Dendrimers in Neurodegenerative Diseases

Neurodegenerative diseases (NDs), such as Parkinson’s Disease (PD), Alzheimer’s Disease (AD), Multiple Sclerosis (MS) and amyotrophic lateral sclerosis (ALS), are characterized by progressive loss of structure or function of neurons. Current therapies for NDs are only symptomatic and long-term ineffective. This challenge has promoted the development of new therapies against relevant targets in these pathologies. In this review, we will focus on the most promising therapeutic approaches based on dendrimers (DDs) specially designed for the treatment and diagnosis of NDs. DDs are well-defined polymeric structures that provide a multifunctional platform for developing different nanosystems for a myriad of applications. DDs have been proposed as interesting drug delivery systems with the ability to cross the blood–brain barrier (BBB) and increase the bioavailability of classical drugs in the brain, as well as genetic material, by reducing the synthesis of specific targets, as β-amyloid peptide. Moreover, DDs have been shown to be promising anti-amyloidogenic systems against amyloid-β peptide (Aβ) and Tau aggregation, powerful agents for blocking α-synuclein (α-syn) fibrillation, exhibit anti-inflammatory properties, promote cellular uptake to certain cell types, and are potential tools for ND diagnosis. In summary, DDs have emerged as promising alternatives to current ND therapies since they may limit the extent of damage and provide neuroprotection to the affected tissues.

The Introduction of Dendrimers as a New Approach to Improve the Performance and Quality of Various Blood Products (Platelets, Plasma and Erythrocytes): A 2010-2022 Review Study

Objectives:

Platelet-, erythrocyte- and plasma-related products are vital for some patients. The main problems with these products are storage lesions, shelf life limitations, and function and quality maintenance. Dendrimers, a well-known group of polymeric nanoparticles, may help overcome these challenges due to their special properties.

Methods:

This review article, for the first time, comprehensively discusses studies from 2010 to 2022 on the compatibility of positive, negative, neutral, and modified charge dendrimers with each blood product. Moreover, it provides information regarding dendrimers' applications for improving the quality and function of blood products.

Results:

A total of one hundred and twenty-six studies showed that dendrimers affect blood components depending on their load, size, molecular weight, functional group, concentration, and exposure time. Generally, cationic dendrimers with higher concentrations and molecular weight and larger size showed little hemocompatibility, while anionic or neutral dendrimers with lower concentrations and molecular weight, and small size were more hemocompatible. Further, some modifications of cationic dendrimers were found to improve their compatibility. For erythrocytes, they included PEGylation and thiolation of dendrimers or functionalizing them with cyclic RGD, nmaleyl chitosan, zwitterionic chitosan, prednisolone, or carbohydrates. Additionally, dendrimers functionalized with arginine-birch, lysine-Cbz, polyethylene glycol, polyethylene glycol-cyclic RGD, thiol, TiO2, maltotriose, or streptokinase decreased the platelet toxicity of dendrimers. The dendrimers modified with polyethylene glycol, glucose, and gold nanoparticles showed increased compatibility in the case of albumin products. Moreover, the PAMAM-dendrimer-antibody conjugates had no adverse effect on antibodies. Dendrimers have a wide range of applications, including virus detection kits, synthetic O2 carriers, bacterial nanofilters, drug carriers, anticoagulants, and enhanced blood product storage.

Conclusion:

It can be concluded that due to the outstanding properties of different types of dendrimers, particularly their manipulability, nanomaterials can be promising to enhance the quality of blood products. Thus, further research in this area is required.

Advancements in antimicrobial nanoscale materials and self-assembling systems

Antimicrobial resistance is directly responsible for more deaths per year than either HIV/AIDS or malaria and is predicted to incur a cumulative societal financial burden of at least $100 trillion between 2014 and 2050. Already heralded as one of the greatest threats to human health, the onset of the coronavirus pandemic has accelerated the prevalence of antimicrobial resistant bacterial infections due to factors including increased global antibiotic/antimicrobial use. Thus an urgent need for novel therapeutics to combat what some have termed the 'silent pandemic' is evident. This review acts as a repository of research and an overview of the novel therapeutic strategies being developed to overcome antimicrobial resistance, with a focus on self-assembling systems and nanoscale materials. The fundamental mechanisms of action, as well as the key advantages and disadvantages of each system are discussed, and attention is drawn to key examples within each field. As a result, this review provides a guide to the further design and development of antimicrobial systems, and outlines the interdisciplinary techniques required to translate this fundamental research towards the clinic.

