Multi-Arm Star-Shaped Glycopolymers with Precisely Controlled Core Size and Arm Length

Thermophobic Trehalose Glycopolymers as Smart C-Type Lectin Receptor Vaccine Adjuvants

Herein, this work reports the first synthetic vaccine adjuvants that attenuate potency in response to small, 1-2 °C changes in temperature about their lower critical solution temperature (LCST). Adjuvant additives significantly increase vaccine efficacy. However, adjuvants also cause inflammatory side effects, such as pyrexia, which currently limits their use. To address this, a thermophobic vaccine adjuvant engineered to attenuate potency at temperatures correlating to pyrexia is created. Thermophobic adjuvants are synthesized by combining a rationally designed trehalose glycolipid vaccine adjuvant with thermoresponsive poly-N-isoporpylacrylamide (NIPAM) via reversible addition fragmentation chain transfer (RAFT) polymerization. The resulting thermophobic adjuvants exhibit LCSTs near 37 °C, and self-assembled into nanoparticles with temperature-dependent sizes (90-270 nm). Thermophobic adjuvants activate HEK-mMINCLE and other innate immune cell lines as well as primary mouse bone marrow derived dendritic cells (BMDCs) and bone marrow derived macrophages (BMDMs). Inflammatory cytokine production is attenuated under conditions mimicking pyrexia (above the LCST) relative to homeostasis (37 °C) or below the LCST. This thermophobic behavior correlated with decreased adjuvant Rg is observed by DLS, as well as glycolipid-NIPAM shielding interactions are observed by NOESY-NMR. In vivo, thermophobic adjuvants enhance efficacy of a whole inactivated influenza A/California/04/2009 virus vaccine, by increasing neutralizing antibody titers and CD4+ /44+ /62L+ lung and lymph node central memory T cells, as well as providing better protection from morbidity after viral challenge relative to unadjuvanted control vaccine. Together, these results demonstrate the first adjuvants with potency regulated by temperature. This work envisions that with further investigation, this approach can enhance vaccine efficacy while maintaining safety.

Step-Growth Glycopolymers with a Defined Tacticity for Selective Carbohydrate-Lectin Recognition

Glycopolymers are potent candidates for biomedical applications by exploiting multivalent carbohydrate-lectin interactions. Owing to their specific recognition capabilities, glycosylated polymers can be utilized for targeted drug delivery to certain cell types bearing the corresponding lectin receptors. A fundamental challenge in glycopolymer research, however, is the specificity of recognition to receptors binding to the same sugar unit (e.g., mannose). Variation of polymer backbone chirality has emerged as an effective method to distinguish between lectins on a molecular level. Herein, we present a facile route toward producing glycopolymers with a defined tacticity based on a step-growth polymerization technique using click chemistry. A set of polymers have been fabricated and further functionalized with mannose moieties to enable lectin binding to receptors relevant to the immune system (mannose-binding lectin, dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin, and dendritic and thymic epithelial cell-205). Surface plasmon resonance spectrometry was employed to determine the kinetic parameters of the step-growth glycopolymers. The results highlight the importance of structural complexity in advancing glycopolymer synthesis, yet multivalency remains a main driving force in lectin recognition.

Double hydrophilic copolymers - synthetic approaches, architectural variety, and current application fields

Solubility and functionality of polymeric materials are essential properties determining their role in any application. In that regard, double hydrophilic copolymers (DHC) are typically constructed from two chemically dissimilar but water-soluble building blocks. During the past decades, these materials have been intensely developed and utilised as, e.g., matrices for the design of multifunctional hybrid materials, in drug carriers and gene delivery, as nanoreactors, or as sensors. This is predominantly due to almost unlimited possibilities to precisely tune DHC composition and topology, their solution behavior, e.g., stimuli-response, and potential interactions with small molecules, ions and (nanoparticle) surfaces. In this contribution we want to highlight that this class of polymers has experienced tremendous progress regarding synthesis, architectural variety, and the possibility to combine response to different stimuli within one material. Especially the implementation of DHCs as versatile building blocks in hybrid materials expanded the range of water-based applications during the last two decades, which now includes also photocatalysis, sensing, and 3D inkjet printing of hydrogels, definitely going beyond already well-established utilisation in biomedicine or as templates.

Hierarchy of Complex Glycomacromolecules: From Controlled Topologies to Biomedical Applications

Carbohydrates bearing a distinct complexity use a special code (Glycocode) to communicate with carbohydrate-binding proteins at a high precision to manipulate biological activities in complex biological environments. The level of complexity in carbohydrate-containing macromolecules controls the amount and specificity of information that can be stored in biomacromolecules. Therefore, a better understanding of the glycocode is crucial to open new areas of biomedical applications by controlling or manipulating the interaction between immune cells and pathogens in terms of trafficking and signaling, which would become a powerful tool to prevent infectious diseases. Even though a certain level of progress has been achieved over the past decade, synthetic glycomacromolecules are still lagging far behind naturally existing glycans in terms of complexity and precision because of insufficient and inefficient synthetic techniques. Currently, specific targeting at a cellular level using synthetic glycomacromolecules is still challenging. It is obvious that multidisciplinary collaborations are essential between different specialized disciplines to enhance the carbohydrate receptor-targeting paradigm for new biomedical applications. In this Perspective, recent developments in the synthesis of sophisticated glycomacromolecules are highlighted, and their biological and biomedical applications are also discussed in detail.

Tailor-made Glycopolymers via Reversible Deactivation Radical Polymerization: Design, Properties and Applications

Investigating the underlying mechanism of biological interactions using glycopolymer is becoming increasingly important owing to their unique recognition properties. The multivalent interactions between lectin and glycopolymer are significantly influenced by...

Degradable thiomethacrylate core-crosslinked star-shaped polymers

Degradable polymers are considered to present a promising solution to combat plastic pollution. However, many polymers are based on ester and amide bonds, which often require high temperatures and acidic/basic...

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.

Detailed GPC analysis of poly(N-isopropylacrylamide) with core cross-linked star architecture

Core cross-linked star shaped polymers possess unique physical properties that can be utilized as drug transporters for biomedical applications.

Thiol-Bromo Click Reaction for One-Pot Synthesis of Star-Shaped Polymers

Star-shaped polymers have unique physical properties and they are sought after materials in industry. However, the ease of synthesis is essential for translation of these materials into large-scale applications. Herein, a highly efficient synthetic method to prepare star-shaped polymers by combination of Cu-mediated reversible deactivation radical polymerization (Cu-RDRP) and thiol-bromo click reaction is described. Well-defined linear and block polymers with a very high bromine chain end fidelity are obtained via Cu-RDRP and subsequently react with multi-functional thiol compounds. High coupling efficiencies of larger than 90% are obtained owing to the quick and efficient reaction between thiols and alkyl bromides. Moreover, the arms of the obtained star-shaped polymers are linked via thioether bonds to the core, making them susceptible for oxidative degradation.