Self-assembly Of Amphiphiles Research Articles

ROAMing in mutable voids: Polymer free volumes from wobbling vibrational probes.

Polymers and polymeric materials exhibit flexibility between neighboring components of their molecular chains, permitting disordered conformations relative to the crystalline state. The disordered chain conformations lead to entanglements between neighboring chains, and the local intersections of polymer chains lead to voids in the material. Such voids or holes are named polymer free volume elements (FVEs). In their study of how FVEs in polymeric materials are related to their intrinsic microporosity and transport of gases, Budd, McKeown, and Fritsch (1) found inspiration from Lucretius. To paraphrase Lucretius’ teachings about atomistic theories from the Greeks, “Nature …has two forms …: the bodies, and the void where the bodies are placed and travel their varied paths” (ref. 1, p. 1977). More recently, we find that FVE sizes are key descriptors in molecular theories of polymers, polymeric materials, and glasses (1⇓⇓⇓–5). FVE distributions are critically important in applications of such materials to self-assembled amphiphiles (6), polymer composites (7), and perm-selective membranes (8). Thus, a great deal of attention has been paid to characterizing FVEs; the major methods used in these measurements are discussed below. Knowledge of FVE distributions in polymeric materials is needed for engineering of structural plastics. High-strength products require treatment to control and minimize the FVEs. One example is the processing of polyethylene chains (comprising repeats of the C H 2 group). When long polyethylene chains are extruded to maximize their alignment, the result is high-density polyethylene (HDPE), a widely used plastic material that we consume in vast quantities. Voids in HDPE result from shorter chains, poor chain alignment, and exposure to higher temperatures, so an increase in the number and size of FVEs correlates with a reduction in structural integrity. In other applications, such as using polymers to engineer perm-selective membranes for gas separations, increasing … [↵][1]1Email: ecastner{at}chem.rutgers.edu. [1]: #xref-corresp-1-1

Amphiphilic Nucleobase-Containing Polypeptide Copolymers-Synthesis and Self-Assembly.

Nucleobase-containing polymers are an emerging class of building blocks for the self-assembly of nanoobjects with promising applications in nanomedicine and biology. Here we present a macromolecular engineering approach to design nucleobase-containing polypeptide polymers incorporating thymine that further self-assemble in nanomaterials. Diblock and triblock copolypeptide polymers were prepared using sequential ring-opening polymerization of γ-Benzyl-l-glutamate N-carboxyanhydride (BLG-NCA) and γ-Propargyl-l-glutamate N-carboxyanhydride (PLG-NCA), followed by an efficient copper(I)-catalyzed azide alkyne cycloaddition (CuAAc) functionalization with thymidine monophosphate. Resulting amphiphilic copolymers were able to spontaneously form nanoobjects in aqueous solutions avoiding a pre-solubilization step with an organic solvent. Upon self-assembly, light scattering measurements and transmission electron microscopy (TEM) revealed the impact of the architecture (diblock versus triblock) on the morphology of the resulted nanoassemblies. Interestingly, the nucleobase-containing nanoobjects displayed free thymine units in the shell that were found available for further DNA-binding.

Engineering the Cellulose Fiber Interface in a Polymer Composite by Mussel-Inspired Adhesive Nanoparticles with Intrinsic Stress-Sensitive Responsivity

The interface between the fiber and matrix plays a key role in polymer composite performance and is adapted by chemical modification of the fiber surface. In this study, biomimetic adhesive nanoparticles formed by the self-assembly of polymer-peptide amphiphiles with a polydiacetelyene tail and local presentation of 3-hydroxyphenylalanine or DOPA adhesive groups at the outer surface are adsorbed on cellulose fiber surfaces for (i) probing the nanoscale adhesion in combination with a functionalized atomic force microscopy tip and (ii) evaluating the macroscale adhesion by single-fiber pull out tests from a solvent cast cellulose/poly(methyl methacrylate) composite. The interface properties are altered by changing the structure of the nanoparticles into either vesicular or planar shapes depending on the number of incorporated amphiphiles with adhesive groups and the nanoparticle concentration at the cellulose fiber surface. Based on nanoscale adhesive measurements, the adhesion force on modified cellulose fibers increases as a function of the nanoparticle concentration and is higher for the vesicular than for the planar nanoparticle structures. However, the local presentation and number of adhesive groups seems to rule over the surface roughness effects. From macrosale tests, an optimum concentration of adhesive vesicles provides maximum interface strength, while the formation of nanoparticle multilayers at higher concentrations results in lower interface adhesion. In addition, the intrinsic fluorescent properties of the adhesive vesicles under mechanical stress provide a unique tool to evaluate local failure and stress concentrations in the fiber/matrix interface. The incorporation of both adhesive and sensitive properties and versatility of the adhesive functional group may be an attractive strategy for the surface modification of fiber-reinforced composites in general.