Peptide mimotopes to emulate carbohydrates

Glycoconjugates on animal cell surfaces are involved in numerous biological functions and diseases, especially the adhesion/metastasis of cancer cells, infection, and the onset of glycan-related diseases. In addition to glycoantigen detection, the regulation of glycan (carbohydrate)-protein interactions is needed to develop therapeutic strategies for glycan-related diseases. Preparation of a diverse range of glycan derivatives requires a massive effort, but the preparation and identification of alternative glycan-mimetic peptide mimotopes may provide a solution to this issue. Peptide mimotopes are recognized by glycan-binding proteins, such as lectins, enzymes, and antibodies, alternative to glycan ligands. Phage-display technology is the first choice in the selection of "glycan (carbohydrate)-mimetic peptide mimotopes" from a large repertoire of library sequences. This tutorial review describes the advantages of peptide mimotopes in comparison to glycan ligands, as well as their structural and functional mimicry. The detailed library design is followed by a description of the strategy used to improve affinity, and finally, an outline of the vaccine application of glycan-mimetic peptides is provided.

Carbosilane Glycodendrimers for Anticancer Drug Delivery: Synthetic Route, Characterization, and Biological Effect of Glycodendrimer-Doxorubicin Complexes

The complexity of drug delivery mechanisms calls for the development of new transport system designs. Here, we report a robust synthetic procedure toward stable glycodendrimer (glyco-DDM) series bearing glucose, galactose, and oligo(ethylene glycol)-modified galactose peripheral units. In vitro cytotoxicity assays showed exceptional biocompatibility of the glyco-DDMs. To demonstrate applicability in drug delivery, the anticancer agent doxorubicin (DOX) was encapsulated in the glyco-DDM structure. The anticancer activity of the resulting glyco-DDM/DOX complexes was evaluated on the noncancerous (BJ) and cancerous (MCF-7 and A2780) cell lines, revealing their promising generation- and concentration-dependent effect. The glyco-DDM/DOX complexes show gradual and pH-dependent DOX release profiles. Fluorescence spectra elucidated the encapsulation process. Confocal fluorescence microscopy demonstrated preferential cancer cell internalization of the glyco-DDM/DOX complexes. The conclusions were supported by computer modeling. Overall, our results are consistent with the assumption that novel glyco-DDMs and their drug complexes are very promising in drug delivery and related applications.

Recent Advances and Challenges in Nanodelivery Systems for Antimicrobial Peptides (AMPs)

Antimicrobial peptides (AMPs) can be used as alternative therapeutic agents to traditional antibiotics. These peptides have abundant natural template sources and can be isolated from animals, plants, and microorganisms. They are amphiphilic and mostly net positively charged, and they have a broad-spectrum inhibitory effect on bacteria, fungi, and viruses. AMPs possess significant rapid killing effects and do not interact with specific receptors on bacterial surfaces. As a result, drug resistance is rarely observed with treatments. AMPs, however, have some operational problems, such as a susceptibility to enzymatic (protease) degradation, toxicity in vivo, and unclear pharmacokinetics. However, nanodelivery systems loaded with AMPs provide a safe mechanism of packaging such peptides before they exert their antimicrobial actions, facilitate targeted delivery to the sites of infection, and control the release rate of peptides and reduce their toxic side effects. However, nanodelivery systems using AMPs are at an early stage of development and are still in the laboratory phase of development. There are also some challenges in incorporating AMPs into nanodelivery systems. Herein, an insight into the nanotechnology challenges in delivering AMPs, current advances, and remaining technological challenges are discussed in depth.

