Assembly Of Polymers Research Articles

Uncovering tetrazoles as building blocks for constructing discrete and polymeric assemblies.

Metal-organic self-assembly with flexible moieties is a budding field of research due to the possibility of the formation of unique architectures. Tetrazole, characterised by four nitrogen atoms in a five-member ring, exhibits immense potential as a component. Tetrazole offers four coordination sites for binding to the metal centre with nine distinct binding modes, leading to various assemblies. This review highlights different polymeric and discrete tetrazole-based assemblies and their functions. The meticulous manipulation of stoichiometry, ligands, and metal ions required for constructing discrete assemblies has also been discussed. The different applications of these architectures in separation, catalysis and detection have also been accentuated. The latter section of the review consolidates tetrazole-based cage composites, highlighting their applications in cell imaging and photocatalytic applications.

Hydrophobicity as a tool for programming sequential mesophase transitions of enzyme-responsive polymeric amphiphiles.

The ability of polymeric assemblies to undergo programmable cascades of mesophase transitions is prevalent in many systems in nature, where structural and functional features are tightly bound to maximize activity. In this study, we have examined the ability to program the mesophase transition rates of co-assembled enzyme-responsive polymeric micelles, through fine adjustments of the hydrophobicity of their amphiphilic components. We have utilized the different reactivities of di- and tri-block amphiphiles toward enzymatic degradation as a tool for programming formulations to undergo sequential enzymatically induced transitions from micelles to hydrogels and finally to dissolved polymers. By varying the aliphatic end-groups of PEG-dendron di-block and tri-block amphiphiles, we could demonstrate the remarkable impact of minor modifications to the di-block amphiphiles' structure and hydrophobicity on the transition rates between the different mesophases, ranging from a few hours to a week. Additionally, the study reveals how altering the relative hydrophobicity of its amphiphilic components influences the formulation ratio and enzymatic selectivity, as well as the stability and degradation rate of the resulting hydrogels. The findings underscore the importance of molecular architecture and hydrophobicity as key parameters in the design of programmable enzyme-responsive polymeric assemblies, offering insights into the ability to precisely control multi-step mesophase transitions for tailored functionality.

Studying Microtubule Dynamics in Human Neurons: Two-Dimensional Microtubule Tracing and Kymographs in iPSC- and SH-SY5Y-Derived Neurons for Tau Research.

The study of microtubule (MT) dynamics is essential for the understanding of cellular transport, cell polarity, axon formation, and other neurodevelopmental mechanisms. All these processes rely on the constant transition between assembly and disassembly of tubulin polymers to/from MTs, known as dynamic instability. This process is well-regulated, among others, by phosphorylation of microtubule-associated proteins (MAP), including the Tau protein. Protein kinases, in particular the microtubule affinity regulating kinase (MARK), regulate the MT-Tau interaction, inducingTau dissociation by phosphorylation. Phosphorylated Tau dissociates from microtubules forming insoluble aggregates known as neurofibrillary tangles. These accumulations of hyperphosphorylated Tau in the neurons disrupt the physiological MT-based transport machinery within the cell and can potentially lead to the development of neurodegenerative disorders, such as Alzheimer's disease (AD) and related tauopathies. Further investigations on the MT cytoskeleton dynamics are essential as they may elucidate pathomechanisms of neurodegenerative diseases - particularly tauopathies - as well as fundamental neurodevelopmental processes.The study of thedynamic assembly and disassembly of the MT network requires live-cell imaging rather than conventional immunocytochemistry based on fixed samples. To investigate MT dynamics, we perform live-cell imaging of neurons transfected with a fluorescently tagged version of the microtubule plus-end tracking protein (+TIP) EB3. This protein associates with the growing ends of MTs and thus visualizes MT growth in real time. Our imaging analysis protocol allows the determination of quantity, orientation, and velocity of MT growth in the soma and neurites of transfected neurons,using ImageJ-based tracking software and kymographs. Furthermore, functional effects of Tau and MARK kinases on the MT cytoskeleton can be assessed by overexpression or downregulation experiments of the respective protein prior to the live imaging assay. We use two different human neuronal cell models, naive and differentiated SH-SY5Y neuroblastoma cells, and neurons derived from induced pluripotent stem cells (iPSCs), both of which have shown success as models to study Tau-related pathologies.This protocol describes an optimized method for analysis of microtubule dynamics using fluorescent tagged EB3 protein as microtubule plus end marker. In this chapter, we outline the process of neuronal transfection, live-cell imaging, and necessary time-lapse image analysis based on ImageJ in two human-derived neuronal systems, which are suitable for the analysis of Tau trafficking and sorting studies.

