Glycodendrimersomes from Sequence-Defined Janus Glycodendrimers Reveal High Activity and Sensor Capacity for the Agglutination by Natural Variants of Human Lectins

Accelerated Ten-Gram-Scale Synthesis of One-Component Multifunctional Sequence-Defined Ionizable Amphiphilic Janus Dendrimer 97

One-component multifunctional sequence-defined ionizable amphiphilic Janus dendrimers (IAJDs) were discovered in our laboratories in 2021 to represent a new class of synthetic vectors for the targeted delivery of messenger RNA (mRNA). They coassemble with mRNA by simple injection of their ethanol solution into a pH 4 acetate buffer containing the nucleic acid into monodisperse dendrimersome nanoparticles (DNPs) with predictable dimensions. DNPs are competitive with 4-component lipid nanoparticles (LNPs), which are used in commercial COVID-19 vaccines, except that IAJDs are prepared in fewer reaction steps than each individual component of the LNPs. This simple methodology for the synthesis of IAJDs and their coassembly with mRNA into DNPs, together with the precise placement of their individual components and indefinite stability at room temperature in air, make them attractive candidates for the development of nanomedicine-based targeted mRNA delivery. Access to the large-scale synthesis of IAJDs without the need for sophisticated technologies, instrumentation, and synthetic skills is expected to open numerous new opportunities worldwide in nanomedicine. The goal of this publication is to report an accelerated ten-gram-scale synthesis of IAJD97 from inexpensive food additives obtained from renewable plant phenolic acid starting materials by methodologies accessible to any laboratory. This accelerated synthesis can be accomplished in 4 days. We expect that the work reported here will impact the field of nanomedicine in both developed and less developed countries.

Biocompatible Glycopolymer-PLA Amphiphilic Hybrid Block Copolymers with Unique Self-Assembly, Uptake, and Degradation Properties

The self-assembly of Janus-type amphiphilic hybrid block copolymers composed of hydrophilic/hydrophobic layers has shown promise for drug encapsulation and delivery. Saccharides have previously been incorporated to improve the biocompatibility of self-assembled structures; however, glycopolymer block copolymers have been less explored, and their structure-property relationships are not well understood. In this study, novel glycopolymer-branched poly(lactic acid) (PLA) block copolymers were synthesized via thiol-ene coupling and their composition-dependent morphologies were elucidated. Stability as a function of pH, dye uptake capabilities, and cytotoxicity were evaluated. Systems with a hydrophilic weight ratio of 30% were found to produce bilayer nanoparticles, while systems with a hydrophilic weight ratio of 60% form micelles upon self-assembly in aqueous media. Regardless of composition and morphology, all systems exhibited uptake of both hydrophobic (curcumin, DL % from 4.25 to 11.55) and hydrophilic (methyl orange, DL % from 4.08 to 5.88) dye molecules with release profiles dependent on composition. Furthermore, all of the nanoparticles exhibited low cytotoxicity, confirming their potential for biomedical applications.

From Frank-Kasper, Quasicrystals, and Biological Membrane Mimics to Reprogramming In Vivo the Living Factory to Target the Delivery of mRNA with One-Component Amphiphilic Janus Dendrimers

This Perspective is dedicated to the 25th Anniversary of Biomacromolecules. It provides a personal view on the developing field of the polymer and biology interface over the 25 years since the journal was launched by the American Chemical Society (ACS). This Perspective is meant to bridge an article published in the first issue of the journal and recent bioinspired developments in the laboratory of the corresponding author. The discovery of supramolecular spherical helices self-organizing into Frank-Kasper and quasicrystals as models of icosahedral viruses, as well as of columnar helical assemblies that mimic rodlike viruses by supramolecular dendrimers, is briefly presented. The transplant of these assemblies from supramolecular dendrimers to block copolymers, giant surfactants, and other self-organized soft matter follows. Amphiphilic self-assembling Janus dendrimers and glycodendrimers as mimics of biological membranes and their glycans are discussed. New concepts derived from them that evolved in the in vivo targeted delivery of mRNA with the simplest one-component synthetic vector systems are introduced. Some synthetic methodologies employed during the synthesis and self-assembly are explained. Unraveling bioinspired applications of novel materials concludes this brief 25th Anniversary Perspective of Biomacromolecules.

The Constitutional Isomerism of One-Component Ionizable Amphiphilic Janus Dendrimers Orchestrates the Total and Targeted Activities of mRNA Delivery

Constitutional isomerism has been previously demonstrated by one of our laboratories to represent a powerful design strategy for the elaboration of complex functional self-organizations. Here we report the design, synthesis, and characterization of 14 positional, skeletal, and functional constitutional isomeric one-component, multifunctional, sequence-defined, amphiphilic ionizable Janus dendrimers (IAJDs). Their coassembly by simple injection with luciferase mRNA (Luc-mRNA) to form dendrimersome nanoparticles (DNPs) was studied. Subsequently, the resulting DNPs were employed to investigate, with screening experiments, the delivery of Luc-mRNA in vivo. Constitutional isomerism was shown to produce changes of up to two orders of magnitude of the total-body luciferase activity and targeted luciferase activity to the spleen and liver, of up to three orders of magnitude difference in targeted luciferase activity to the lungs and up to six orders of magnitude to lymph nodes. These results indicate that constitutional isomerism may represent not only a simple but also an important synthetic strategy that most probably may impact the activity of all components of synthetic vectors used in RNA-based nanomedicine, including in mRNA vaccines and therapeutics.

Glycan-Driven Formation of Raft-Like Domains with Hierarchical Periodic Nanoarrays on Dendrimersome Synthetic Cells

The accurate spatial segregation into distinct phases within cell membranes coordinates vital biochemical processes and functionalities in living organisms. One of nature's strategies to localize reactivity is the formation of dynamic raft domains. Most raft models rely on liquid-ordered L0 phases in a liquid-disordered Ld phase lacking correlation and remaining static, often necessitating external agents for phase separation. Here, we introduce a synthetic system of bicomponent glycodendrimersomes coassembled from Janus dendrimers and Janus glycodendrimers (JGDs), where lactose-lactose interactions exclusively drive lateral organization. This mechanism results in modulated phases across two length scales, yielding raft-like microdomains featuring nanoarrays at the nanoscale. By varying the density of lactose and molecular architecture of JGDs, the nanoarray type and size, shape, and spacing of the domains were controlled. Our findings offer insight into the potential primordial origins of rudimentary raft domains and highlight the crucial role of glycans within the glycocalyx.

Dendrimersomes: Biomedical applications

In recent years, dendrimer-based vesicles, known as dendrimersomes, have garnered significant attention as highly promising alternatives to lipid vesicles in a variety of biomedical applications. Dendrimersomes offer several advantages, including relatively straightforward synthesis, non-immunogenic properties, stability in circulation, and minimal size variability. These vesicles are composed of Janus dendrimers, which are polymers characterized by two dendritic wedges with different terminal groups - hydrophilic and hydrophobic. This dendrimer structure enables the self-assembly of dendrimersomes. The purpose of this highlight is to provide an overview of recent advancements achieved through the utilization of biomimetic dendrimersomes in various biomedical applications such as drug and nucleic acid delivery.