Long-Term Retarded Release for the Proteasome Inhibitor Bortezomib through Temperature-Sensitive Dendritic Glycopolymers as Drug Delivery System from Calcium Phosphate Bone Cement

For the local treatment of bone defects, highly adaptable macromolecular architectures are still required as drug delivery system (DDS) in solid bone substitute materials. Novel DDS fabricated by host-guest interactions between β-cyclodextrin-modified dendritic glycopolymers and adamantane-modified temperature-sensitive polymers for the proteasome inhibitor bortezomib (BZM) is presented. These DDS induce a short- and long-term (up to two weeks) retarded release of BZM from calcium phosphate bone cement (CPC) in comparison to a burst release of the drug alone. Different release parameters of BZM/DDS/CPC are evaluated in phosphate buffer at 37 °C to further improve the long-term retarded release of BZM. This is achieved by increasing the amount of drug (50-100 µg) and/or DDS (100-400 µg) versus CPC (1 g), by adapting the complexes better to the porous bone cement environment, and by applying molar ratios of excess BZM toward DDS with 1:10, 1:25, and 1:100. The temperature-sensitive polymer shells of BZM/DDS complexes in CPC, which allow drug loading at room temperature but are collapsed at body temperature, support the retarding long-term release of BZM from DDS/CPC. Thus, the concept of temperature-sensitive DDS for BZM/DDS complexes in CPC works and matches key points for a local therapy of osteolytic bone lesions.

A biocompatible supramolecular hydrogel with multivalent galactose ligands inhibiting Pseudomonas aeruginosa virulence and growth

In recent years, peptide self-assembly proved to be an efficient strategy to create complex structures or functional materials with nanoscale precision. In this work, we designed and synthesized a novel glycopeptide molecule with a galactose moiety through peptide galactosylation. Then relying on peptide self-assembling strategies, we created a supramolecular hydrogel with multivalent galactose ligands on the surface of self-assembled nanofibers for molecular recognition and interactions. Because of multivalent galactose-LecA interactions, the self-assemblies of glycopeptide could target P. aeruginosa specifically, and acted as anti-virulence and antibacterial agents to inhibit biofilm formation and bacterial growth of P. aeruginosa. Moreover, in association with polymyxin B, a common antibiotic, the glycopeptide hydrogel exhibited a synergistic growth inhibition effect on biofilm colonization of P. aeruginosa.

Carbohydrate supramolecular chemistry: beyond the multivalent effect

(Hetero)multivalency acts as a multichannel switch that shapes the supramolecular properties of carbohydrates in an intrinsically multifactorial biological context.

Fluorescent glycoconjugates and their applications

Fluorescent glycoconjugates are discussed for their applications in biology in vitro, in cell assays and in animal models. Advantages and limitations are presented for each design using a fluorescent core conjugated with glycosides, or vice versa.

Feasibility of cationic carbosilane dendrimers for sustainable protein sample preparation

Protein sample preparation is the bottleneck in the analysis of proteins. The aim of this work is to evaluate the feasibility of carbosilane dendrimers functionalized with cationic groups to make easier this step. Anionic carbosilane dendrimers (sulphonate- and carboxylate-terminated) have already demonstrated their interaction with proteins and their potential in protein sample preparation. In this work, interactions between positively charged carbosilane dendrimers and different model proteins were studied when working under different pH conditions, dendrimer concentrations, and dendrimer generations. Amino- and trimethylammonium-terminated carbosilane dendrimers presented, in some cases, weak interactions with proteins. Unlike them, carbosilane dendrimers with terminal dimethylamino groups could interact, in many cases, with proteins and these interactions were affected by the pH, the dendrimer concentration, and the dendrimer generation. Moreover, dendrimer precipitation was observed at all pHs, although just second and fourth generation (2 G and 4 G) dendrimers resulted in the formation of complexes with proteins. Under experimental conditions promoting dendrimer-protein interactions, 2 G dimethylamino-terminated dendrimers were proposed as an alternative to other methods used in analytical chemistry or analysis in which an organic solvent or a resin are required to enrich/purify proteins in a complex sample.

