Cylindrical polymer brushes (CPBs) enable remarkable control over nanoparticle properties solely through sequential polymerization. The spatial dimensions and functionality of the resulting polymeric nanoparticles can be adjusted by the ratio of backbone to side chain length and the chemical nature of both parts. In this work, we present a convenient and straightforward synthetic pathway to polypept(o)ide-based CPBs using a "grafting-from" strategy utilizing poly-l-lysine (pLys) as the macroinitiator backbone and polysarcosine (pSar) as the side chain. End-capping of pSar chains with azido-butyric acid pentafluorophenyl ester enables facile surface functionalization by click chemistry (e.g., dye labeling). This strategy allows for straightforward control over nanoparticle size (Rh from 12 to 41 nm), shape (aspect ratio from 1.7 to 8.3), and molecular weights (from 350 to 2980 kg mol-1). Despite the high grafting density of pSar side chains from the pLys backbone (>85%), enzymatic degradation is feasible by the natural protease B fromStreptomyces griseusand enables the analysis of pSar side chains upon cleavage (Đ = 1.03-1.04). Interestingly, these CPBs exhibit thermal stability in phosphate-buffered saline at elevated temperatures (60 °C for 24 h) and display notable circulation in zebrafish embryos (up to 3 days). Therefore, CPBs based on polypept(o)ides not only allow for precise tuning of size, shape, and surface functionality but also display high biocompatibility and extended circulation time in zebrafish, leveraging the stealth-like properties of pSar.

Multivalent binding and the resulting dynamical clustering of receptors and ligands are known to be key features in biological interactions. For optimizing biomaterials capable of similar dynamical features, it is essential to understand the first step of these interactions, namely the multivalent molecular recognition between ligands and cell receptors. Here, we present the reciprocal cooperation between dynamic ligands in supramolecular polymers and dynamic receptors in model cell membranes, determining molecular recognition and multivalent binding via receptor clustering. The nonlinear dependences of the ligand concentration, receptors, and their binding affinity are observed experimentally by fluorescence and superresolution fluorescence microscopies, revealing a valency-dependent clustering mode of anchoring. The mechanism is supported by stochastic modeling demonstrating that such nonlinear dependence is unlikely in the absence of any dynamics and superselectivity. Using a coarse-grained molecular model, the subtle competition between local and global entropies that controls this anchoring mechanism explains the clustering. Further investigation using single particle tracking reveals the presence of two populations of bound and unbound receptors after the clustering process. The result of this study highlights the importance of reciprocity of dynamics in supramolecular polymer and lipid membrane for recruitment, multivalent binding, and clustering, all of which are crucial elements in the design of materials capable of actively interacting with biological targets.

ALK-positive NSCLC patients demonstrate initial responses to ALK tyrosine kinase inhibitor (TKI) treatments, but eventually develop resistance, causing rapid tumor relapse and poor survival rates. Growing evidence suggests that the combination of drug and immune therapies greatly improves patient survival; however, due to the low immunogenicity of the tumors, ALK-positive patients do not respond to currently available immunotherapies. Tumor-associated macrophages (TAMs) play a crucial role in facilitating lung cancer growth by suppressing tumoricidal immune activation and absorbing chemotherapeutics. However, they can also be programmed toward a pro-inflammatory tumor suppressive phenotype, which represents a highly active area of therapy development. Iron loading of TAMs can achieve such reprogramming correlating with an improved prognosis in lung cancer patients. We previously showed that superparamagnetic iron oxide nanoparticles containing core-cross-linked polymer micelles (SPION-CCPMs) target macrophages and stimulate pro-inflammatory activation. Here, we show that SPION-CCPMs stimulate TAMs to secrete reactive nitrogen species and cytokines that exert tumoricidal activity. We further show that SPION-CCPMs reshape the immunosuppressive Eml4-Alk lung tumor microenvironment (TME) toward a cytotoxic profile hallmarked by the recruitment of CD8(+) T cells, suggesting a multifactorial benefit of SPION-CCPM application. When intratracheally instilled into lung cancer-bearing mice, SPION-CCPMs delay tumor growth and, after first line therapy with a TKI, halt the regrowth of relapsing tumors. These findings identify SPIONs-CCPMs as an adjuvant therapy, which remodels the TME, resulting in a delay in the appearance of resistant tumors.