Lactose-Functionalized Carbosilane Glycodendrimers Are Highly Potent Multivalent Ligands for Galectin-9 Binding: Increased Glycan Affinity to Galectins Correlates with Aggregation Behavior

Galectins, the glycan binding proteins, and their respective carbohydrate ligands represent a unique fundamental regulatory network modulating a plethora of biological processes. The advances in galectin-targeted therapy must be based on a deep understanding of the mechanism of ligand-protein recognition. Carbosilane dendrimers, the well-defined and finely tunable nanoscaffolds with low toxicity, are promising for multivalent carbohydrate ligand presentation to target galectin receptors. The study discloses a synthetic method for two types of lactose-functionalized carbosilane glycodendrimers (Lac-CS-DDMs). Furthermore, we report their outstanding, dendritic effect-driven affinity to tandem-type galectins, especially Gal-9. In the enzyme-linked immunosorbent assay, the affinity of the third-generation multivalent dendritic ligand bearing 32 lactose units to Gal-9 reached nanomolar values (IC50 = 970 nM), being a 1400-fold more effective inhibitor than monovalent lactose for this protein. This demonstrates a game-changing impact of multivalent presentation on the inhibitory effect of a ligand as simple as lactose. Moreover, using DLS hydrodynamic diameter measurements, we correlated the increased affinity of the glycodendrimer ligands to Gal-3 and Gal-8 but especially to Gal-9 with the formation of relatively uniform and stable galectin/Lac-CS-DDM aggregates.

Targeted and Equally Distributed Delivery of mRNA to Organs with Pentaerythritol-Based One-Component Ionizable Amphiphilic Janus Dendrimers

Delivery of nucleic acids with viral and synthetic vectors has pioneered genetic nanomedicine. Four-component lipid nanoparticles (LNPs) consisting of ionizable lipids, phospholipids, cholesterol, and PEG-conjugated lipids, assembled by microfluidic or T-tube, are the benchmark synthetic vector for delivery of mRNA. One-component multifunctional sequence-defined ionizable amphiphilic Janus dendrimer (IAJD) delivery systems for mRNA were developed by us to complement LNPs. IAJDs consist of multifunctional hydrophilic low-generation dendrons or minidendrons conjugated to hydrophobic dendrons. They were inspired by amphiphilic Janus dendrimers and glycodendrimers. IAJDs coassemble with mRNA into predictable-size vesicles, named dendrimersome nanoparticles (DNPs), by simple injection in acetate buffer, rather than by the complex technology required by LNPs. Assembly of DNPs by simple injection together with sequence design in the hydrophilic and hydrophobic modules of IAJDs endowed rapid screening to access discovery. Molecular design principles for targeted delivery were elaborated when the branching points of IAJDs were constructed from symmetrically and nonsymmetrically substituted plant phenolic acids interconnected by pentaerythritol (PE). Here, we report the first library containing simplified IAJDs constructed in only three steps from symmetrically trialkylated PE in the hydrophobic domain and four different piperazine-based ionizable amines in the hydrophilic part. Rapid coassembly with mRNA and in vivo screening led to the discovery of the two most active IAJDs targeting the spleen, liver, and lymph nodes, one predominantly to the spleen and liver and six delivering equally to the spleen, liver, lung, and lymph nodes. These IAJDs represent the simplest synthetic vectors and the first viral or synthetic system delivering equally to multiple organs.

Screening Libraries to Discover Molecular Design Principles for the Targeted Delivery of mRNA with One-Component Ionizable Amphiphilic Janus Dendrimers Derived from Plant Phenolic Acids

Viral and synthetic vectors to deliver nucleic acids were key to the rapid development of extraordinarily efficient COVID-19 vaccines. The four-component lipid nanoparticles (LNPs), containing phospholipids, PEG-conjugated lipids, cholesterol, and ionizable lipids, co-assembled with mRNA via a microfluidic technology, are the leading nonviral delivery vector used by BioNTech/Pfizer and Moderna to access COVID-19 mRNA vaccines. LNPs exhibit a statistical distribution of their four components when delivering mRNA. Here, we report a methodology that involves screening libraries to discover the molecular design principles required to realize organ-targeted mRNA delivery and mediate activity with a one-component ionizable multifunctional amphiphilic Janus dendrimer (IAJD) derived from plant phenolic acids. IAJDs co-assemble with mRNA into monodisperse dendrimersome nanoparticles (DNPs) with predictable dimensions, via the simple injection of their ethanol solution in a buffer. The precise location of the functional groups in one-component IAJDs demonstrated that the targeted organs, including the liver, spleen, lymph nodes, and lung, are selected based on the hydrophilic region, while activity is associated with the hydrophobic domain of IAJDs. These principles, and a mechanistic hypothesis to explain activity, simplify the synthesis of IAJDs, the assembly of DNPs, handling, and storage of vaccines, and reduce price, despite employing renewable plant starting materials. Using simple molecular design principles will lead to increased accessibility to a large diversity of mRNA-based vaccines and nanotherapeutics.

Stimuli-Responsive Principles of Supramolecular Organizations Emerging from Self-Assembling and Self-Organizable Dendrons, Dendrimers, and Dendronized Polymers

All activities of our daily life, of the nature surrounding us and of the entire society and its complex economic and political systems are affected by stimuli. Therefore, understanding stimuli-responsive principles in nature, biology, society, and in complex synthetic systems is fundamental to natural and life sciences. This invited Perspective attempts to organize, to the best of our knowledge, for the first time the stimuli-responsive principles of supramolecular organizations emerging from self-assembling and self-organizable dendrons, dendrimers, and dendronized polymers. Definitions of stimulus and stimuli from different fields of science are first discussed. Subsequently, we decided that supramolecular organizations of self-assembling and self-organizable dendrons, dendrimers, and dendronized polymers may fit best in the definition of stimuli from biology. After a brief historical introduction to the discovery and development of conventional and self-assembling and self-organizable dendrons, dendrimers, and dendronized polymers, a classification of stimuli-responsible principles as internal- and external-stimuli was made. Due to the enormous amount of literature on conventional dendrons, dendrimers, and dendronized polymers as well as on their self-assembling and self-organizable systems we decided to discuss stimuli-responsive principles only with examples from our laboratory. We apologize to all contributors to dendrimers and to the readers of this Perspective for this space-limited decision. Even after this decision, restrictions to a limited number of examples were required. In spite of this, we expect that this Perspective will provide a new way of thinking about stimuli in all fields of self-organized complex soft matter.