Dendrimers in the context of nanomedicine

Dendrimers are globular structures, presenting an initiator core, repetitive layers starting radially from the core and terminal groups on the surface, resembling tree architecture. These structures have been studied in many biological applications, as drug, DNA, RNA and proteins delivery, as well as imaging and radiocontrast agents. With reference to that, this review focused in providing examples of dendrimers used in nanomedicine. Although most studies emphasize cancer, there are others which reveal action in the neurosystem, reducing either neuroinflammation or protein aggregation. Dendrimers can carry bioactive compounds by covalent bond (dendrimer prodrug), or by ionic interaction or adsortion in the internal space of the nanostructure. Additionally, dendrimers can be associated with other polymers, as PEG (polyethylene glycol), and with targeting structures as aptamers, antibodies, folic acid and carbohydrates. Their products in preclinical/clinical trial and those in the market are also discussed, with a total of six derivatives in clinical trials and seven products available in the market.

Preparation of Functional Monomers as Precursors of Bioprobes from a Common Styrene Derivative and Polymer Synthesis

CM-Str (4-(Chloromethyl)styrene) was used as a useful starting material for the construction of a series of functional monomers. Substitution of the chlorine to the corresponding azide was performed, and the reduction of the azide proceeded smoothly to afford an aminostyrene, which was used as a common precursor for the preparation of functional monomers. Condensation of the amine with a fluorophore, biotin and carbohydrate was accomplished. Among the monomers, a carbohydrate monomer was polymerized with or without acrylamide as a model polymerization to yield the corresponding water-soluble glycopolymers, and biological evaluations of the glycopolymers for a lectin, and wheat germ agglutinin (WGA), were carried out on the basis of the fluorescence change of tryptophan in the WGA.

Selective Sensing and Imaging of Penicillium italicum Spores and Hyphae Using Carbohydrate-Lectin Interactions

The blue-green mold Penicillium italicum is among the most problematic post-harvest plant infections limiting the integrity of citrus and many other crops during storage and transportation, but there is no sensor for its on-site or field detection. We hereby, for the first time, report the development of novel biomolecular sensor for assessing the presence of P. italicum spores and hyphae using carbohydrate-lectin recognitions. Two approaches were developed: (i) lateral tests using standalone poly(amic) acid (PAA) membranes and glass surfaces and (ii) quantitative tests on 96-well polystyrene plates and paper electrodes. In both cases, the surfaces were functionalized with novel derivatized sugar based ligands while staining was performed with gold nanoparticles. Both approaches provided strong signals for 10⁴ spores/mL of P. italicum isolated from experimentally infected lemons as the lowest-reliable concentration. The 96-well plate-based gave the most sensitive detection with a 4 × 10² spores/mL limit of detection, a linear dynamic range between 2.9 × 10³ and 6.02 × 10⁴ spores/mL ( R² = 0.9939) and standard deviation of less than 5% for five replicate measurements. The selectivity of the ligands was tested against Trichaptum biforme, Glomerulla cingulata ( Colletotrichum gloeosporioides), and Aspergillus nidulans fungi species. The highest selectivity was obtained using the sugar-based gold-nanoparticles toward both the spores and the hyphae of P. italicum. The advanced specificity was provided by the utilized sugar ligands employed in the synthesis of gold nanoparticles and was independent from size and shapes of the AuNPs. Accuracy of the sensor response showed dramatic dependence on the sample preparation. In the case of 5-10 min centrifugation at 600 rpm, the spores can be isolated free from hyphae and conidiophore, for which spiked recovery was up to 95% (std ±4). In contrast, for gravity-based precipitation of hyphae, the spiked recovery was 88% (std 11).

A rapid-response ultrasensitive biosensor for influenza virus detection using antibody modified boron-doped diamond

According to the World Health Organization (WHO), almost 2 billion people each year are infected worldwide with flu-like pathogens including influenza. This is a contagious disease caused by viruses belonging to the family Orthomyxoviridae. Employee absenteeism caused by flu infection costs hundreds of millions of dollars every year. To successfully treat influenza virus infections, detection of the virus during the initial development phase of the infection is critical, when tens to hundreds of virus-associated molecules are present in the patient's pharynx. In this study, we describe a novel universal diamond biosensor, which enables the specific detection of the virus at ultralow concentrations, even before any clinical symptoms arise. A diamond electrode is surface-functionalized with polyclonal anti-M1 antibodies, which then serve to identify the universal biomarker for the influenza virus, M1 protein. The absorption of the M1 protein onto anti-M1 sites of the electrode change its electrochemical impedance spectra. We achieved a limit of detection of 1 fg/ml in saliva buffer for the M1 biomarker, which corresponds to 5-10 viruses per sample in 5 minutes. Furthermore, the universality of the assay was confirmed by analyzing different strains of influenza A virus.