Elucidating the assembly of nanoparticle organic hybrid materials (NOHMs) near an electrode interface with varying potential using neutron reflectivity.

A critical concern regarding electrolyte formulation in an electrochemical environment is the impact of the interaction of the multiple components (i.e., supporting electrolyte or additive) with the electrode surface. Recently, liquid-like neat Nanoparticle Organic Hybrid Materials (NOHMs) have been considered as an electrolyte component to improve the transport of redox-active species to the electrode surface. However, the structure and assembly of the NOHMs near the electrode surface is unknown and could significantly impact the electrode-electrolyte interface. Hence, we have investigated the depth profile of polyetheramine (HPE) polymer and NOHM-I-HPE (nanoparticles with ionically bonded HPE polymer) in deuterated water (D2O) in the presence of two different salts (KHCO3 and ZnCl2) near two different electrode surfaces using neutron reflectometry. Moreover, the depth profile of the NOHM-I-HPE near the electrode surface in a potential has also been studied with in situ reflectivity experiments. Our results indicate that a change in the chemical structure/hydrophilicity of the electrode surface does not significantly impact the ordering of HPE polymer or NOHM-I-HPE near the surface. This study also indicates that the NOHM-I-HPE particles form a clear layer near the electrode surface immediately above an adsorbed layer of free polymer on the electrode surface. The addition of salt does not impact the layering of NOHM-I-HPE, though it does alter the conformation of the polymer grafted to the nanoparticle surface and free polymer sequestered near the surface. Finally, the application of negative potential results in an increased amount of free polymer near the electrode surface. Correlating the depth profile of free polymer and NOHM-I-HPE particles with the electrochemical performance indicates that this assembly of free polymer near the electrode surface in NOHM-I-HPE solutions contributes to the higher current density of the system. Therefore, this holistic study offers insight into the importance of the assembly of NOHM-I-HPE electrolyte and free polymer near the electrode surface in an electrochemical milieu on its performance.

Synthesis and pH-responsive properties of bacteria mimicking hydrogel capsules

Synthetic imitation of nonspherical microorganisms can enhance therapeutic delivery in the body. Hydrogel microcapsules with bacteria-mimicking shapes were synthesized through a multilayer assembly of polymers on sacrificial microparticle surfaces.

Synergistic enhancement of photoelectrocatalytic activity and photostability in CdS photoanodes by ultrathin polydopamine layer

CdS-based photocatalyst and photoanode have recently drawn the attention of several investigators primarily in connection with its excellent visible light response in various catalytic reactions involving light, especially photoelectrochemical (PEC) water splitting. The present approach highlights the concept of constructing a biological functional layer incorporated for photochemical instable semiconductors for practical PEC applications. However, practical applications of CdS-based photoanodes are limited by rapid charge recombination and severe photo corrosion. This study introduces a novel approach to enhance reaction kinetics and stability. We present a CdS nanorod photoanode with an ultrathin layer of polydopamine (PDA), prepared through a conformal polymerization assembly process, which serves as a robust platform for subsequent assembly of hole cocatalysts FeOOH. The resulting sandwich structure of CdS/PDA/FeOOH photoanode demonstrates an incident to current efficiency (IPCE) of 7.1% at 420 nm and a photocurrent of 1.9 mA/cm2 at 1.23 V versus the reversible hydrogen potential (RHE). The integrated photoanode exhibits significantly prolonged photostability compared to CdS, CdS/PDA, and CdS/FeOOH photoanodes. The significance of this work lies in constructing a FeOOH structure (with hole extraction and consumption capabilities) on the CdS outermost layer using an easy-to-operate preparation process, thereby revealing the ability of PDA to enable the passage of photogenerated holes. The present approach highlights the concept of integrating biologically functional layers to stabilize photochemically unstable semiconductors for practical PEC applications.