Models for the solubility calculation of a CO2/polymer system: A review

Multiscale models are modeled at different time and spatial scales to achieve the spans among the micro-, meso-, and macroscales. The multiscale study of solubility is the most effective way to reveal its essence, which is widely used in the extraction, separation, material modification, and preparation of new materials. In this article, the progress of solubility-calculation models for CO2/polymer systems at the micro-, meso-, and macroscales is surveied. The research situation of the thermodynamic-calculation model and modern computer simulation at the macroscale is discussed, and the calculation model of molecular dynamics and particle dynamics at the micro- and mesoscales are analyzed. Focus is also given on the development trend of solubility-calculation models at different scales, particularly the mechanism and interpretability of solubility calculation at the macroscopic scale. The possible development directions of solubility big data, such as acquisition, storage, search, sharing, mining, and analysis under the background of big data, are proposed. The authors further describe the development directions of particle dynamics, coarse-grained method, and translink method on the basis of evolutionary algorithm at the micro- and mesoscales. The multiscale methods mentioned in this paper can serve as a reference in many fields, such as polymer self-assembly, phase rheological property, phase separation of block copolymers, amphiphilic molecular self-assembly into membranes, transformation and separation of vesicle morphology, and kinetic analysis. Multiscale research of solubility big data combined with deep learning and artificial intelligence may become important research directions in the future.

Self-Assembly of Tetraphenylethylene-Based Amphiphiles in Aqueous Methanol Solution into Two-Dimensional Chiral Sheets for Enantioselective Sorption.

Most synthetic building blocks self-assemble into one- or three-dimensional architectures. However, fewer examples have been reported on the aggregation of amphiphiles to form optically-active two-dimensional (2D) structures. Herein, we report the self-assembly of tetraphenylethylene (TPE)-containing hydrophilic dendrons into 2D sheet structures in aqueous methanol solution. TEM and AFM investigations showed that the self-assembly of disubstituted TPE generates helical nanofibers as an intermediate structure which, in turn, laterally associate into a chiral sheet structure with a thickness of 4.6 nm, whereas tetrasubstituted TPE self-assembles into a nonchiral sheet structure with a thickness of 3.8 nm. In great contrast to the nonchiral sheets, the chiral sheets are able to preferentially absorb the d-enantiomer in a racemic phenylalanine derivative solution accompanied by fluorescence enhancement, thus indicating that the single-layered chiral sheets act as an enantioselective membrane that can be used for fluorescence sensing.

A multifunctional surfactant catalyst inspired by hydrolases.

The remarkable power of enzymes to undertake catalysis frequently stems from their grouping of multiple, complementary chemical units within close proximity around the enzyme active site. Motivated by this, we report here a bioinspired surfactant catalyst that incorporates a variety of chemical functionalities common to hydrolytic enzymes. The textbook hydrolase active site, the catalytic triad, is modeled by positioning the three groups of the triad (-OH, -imidazole, and -CO2H) on a single, trifunctional surfactant molecule. To support this, we recreate the hydrogen bond donating arrangement of the oxyanion hole by imparting surfactant functionality to a guanidinium headgroup. Self-assembly of these amphiphiles in solution drives the collection of functional headgroups into close proximity around a hydrophobic nano-environment, affording hydrolysis of a model ester at rates that challenge α-chymotrypsin. Structural assessment via NMR and XRD, paired with MD simulation and QM calculation, reveals marked similarities of the co-micelle catalyst to native enzymes.

Preparation and Properties of Stereocomplex of Poly(lactic acid) and Its Amphiphilic Copolymers Containing Glucose Groups.