Multivalency as an action principle in multimodal lectin recognition and glycosidase inhibition: a paradigm shift driven by carbon-based glyconanomaterials

The last decade has witnessed a series of discoveries that question the traditional paradigm of multivalency as a "safe" strategy to enhance the binding affinity of a lectin receptor to its cognate carbohydrate ligand. Upon following the initial reports on the supplementary effects operating in the presence of a third carbohydrate species (heteromultivalent effect), the observation of functional promiscuity of glyco(mimetic)ligands elicited by (hetero)multivalency, spreading from lectins to glycoprocessing enzymes (inhibitory multivalent effect), has raised concerns about the potential consequences of glyconanomaterials binding to non-cognate proteins and creating messiness or noise in the processes they participate in. Carbon-based glycomaterials, specifically glyconanodiamonds and glycofullerenes, have been instrumental in increasing our awareness of the frequency of these lectin-enzyme crosstalk behaviours elicited by multivalency, driving a reformulation of the rules and concepts in glycoscience towards a "generalized multivalency" scenario.

Construction of giant glycosidase inhibitors from iminosugar-substituted fullerene macromonomers

An ultra-fast synthetic procedure based on grafting of twelve fullerene macromonomers onto a fullerene hexa-adduct core was used for the preparation of a giant molecule with 120 peripheral iminosugar residues. The inhibition profile of this giant iminosugar ball was evaluated against various glycosidases. In the particular case of the Jack bean α-mannosidase, a dramatic enhancement of the glycosidase inhibitory effect was observed for the giant molecule with 120 peripheral subunits as compared to that of the corresponding mono- and dodecavalent model compounds.

Nanotechnology in Glycomics: Applications in Diagnostics, Therapy, Imaging, and Separation Processes

This review comprehensively covers the most recent achievements (from 2013) in the successful integration of nanomaterials in the field of glycomics. The first part of the paper addresses the beneficial properties of nanomaterials for the construction of biosensors, bioanalytical devices, and protocols for the detection of various analytes, including viruses and whole cells, together with their key characteristics. The second part of the review focuses on the application of nanomaterials integrated with glycans for various biomedical applications, that is, vaccines against viral and bacterial infections and cancer cells, as therapeutic agents, for in vivo imaging and nuclear magnetic resonance imaging, and for selective drug delivery. The final part of the review describes various ways in which glycan enrichment can be effectively done using nanomaterials, molecularly imprinted polymers with polymer thickness controlled at the nanoscale, with a subsequent analysis of glycans by mass spectrometry. A short section describing an active glycoprofiling by microengines (microrockets) is covered as well.

The Impact of Heteromultivalency in Lectin Recognition and Glycosidase Inhibition: An Integrated Mechanistic Study

The vision of multivalency as a strategy limited to achieve affinity enhancements between a protein receptor and its putative sugar ligand (glycotope) has proven too simplistic. On the one hand, binding of a glycotope in a dense glycocalix-like construct to a lectin partner has been shown to be sensitive to the presence of a third sugar entity (heterocluster effect). On the other hand, several carbohydrate processing enzymes (glycosidases and glycosyltransferases) have been found to be also responsive to multivalent presentations of binding partners (multivalent enzyme inhibition), a phenomenon first discovered for iminosugar-type inhibitory species (inhitopes) and recently demonstrated for multivalent carbohydrate constructs. By assessing a series of homo- and heteroclusters combining α-d-glucopyranosyl-related glycotopes and inhitopes, it was shown that multivalency and heteromultivalency govern both kinds of events, allowing for activation, deactivation or enhancement of specific recognition phenomena towards a spectrum of lectin and glycosidase partners in a multimodal manner. This unified scenario originates from the ability of (hetero)multivalent architectures to trigger glycosidase binding modes that are reminiscent of those harnessed by lectins, which should be considered when profiling the biological activity of multivalent architectures.