Advances in polymer chemistry can provide convenient access to more complex polymeric architectures, such as miktoarm star polymers. In comparison to their linear counterparts, the physical properties of miktoarm star polymers can substantially differ. Their complex synthesis, characterization, and purification, however, makes it a challenging task to prepare well-defined structures with multiple arms of adjustable chemical nature. In this work, well-defined cross-linkable polypept(o)ide-based AB3 miktoarm star polymers were achieved, taking advantage of a novel asymmetric tetrafunctional initiator system with different orthogonal protecting groups. The first controlled living ring-opening polymerization (ROP) of sarcosine N-carboxyanhydride yields a three-armed polysarcosine (pSar) macroinitiator with low molecular weight dispersity (Đ ∼ 1.1), while a reactive polypeptide arm can be synthesized upon cleavage of the remaining protective group. The established reactive S-alkylsulfonyl protecting group bearing polypeptides poly(S-ethylsulfonyl-l-cysteine) (pCys(SO2Et)) and poly(S-ethylsulfonyl-l-homocysteine) (pHcy(SO2Et) were implemented into the asymmetric star architecture. The presence of the well-defined cross-linkable AB3 PeptoMiktoStars was verified through the characterization via 1H NMR, 1H DOSY, and SEC, revealing structures with dispersity indices of 1.1–1.2 and precise control over the degree of polymerization of each individual polymer chain. In aqueous solution, both types of PeptoMiktoStars form polymeric micelles. The size and morphology can be tuned by secondary structure directed self-assembly: the pHcy(SO2Et)20(pSar100)3 polymers form spherical micelles whilst the pCys(SO2Et)20(pSar100)3 assembled into worm-like micelles. Therefore, this synthetic methodology provides not only access to well-defined reactive miktoarm star polymers, but also allows for the engineering of polymeric micelles based on PeptoMiktoStars.

Synthetic supramolecular polymers and hydrogels in water are emerging as promising biomaterials due to their modularity and intrinsic dynamics. Here, we introduce temperature sensitivity into the nonfunctionalized benzene-1,3,5-tricarboxamide (BTA-EG(4)) supramolecular system by incorporating a poly(N-isopropylacrylamide)-functionalized (BTA-PNIPAM) moiety, enabling 3D cell encapsulation applications. The viscous and structural properties in the solution state as well as the mechanical and dynamic features in the gel state of BTA-PNIPAM/BTA-EG(4) mixtures were investigated and modulated. In the dilute state (c similar to mu M), BTA-PNIPAM acted as a chain capper below the cloud point temperature (T-cp = 24 degrees C) but served as a cross-linker above T-cp. At higher concentrations (c similar to mM), weak or stiff hydrogels were obtained, depending on the BTA-PNIPAM/BTA-EG(4) ratio. The mixture with the highest BTA-PNIPAM ratio was similar to 100 times stiffer and similar to 10 times less dynamic than BTA-EG(4) hydrogel. Facile cell encapsulation in 3D was realized by leveraging the temperature-sensitive sol-gel transition, opening opportunities for utilizing this hydrogel as an extracellular matrix mimic.

Liquid–liquid phase separation (LLPS) of biopolymers has recently been shown to play a central role in the formation of membraneless organelles with a multitude of biological functions 1 – 3 . The interplay between LLPS and macromolecular condensation is part of continuing studies 4 , 5 . Synthetic supramolecular polymers are the non-covalent equivalent of macromolecules but they are not reported to undergo LLPS yet. Here we show that continuously growing fibrils, obtained from supramolecular polymerizations of synthetic components, are responsible for phase separation into highly anisotropic aqueous liquid droplets (tactoids) by means of an entropy-driven pathway. The crowding environment, regulated by dextran concentration, affects not only the kinetics of supramolecular polymerizations but also the properties of LLPS, including phase-separation kinetics, morphology, internal order, fluidity and mechanical properties of the final tactoids. In addition, substrate–liquid and liquid–liquid interfaces proved capable of accelerating LLPS of supramolecular polymers, allowing the generation of a myriad of three-dimensional-ordered structures, including highly ordered arrays of micrometre-long tactoids at surfaces. The generality and many possibilities of supramolecular polymerizations to control emerging morphologies are demonstrated with several supramolecular polymers, opening up a new field of matter ranging from highly structured aqueous solutions by means of stabilized LLPS to nanoscopic soft matter.