The stereocomplex of poly(lactic acid) containing glucose groups (sc-PLAG) was prepared by solution blending from equal amounts of poly(l-lactic acid) (PLLA) and poly(d-lactic acid-co-glucose) (PDLAG), which were synthesized from l- and d-lactic acid and glucose by melt polycondensation. The methods, including 1H nuclear magnetic resonance spectroscopy (1H NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), polarizing microscope (POM), scanning electron microscope (SEM), transmission electron microscope (TEM), and contact angle were used to determine the effects of the stereocomplexation of enantiomeric poly(lactic acid) (PLA) units, the amphiphilicity due to glucose residues and lactic acid units, and the interaction of glucose residues with lactic units on the crystallization performance, hydrophilicity, thermal stability, and morphology of samples. The results showed PDLAG was multi-armed, and partial OH groups of glucose residues in PDLAG might remain unreacted. The molecular weight (Mw), dispersity (Ɖ), and glucose proportion in the chain of PDLAG thereby had significant effects on sc-PLAG. There were the stereocomplexation of enantiomeric lactic units and the amphiphilic self-assembly of PDLAG in sc-PLAG, which resulted in glucose groups mainly in the surface phase and lactic units in the bulk phase. The sc-PLAG only possessed the stereocomplex crystal owing to the interaction between nearly equimolar of l-lactic units of PLLA and d-lactic units of PDLAG, and had no homo-crystallites of l- or d-lactic units, which improved the melting temperature (Tm) of sc-PLAG about 50 °C higher than that of PLLA. Glucose groups in sc-PLAG played an important role by forming heterogeneous nucleation, promoting amphiphilic self-assembly, and affecting the ordered arrangement of lactic units. The glass transition temperature (Tg), the melting temperature (Tm), crystallinity, crystallization rate, and water absorption of sc-PLAG showed similar changes with the increased glucose content in feeding. All these parameters increased at first, and the maximum appeared as glucose content in feeding about 2%, such as the maximum crystallinity of 48.8% and the maximum water absorption ratio being 11.7%. When glucose content in feeding continued increasing, all these performances showed a downward trend due to the decrease of arrangement regularity of lactic acid chains caused by glucose groups. Moreover, the contact angle of sc-PLAG decreased gradually with the increased glucose content in feeding to obtain the minimum 77.5° as the glucose content in feeding being 5%, while that of PLLA was 85.0°. The sc-PLAG possessed a regular microsphere structure, and its microspheres with a diameter of about 200 nm could be observed. In conclusion, sc-PLAG containing proper glucose amount could effectively enhance the crystallinity, hydrophilicity, and thermal stability of PLA material, which is useful for drug delivery, a scaffold for tissue engineering, and other applications of biomedicine.

Twisting of Charged Nanoribbons to Helicoids Driven by Electrostatics.

Charged amphiphiles in solution usually self-assemble into flat nanoribbons that spontaneously twist into different shapes. The role of electrostatics in this process is still under strong debate. This work studies the electrostatic free energy of twisting a nanoribbon at the level of the nonlinear Poisson-Boltzmann approximation. It is shown that helicoid-shaped ribbons are more stable than flat ribbons, while other shapes under consideration (cylindrical helixes and bent ribbons) are always less stable than the flat ribbon. The unexpected electrostatics-driven twisting of the ribbon into a helicoid is ascribed to the increase in its perimeter with increasing degree of twisting, as charges near the edge of the ribbon are electrostatically more stable than those near its center. This argument successfully explains the effects of salt concentration and the width of the ribbon on the optimal twisting period and allows us to approximately describe the problem of ribbon twisting in terms of two dimensionless variables that combine the helicoid twisting period, the Debye length of the solution, and the width of the ribbon. The magnitude of the electrostatic twisting energy predicted by our calculations is comparable to that of restoring elastic forces for typical ribbons of self-assembled amphiphiles, which indicates that electrostatics plays an important role in determining the equilibrium shape of charged nanoribbons.

Dissipative Self-Assembly of Dynamic Multicompartmentalized Microsystems with Light-Responsive Behaviors

Summary Living cells are compartmentalized systems operating far from thermodynamic equilibrium and consume energy from the environment to carry out their functions. The construction of biomimetic synthetic compartments has both scientific and technological value. Despite many advances, the assembly of synthetic compartments that present nonequilibrium behaviors based on dissipative (or transient) self-assembly remains a grand challenge. Here, we describe the design and synthesis of multicompartmental systems with an active microstructure and complex behaviors. By including an artificial pathway for energy dissipation, we demonstrate the autonomous generation of active polymeric systems using a strategy based on polymerization-induced self-assembly (PISA), driven by chemical fuel. Remarkably, these self-organized synthetic systems exhibit a dynamic change in their multicompartmental structures when exposed to light. This work introduces a strategy toward the design and construction of synthetic compartments with a dynamic structure and also presents pathways to engineer materials with spatially controllable structures and functionalities.

