Mannosylated brush copolymers based on poly(ethylene glycol) and poly(ε-caprolactone) as multivalent lectin-binding nanomaterials

Application prospect of polysaccharide in the development of vaccine adjuvants

Vaccination is an effective strategy for preventing infectious diseases. Subunit vaccines offer more precise targeting and safer protection compared with traditional inactivated virus vaccines. However, due to their poor immunogenicity, subunit vaccines necessitate the use of adjuvants to stimulate the immune system. Adjuvants have long been incorporated into vaccines to enhance the body's immune response, allowing for reduced dosage and lower production costs. Despite the development of numerous vaccine adjuvants, few exhibit the necessary potency and low toxicity for clinical use, often due to limited efficacy or adverse side effects. This underscores the urgent need for novel human vaccine adjuvants that are safe, effective, and cost-efficient. Recent studies have identified certain natural polysaccharides as promising human vaccine adjuvants due to their immunostimulatory properties, low toxicity, and high safety profiles, which enhance both humoral and cellular immunity. These natural polysaccharides are primarily derived from traditional Chinese medicine (TCM) plants, bacteria, and yeast. This review comprehensively analyzes several promising polysaccharide adjuvants, discussing their clinical applications, market potential, and immunoregulatory activities. In summary, the future prospects of polysaccharides provide valuable insights for the application and development of vaccine adjuvants.

Design of fluorinated stealth poly(ε-caprolactone) nanocarriers

The covalent functionalization of polymers with fluorinated moieties represents a promising strategy for the development of multimodal systems. Moreover, polymer fluorination often endows the resulting nanocarriers with improved colloidal stability in the biological environment. In this work, we developed fluorinated pegylated (PEG) biodegradable poly(ε-caprolactone) (PCL) drug nanocarriers showing both high colloidal stability and stealth properties, as well as being (19F)-Nuclear Magnetic Resonance (NMR) detectable. The optimized nanocarriers were obtained mixing a PEG-PCL block copolymer with a nonafluoro-functionalized PCL polymer. The role of PEGylation and fluorination on self-assembly and colloidal behavior of the obtained nanoparticles (NPs) was investigated, as well as their respective role on stealth properties and colloidal stability. To prove the feasibility of the developed NPs as potential 19F NMR detectable drug delivery systems, a hydrophobic drug was successfully encapsulated, and the maintenance of the relevant 19F NMR properties evaluated. Drug-loaded fluorinated NPs still retained a sharp and intense 19F NMR signal and good relaxivity parameters (i.e., T1 and T2 relaxation times) in water, which were not impaired by drug encapsulation.

Programmable synthesis of well-defined, glycosylated iron(ii) supramolecular assemblies with multivalent protein-binding capabilities

Multivalency plays a key role in achieving strong, yet reversible interactions in nature, and provides critical chemical organization in biological recognition processes. Chemists have taken an interest in designing multivalent synthetic assemblies to both better understand the underlying principles governing these interactions, and to build chemical tools that either enhance or prevent such recognition events from occurring in biology. Rationally tailoring synthetic strategies to achieve the high level of chemical control and tunability required to mimic these interactions, however, is challenging. Here, we introduce a systematic and modular synthetic approach to the design of well-defined molecular multivalent protein-binding constructs that allows for control over size, morphology, and valency. A series of supramolecular mono-, bi-, and tetrametallic Fe(ii) complexes featuring a precise display of peripheral saccharides was prepared through coordination-driven self-assembly from simple building blocks. The molecular assemblies are fully characterized, and we present the structural determination of one complex in the series. The mannose and maltose-appended assemblies display strong multivalent binding to model lectin, Concanavalin A (K _d values in μM), where the strength of the binding is a direct consequence of the number of saccharide units decorating the molecular periphery. This versatile synthetic strategy provides chemical control while offering an easily accessible approach to examine important design principles governing structure-function relationships germane to biological recognition and binding properties.

Polymer-Based Drug-Free Therapeutics for Anticancer, Anti-Inflammatory, and Antibacterial Treatment

This paper summarizes the area of biomedicinal polymers, which serve as nanomedicines even though they do not contain any anticancer or antiinflammatory drugs. These polymer nanomedicines with unique design are in the literature highlighted as a novel class of therapeutics called "drug-free macromolecular therapeutics." Their therapeutic efficacy is based on the tailored multiple presentations of biologically active vectors, i.e., peptides, oligopeptides, or oligosaccharides. Thus, they enable, for example, to directly induce the apoptosis of malignant cells by the crosslinking of surface slowly internalizing receptors, or to deplete the efficacy of tumor-associated proteins. The precise biorecognition of natural binding motifs by multiple vectors on the polymer construct remains the crucial part in the designing of these drug-free nanomedicines. Here, the rationales, designs, synthetic approaches, and therapeutic potential of drug-free macromolecular therapeutics consisting of various active vectors are described in detail. Recent developments and achievements for namely B-cell lymphoma treatment, Gal-3-positive tumors, inflammative liver injury, and bacterial treatment are reviewed and highlighted. Finally, a possible future prospect within this highly exciting new field of nanomedicine research is presented.

Glycopolymer Brushes by Reversible Deactivation Radical Polymerization: Preparation, Applications, and Future Challenges

The cellular surface contains specific proteins, also known as lectins, that are carbohydrates receptors involved in different biological events, such as cell-cell adhesion, cell recognition and cell differentiation. The synthesis of well-defined polymers containing carbohydrate units, known as glycopolymers, by reversible deactivation radical polymerization (RDRP) methods allows the development of tailor-made materials with high affinity for lectins because of their multivalent interaction. These polymers are promising candidates for the biomedical field, namely as novel diagnostic disease markers, biosensors, or carriers for tumor-targeted therapy. Although linear glycopolymers are extensively studied for lectin recognition, branched glycopolymeric structures, such as polymer brushes can establish stronger interactions with lectins. This specific glycopolymer topology can be synthesized in a bottlebrush form or grafted to/from surfaces by using RDRP methods, allowing a precise control over molecular weight, grafting density, and brush thickness. Here, the preparation and application of glycopolymer brushes is critically discussed and future research directions on this topic are suggested.