Assembling Complex Macromolecules and Self-Organizations of Biological Relevance with Cu(I)-Catalyzed Azide-Alkyne, Thio-Bromo, and TERMINI Double "Click" Reactions

In 2022, the Nobel Prize in Chemistry was awarded to Bertozzi, Meldal, and Sharpless "for the development of click chemistry and biorthogonal chemistry". Since 2001, when the concept of click chemistry was advanced by Sharpless laboratory, synthetic chemists started to envision click reactions as the preferred choice of synthetic methodology employed to create new functions. This brief perspective will summarize research performed in our laboratories with the classic Cu(I)-catalyzed azide-alkyne click (CuAAC) reaction elaborated by Meldal and Sharpless, with the thio-bromo click (TBC) and with the less-used, irreversible TERminator Multifunctional INItiator (TERMINI) dual click (TBC) reactions, the last two elaborated in our laboratory. These click reactions will be used to assemble, by accelerated modular-orthogonal methodologies, complex macromolecules and self-organizations of biological relevance. Self-assembling amphiphilic Janus dendrimers and Janus glycodendrimers together with their biological membrane mimics known as dendrimersomes and glycodendrimersomes as well as simple methodologies to assemble macromolecules with perfect and complex architecture such as dendrimers from commercial monomers and building blocks will be discussed. This perspective is dedicated to the 75th anniversary of Professor Bogdan C. Simionescu, the son of my (VP) Ph.D. mentor, Professor Cristofor I. Simionescu, who as his father, took both science and science administration in his hands, and dedicated his life to handling them in a tandem way, to their best.

Properties and Bioapplications of Amphiphilic Janus Dendrimers: A Review

Amphiphilic Janus dendrimers are arrangements containing both hydrophilic and hydrophobic units, capable of forming ordered aggregates by intermolecular noncovalent interactions between the dendrimer units. Compared to conventional dendrimers, these molecular self-assemblies possess particular and effective attributes i.e., the presence of different terminal groups, essential to design new elaborated materials. The present review will focus on the pharmaceutical and biomedical application of amphiphilic Janus dendrimers. Important information for the development of novel optimized pharmaceutical formulations, such as structural classification, synthetic pathways, properties and applications, will offer the complete characterization of this type of Janus dendrimers. This work will constitute an up-to-date background for dendrimer specialists involved in designing amphiphilic Janus dendrimer-based nanomaterials for future innovations in this promising field.

Self-Assembly of Glycerol-Amphiphilic Janus Dendrimers Amplifies and Indicates Principles for the Selection of Stereochemistry by Biological Membranes

The principles for the selection of the stereochemistry of phospholipids of biological membranes remain unclear and continue to be debated. Therefore, any new experiments on this topic may help progress in this field. To address this question, three libraries of constitutional isomeric glycerol-amphiphilic Janus dendrimers (JDs) with nonsymmetric homochiral, racemic, and symmetric achiral branching points were synthesized by an orthogonal-modular-convergent methodology. These JDs amplify self-assembly, and therefore, monodisperse vesicles known as dendrimersomes (DSs) with predictable dimensions programmed by JD concentration were assembled by rapid injection of their ethanol solution into water. DSs of homochiral JD enantiomers, racemic, including mixtures of different enantiomers, and achiral exhibited similar DS size-concentration dependence. However, the number of bilayers of DSs assembled from homochiral, achiral, and racemic JDs determined by cryo-TEM were different. Statistical analysis of the number of bilayers and coarse-grained molecular dynamics simulations demonstrated that homochiral JDs formed predominantly unilamellar DSs. Symmetric achiral JDs assembled only unilamellar DSs while racemic JDs favored multilamellar DSs. Since cell membranes are unilamellar, these results indicate a new rationale for nonsymmetric homochiral vs racemic selection. Simultaneously, these experiments imply that the symmetric achiral lipids forming more stable membrane, probably had been the preferable assemblies of prebiotic cell membranes.

Multivalent glycosystems for human lectins

Human lectins are involved in a wide variety of biological processes, both physiological and pathological, which have attracted the interest of the scientific community working in the glycoscience field. Multivalent glycosystems have been employed as useful tools to understand carbohydrate-lectin binding processes as well as for biomedical applications. The review shows the different scaffolds designed for a multivalent presentation of sugars and their corresponding binding studies to lectins and in some cases, their biological activities. We summarise this research by organizing based on lectin types to highlight the progression in this active field. The paper provides an overall picture of how these contributions have furnished relevant information on this topic to help in understanding and participate in these carbohydrate-lectin interactions.

Synthesis of Fluorescent, Dumbbell-Shaped Polyurethane Homo- and Heterodendrimers and Their Photophysical Properties

Fluorescent dendrimers have wide applications in biomedical and materials science. Here, we report the synthesis of fluorescent polyurethane homodendrimers and Janus dendrimers, which often pose challenges due to the inherent reactivity of isocyanates. Polyurethane dendrons (G1-G3) were synthesized via a convergent method using a one-pot multicomponent Curtius reaction as a crucial step to establish urethane linkages. The alkyne periphery of the G1-G3 dendrons was modified by a copper catalyzed azide-alkyne click reaction (CuAAC) to form fluorescent dendrons. In the reaction of the surfaces functionalized two different dendrons with a difunctional core, a mixture of three dendrimers consisting of two homodendrimers and a Janus dendrimer were obtained. The Janus dendrimer accounted for a higher proportion in the products' distribution, being as high as 93% for G3. The photophysical properties of Janus dendrimers showed the fluorescence resonance energy transfer (FRET) from one to the other fluorophore of the dendrimer. The FRET observation accompanied by a large Stokes shift make these dendrimers potential candidates for the detection and tracking of interactions between the biomolecules, as well as potential candidates for fluorescence imaging.

Polymer-tethered glyconanoparticle colourimetric biosensors for lectin binding: structural and experimental parameters to ensure a robust output

Glycan-lectin interactions play essential roles in biology; as the site of attachment for pathogens, cell-cell communication, and as crucial players in the immune system. Identifying if a new glycan (natural or unnatural) binds a protein partner, or if a new protein (or mutant) binds a glycan remains a non-trivial problem, with few accessible or low-cost tools available. Micro-arrays allow for the interrogation of 100's of glycans but are not widely available in individual laboratories. Biophysical techniques such as isothermal titration calorimetry, surface plasmon resonance spectrometry, biolayer interferometry and nuclear magnetic resonance spectroscopy all provide detailed understanding of glycan binding but are relatively expensive. Glycosylated plasmonic nanoparticles based on gold cores with polymeric tethers have emerged as biosensors to detect glycan-protein binding, based on colourimetric (red to blue) outputs which can be easily interpreted by a simple UV-visible spectrometer or by eye. Despite the large number of reports there are no standard protocols for each system or recommended start points, to allow a new user to deploy this technology. Here we explore the key parameters of nanoparticle size, polymeric tether length and gold concentration to provide some guidelines for how polymer-tethered glycosylated gold nanoparticles can be used to probe a new glycan/protein interactions, with minimal optimisation barriers. This work aimed to remove the need to explore chemical and nanoparticle space and hence remove a barrier for other users when deploying this system. We show that the concentration of the gold core is crucial to balance strong responses versus false positives and recommend a gold core size and polymer tether length which balances sufficient colloidal stability and output. Whilst subtle differences between glycans/lectins will impact the outcomes, these parameters should enable a lab user to quickly evaluate binding using minimal quantities of the glycan and lectin, to select candidates for further study.