Entropy-driven segregation and budding in hybrid vesicles of binary nanoparticle amphiphiles

Self-assembly of giant building blocks beyond conventional molecules offers tremendous opportunities for the fabrication of new-generation structural materials. This work describes the macroscopic colloidal segregation in the vesicular self-assembly of binary nanoparticle amphiphiles (NPAMs) consisting of block copolymer-grafted nanoparticles in solution. Depending on their relative size and concentration, binary NPAMs with distinctive sizes assemble into hybrid vesicles with different morphologies, namely, homogeneous vesicles, patchy vesicles, and yolk/shell vesicles. The segregation of NPAMs confined within or escaped from the vesicular membrane is driven by the conformational entropy gain of end-grafted copolymer ligands. The effect of NPAM size and concentration on the morphological transition of vesicles is mapped in a phase diagram. Moreover, a vesicular fusion/budding mechanism is proposed to illustrate the formation of uniform vesicles with yolks inside. The hybrid vesicles have potential applications in cancer imaging, biosensing, and drug delivery.

Nanoscale Self-Assembly for Therapeutic Delivery.

Self-assembly is the process of association of individual units of a material into highly arranged/ordered structures/patterns. It imparts unique properties to both inorganic and organic structures, so generated, via non-covalent interactions. Currently, self-assembled nanomaterials are finding a wide variety of applications in the area of nanotechnology, imaging techniques, biosensors, biomedical sciences, etc., due to its simplicity, spontaneity, scalability, versatility, and inexpensiveness. Self-assembly of amphiphiles into nanostructures (micelles, vesicles, and hydrogels) happens due to various physical interactions. Recent advancements in the area of drug delivery have opened up newer avenues to develop novel drug delivery systems (DDSs) and self-assembled nanostructures have shown their tremendous potential to be used as facile and efficient materials for this purpose. The main objective of the projected review is to provide readers a concise and straightforward knowledge of basic concepts of supramolecular self-assembly process and how these highly functionalized and efficient nanomaterials can be useful in biomedical applications. Approaches for the self-assembly have been discussed for the fabrication of nanostructures. Advantages and limitations of these systems along with the parameters that are to be taken into consideration while designing a therapeutic delivery vehicle have also been outlined. In this review, various macro- and small-molecule-based systems have been elaborated. Besides, a section on DNA nanostructures as intelligent materials for future applications is also included.

Hydrophobization of Cellulose Nanocrystals for Aqueous Colloidal Suspensions and Gels.

Surface hydrophobization of cellulose nanomaterials has been used in the development of nanofiller-reinforced polymer composites and formulations based on Pickering emulsions. Despite the well-known effect of hydrophobic domains on self-assembly or association of water-soluble polymer amphiphiles, very few studies have addressed the behavior of hydrophobized cellulose nanomaterials in aqueous media. In this study, we investigate the properties of hydrophobized cellulose nanocrystals (CNCs) and their self-assembly and amphiphilic properties in suspensions and gels. CNCs of different hydrophobicity were synthesized from sulfated CNCs by coupling primary alkylamines of different alkyl chain lengths (6, 8, and 12 carbon atoms). The synthetic route permitted the retention of surface charge, ensuring good colloidal stability of hydrophobized CNCs in aqueous suspensions. We compare surface properties (surface charge, ζ potential), hydrophobicity (water contact angle, microenvironment probing using pyrene fluorescence emission), and surface activity (tensiometry) of different hydrophobized CNCs and hydrophilic CNCs. Association of hydrophobized CNCs driven by hydrophobic effects is confirmed by X-ray scattering (SAXS) and autofluorescent spectroscopy experiments. As a result of CNC association, CNC suspensions/gels can be produced with a wide range of rheological properties depending on the hydrophobic/hydrophilic balance. In particular, sol-gel transitions for hydrophobized CNCs occur at lower concentrations than hydrophilic CNCs, and more robust gels are formed by hydrophobized CNCs. Our work illustrates that amphiphilic CNCs can complement associative polymers as modifiers of rheological properties of water-based systems.

Alkoxy- and Silanol-Functionalized Cage-Type Oligosiloxanes as Molecular Building Blocks to Construct Nanoporous Materials.

