembly process to the energy landscapes that dictate the thermodynamics and kinetics of the process. We discuss the effect of different factors that affect the kinetics of the self-assembly of peptide fibrils and how this is related to the macroscopic gelation process. We provide our understanding on the molecular origin of the complex and rugged energy landscape for the self-assembly of peptide hydrogels. The hierarchical self-assembled structures and the diverse self-assembling mechanism make it difficult and challenging to rationally design the physical and chemical properties of peptide hydrogels at the molecular level. We also give our personal perspective to the potential future directions in this field.

The single-chain elasticity of a completely unfolded protein ((I27)₈, modules of human cardiac titin) is studied in different liquid environments by the atomic force microscopy (AFM)-based single molecule force spectroscopy (SMFS). The experimental results show that there is a clear deviation between the force curves obtained in the aqueous and nonaqueous environments. Such a deviation can be attributed to the additional energy consumed by the rearrangement of the bound water molecules around the chain of the completely unfolded (I27)₈ chain upon stretching in aqueous solution, which is very similar to the partial dehydration process from a denatured/unfolded to a native/folded protein. Through the analysis of the free energy changes involved in protein folding, we conclude that it is due to the weak disturbance of water molecules and the special backbone structures of proteins that the self-assembly of proteins can be achieved in physiological conditions. We speculate that water is likely to be an important criterion for the selection of self-assembling macromolecules in the prebiotic chemical evolution.

The morphologies of poly(L-lactic acid) (PLLA) spherulites, when crystallized within the pre-existed poly(oxymethylene) (POM) crystal frameworks, have been investigated. PLLA/POM blend is a melt-miscible crystalline/crystalline blend system. Owing to the lower melting point but much faster crystallization rate than PLLA, POM crystallized first upon cooling from the melt state and then melted first during the subsequent heating process in this blend system. Lamellar assembly of PLLA crystals within the pre-existed POM spherulitic frameworks was directly observed with the polarized light microscopy by selectively melting the POM frameworks. The investigation indicated that PLLA crystals fully replicated the spherulitic morphology and optical birefringence of the POM crystal frameworks, which was independent of T_c. On the other hand, POM could also duplicate the pre-existed PLLA morphologies. The result obtained provides us a possibility to design the lamellar assembly and crystal structures of polymer crystals in miscible crystalline/crystalline polymer blends.

Dextran-poly(glycidyl methacrylate) (Dex-PGMA) nano-suitcases were synthesized efficiently via a graft copolymerization induced self-assembly (GISA) approach. On this basis, the Dex-PGMA nano-suitcases were modified with hydrazide, and the attachment of multiple chelated Gd(ó) ions to the interior of the nano-suitcases affords nanoscale MRI contrast agents with high relaxivity values. The highly fenestrated dextran shell of the nano-suitcases assures water exchange which readily occurs between the surrounding environment and the Gd(ó) ions encapsulated within the hybrid nano-suitcases. The complexation between the hydrophilic hydrazide interior of the nano-suitcases and Gd(ó) ions results in an impressive Gd payload at 22.6 wt% in the hybrid nano-suitcases. The longitudinal relaxivity (r₁) of the hybrid nano-suitcases is reported as 44.4 L/(mmol·s), which is 9-14 folds of that of commercial Gd-DTPA agents. In vivo MRI studies demonstrate that the hybrid nano-suitcases accumulated in the lymph node of the rat due to their nanoscale dimensions and displayed strong signals in vivo. The results indicated that the hybrid nano-suitcases provide a promising platform for the diagnosis of lymph node related diseases.

Coordination-driven self-assembly strategy has demonstrated the efficiency and versatility to construct well-ordered supramolecular coordination complexes (SCCs) such as discrete metallacycles and metallacages. In recent years, it has aroused tremendous interest to build more complexed self-assembled structures via the implementation of additional non-covalent recognition motifs on the SCCs platform. In this work, we have successfully attained this objective, with the elaborate manipulation of non-interfering pyridine-Pt²⁺ and molecular tweezer/guest complexation in a hierarchical self-assembly manner. The resulting SCCs-based linear supramolecular polymers exhibit intriguing NIR-emissive behaviors, primarily attributed to the presence of intermolecular Pt(Ⅱ)-Pt(Ⅱ) metal-metal interactions in the non-covalent tweezering structure. Hence, supramolecular engineering of multiple non-covalent interactions offers a feasible avenue toward functional materials with tailored properties.

Despite the fact that some progress has been made in the self-assembly of H-shaped polymers, the corresponding self-assemblies that respond to external stimulus and are further utilized to adjust the release of drugs are still deficient. The stimuli-responsive segments with amphiphilic H-shaped structure are generally expected to enhance the controllability of self-assembly process. The synthesis and self-assembly behavior of thermo-responsive amphiphilic H-shaped polymers with poly(ethylene glycol) (PEG), polytetrahydrofuran (PTHF) and poly(N-isopropyl acrylamide) (PNIPAM) as building blocks are reported in this paper. The inner architecture structure and size of complex micelles formed by H-shaped self-assemblies were effectively adjusted when the solution temperature was increased above the lower critical solution temperature of PNIPAM segments. Furthermore, it was found that the architecture of self-assemblies underwent a transition from the complex micelles based on primary micelles with hybrid PEG/PNIPAM shells to large complex micelles based on primary micelles with hybrid PTHF/PNIPAM cores and PEG shells during the thermal-induced self-assembly process. The adjustable release rate of doxorubicin (DOX) from the DOX-loaded complex micelles and basic cell experiments further proved the feasibility of these self-assemblies as the thermal-responsive drug delivery system.

We present a new cyclometalated Ir(Ⅲ) complexes IrBDP, which could self-assemble into organic nanoparticles (IrBDP NPs). IrBDP NPs show enhanced photodynamic effect and can be engulfed by HeLa cells for cell imaging as well as photodynamic therapy (PDT) upon low energy irradiation.