Combinatorial synthesis enables scalable designer detergents for membrane protein studies

Non-ionic detergents with tailor-made properties are indispensable tools for today's world applications, such as cleaning, disinfection, and drug discovery. To facilitate their challenging production, herein we introduce a new detergent class, namely scalable hybrid detergents. We report a combinatorial synthesis strategy that allows us to fuse head groups of different detergents into hybrid detergents with unbeatable ease. Importantly, combinatorial synthesis also enables the choice between (i) high-throughput preparation of detergents for small scale applications and (ii) large scale preparation of individual detergents. This combinatorial synthesis strategy enables an unprecedented fine tuning of detergent properties, such as overall polarity and shape, which are determining factors in applications, such as membrane protein research. Our data show that membrane protein purification parameters, such as protein yields and activity, can be linked to overall polarity and shape. Conveniently, both parameters can be theoretically described by means of the hydrophilic-lipophilic balance (HLB) and packing parameter concepts. Both concepts are principally applicable to all non-ionic detergent classes, which facilitates the identification of widely applicable design guidelines for the predictable optimization of non-ionic detergents. Our findings permit access to a yet unexplored chemical space of the detergentome, therefore creating new possibilities for structure-property relationship studies. Seen from a broader perspective, combinatorial synthesis will facilitate the preparation of designer detergents with tailor-made properties for future applications in today's world.

Tailored Solid-State Carbohydrate Nanostructures Based on Star-Shaped Discrete Block Co-Oligomers

Carbohydrates are key building blocks for advanced functional materials owing to their biological functions and unique material properties. Here, we propose a star-shaped discrete block co-oligomer (BCO) platform to access carbohydrate nanostructures in bulk and thin-film states via the microphase separation of immiscible carbohydrate and hydrophobic blocks (maltooligosaccharides with 1-4 glucose units and solanesol, respectively). BCOs with various star-shaped architectures and saccharide volume fractions were synthesized using a modular approach. In the bulk, the BCOs self-assembled into common lamellar, cylindrical, and spherical carbohydrate microdomains as well as double gyroid, hexagonally perforated lamellar, and Fddd network morphologies with domain spacings of ∼7 nm. In thin films, long-range-ordered periodic carbohydrate microdomains were fabricated via spin coating. Such controlled spatial arrangements of functional carbohydrate moieties on the nanoscale have great application potential in biomedical and nanofabrication fields.

Glycosylated gold nanoparticles in point of care diagnostics: from aggregation to lateral flow

Current point-of-care lateral flow immunoassays, such as the home pregnancy test, rely on proteins as detection units (e.g. antibodies) to sense for analytes. Glycans play a fundamental role in biological signalling and recognition events such as pathogen adhesion and hence they are promising future alternatives to antibody-based biosensing and diagnostics. Here we introduce the potential of glycans coupled to gold nanoparticles as recognition agents for lateral flow diagnostics. We first introduce the concept of lateral flow, including a case study of lateral flow use in the field compared to other diagnostic tools. We then introduce glycosylated materials, the affinity gains achieved by the cluster glycoside effect and the current use of these in aggregation based assays. Finally, the potential role of glycans in lateral flow are explained, and examples of their successful use given.

Antibody-based lateral flow (immune) assays are well established, but here the emerging concept and potential of using glycans as the detection agents is reviewed.

The Unexpected Importance of the Primary Structure of the Hydrophobic Part of One-Component Ionizable Amphiphilic Janus Dendrimers in Targeted mRNA Delivery Activity

Viral and synthetic vectors for delivery of nucleic acids impacted genetic nanomedicine by aiding the rapid development of the extraordinarily efficient Covid-19 vaccines. Access to targeted delivery of nucleic acids is expected to expand the field of nanomedicine beyond most expectations. Both viral and synthetic vectors have advantages and disadvantages. The major advantage of the synthetic vectors is their unlimited synthetic capability. The four-component lipid nanoparticles (LNPs) are the leading nonviral vector for mRNA used by Pfizer and Moderna in Covid-19 vaccines. Their synthetic capacity inspired us to develop a one-component multifunctional sequence-defined ionizable amphiphilic Janus dendrimer (IAJD) delivery system for mRNA. The first experiments on IAJDs provided, through a rational-library design combined with orthogonal-modular accelerated synthesis and sequence control in their hydrophilic part, some of the most active synthetic vectors for the delivery of mRNA to lung. The second experiments employed a similar strategy, generating, by a less complex hydrophilic structure, a library of IAJDs targeting spleen, liver, and lung. Here, we report preliminary studies designing the hydrophobic region of IAJDs by using dissimilar alkyl lengths and demonstrate the unexpectedly important role of the primary structure of the hydrophobic part of IAJDs by increasing up to 90.2-fold the activity of targeted delivery of mRNA to spleen, lymph nodes, liver, and lung. The principles of the design strategy reported here and in previous publications indicate that IAJDs could have a profound impact on the future of genetic nanomedicine.

Dynamic Glycopeptide Dendrimers: Synthesis and Their Controllable Self-Assembly into Varied Glyco-Nanostructures for the Biomimicry of Glycans

A library of 14 dynamic glycopeptide amphiphilic dendrimers composed of 14 hydrophilic and bioactive saccharides (seven kinds) as dendrons and 7 hydrophobic peptides (di- and tetrapeptides) as arms with β-cyclodextrin (CD) as a core were facially designed and synthesized in several steps. Fourteen saccharides were first conjugated to the C-2 and C-3 positions of CD, forming glycodendrons. Subsequently, seven oligopeptide arms were introduced at the C-6 positions of a CD moiety by an acylhydrazone dynamic covalent bond, resulting in unique Janus amphiphilic glycopeptide dendrimers with precise and varied molecular structures. The kinds of hydrophilic parts of saccharides and hydrophobic parts of peptides were easily varied to prepare a series of amphiphilic Janus glycopeptide dendrimers. Intriguingly, these obtained amphiphilic glycopeptide dendrimers showcased very different self-assembly behaviors from the traditional amphiphilic linear block-copolymers and self-assembled into different glyco-nanostructures with controllable morphologies including glycospheres, worm-like micelles, and fibers depending upon the repeat unit ratio of saccharides and phenylalanine. Both glycodendrons and glycopeptide assemblies displayed strong and specific recognitions with C-type mannose-specific lectin. Moreover, these glycopeptide nanomaterials can encapsulate exemplary hydrophobic molecules such as Nile red (NR). The dye-loaded glycopeptide nanostructures showed a pH-controllable release behavior around the physiological and acidic tumor environment. Furthermore, cell experiments demonstrated that such glyco-nanostructures can further facilitate the functions of a model drug of the pyridone agent to reduce the expression of monocyte chemotactic protein-1 (MCP-1) and interleukin -1beta (IL-1β) in the primary peritoneal macrophages via encapsulating drugs. Considering all the abovementioned advantages including unique and precise structures, bioactivity, targeting, and controllable cargo release, we believe that these findings can not only enrich the library of glycopeptides but also provide a new avenue to the fabrication of smart and structure-controllable glyco-nanomaterials which hold great potential biological applications such as targeted delivery and release of therapeutic and bioactive molecules.