Siloxane-based materials have a wide range of applications. Cage-type oligosiloxanes have attracted significant attention as molecular building blocks to construct novel siloxane-based nanoporous materials with promising applications such as in catalysis and adsorption. This paper reviews recent progress in the preparation of siloxane-based nanoporous materials using alkoxy- and silanol-functionalized cage siloxanes. The arrangement of cage siloxanes units is controlled by various methods, including amphiphilic self-assembly, hydrogen bonding of silanol groups, and regioselective functionalization, toward the preparation of ordered nanoporous siloxane-based materials.

Color-tunable single-fluorophore supramolecular system with assembly-encoded emission

Regulating the fluorescent properties of organic small molecules in a controlled and dynamic manner has been a fundamental research goal. Although several strategies have been exploited, realizing multi-color molecular emission from a single fluorophore remains challenging. Herein, we demonstrate an emissive system by combining pyrene fluorophore and acylhydrazone units, which can generate multi-color switchable fluorescent emissions at different assembled states. Two kinds of supramolecular tools, amphiphilic self-assembly and γ-cyclodextrin mediated host-guest recognition, are used to manipulate the intermolecular aromatic stacking distances, resulting in the tunable fluorescent emission ranging from blue to yellow, including a pure white-light emission. Moreover, an external chemical signal, amylase, is introduced to control the assembly states of the system on a time scale, generating a distinct dynamic emission system. The dynamic properties of this multi-color fluorescent system can be also enabled in a hydrogel network, exhibiting a promising potential for intelligent fluorescent materials.

Programmed Recognition between Complementary Dinucleolipids To Control the Self-Assembly of Lipidic Amphiphiles.

One of the major goals in systems chemistry is to create molecular assemblies with emergent properties that are characteristic of life. An interesting approach toward this goal is based on merging different biological building blocks into synthetic systems with properties arising from the combination of their molecular components. The covalent linkage of nucleic acids (or their constituents: nucleotides, nucleosides and nucleobases) with lipids in the same hybrid molecule leads, for example, to the so-called nucleolipids. Herein, we describe nucleolipids with a very short sequence of two nucleobases per lipid, which, in combination with hydrophobic effects promoted by the lipophilic chain, allow control of the self-assembly of lipidic amphiphiles to be achieved. The present work describes a spectroscopic and microscopy study of the structural features and dynamic self-assembly of dinucleolipids that contain adenine or thymine moieties, either pure or in mixtures. This approach leads to different self-assembled nanostructures, which include spherical, rectangular and fibrillar assemblies, as a function of the sequence of nucleobases and chiral effects of the nucleolipids involved. We also show evidence that the resulting architectures can encapsulate hydrophobic molecules, revealing their potential as drug delivery vehicles or as compartments to host interesting chemistries in their interior.

Supramolecular thermogels from branched PCL-containing polyurethanes.

Thermogels are temperature-responsive hydrogels which are most commonly formed by supramolecular self-assembly of polymer amphiphiles comprising of both hydrophobic and hydrophilic segments. Although polyurethane thermogels have shown great promise as biomaterials, their synthesis by step-growth polymerisation of diols and diisocyanates can also result in formation of allophanate branches, which arise from the reaction between free isocyanate groups and urethane linkages along the polymer backbone. In this paper, we investigate the effects of different synthetic conditions on the degree of allophanate branching on polyurethane amphiphiles, and explore the influences of these branches on the polymers' critical micelle concentration (CMC), thermodynamics of micellization and subsequent thermogel properties. Our findings offer new insights into the relationship between polymer structure, micelle and gel properties. These results highlight the importance of taking polymer branching into account for understanding the hierarchical self-assembly of polymer amphiphiles and the resulting thermogel properties and behaviour.

Phototheranostic DNA micelles from the self-assembly of DNA-BODIPY amphiphiles for the thermal ablation of cancer cells.

Design of phototheranostic agents in a single step approach is one of the challenges in cancer therapy. Herein, a one-step strategy based on amphiphilicity-driven self-assembly of DNA-BODIPY amphiphiles for the design of a new class of micelles, which offer all three phototheranostic functions, is reported. These include (i) strong emission at NIR (φf = 30%) for imaging, (ii) high photothermal conversion (η = 52%) for PTT and (iii) an ssDNA-based shell for the integration of cell targeting moieties. Selective uptake of DNA micelles into a target cancer cell and its killing by laser irradiation (635 nm) are also demonstrated. Furthermore, the excellent biocompatibility, ultrasmall nanosize and high stability of DNA micelles are promising for in vivo applications.