Improving target versus off-target ratio in nanomedicine remains a major challenge for increasing drug bioavailability and reducing toxicity. Active targeting using ligands on nanoparticle surfaces is a key approach but has limited clinical success. A potential issue is the integration of targeting ligands also changes the physicochemical properties of nanoparticles (passive targeting). Direct studies to understand the mechanisms of active targeting and off-targeting in vivo are limited by the lack of suitable tools. Here, the biodistribution of a representative active targeting liposome is analyzed, modified with an apolipoprotein E (ApoE) peptide that binds to the low-density lipoprotein receptor (LDLR), using zebrafish embryos. The ApoE liposomes demonstrated the expected liver targeting effect but also accumulated in the kidney glomerulus. The ldlra(-/-) zebrafish is developed to explore the LDLR-specificity of ApoE liposomes. Interestingly, liver targeting depends on the LDLR-specific interaction, while glomerular accumulation is independent of LDLR and peptide sequence. It is found that cationic charges of peptides and the size of liposomes govern glomerular targeting. Increasing the size of ApoE liposomes can avoid this off-targeting. Taken together, the study shows the potential of the zebrafish embryo model for understanding active and passive targeting mechanisms, that can be used to optimize the design of nanoparticles.

The supramolecular assembly of proteins into irreversible fibrils is often associated with diseases in which aberrant phase transitions occur. Due to the complexity of biological systems and their surrounding environments, the mechanism underlying phase separation-mediated supramolecular assembly is poorly understood, making the reversal of so-called irreversible fibrillization a significant challenge. Therefore, it is crucial to develop simple model systems that provide insights into the mechanistic process of monomers to phase-separated droplets and ordered supramolecular assemblies. Such models can help in investigating strategies to either reverse or modulate these states. Herein, we present a simple synthetic model system composed of three components, including a benzene-1,3,5-tricarboxamide-based supramolecular monomer, a surfactant, and water, to mimic the condensate pathway observed in biological systems. This highly dynamic system can undergo "micelle-droplet-fiber" transition over time and space with a concentration gradient field, regulated by competitive interactions. Importantly, manipulating these competitive interactions through guest molecules, temperature changes, and cosolvents can reverse ordered fibers into a disordered liquid or micellar state. Our model system provides new insights into the critical balance between various interactions among the three components that determine the pathway and reversibility of the process. Extending this "competitive interaction" approach from a simple model system to complex macromolecules, e.g., proteins, could open new avenues for biomedical applications, such as condensate-modifying therapeutics.

Abstract Liquid-liquid phase separation (LLPS) of biopolymers has recently been shown to play a central role in the formation of membraneless organelles with a multitude of biological functions1–3. Whether LLPS induces protein condensation and/or that associative interactions are required for LLPS is part of ongoing studies4,5. Biofilaments such as actin, amyloid fibrils, collagen and nanocellulose can form structured liquids or liquid crystals in vitro6–9. Here we present that the supramolecular polymerization of a variety of monomers is responsible for phase separation into anisotropic liquid droplets (tactoids) via an entropy-driven pathway. The crowding environment regulated by the concentration of dextran can influence not only supramolecular polymerizations but also properties of the LLPS, including phase separation kinetics, morphology, internal order, fluidity, and mechanical properties of the final tactoids. In addition, substrate-liquid and liquid-liquid interfaces were found to be able to accelerate the LLPS of supramolecular polymers, allowing the generation of a myriad of 3D-ordered structures, including highly ordered arrays of micrometer long tactoids at surfaces. The generality and many possibilities of supramolecular polymers to control emerging morphologies are shown with several supramolecular polymers, which opens a new area of matter ranging from highly structured aqueous solutions via stabilized LLPS to nanoscopic soft matter.

L droplets, formed through noncovalent interactions of small molecules or macromolecules, have revolutionized our understanding of cellular organization and function since the discovery of biomolecular condensates in the cellular realm. These liquid droplets are generated via liquid−liquid phase separation (LLPS), referring to the spontaneous separation of (macro)molecules in distinct concentrated and diluted liquid phases driven by weak noncovalent interactions, such as electrostatic, π−π, cation−π, and hydrophobic interactions (Figure 1A). The reversible nature of these

Benzene-1,3,5-tricarboxamide (BTA) glyco-monomers containing one, two or three mannose units are synthesized and formulated into differently patterned supramolecular glycopolymers through homo-assembly or co-assembly with non-functionalized BTAs. Unfortunately, no cellular activity could be detected. Excitingly, these glyco-BTA monomers could be formulated into hydrogels, paving the way for (immune) cell culture.