Targeted Delivery of mRNA with One-Component Ionizable Amphiphilic Janus Dendrimers

Targeted and efficient delivery of nucleic acids with viral and synthetic vectors is the key step of genetic nanomedicine. The four-component lipid nanoparticle synthetic delivery systems consisting of ionizable lipids, phospholipids, cholesterol, and a PEG-conjugated lipid, assembled by microfluidic or T-tube technology, have been extraordinarily successful for delivery of mRNA to provide Covid-19 vaccines. Recently, we reported a one-component multifunctional sequence-defined ionizable amphiphilic Janus dendrimer (IAJD) synthetic delivery system for mRNA relying on amphiphilic Janus dendrimers and glycodendrimers developed in our laboratory. Amphiphilic Janus dendrimers consist of functional hydrophilic dendrons conjugated to hydrophobic dendrons. Co-assembly of IAJDs with mRNA into dendrimersome nanoparticles (DNPs) occurs by simple injection in acetate buffer, rather than by microfluidic devices, and provides a very efficient system for delivery of mRNA to lung. Here we report the replacement of most of the hydrophilic fragment of the dendron from IAJDs, maintaining only its ionizable amine, while changing its interconnecting group to the hydrophobic dendron from amide to ester. The resulting IAJDs demonstrated that protonated ionizable amines play dual roles of hydrophilic fragment and binding ligand for mRNA, changing delivery from lung to spleen and/or liver. Replacing the interconnecting ester with the amide switched the delivery back to lung. Delivery predominantly to liver is favored by pairs of odd and even alkyl groups in the hydrophobic dendron. This simple structural change transformed the targeted delivery of mRNA mediated with IAJDs, from lung to liver and spleen, and expands the utility of DNPs from therapeutics to vaccines.

Multivalent glycans for biological and biomedical applications

Recognition of glycans by proteins plays a crucial role in a variety of physiological processes in cells and living organisms. In addition, interactions of glycans with proteins are involved in the development of diverse diseases, such as pathogen infection, inflammation and tumor metastasis. It is well-known that multivalent glycans bind to proteins much more strongly than do their monomeric counterparts. Owing to this property, numerous multivalent glycans have been utilized to elucidate glycan-mediated biological processes and to discover glycan-based biomedical agents. In this review, we discuss recent advances (2014-2020) made in the development and biological and biomedical applications of synthetic multivalent glycans, including neoglycopeptides, neoglycoproteins, glycodendrimers, glycopolymers, glyconanoparticles and glycoliposomes. We hope this review assists researchers in the design and development of novel multivalent glycans with predictable activities.

One-Component Multifunctional Sequence-Defined Ionizable Amphiphilic Janus Dendrimer Delivery Systems for mRNA

Efficient viral or nonviral delivery of nucleic acids is the key step of genetic nanomedicine. Both viral and synthetic vectors have been successfully employed for genetic delivery with recent examples being DNA, adenoviral, and mRNA-based Covid-19 vaccines. Viral vectors can be target specific and very efficient but can also mediate severe immune response, cell toxicity, and mutations. Four-component lipid nanoparticles (LNPs) containing ionizable lipids, phospholipids, cholesterol for mechanical properties, and PEG-conjugated lipid for stability represent the current leading nonviral vectors for mRNA. However, the segregation of the neutral ionizable lipid as droplets in the core of the LNP, the "PEG dilemma", and the stability at only very low temperatures limit their efficiency. Here, we report the development of a one-component multifunctional ionizable amphiphilic Janus dendrimer (IAJD) delivery system for mRNA that exhibits high activity at a low concentration of ionizable amines organized in a sequence-defined arrangement. Six libraries containing 54 sequence-defined IAJDs were synthesized by an accelerated modular-orthogonal methodology and coassembled with mRNA into dendrimersome nanoparticles (DNPs) by a simple injection method rather than by the complex microfluidic technology often used for LNPs. Forty four (81%) showed activity in vitro and 31 (57%) in vivo. Some, exhibiting organ specificity, are stable at 5 °C and demonstrated higher transfection efficiency than positive control experiments in vitro and in vivo. Aside from practical applications, this proof of concept will help elucidate the mechanisms of packaging and release of mRNA from DNPs as a function of ionizable amine concentration, their sequence, and constitutional isomerism of IAJDs.

Photoresponsive glyco-nanostructures integrated from supramolecular metallocarbohydrates for the reversible capture and release of lectins

Photo-controllable capture and release of proteins by glyco-nanostructures.

Synthesis of Dendritic Glycoclusters and Their Applications for Supramolecular Gelation and Catalysis

Glycoclusters with three, four, and six arms of glycosyl triazoles were designed, synthesized, and characterized. The self-assembling properties of these molecules and their catalytic activity as ligands in copper-catalyzed azide and alkyne cycloaddition (CuAAC) reactions were studied. The compounds with a lower number of branches exhibit excellent gelation properties and can function as supramolecular gelators. The resulting gels were characterized using optical microcopy and atomic force microscopy. The glycoconjugates containing six branches showed significant catalytic activity for copper sulfate mediated cycloaddition reactions. In aqueous solutions, 1 mol % of glycoclusters to substrates was efficient at accelerating these reactions. Several trimeric compounds were found to be capable of forming co-gels with the catalytically active hexameric compounds. Using the organogels formed by the glycoconjugates as supramolecular catalysts, efficient catalysis was demonstrated for several CuAAC reactions. The metallogels with CuSO₄ were also prepared as gel columns, which can be reused for the cycloaddition reactions several times. These include the preparation of a few glycosyl triazoles and aryl triazoles and isoxazoles. We expect that these sugar-based soft biomaterials will have applications beyond supramolecular catalysis for copper-catalyzed cycloaddition reactions. They may also be useful as ligands or gel matrixes for other metal-ion catalyzed organic reactions.

From examining the relationship between (corona)viral adhesins and galectins to glyco-perspectives

Glycan-lectin recognition is vital to processes that impact human health, including viral infections. Proceeding from crystallographical evidence of case studies on adeno-, corona-, and rotaviral spike proteins, the relationship of these adhesins to mammalian galectins was examined by computational similarity assessments. Intrafamily diversity among human galectins was in the range of that to these viral surface proteins. Our findings are offered to inspire the consideration of lectin-based approaches to thwart infection by present and future viral threats, also mentioning possible implications for vaccine development.

Introducing affinity and selectivity into galectin-targeting nanoparticles with fluorinated glycan ligands

Galectins are potential biomarkers and therapeutic targets. However, galectins display broad affinity towards β-galactosides meaning glycan-based (nano)biosensors lack the required selectivity and affinity. Using a polymer-stabilized nanoparticle biosensing platform, we herein demonstrate that the specificity of immobilised lacto-N-biose towards galectins can be 'turned on/off' by using site-specific glycan fluorination and in some cases reversal of specificity can be achieved. The panel of fluoro-glycans were obtained by a chemoenzymatic approach, exploiting BiGalK and BiGalHexNAcP enzymes from Bifidobacterium infantis which are shown to tolerate fluorinated glycans, introducing structural diversity which would be very laborious by chemical methods alone. These results demonstrate that integrating non-natural, fluorinated glycans into nanomaterials can encode unprecedented selectivity with potential applications in biosensing.