Lyotropic liquid crystal phase behavior of a cationic amphiphile in aqueous and non-stoichiometric protic ionic liquid mixtures.

Protic ionic liquids (PILs) are the largest and most tailorable known class of non-aqueous solvents which possess the ability to support amphiphile self-assembly. However, little is known about the effect of solvent additives on this ability. In this study, the lyotropic liquid crystal phase (LLCP) behavior of the cationic surfactant cetyltrimethylammonium bromide (CTAB) was investigated in the model PILs of ethylammonium nitrate (EAN) and ethanolammonium nitrate (EtAN), and derived multi-component solvent systems containing them to determine phase formation and diversity with changing solvent composition. The solvent systems were composed of water, nitric acid and ethylamine (or ethanolamine), with 26 unique compositions for each PIL covering the apparent pH and ionicity ranges of 0-13.5 and 0-11 M, respectively. The LLCPs were studied using cross polarized optical microscopy (CPOM) and small and wide-angle X-ray scattering (SAXS/WAXS). Partial phase diagrams were constructed for CTAB concentrations of 50 wt% and 70 wt% in the temperature range of 25 °C to 75 °C to characterise the effect of surfactant concentration and temperature on the LLCPs in each solvent environment. Normal micellar (L1), hexagonal (H1) and bicontinuous cubic (V1) phases were identified at both surfactant concentrations, and from temperatures as low as 35 °C, with large variations dependent on the solvent composition. The thermal stability and diversity of phases were greater and broader in solvent compositions with excess precursor amines present compared to those in the neat PILs. In acid-rich solvent combinations, the same phase diversity was found, though with reduced onset temperatures of phase formation; however, some structural changes were observed which were attributed to oxidation/decomposition of CTAB in a nitric acid environment. This study showed that the ability of PIL solutions to support amphiphile self-assembly can readily be tuned, and that the ability of PILs to promote amphiphile self-assembly is robust, even with other solvent species present.

Novel polymeric micelles as enzyme-sensitive nuclear-targeted dual-functional drug delivery vehicles for enhanced 9-nitro-20(S)-camptothecin delivery and antitumor efficacy.

9-Nitro-20(S)-camptothecin (9-NC) is a broad-spectrum antitumor drug used in tumor treatments, but its clinical applications and antitumor efficacy are limited by its structural instability, poor solubility, and extremely low drug utilization in tumor tissues. In this study, enzyme-sensitive nuclear-targeted dual-functional polymeric micelles were developed for 9-NC delivery with a high drug loading content (12.93 ± 0.88%), steady-state circulation, and a rapid attack at the "heart" of tumor cells. Briefly, chrysin (CHR) as a π-conjugated moiety was immobilized on the PCL terminal in the TAT-PCL amphiphiles and combined with the ALAL peptide as a linker on HA chains to yield the ultimate CHR-PCL-TAT-ALAL-HA (HATPC) amphiphiles. Spherical 9-NC-loaded micelles were obtained from the self-assembly of the dual-functional amphiphiles comprising HATPC and 9-NC with uniform nanosize (121.6 ± 5.79 nm), well-distributed morphology (PDI: 0.256), and negative surface charge (-23.2 ± 0.5 mV), yielding high stability during blood circulation. In this drug delivery system, HA acts as an active tumor-targeting instrument via CD44-receptor-mediated endocytosis; further, the ALAL peptide could be cutoff in the lysosomes of the tumor cells due to the high expression of cathepsin B, leading to lysosomal escape, while the secondary polymeric micelles targeted the tumor cell nucleus via the exposed TAT peptide. The enzyme sensitivity and nuclei targetability of the 9-NC/HATPC micelles were confirmed by dynamic light scattering and confocal laser scanning microscopy analyses. As compared to free 9-NC and traditional mPEG2k-PCL2k polymeric micelles, 9-NC/HATPC micelles were the most concentrated in the tumor cell nucleus; therefore, they exhibited the highest cytotoxicity against SKOV3 tumor cells both in vitro (IC50 = 0.03 μg mL-1) and in vivo. This enzyme-sensitive nuclear-targeted dual-functional drug delivery system involving HATPC provided a new and promising strategy for enhanced 9-NC delivery and antitumor efficacy.

Towards supramolecular nanostructured materials: control of the self-assembly of ionic bent-core amphiphiles

Bottom-up self-assembly: the formation of mesophases and nanostructures in solution from ionic bent-core dendrimers has been systematically studied by molecular design.