To expand the single-dose duration over which noninvasive clinical and preclinical cancer imaging can be conducted with high sensitivity, and well-defined spatial and temporal resolutions, a facile strategy to prepare ultrasmall nanoparticulate X-ray contrast media (nano-XRCM) as dual-modality imaging agents for positron emission tomography (PET) and computed tomography (CT) has been established. Synthesized from controlled copolymerization of triiodobenzoyl ethyl acrylate and oligo(ethylene oxide) acrylate monomers, the amphiphilic statistical iodocopolymers (ICPs) could directly dissolve in water to afford thermodynamically stable solutions with high aqueous iodine concentrations (>140 mg iodine/mL water) and comparable viscosities to conventional small molecule XRCM. The formation of ultrasmall iodinated nanoparticles with hydrodynamic diameters of ca. 10 nm in water was confirmed by dynamic and static light scattering techniques. In a breast cancer mouse model, in vivo biodistribution studies revealed that the 64Cu-chelator-functionalized iodinated nano-XRCM exhibited extended blood residency and higher tumor accumulation compared to typical small molecule imaging agents. PET/CT imaging of tumor over 3 days showed good correlation between PET and CT signals, while CT imaging allowed continuous observation of tumor retention even after 10 days post-injection, enabling longitudinal monitoring of tumor retention for imaging or potentially therapeutic effect after a single administration of nano-XRCM.

Supramolecular glycopolymers exhibiting inherent dynamicity, tunability, and adaptivity allow us to arrive at a deeper understanding of multivalent carbohydrate-carbohydrate interactions and carbohydrate-protein interactions, both being essential to key biological events. The impacts of the carbohydrate segments in these supramolecular glycopolymers towards their structure, dynamics, and function as biomaterials are addressed in this minireview. Bottlenecks and challenges are discussed, and we speculate about possible future directions.

Fascinating properties are displayed by synthetic multicomponent supramolecular systems that comprise a manifold of competitive interactions, thereby mimicking natural processes. We present the integration of two reentrant phase transitions based on an unexpected dilution-induced assembly process using supramolecular polymers and surfactants. The co-assembly of the water-soluble benzene-1,3,5-tricarboxamide (BTA-EG 4 ) and a surfactant at a specific ratio yielded small-sized aggregates. These interactions were modeled using the competition between self-sorting and co-assembly of both components. The small-sized aggregates were transformed into supramolecular polymer networks by a twofold dilution in water without changing their ratio. Kinetic experiments show the in situ growth of micrometer-long fibers in the dilution process. We were able to create systems that undergo fully reversible hydrogel-solution-hydrogel-solution transitions upon dilution by introducing another orthogonal interaction.

Synthetic water-compatible supramolecular polymers based on benzene-1,3,5-tricarboxamides (BTAs) have attracted a lot of interest in recent years, as they are uniquely suited to generate functional multicomponent biomaterials. Their morphologies and intrinsic dynamic behaviour mimic fibrous structures found in nature. Moreover, their modularity allows control of the density of functionalities presented on the surface of the fibres when using functionalized BTA monomers. However, such moieties generally comprise a functionality on only one of three side chains, resulting in lengthy synthetic protocols and limited yields. In this work, we avert the need for desymmetrization of the core by starting from commercially available 5-aminoisophthalic acid. This approach eliminates the statistical reactions and reduces the number of synthetic steps. It also leads to the inversion of the connectivity of one of the amides to the benzene core. By combining spectroscopy, light scattering and cryogenic transmission electron microscopy, we confirm that the inversed amide BTAs (iBTAs) form intermolecular hydrogen bonds and assemble into supramolecular polymers, like previously used symmetrical BTAs, albeit with a slight decrease in water solubility. Solubility problems were overcome by incorporating iBTAs into conventional BTA-based supramolecular polymers. These two-component mixtures formed supramolecular fibres with a morphology and dynamic behaviour similar to BTA-homopolymers. Finally, iBTAs were decorated with a fluorescent dye to demonstrate the synthesis of functional monomers, and to visualize their co-assembly with BTAs. Our results show that functionality can be introduced into supramolecular polymers with monomers that slightly differ in their core structure while maintaining the structure and dynamics of the fibres.