Odd-even effect in chiral side-chain cyanobiphenyl block copolymer assemblies prepared by polymerization-induced chiral self-assembly.

The precise control of the chirality of polymer assemblies is a challenge faced by scientists and has received significant attention in recent years. In this study, we employed the polymerization-induced chiral self-assembly (PICSA) method to create chiral side-chain cyanobiphenyl (CB) block copolymer (BCP) assemblies. The flexible spacers in chiral CB monomers were regulated to exhibit two distinct odd-even effects in the supramolecular asymmetrical arrangement of the CB mesogens inside BCP assemblies. The research results indicated that the liquid crystalline properties of CB mesogens significantly influence the magnitude and sign of their chiroptical properties. These findings have significant implications for the design of polymer assemblies with designable chiroptical functions.

Brownian motion of soft particles near a fluctuating lipid bilayer.

The dynamics of a soft particle suspended in a viscous fluid can be changed by the presence of an elastic boundary. Understanding the mechanisms and dynamics of soft-soft surface interactions can provide valuable insights into many important research fields, including biomedical engineering, soft robotics development, and materials science. This work investigates the anomalous transport properties of a soft nanoparticle near a visco-elastic interface, where the particle consists of a polymer assembly in the form of a micelle and the interface is represented by a lipid bilayer membrane. Mesoscopic simulations using a dissipative particle dynamics model are performed to examine the impact of micelle's proximity to the membrane on its Brownian motion. Two different sizes are considered, which correspond to ≈10-20nm in physical units. The wavelengths typically seen by the largest micelle fall within the range of wavenumbers where the Helfrich model captures fairly well the bilayer mechanical properties. Several independent simulations allowed us to compute the micelle trajectories during an observation time smaller than the diffusive time scale (whose order of magnitude is similar to the membrane relaxation time of the largest wavelengths), this time scale being hardly accessible by experiments. From the probability density function of the micelle normal position with respect to the membrane, it is observed that the position remains close to the starting position during ≈0.05τd (where τd corresponds to the diffusion time), which allowed us to compare the negative excess of mean-square displacement (MSD) to existing theories. In that time range, the MSD exhibits different behaviors along parallel and perpendicular directions. When the micelle is sufficiently close to the bilayer (its initial distance from the bilayer equals approximately twice its gyration radius), the micelle motion becomes quickly subdiffusive in the normal direction. Moreover, the temporal evolution of the micelle MSD excess in the perpendicular direction follows that of a nanoparticle near an elastic membrane. However, in the parallel direction, the MSD excess is rather similar to that of a nanoparticle near a liquid interface.

Lanthanide‐Containing Heteropolyoxomolybdate as Precursor to Porous Complex Oxides via Polymeric Micelle Assembly and Its Heterostructure with Carbon Dots for Anticounterfeiting Application

AbstractThe fabrication of porous complex oxides with intriguing opto‐functional properties remains a challenge that requires innovative synthetic strategies. In this work, a facile soft template method is developed based on stable micellar solutions formed with lanthanide‐containing heteropolyoxomolybdate and alkaline earth citrates as metal salt precursors and block copolymer as templates. The resulting structures exhibit an effective interfacial Förster resonance energy transfer (IFRET) between the porous CaMoO4:Eu3+ (CEMO) host and the embedded surface‐active carbon dots through the conjugated bonds between Ca2+/Mo6+ cations and the C═O functional groups. Such IFRET process extends of Eu3+ absorption band toward the UV and blue regions, enabling the proof‐of‐concept demonstration of multiresponsive anticounterfeiting codes. The study not only presents a new strategy to prepare porous lanthanide‐doped complex oxides but also provides a feasible way to achieve spectral regulation through interfacial interaction for multifunctional luminescent materials.