Glycopolymer ornamented octa-arm POSS based organic-inorganic hybrid star block copolymer as a lectin binding ligand

In this study, a polyhedral oligomeric silsesquioxane-polycaprolactone (POSS-PCL)-cored octa-arm star-shaped glyco block copolymer (BCP), poly(ε-caprolactone)-b-poly(glucopyranose) (Star-POSS-PCL-b-PGlc) was successfully synthesized via the combination of ring opening polymerization (ROP) and MADIX (macromolecular design by interchange of xanthate) polymerization technique. Herein, initially octa(3-hydroxy-3-methylbutyl dimethylsiloxy) POSS (Star-POSS) was utilized to initiate the ROP of the ε-caprolactone to get octa-arm star-shaped Star-POSS-PCL. A successive bromination followed by xanthation of the synthesized Star-POSS-PCL polymer allowed us to further polymerize 3-O-acryloyl-1,2:5,6-di-O-isopropylidene-α-D-glucofuranose (AIpGlc) via MADIX polymerization. Formation of the star-shaped block copolymer (BCP) was characterized using ¹H NMR, FT-IR and DSC analyses. The morphology and the aqueous solution behavior of the Star-POSS-PCL-b-PGlc were analyzed using FESEM, HRTEM and DLS analyses, respectively. The lectin-binding efficiency of the star-shaped BCP having different glycopolymer block length was studied using turbidimetry assay and fluorescence quenching titration (FQT) using photoluminescence spectroscopy (PL). Here, FITC labeled concanavalin A (FITC-Con A) was used as a model lectin. The cytotoxicity study of the star-shaped BCPs over the human fibroblast cells revealed the non-toxic nature of the BCPs which open up its great potential towards drug delivery vector.

Direct Visualization of Vesicle Disassembly and Reassembly Using Photocleavable Dendrimers Elucidates Cargo Release Mechanisms

Release of cargo molecules from cell-like nanocarriers can be achieved by chemical perturbations, including changes to pH and redox state and via optical modulation of membrane properties. However, little is known about the kinetics or products of vesicle breakdown due to limitations in real-time imaging at nanometer length scales. Using a library of 12 single-single type photocleavable amphiphilic Janus dendrimers, we developed a self-assembling light-responsive dendrimersome vesicle platform. A photocleavable ortho-nitrobenzyl inserted between the hydrophobic and hydrophilic dendrons of amphiphilic Janus dendrimers allowed for photocleavage and disassembly of their supramolecular assemblies. Distinct methods used to self-assemble amphiphilic Janus dendrimers produced either nanometer size small unilamellar vesicles or micron size giant multilamellar and onion-like dendrimersomes. In situ observation of giant photosensitive dendrimersomes via confocal microscopy elucidated rapid morphological transitions that accompany vesicle breakdown upon 405 nm laser illumination. Giant dendrimersomes displayed light-induced cleavage, disassembling and reassembling into much smaller vesicles at millisecond time scales. Additionally, photocleavable vesicles demonstrated rapid release of molecular and macromolecular cargos. These results guided our design of multilamellar particles to photorelease surface-attached proteins, photoinduce cargo recruitment, and photoconvert vesicle morphology. Real-time characterization of the breakdown and reassembly of lamellar structures provides insights on partial cargo retention and informs the design of versatile, optically regulated carriers for applications in nanoscience and synthetic biology.

Nanovesicles displaying functional linear and branched oligomannose self-assembled from sequence-defined Janus glycodendrimers

Synthetic macromolecules that mimic glycolipids, named Janus glycodendrimers (JGDs), have been shown to self-assemble into nanoscale vesicles displaying glycans on their outer surface, similar to the glycocalyx coating of eukaryotic cells, bacteria, and viruses. Specifically, both linear and branched oligosaccharides synthesized by automated glycan assembly, with hydrophobic linkers, have been used to create JGDs via an isothiocyanate–amine coupling reaction. Surprisingly, in spite of the hydrophobic linker, these JGDs self-organize into nanovesicles exhibiting lamellar surface morphologies, which mimic the recognition structures of cell-surface glycans and viral glycoproteins. Therefore, they are likely to be useful in helping elucidate mechanisms of significance for translational medicine such as the camouflage functionality employed by viruses to evade recognition.

Cell surfaces are often decorated with glycoconjugates that contain linear and more complex symmetrically and asymmetrically branched carbohydrates essential for cellular recognition and communication processes. Mannose is one of the fundamental building blocks of glycans in many biological membranes. Moreover, oligomannoses are commonly found on the surface of pathogens such as bacteria and viruses as both glycolipids and glycoproteins. However, their mechanism of action is not well understood, even though this is of great potential interest for translational medicine. Sequence-defined amphiphilic Janus glycodendrimers containing simple mono- and disaccharides that mimic glycolipids are known to self-assemble into glycodendrimersomes, which in turn resemble the surface of a cell by encoding carbohydrate activity via supramolecular multivalency. The synthetic challenge of preparing Janus glycodendrimers containing more complex linear and branched glycans has so far prevented access to more realistic cell mimics. However, the present work reports the use of an isothiocyanate-amine “click”-like reaction between isothiocyanate-containing sequence-defined amphiphilic Janus dendrimers and either linear or branched oligosaccharides containing up to six monosaccharide units attached to a hydrophobic amino-pentyl linker, a construct not expected to assemble into glycodendrimersomes. Unexpectedly, these oligoMan-containing dendrimers, which have their hydrophobic linker connected via a thiourea group to the amphiphilic part of Janus glycodendrimers, self-organize into nanoscale glycodendrimersomes. Specifically, the mannose-binding lectins that best agglutinate glycodendrimersomes are those displaying hexamannose. Lamellar “raft-like” nanomorphologies on the surface of glycodendrimersomes, self-organized from these sequence-defined glycans, endow these membrane mimics with high biological activity.

Magnifying the Structural Components of Biomembranes: A Prototype for the Study of the Self-Assembly of Giant Lipids

How biomembranes are self-organized to perform their functions remains a pivotal issue in biological and chemical science. Understanding the self-assembly principles of lipid-like molecules hence becomes crucial. Herein, we report the mesostructural evolution of amphiphilic sphere-rod conjugates (giant lipids), and study the roles of geometric parameters (head-tail ratio and cross-sectional area) during this course. As a prototype system, giant lipids resemble natural lipidic molecules by capturing their essential features. The self-assembly behavior of two categories of giant lipids (I-shape and T-shape, a total of 8 molecules) is demonstrated. A rich variety of mesostructures is constructed in solution state and their molecular packing models are rationally understood. Giant lipids recast the phase behavior of natural lipids to a certain degree and the abundant self-assembled morphologies reveal distinct physiochemical behaviors when geometric parameters deviate from natural analogues.