Synthetic water-compatible supramolecular polymers based on benzene-1,3,5-tricarboxamides (BTAs) have attracted a lot of interest in recent years, as they are uniquely suited to generate functional multicomponent biomaterials. Their morphologies and intrinsic dynamic behaviour mimic fibrous structures found in nature. Moreover, their modularity allows control of the density of functionalities presented on the surface of the fibres when using functionalized BTA monomers. However, such moieties generally comprise a functionality on only one of three side chains, resulting in lengthy synthetic protocols and limited yields. In this work, we avert the need for desymmetrization of the core by starting from commercially available 5-aminoisophthalic acid. This approach eliminates the statistical reactions and reduces the number of synthetic steps. It also leads to the inversion of the connectivity of one of the amides to the benzene core. By combining spectroscopy, light scattering and cryogenic transmission electron microscopy, we confirm that the inversed amide BTAs (iBTAs) form intermolecular hydrogen bonds and assemble into supramolecular polymers, like previously used symmetrical BTAs, albeit with a slight decrease in water solubility. Solubility problems were overcome by incorporating iBTAs into conventional BTA-based supramolecular polymers. These two-component mixtures formed supramolecular fibres with a morphology and dynamic behaviour similar to BTAhomopolymers. Finally, iBTAs were decorated with a fluorescent dye to demonstrate the synthesis of functional monomers, and to visualize their co-assembly with BTAs. Our results show that functionality can be introduced into supramolecular polymers with monomers that slightly differ in their core structure while maintaining the structure and dynamics of the fibres.

In only a few decades, lithium-ion batteries have revolutionized technologies, enabling the proliferation of portable devices and electric vehicles 1 , with substantial benefits for society. However, the rapid growth in technology has highlighted the ethical and environmental challenges of mining lithium, cobalt and other mineral ore resources, and the issues associated with the safe usage and non-hazardous disposal of batteries 2 . Only a small fraction of lithium-ion batteries are recycled, further exacerbating global material supply of strategic elements 3 – 5 . A potential alternative is to use organic-based redox-active materials 6 – 8 to develop rechargeable batteries that originate from ethically sourced, sustainable materials and enable on-demand deconstruction and reconstruction. Making such batteries is challenging because the active materials must be stable during operation but degradable at end of life. Further, the degradation products should be either environmentally benign or recyclable for reconstruction into a new battery. Here we demonstrate a metal-free, polypeptide-based battery, in which viologens and nitroxide radicals are incorporated as redox-active groups along polypeptide backbones to function as anode and cathode materials, respectively. These redox-active polypeptides perform as active materials that are stable during battery operation and subsequently degrade on demand in acidic conditions to generate amino acids, other building blocks and degradation products. Such a polypeptide-based battery is a first step to addressing the need for alternative chemistries for green and sustainable batteries in a future circular economy.

The use of supramolecular polymers to construct functional biomaterials is gaining more attention due to the tunable dynamic behavior and fibrous structures of supramolecular polymers, which resemble those found in natural systems, such as the extracellular matrix. Nevertheless, to obtain a biomaterial capable of mimicking native systems, complex biomolecules should be incorporated, as they allow one to achieve essential biological processes. In this study, supramolecular polymers based on water-soluble benzene-1,3,5-tricarboxamides (BTAs) were assembled in the presence of hyaluronic acid (HA) both in solution and hydrogel states. The coassembly of BTAs bearing tetra(ethylene glycol) at the periphery (BTA-OEG4) and HA at different ratios showed strong interactions between the two components that led to the formation of short fibers and heterogeneous hydrogels. BTAs were further covalently linked to HA (HA-BTA), resulting in a polymer that was unable to assemble into fibers or form hydrogels due to the high hydrophilicity of HA. However, coassembly of HA-BTA with BTA-OEG4 resulted in the formation of long fibers, similar to those formed by BTA-OEG4 alone, and hydrogels were produced with tunable stiffness ranging from 250 to 700 Pa, which is 10-fold higher than that of hydrogels assembled with only BTA-OEG4. Further coassembly of BTA-OEG4 fibers with other polysaccharides showed that except for dextran, all polysaccharides studied interacted with BTA-OEG4 fibers. The possibility of incorporating polysaccharides into BTA-based materials paves the way for the creation of dynamic complex biomaterials.