A reusable supramolecular platform for the specific capture and release of proteins and bacteria

A re-usable supramolecular platform with the capability of high-efficiency capture and on-demand release of specific proteins and bacteria was developed.

Phosphonium carbosilane dendrimers for biomedical applications – synthesis, characterization and cytotoxicity evaluation

Phosphonium carbosilane dendrimers could represent an alternative to ammonium ones in gene therapy applications with high potential of mitochondrial targeting.

Host–guest interactions and controllable capture and release of proteins based on cationic perylene bisimides

A system of controllable capture and release of protein was constructed by multiple, interconnected supramolecular binding modules based on lactose modified mono-cationic perylene bisimide derivatives, cucurbit[8]uril (CB[8]), 1-adamantanamine (ADA) and peanut agglutinin (PNA) lectins.

Highly sensitive detection of influenza virus by boron-doped diamond electrode terminated with sialic acid-mimic peptide

The progression of influenza varies according to age and the presence of an underlying disease; appropriate treatment is therefore required to prevent severe disease. Anti-influenza therapy, such as with neuraminidase inhibitors, is effective, but diagnosis at an early phase of infection before viral propagation is critical. Here, we show that several dozen plaque-forming units (pfu) of influenza virus (IFV) can be detected using a boron-doped diamond (BDD) electrode terminated with a sialic acid-mimic peptide. The peptide was used instead of the sialyloligosaccharide receptor, which is the common receptor of influenza A and B viruses required during the early phase of infection, to capture IFV particles. The peptide, which was previously identified by phage-display technology, was immobilized by click chemistry on the BDD electrode, which has excellent electrochemical characteristics such as low background current and weak adsorption of biomolecules. Electrochemical impedance spectroscopy revealed that H1N1 and H3N2 IFVs were detectable in the range of 20-500 pfu by using the peptide-terminated BDD electrode. Our results demonstrate that the BDD device integrated with the receptor-mimic peptide has high sensitivity for detection of a low number of virus particles in the early phase of infection.

Inorganic dendrimers: recent advances for catalysis, nanomaterials, and nanomedicine

Dendrimers are hyperbranched polymers having a perfectly defined structure because they are synthesized step-by-step in an iterative fashion, and not by polymerization reactions. Some dendrimers are considered as inorganic, as they possess inorganic atoms at each branching point. Among numerous examples, two families of inorganic dendrimers have emerged as particularly promising: silicon-containing dendrimers, particularly carbosilanes, and phosphorus-containing dendrimers, particularly phosphorhydrazones. This tutorial review will display the main properties of both families of dendrimers in the fields of catalysis, materials and biology/nanomedicine. Emphasis will be put on the most recent and promising examples.

Synthesis and characterization of carbosilane dendrimer–sodium montmorillonite clay nanocomposites. Experimental and theoretical studies

Novel organic/inorganic hybrid materials with carbosilane fillers were developed.

Structure–activity relationship study of cationic carbosilane dendritic systems as antibacterial agents

The bactericidal activity of a library of cationic dendritic systems depends on the hydrophilic/hydrophobic structural balance, being the presence of a sulfur atom proximal to the peripheral ammonium functions of relevance.

Novel naproxen-peptide-conjugated amphiphilic dendrimer self-assembly micelles for targeting drug delivery to osteosarcoma cells

The aim of the current study was to synthesize and prepare novel self-assembly micelles loaded with curcumin (Cur) based on naproxen (Nap)-conjugated amphiphilic peptide dendrimers.

Functional dendritic compounds: potential prospective candidates for dental restorative materials and in situ re-mineralization of human tooth enamel

This review provides a snapshot of recent progress in the synthesis and application of dendritic compounds as potential prospective candidates for dental restorative materials andin siture-mineralization of human tooth enamel.

