Hyperbranched Core Research Articles

PH-Responsive Charge Convertible Hyperbranched Poly(ionic liquid) Nanoassembly with High Biocompatibility for Resistance-Free Antimicrobial Applications.

As a potential alternative to antibiotics, hyperbranched poly(ionic liquid)s (HPILs) have demonstrated significant potential in combating bacterial biofilms. However, their high cation density poses a high risk of toxicity, greatly limiting their in vivo applications. In this study, we constructed a biocompatible HPIL (HPIL-Glu) from a hyperbranched polyurea core with modified terminals featuring charge-convertible ionic liquids. These ionic liquid moieties consist of an ammonium-based cation and a gluconate (Glu) organic counter. HPIL-Glu could form a homogeneous nanoassembly in water and exhibited a pH-responsive charge conversion property. Under neutral conditions, Glu shielded the positively charged surface, minimizing the toxicity. In a mildly acidic environment, Glu protonation exposes cationic moieties to biofilm eradication. Comprehensive antimicrobial assessments demonstrate that HPIL-Glu effectively kills bacteria and promotes the healing of bacteria-infected chronic wounds. Furthermore, prolonged exposure to HPIL-Glu does not induce antimicrobial resistance.

Fluorene-carbazole-based hyperbranched polymers with linear red TADF chromophores for high-efficiency white and red electroluminescent devices

Solution-processed polymer light emitting devices (PLEDs) using high-quality thermally activated delayed fluorescence (TADF) polymers as the emitting layers are attractive, however, high-efficiency white-light TADF polymers are very rare because of the complicated radiative transition channels. In this study, a series of hyperbranched TADF conjugated polymers were designed and synthesized which adopted the linear D-A-type TADF emitter of 1,8-naphthalimide-acridine as red chromophores, conjugated poly(fluorene-carbazole) as the blue backbone and triphenylamine as the hyperbranched cores. By adjusting the appropriate feed ratios of monomers, energy transfer process from the blue backbone to the red chromophores could be regulated and HR0.8 film had the highest photoluminescent quantum yield of 24%. Consequently, its doped electroluminescent device showed the cold-white emission with the CIE color coordinates of (0.35, 0.23) and the maximum EQE of 6.82%. By simply raising the concentration of the red chromophore in the polymers, the rapid reverse intersystem crossing (RISC) process and the enlarged energy gap between S1 and T1 were achievable.

Synthesis and Morphology Characteristics of New Highly Branched Polycaprolactone PCL.

A simple and efficient method for the synthesis of biodegradable, highly branched polycaprolactone (PCL) is presented. The solvent-free (bulk) reaction was carried out via ring opening polymerization (ROP), catalyzed by tin octanoate Sn(Oct)2, and it employed hyperbranched polyamide (HPPA) as a macro-initiator. The core-shell structure of the obtained products (PCL-HPPA), with the hyperbranched HPPA core and linear PCL chains as shell, was in the focus of the product characterization. 1H nuclear magnetic resonance (1H NMR) and elemental analysis confirmed the covalent incorporation of the HPPA in the products, as well as a high degree of grafting conversion of its amino functional groups. Confocal Raman Micro spectroscopy, and especially Time-of-Flight Secondary Ion Mass Spectrometry, further supported the existence of a core-shell structure in the products. Direct observation of macromolecules by means of cryogenic transmission electron microscopy, as well as gel permeation chromatography (GPC), suggested the existence of a minor 'aggregated' product fraction with multiple HPPA cores, which was attributed to transesterification reactions. Differential scanning calorimetry, as well as X-ray diffraction, demonstrated that the PCL-HPPA polymers displayed a similar degree of crystallinity to linear neat PCL, but that the branched products possessed smaller and less regular crystallites.