Folding control of a non-natural glycopeptide using saccharide-coded structural information for polypeptides

We synthesized “glyco-arylopeptides”, whose folding structure significantly changes depending on the kind of saccharide in their side chain. The saccharide moiety interacts with the main chain via hydrogen bonding, and the non-natural polypeptides form two well-defined architectures—(P)-3₁- and (M)-4₁-helices—depending on the length of the saccharide chains and even the configuration of a single stereo-genic center in the epimers.

Structural design and antimicrobial properties of polypeptides and saccharide–polypeptide conjugates

The development and progress of antimicrobial polypeptides and saccharide–polypeptide conjugates in regards to their structural design, biological functions and antimicrobial mechanism.

Diversiform and Transformable Glyco-Nanostructures Constructed from Amphiphilic Supramolecular Metallocarbohydrates through Hierarchical Self-Assembly: The Balance between Metallacycles and Saccharides

During the past decade, self-assembly of saccharide-containing amphiphilic molecules toward bioinspired functional glycomaterials has attracted continuous attention due to their various applications in fundamental and practical areas. However, it still remains a great challenge to prepare hierarchical glycoassemblies with controllable and diversiform structures because of the complexity of saccharide structures and carbohydrate-carbohydrate interactions. Herein, through hierarchical self-assembly of modulated amphiphilic supramolecular metallocarbohydrates, we successfully prepared various well-defined glyco-nanostructures in aqueous solution, including vesicles, solid spheres, and opened vesicles depending on the molecular structures of metallocarbohydrates. More attractively, these glyco-nanostructures can further transform into other morphological structures in aqueous solutions such as worm-like micelles, tubules, and even tupanvirus-like vesicles (TVVs). It is worth mentioning that distinctive anisotropic structures including the opened vesicles (OVs) and TVVs were rarely reported in glycobased nano-objects. This intriguing diversity was mainly controlled by the subtle structural trade-off of the two major components of the amphiphiles, i.e., the saccharides and metallacycles. To further understand this precise structural control, molecular simulations provided deep physical insights on the morphology evolution and balancing of the contributions from saccharides and metallacycles. Moreover, the multivalency of glyco-nanostructures with different shapes and sizes was demonstrated by agglutination with a diversity of sugar-binding protein receptors such as the plant lectins Concanavalin A (ConA). This modular synthesis strategy provides access to systematic tuning of molecular structure and self-assembled architecture, which undoubtedly will broaden our horizons on the controllable fabrication of biomimetic glycomaterials such as biological membranes and supramolecular lectin inhibitors.

Sequence-Defined Dendrons Dictate Supramolecular Cogwheel Assembly of Dendronized Perylene Bisimides

A dendronized perylene bisimide (PBI) that self-organizes into hexagonal arrays of supramolecular double helices with identical single-crystal-like order that disregards chirality was recently reported. A cogwheel model of self-assembly that explains this process was proposed. Accessing the highly ordered cogwheel phase required very slow heating and cooling or extended periods of annealing. Analogous PBIs with linear alkyl chains did not exhibit the cogwheel assembly. Here a library of sequence-defined dendrons containing all possible compositions of linear and racemic alkyl chains was employed to construct self-assembling PBIs. Thermal and structural analysis of their assemblies by differential scanning calorimetry (DSC) and fiber X-ray diffraction (XRD) revealed that the incorporation of n-alkyl chains accelerates the formation of the high order cogwheel phase, rendering the previously invisible phase accessible under standard heating and cooling rates. Small changes to the primary structure, as constitutional isomerism, result in significant changes to macroscopic properties such as melting of the periodic array. This study demonstrated how changes to the sequence-defined primary structure, including the relocation of methyl groups between two constitutional isomers, dictate tertiary and quaternary structure in hierarchical assemblies. This led to the discovery of a sequence that self-organizes the cogwheel assembly much faster than even the corresponding homochiral compounds and demonstrated that defined-sequence, which has long been recognized as a determinant for the complex structure of biomacromolecules including proteins and nucleic acids, plays the same role also in supramolecular synthetic systems.

pH-Responsive Micellar Nanoassemblies from Water-Soluble Telechelic Homopolymers Endcoding Acid-Labile Middle-Chain Groups in Their Hydrophobic Sequence-Defined Initiator Residue

A middle-chain cleavable telechelic poly(oligoethylene glycol) methyl ether acrylate) (MCCT-POEGA-Br) was synthesized by single-electron transfer living radical polymerization (SET-LRP) initiated from an acetal-containing hydrophobic sequence-defined difunctional initiator. In aqueous medium, above a certain concentration, this hydrophilic homopolymer self-assembled into nanogel-like large micelles that exhibit an encapsulating capacity for both hydrophobic and hydrophilic cargo. The sequence-defined cleavage pattern encoded in the initiator residue allowed precise middle-chain cleavage, leading to quantitative disassembly of the corresponding nanoobjects. Dye release studies performed in an acidic environment demonstrated the potential of this new design concept in the preparation of pH-responsive nanocarriers. In addition, fluorescently tagged nanoassemblies could also be obtained via the thio-bromo "click" modification of MCCT-POEGA-Br prior to self-assembly. This strategy may provide facile access to a diversity of multistimuli-responsive nanocarriers based on commercially available hydrophilic monomers and sequence-defined difunctional initiators synthesized by this simple design strategy.

Encapsulation of hydrophobic components in dendrimersomes and decoration of their surface with proteins and nucleic acids

Reconstructing the functions of living cells using nonnatural components is one of the great challenges of natural sciences. Compartmentalization, encapsulation, and surface decoration of globular assemblies, known as vesicles, represent key early steps in the reconstitution of synthetic cells. Here we report that vesicles self-assembled from amphiphilic Janus dendrimers, called dendrimersomes, encapsulate high concentrations of hydrophobic components and do so more efficiently than commercially available stealth liposomes assembled from phospholipid components. Multilayer onion-like dendrimersomes demonstrate a particularly high capacity for loading low-molecular weight compounds and even folded proteins. Coassembly of amphiphilic Janus dendrimers with metal-chelating ligands conjugated to amphiphilic Janus dendrimers generates dendrimersomes that selectively display folded proteins on their periphery in an oriented manner. A modular strategy for tethering nucleic acids to the surface of dendrimersomes is also demonstrated. These findings augment the functional capabilities of dendrimersomes to serve as versatile biological membrane mimics.

Effects of linker and liposome anchoring on lactose-functionalized glycomacromolecules as multivalent ligands for binding galectin-3

In this work, we present a bottom-up approach for the synthesis of lactose-functionalized glycomacromolecules and glycofunctionalized liposomes and apply these compounds to investigate their effects of multivalent presentation on binding to galectin-3. Step-wise assembly of tailor-made building blocks on solid supports was used to synthesize a series of oligo(amidoamine) scaffolds that were further conjugated to lactose via copper catalyzed 1,3-dipolar cycloaddition. Binding studies with galectin-3 revealed affinities in the micromolar range that increased with increasing carbohydrate valency, and decreased with increasing size and linker flexibility. To further explore their multivalency, selected glycomacromolecules were conjugated to lipids and used in liposomal formulations. Binding studies show a further increase in binding in nanomolar ranges in dependence of both ligand structure and liposomal presentation, demonstrating the power of combining the two approaches.