(Invited) Mesoporous Metallic Materials Electrodeposited from Polymeric Micelle Assemblies for Energy Applications

The surfactant-assisted electrodeposition is an effective means to obtain high-quality mesoporous materials in a rather simple synthesis approach. Commercial or home-made block copolymers can be dissolved in aqueous media above their critical micelle concentration to serve as a soft template in the so-called electrodeposition from polymeric micelle assemblies or micelle-assisted electrodeposition in short [1]. The nanoscale porosity of the resulting films, which extends throughout the whole surface and entire film thickness, endow them with large surface-to-volume (S/V) ratios. Such large S/V ratios are particularly amenable for (electro)catalytic applications and, whenever the alloy presents ferromagnetic properties, for magnetoelectric purposes. In our group, mesoporous Cu-Ni, Co-Pt, Ni-Pt and Fe-Pt alloys with pore size around 10 nm have been electrodeposited from Pluronic P-123 containing solutions [2-4]. Similarly, mesoporous Ni films with larger pore diameters (25 - 600 nm) have been deposited using custom-made PS-b-P4VP block copolymer micelles [5]. Even, the double template approach can be utilized to obtain, for example, matrices of mesoporous Co-Pt microdisks when the micelle-assisted electrodeposition is performed on optically lithographed substrates [6], or nanoporous Fe-Pd nanowires using anodized alumina and P-123 as hard and soft templates, respectively [7]. The introduction of an equilibration time between electrolyte preparation and deposition has been determined key in some cases to consistently reproduce the films mesoporosity [8].The electrodeposited mesoporous metallic materials exhibit higher electrocatalytic activity towards hydrogen evolution reaction (HER) in either acid or alkaline media compared to their dense counterparts [3]. In addition, their durability is not severely compromised in spite of the much larger surface exposed to the media. On the other hand, modulation of their magnetic properties with voltage is also possible when these films are electrolyte-gated in aprotic polar solvents like propylene carbonate. The intense electric field strength created at the film / electrolyte interface thanks to the built-in electric double layer allows for tuning of the coercivity (HC) or the saturation magnetization upon voltage application by virtue of different, but often concomitant, mechanisms taking place, like charge carrier accumulation and oxygen migration [6,9]. Variations greater than 30% in HC have been achieved.In this talk I will summarize the main synthesis-wise milestones achieved during the research in the field and the benefits brought by mesoporous alloys to electrocatalysis and magnetoelectricity.[1] C. Li et al. Acc. Chem. Res. 51 (2018) 1764[2] J. Zhang et al. ACS Appl. Mater. Interfaces 10 (2018) 14877[3] K. Eiler et al. Appl. Cat. B 265 (2020) 118597[4] E. Isarain‐Chávez et al. ChemSusChem 11 (2018) 367[5] R. Fagotto Clavijo et al. Cat. Today, in press.[6] C. Navarro-Senent et al. ACS Appl. Mater. Interfaces 10 (2018) 44897[7] D. Raj et al. Nanomaterials 13 (2023) 403[8] C. Navarro-Senent et al. Electrochim. Acta 358 (2020) 136940[9] C. Navarro-Senent et al. APL Materials 7 (2019) 030701

Unraveling Dynamic Helicity Inversion and Chirality Transfer through the Synthesis of Discrete Azobenzene Oligomers by an Iterative Exponential Growth Strategy.

Unraveling the chirality transfer mechanism of polymer assemblies and controlling their handedness is beneficial for exploring the origin of hierarchical chirality and developing smart materials with desired chiroptical activities. However, polydisperse polymers often lead to an ambiguous or statistical evaluation of the structure-property relationship, and it remains unclear how the iterative number of repeating units function in the helicity inversion of polymer assemblies. Herein, we report the macroscopic helicity and dynamic manipulation of the chiroptical activity of supramolecular assemblies from discrete azobenzene-containing oligomers (azooligomers), together with the helicity inversion and morphological transition achieved solely by changing the iterative chain lengths. The corresponding assemblies also differ from their polydisperse counterparts in terms of thermodynamic properties, chiroptical activities, and morphological control.