Immobilization of multivalent glycoprobes on gold surfaces for sensing proteins and macrophages

A non-covalent host–guest strategy to immobilize heptavalent glyco-β-cyclodextrin on gold-coated glass slides to study multivalent carbohydrate–protein interactions is described.

Galectin Binding to Neo-Glycoproteins: LacDiNAc Conjugated BSA as Ligand for Human Galectin-3

Carbohydrate-lectin interactions are relatively weak. As they play an important role in biological recognition processes, multivalent glycan ligands are designed to enhance binding affinity and inhibitory potency. We here report on novel neo-glycoproteins based on bovine serum albumin as scaffold for multivalent presentation of ligands for galectins. We prepared two kinds of tetrasaccharides (N-acetyllactosamine and N,N-diacetyllactosamine terminated) by multi-step chemo-enzymatic synthesis utilizing recombinant glycosyltransferases. Subsequent conjugation of these glycans to lysine groups of bovine serum albumin via squaric acid diethyl ester yielded a set of 22 different neo-glycoproteins with tuned ligand density. The neo-glycoproteins were analyzed by biochemical and chromatographic methods proving various modification degrees. The neo-glycoproteins were used for binding and inhibition studies with human galectin-3 showing high affinity. Binding strength and inhibition potency are closely related to modification density and show binding enhancement by multivalent ligand presentation. At galectin-3 concentrations comparable to serum levels of cancer patients, we detect the highest avidities. Selectivity of N,N-diacetyllactosamine terminated structures towards galectin-3 in comparison to galectin-1 is demonstrated. Moreover, we also see strong inhibitory potency of our scaffolds towards galectin-3 binding. These novel neo-glycoproteins may therefore serve as selective and strong galectin-3 ligands in cancer related biomedical research.

Self-assembled glycopeptide nanofibers as modulators of galectin-1 bioactivity

Galectins are carbohydrate-binding proteins that act as extracellular signaling molecules in various normal and pathological processes. Galectin bioactivity is mediated by specific non-covalent interactions with cell-surface and extracellular matrix (ECM) glycoproteins, which can enhance or inhibit signaling events that influence various cellular behaviors, including adhesion, proliferation, differentiation, and apoptosis. Here, we developed a materials approach to modulate galectin bioactivity by mimicking natural galectin-glycoprotein interactions. Specifically, we created a variant of a peptide that self-assembles into β-sheet nanofibers under aqueous conditions, QQKFQFQFEQQ (Q11), which has an asparagine residue modified with the monosaccharide N-acetylglucosamine (GlcNAc) at its N-terminus (GlcNAc-Q11). GlcNAc-Q11 self-assembled into β-sheet nanofibers under similar conditions as Q11. Nanofibrillar GlcNAc moieties were efficiently converted to the galectin-binding disaccharide N-acetyllactosamine (LacNAc) via the enzyme β-1,4-galactosyltransferase and the sugar donor UDP-galactose, while retaining β-sheet structure and nanofiber morphology. LacNAc-Q11 nanofibers bound galectin-1 and -3 in a LacNAc concentration-dependent manner, although nanofibers bound galectin-1 with higher affinity than galectin-3. In contrast, galectin-1 bound weakly to GlcNAc-Q11 nanofibers, while no galectin-3 binding to these nanofibers was observed. Galectin-1 binding to LacNAc-Q11 nanofibers was specific because it could be inhibited by excess soluble β-lactose, a galectin-binding carbohydrate. LacNAc-Q11 nanofibers inhibited galectin-1-mediated apoptosis of Jurkat T cells in a LacNAc concentration-dependent manner, but were unable to inhibit galectin-3 activity, consistent with galectin-binding affinity of the nanofibers. We envision that glycopeptide nanofibers capable of modulating galectin-1 bioactivity will be broadly useful as biomaterials for various medical applications, including cancer therapeutics, immunotherapy, tissue regeneration, and viral prophylaxis.

Dendritic glycopolymers based on dendritic polyamine scaffolds: view on their synthetic approaches, characteristics and potential for biomedical applications

The potential of dendritic glycopolymers based on dendritic polyamine scaffolds for biomedical applications is presented and compared with that of the structurally related anti-adhesive dendritic glycoconjugates.