Synthesis of Stimuli-Responsive Heterofunctional Dendrimer by Passerini Multicomponent Reaction

We report the synthesis of a structurally diverse amphiphilic dendrimer with oxidation and ultraviolet light-sensitive groups incorporated in the dendrimer interior. Convergent synthesis is utilized by reacting branched repeating units with a nonbranched functional molecule by two synthetic strategies, Passerini multicomponent reaction and azide-alkyne cycloaddition reaction. The periphery of dendrimer was functionalized by methoxy poly(ethylene glycol) to obtain a dendrimer with a hydrophobic core and hydrophilic peripheral chains. The G2-PEG dendrimer characterized by NMR, GPC, and MALDI-TOF MS for structural integrity and oxidation- and photo-triggered degradations of the G2-PEG dendrimer was investigated. The self-assembled morphology of the dendrimer in the presence of organic dye was also investigated by TEM and DLS analyses, together with dissipative particle dynamics simulation. The encapsulation of dye molecules in self-assembled nanospheres of the dendrimer and their responsive releases, triggered by the efficient disassembly of a dendrimer, have been demonstrated.

Encoding biological recognition in a bicomponent cell-membrane mimic

Self-assembling dendrimers have facilitated the discovery of periodic and quasiperiodic arrays of supramolecular architectures and the diverse functions derived from them. Examples are liquid quasicrystals and their approximants plus helical columns and spheres, including some that disregard chirality. The same periodic and quasiperiodic arrays were subsequently found in block copolymers, surfactants, lipids, glycolipids, and other complex molecules. Here we report the discovery of lamellar and hexagonal periodic arrays on the surface of vesicles generated from sequence-defined bicomponent monodisperse oligomers containing lipid and glycolipid mimics. These vesicles, known as glycodendrimersomes, act as cell-membrane mimics with hierarchical morphologies resembling bicomponent rafts. These nanosegregated morphologies diminish sugar-sugar interactions enabling stronger binding to sugar-binding proteins than densely packed arrangements of sugars. Importantly, this provides a mechanism to encode the reactivity of sugars via their interaction with sugar-binding proteins. The observed sugar phase-separated hierarchical arrays with lamellar and hexagonal morphologies that encode biological recognition are among the most complex architectures yet discovered in soft matter. The enhanced reactivity of the sugar displays likely has applications in material science and nanomedicine, with potential to evolve into related technologies.

Design-functionality relationships for adhesion/growth-regulatory galectins

Glycan-lectin recognition is assumed to elicit its broad range of (patho)physiological functions via a combination of specific contact formation with generation of complexes of distinct signal-triggering topology on biomembranes. Faced with the challenge to understand why evolution has led to three particular modes of modular architecture for adhesion/growth-regulatory galectins in vertebrates, here we introduce protein engineering to enable design switches. The impact of changes is measured in assays on cell growth and on bridging fully synthetic nanovesicles (glycodendrimersomes) with a chemically programmable surface. Using the example of homodimeric galectin-1 and monomeric galectin-3, the mutual design conversion caused qualitative differences, i.e., from bridging effector to antagonist/from antagonist to growth inhibitor and vice versa. In addition to attaining proof-of-principle evidence for the hypothesis that chimera-type galectin-3 design makes functional antagonism possible, we underscore the value of versatile surface programming with a derivative of the pan-galectin ligand lactose. Aggregation assays with N,N'-diacetyllactosamine establishing a parasite-like surface signature revealed marked selectivity among the family of galectins and bridging potency of homodimers. These findings provide fundamental insights into design-functionality relationships of galectins. Moreover, our strategy generates the tools to identify biofunctional lattice formation on biomembranes and galectin-reagents with therapeutic potential.

Screening Libraries of Amphiphilic Janus Dendrimers Based on Natural Phenolic Acids to Discover Monodisperse Unilamellar Dendrimersomes

Natural, including plant, and synthetic phenolic acids are employed as building blocks for the synthesis of constitutional isomeric libraries of self-assembling dendrons and dendrimers that are the simplest examples of programmed synthetic macromolecules. Amphiphilic Janus dendrimers are synthesized from a diversity of building blocks including natural phenolic acids. They self-assemble in water or buffer into vesicular dendrimersomes employed as biological membrane mimics, hybrid and synthetic cells. These dendrimersomes are predominantly uni- or multilamellar vesicles with size and polydispersity that is predicted by their primary structure. However, in numerous cases, unilamellar dendrimersomes completely free of multilamellar assemblies are desirable. Here, we report the synthesis and structural analysis of a library containing 13 amphiphilic Janus dendrimers containing linear and branched alkyl chains on their hydrophobic part. They were prepared by an optimized iterative modular synthesis starting from natural phenolic acids. Monodisperse dendrimersomes were prepared by injection and giant polydisperse by hydration. Both were structurally characterized to select the molecular design principles that provide unilamellar dendrimersomes in higher yields and shorter reaction times than under previously used reaction conditions. These dendrimersomes are expected to provide important tools for synthetic cell biology, encapsulation, and delivery.

Double-Modified Glycopolymers from Thiolactones to Modulate Lectin Selectivity and Affinity

Multivalent glycomaterials show high affinity toward lectins but are often nonselective as they lack the precise 3-D presentation found in native glycans. Here, thiolactone chemistry is exploited to enable the synthesis of glycopolymers with both a primary binding (galactose) and a variable secondary binding unit in close proximity to each other on the linker. These polymers are used to target the Cholera toxin B subunit, CTxB, inspired by its native branched glycan target, GM-1. The secondary, nonbinding unit was shown to dramatically modulate affinity and selectivity toward the Cholera toxin. These increasingly complex glycopolymers, assembled using accessible chemistry, can help breach the synthetic/biological divide to obtain future glycomimetics.

High-Generation Amphiphilic Janus-Dendrimers as Stabilizing Agents for Drug Suspensions

Pharmaceutical nanosuspensions are formed when drug crystals are suspended in aqueous media in the presence of stabilizers. This technology offers a convenient way to enhance the dissolution of poorly water-soluble drug compounds. The stabilizers exert their action through electrostatic or steric interactions, however, the molecular requirements of stabilizing agents have not been studied extensively. Here, four structurally related amphiphilic Janus-dendrimers were synthesized and screened to determine the roles of different macromolecular domains on the stabilization of drug crystals. Physical interaction and nanomilling experiments have substantiated that Janus-dendrimers with fourth generation hydrophilic dendrons were superior to third generation analogues and Poloxamer 188 in stabilizing indomethacin suspensions. Contact angle and surface plasmon resonance measurements support the hypothesis that Janus-dendrimers bind to indomethacin surfaces via hydrophobic interactions and that the number of hydrophobic alkyl tails determines the adsorption kinetics of the Janus-dendrimers. The results showed that amphiphilic Janus-dendrimers adsorb onto drug particles and thus can be used to provide steric stabilization against aggregation and recrystallization. The modular synthetic route for new amphiphilic Janus-dendrimers offers, thus, for the first time a versatile platform for stable general-use stabilizing agents of drug suspensions.