Unraveling Dynamic Helicity Inversion and Chirality Transfer through the Synthesis of Discrete Azobenzene Oligomers by an Iterative Exponential Growth Strategy

AbstractUnraveling the chirality transfer mechanism of polymer assemblies and controlling their handedness is beneficial for exploring the origin of hierarchical chirality and developing smart materials with desired chiroptical activities. However, polydisperse polymers often lead to an ambiguous or statistical evaluation of the structure–property relationship, and it remains unclear how the iterative number of repeating units function in the helicity inversion of polymer assemblies. Herein, we report the macroscopic helicity and dynamic manipulation of the chiroptical activity of supramolecular assemblies from discrete azobenzene‐containing oligomers (azooligomers), together with the helicity inversion and morphological transition achieved solely by changing the iterative chain lengths. The corresponding assemblies also differ from their polydisperse counterparts in terms of thermodynamic properties, chiroptical activities, and morphological control.

Solid-Phase Electrosynthesis.

ConspectusThe significance of the new synthetic approach is that it can overcome the limitations of conventional methods and produce previously inaccessible polymer structures and materials. The solid-phase synthesis developed by Merrifield in 1964 is widely employed for the synthesis of biological molecules, such as peptides, nucleic acids, and oligosaccharides. Although the variety of iterative reactions available is theoretically implemented for most organic synthesis protocols, they are usually required to have high efficiency against sluggish reaction kinetics at the solid-liquid interface and process with protection and deprotection steps. Generally, unsatisfied reaction dynamics at the solid-liquid interface cannot statistically permit accurate and uniform polymer synthesis of sophisticated structures and functions within an acceptable time scale. To address this challenge, we propose the concept of solid-phase electrosynthesis, which simultaneously enables rapidly surface-initiated uniform electrosynthesis and unidirectional assembly of metallopolymers via kinetically accelerated and statistically allowed iterative growth. In particular, on a self-assembled monolayer (SAM) of the metal complex with electroactive unit A, the iterative monomer with two electroactive units A and B can be alternatively activated by oxidative and reductive potentials for A-A and B-B covalent couplings with the SAM, respectively. This enables topochemical one-by-one additions of the iterative monomers to end-on-oriented self-assembled molecules through alternative redox reactions. Each iterative step is purified by washing. Repeating the same iterative reaction enables further reaction of the unreactive sites on the SAMs and repairs the morphology defects, thereby ensuring the statistically allowed uniform synthesis and fabrication of polymer monolayers. The resulting monolayers exhibit subnanometer-uniform morphology over centimeter-sized areas with crystalline states and show thicknesses similar to theoretical molecular lengths. This demonstrates the unidirectional formation of polymer assemblies, providing a pathway for obtaining highly ordered formation of noncrystalline polymers. The length-controlled electrosynthesis of metallopolymers can be generalized for many types of organic ligands and metal species, enabling quantitative design of the composition and sequence-controlled metallopolymers with the precise relationships of structures and properties. Solid-phase electrosynthesis offers a unique approach to synthesize polymer structures and monolayers with enhanced functionality and superior physical properties, including physical density, modulus, and conductance. Through the utilization of precise and efficient iterative growth, this predictable electrosynthesis, coupled with optical and electrical monitoring, not only expands the scope of current synthetic chemistry but also paves a potential way for the automated generation of optoelectric molecular monolayers with large-area dimensional consistency and enhanced physical performance.

Multishape Programming of Shape Memory Polymer Assemblies Fabricated by Vat Photopolymerization-Based 3D Printing and Interfacial Welding.

The combination of three-dimensional (3D) printing and shape memory polymers (SMP) enables programmable shape morphing of complex 3D structures, which is commonly termed four-dimensional (4D) printing. The process requirements of vat photopolymerization-based 3D printing impose limitations on the molecular structure design of SMPs, making it challenging to achieve triple- or multiple-shaped memory effects. Herein, we printed SMPs with different Tg values and obtained an SMP assembly through interfacial welding. The welding process is facilitated by the dynamic exchange of hindered urethane bonds at the interface. The resulting SMP assembly exhibits a quadruple shape memory effect, enabling programmable sequential deformation. The advantage of this approach is that the molecular design and the corresponding thermodynamic properties of different welding SMP components can be independently adjusted, enabling a greater range of shape and functional variations in the final 3D SMP assembly.

Fabrication of phenolic resin membrane with polyvinyl alcohol fiber skeleton by electrospinning for organic solvent nanofiltration

As an emerging separation technology, organic solvent nanofiltration (OSN) has shown great potential in the chemical, food, and pharmaceutical industries. Considering the excellent solvent resistance of phenolic resin (PR), it has great potential to be employed for the fabrication of OSN membrane. However, the extremely low permeance due to the highly cross-linked network and limited fabrication strategies still hold back the further application of PR. Herein, we develop a novel method to fabricate PR membrane with polyvinyl alcohol (PVA) fiber skeleton for OSN. This is accomplished through the electrospinning of PVA-resol solution, followed by heating to initiate the cross-linking of resol to form PR. After the further reaction with glutaraldehyde (GA), the PR OSN membrane is finally acquired. Benefiting from the homogeneous mixing of PVA with resol in the electrospinning solution, the formed PVA fibers are uniformly embedded in the PR matrix. The space between PVA fiber skeleton with PR matrix could provide additional channels for the transportation of solvent molecules. Compared with those membranes fabricated by traditional casting methods, the permeance of PR/PVA/GA reported here is significantly improved. The molecular weight cut-off (MWCO) of PR/PVA/GA is about 803 Da based on the rejection curve. Meanwhile, the permeance of acetonitrile about 1.3 Lm-2h-1bar−1 is the highest among the studied solvents, while the values are very low for nonpolar solvents, such as hexane and toluene. Additionally, the obtained membrane exhibits excellent anti-compaction ability and long-term stability. As an alternative to phase inversion and interfacial polymerization, the strategy reported here may provide a new way for the assembly of polymers into nanofiltration membranes for diverse separation applications.

Breaking barriers: Unleashing CO2 selectivity with ultrathin poly(1,3-dioxolane) composite membranes produced by continuous assembly of polymers

Carbon dioxide (CO2) emissions have continued to rise with the sustained reliance on fossil fuels. One leading solution to capturing CO2 emissions is ultrathin film composite (UTFC) membranes due to their cost-efficiency and relatively low environmental impact. On-going efforts to overcome the challenges of practical membrane technology have included increased gas selectivity and robustness toward the low partial pressure of CO2 emitted from coal-fired power stations. Poly(1,3-dioxolane) (PDXL) has been discovered to have exceptional CO2/N2 selectivity outperforming similar high-polar polymers including poly(ethylene oxide) (PEO), PolyActive™, and Pebax®. However, designing as a composite membrane with PDXL has never been accomplished due to a vital challenge of poor interlayer adhesion, and this has restricted its further advancements. The surface-confined Continuous Assembly of Polymers (CAP) technology can be used to overcome the issue of poor interlayer adhesion; however this strategy needs to be modified to ensure all layers are covalently linked. In this study, we synthesized crosslinkable poly(1,3-dioxolane) dimethacrylate (PDXLDMA) and fabricated UTFC membranes via a revised CAP process. The resulting PDXL-based UTFC membrane demonstrated the highest CO2/N2 selectivity (71.3) ever achieved under dry conditions, while maintaining a gas permeance of above 1000 GPU. The modified CAP process preserved PDXL's inherent properties in the UTFC membrane and demonstrated excellent chemical and mechanical strength through crosslinked layers and covalent bonding of the multilayer structure.

The structure of the teleost Immunoglobulin M core provides insights on polymeric antibody evolution, assembly, and function

Polymeric (p) immunoglobulins (Igs) serve broad functions during vertebrate immune responses. Typically, pIgs contain between two and six Ig monomers, each with two antigen binding fragments and one fragment crystallization (Fc). In addition, many pIgs assemble with a joining-chain (JC); however, the number of monomers and potential to include JC vary with species and heavy chain class. Here, we report the cryo-electron microscopy structure of IgM from a teleost (t) species, which does not encode JC. The structure reveals four tIgM Fcs linked through eight C-terminal tailpieces (Tps), which adopt a single β-sandwich-like domain (Tp assembly) located between two Fcs. Specifically, two of eight heavy chains fold uniquely, resulting in a structure distinct from mammalian IgM, which typically contains five IgM monomers, one JC and a centrally-located Tp assembly. Together with mutational analysis, structural data indicate that pIgs have evolved a range of assembly mechanisms and structures, each likely to support unique antibody effector functions.

Synthetic Cells Revisited: Artificial Cells Construction Using Polymeric Building Blocks.

The exponential growth of research on artificial cells and organelles underscores their potential as tools to advance the understanding of fundamental biological processes. The bottom-up construction from a variety of building blocks at the micro- and nanoscale, in combination with biomolecules is key to developing artificial cells. In this review, artificial cells are focused upon based on compartments where polymers are the main constituent of the assembly. Polymers are of particular interest due to their incredible chemical variety and the advantage of tuning the properties and functionality of their assemblies. First, the architectures of micro- and nanoscale polymer assemblies are introduced and then their usage as building blocks is elaborated upon. Different membrane-bound and membrane-less compartments and supramolecular structures and how they combine into advanced synthetic cells are presented. Then, the functional aspects are explored, addressing how artificial organelles in giant compartments mimic cellular processes. Finally, how artificial cells communicate with their surrounding and each other such as to adapt to an ever-changing environment and achieve collective behavior as a steppingstone toward artificial tissues, is taken a look at. Engineering artificial cells with highly controllable and programmable features open new avenues for the development of sophisticated multifunctional systems.

ZnO-incorporated alginate assemblies: Tunable pH-responsiveness and improved drug delivery for cancer therapy

Delivering drugs selectively to tumor tissues is a significant challenge in cancer therapy, and pH-responsive polymeric assemblies have shown great potential in achieving this goal. In this study, we developed a pH-responsive alginate-based assemblies, called (amine-modified ZnO)-oxidized alginate-PEG ((ZnO-N)-OAl-PEG), for selective drug delivery in cancer treatment. The incorporation of ZnO-N nanoparticles into the alginate-based assemblies enables pH-responsiveness and maintains stability under physiological conditions. At an acidic pH, (ZnO-N)-OAl-PEG disassembles due to the conversion of ZnO to Zn2+, which triggers the unloading of doxorubicin (DOX) from the imine bond between DOX and alginate. This unloading results in the death of cancer cells and inhibition of tumor growth. The anticancer efficacy of (DOX/ZnO-N)-OAl-PEG was demonstrated in vitro and in vivo, providing promising prospects for cancer treatment based on ZnO-induced pH-responsiveness. These findings may also inspire the development of advanced drug delivery systems (DDSs) for cancer therapy.

A Subtle Change in the Flexible Achiral Spacer Does Matter in Supramolecular Chirality: Two‐Fold Odd‐Even Effect in Polymer Assemblies

AbstractPrecise control over the chirality and morphologies of polymer assemblies, a remaining challenge for both chemists and materials scientists, is receiving ever‐increasing attention in the recent years. Herein, we report the subtle manipulation of the achiral spacers from the chiral stereocenter to the azobenzene (Azo) unit, of which the chiroptical consistency or chiroptical inversion of self‐assemblies could be successfully controlled and present “two‐fold” odd‐even effect. Furthermore, morphological transitions from 0D spherical micelles, 1D worms, and nanowires to 3D vesicles, spindle‐ and dumbbell‐shaped vesicles were also unexpectedly found to exhibit odd‐even correlations. These observations were collectively elucidated by mesomorphic properties, stacking modes, chiroptical dynamics, and stimuli‐responsive behaviors. Negligible modifications to the spacer structures can enable remarkable modulation of supramolecular chirality and anisotropic topologies in polymer assemblies, which is of great significance for the design of complex chiral functional polymers.