Influence of steric configurations in the conjugated polymers using acridine-triazine derivates as green chromophores

High-quality polymers with the advantages of chemical modifiability, good morphological stability, and excellent solubility have a wide application in the field of solution-processed organic light-emitting devices. However, the influence of steric configurations in the conjugated polymers has not been explored in detail. Herein, we designed and synthesized two kinds of green conjugated polymers with hyperbranched structure (HGx, x = 1, 5, 8, 10) and linear structure (LG10), respectively, using 10-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)−9,9-dimethyl-9,10-dihydroacridine (Ac-TRZ) as the chromophores, poly(fluorene-carbazole) as the backbone. Particularly, triphenylamine groups were used as the hyperbranched cores. Owing to the large steric hindrance and multi-arm structure, hyperbranched polymers exhibited higher thermal stability (Tg＞110 ℃) and an effective energy transfer process. Regrettably, both kinds of conjugated polymers had low PLQYs and nanosecond-scale excitons lifetime because the 3LE energy levels induced by the backbone were lower than the 3CT energy levels induced by the green units. By calculation, it is found that fluorescent segments connected to the green units had directly changed the electronic structure. Moreover, the films of linear polymers possessed considerable surface roughness. From the above results, it is confirmed that the rational design of steric conformations in the conjugated polymers is very important for perfecting the thermal stability, photophysical properties, and film morphologies.

Development of a Potassium-Ion-Responsive Star Copolymer with Controlled Aggregation/Dispersion Transition.

Stimuli-responsive star polymers are promising functional materials whose aggregation, adhesion, and interaction with cells can be altered by applying suitable stimuli. Among several stimuli assessed, the potassium ion (K+), which is known to be captured by crown ethers, is of considerable interest because of the role it plays in the body. In this study, a K+-responsive star copolymer was developed using a polyglycerol (PG) core and grafted copolymer arms consisting of a thermo-responsive poly(N-isopropylacrylamide) unit, a metal ion-recognizing benzo-18-crown-6-acrylamide unit, and a photoluminescent fluorescein O-methacrylate unit. Via optimization of grafting density and copolymerization ratio of grafted arms, along with the use of hydrophilic hyperbranched core, microsized aggregates with a diameter of 5.5 μm were successfully formed in the absence of K+ ions without inducing severe sedimentation (the lower critical solution temperature (LCST) was 35.6 °C). In the presence of K+ ions, these aggregates dispersed due to the shift in LCST (47.2 °C at 160 mM K+), which further induced the activation of fluorescence that was quenched in the aggregated state. Furthermore, macrophage targeting based on the micron-sized aggregation state and subsequent fluorescence activation of the developed star copolymers in response to an increase in intracellular K+ concentration were performed as a potential K+ probe or K+-responsive drug delivery vehicle.

Secondary Ammonium-Based Hyperbranched Poly(amidoamine) with Excellent Membrane-Active Property for Multidrug-Resistant Bacterial Infection.

With the rapid emergence of microbial infections induced by "superbugs", public health and the global economy are threatened by the lack of effective and biocompatible antibacterial agents. Herein, we systematically design a series of secondary ammonium-based hyperbranched poly(amidoamine) (SAHBP) with different alkyl chain lengths for probing high-efficacy antibacterial agents. SAHBP modified with alkyl tails at the hyperbranched core could efficiently kill Escherichia coli and Staphylococcus aureus, two types of clinically important bacteria worldwide. The best SAHBP with 12-carbon-long alkyl tails (SAHBP-12) also showed high activity against problematic multidrug-resistant bacteria, including Pseudomonas aeruginosa and methicillin-resistant S. aureus (MRSA). Based on ζ potential, isothermal titration microcalorimetry (ITC), and membrane integrity assays, it is found that SAHBP-12 could attach to the cell membrane via electrostatic adsorption and hydrophobic interactions, following which the integrity of the bacterial cell wall and the cell membrane is disrupted, resulting in severe cell membrane damage and the leakage of cytoplasmic contents, finally causing bacterial cell death. Impressively, benefiting from excellent membrane-active property, SAHBP-12 exhibited robust therapeutic efficacy in MRSA-infected mice wounds. Moreover, SAHBP-12 also showed excellent biosafety in vitro and in vivo, which undoubtedly distinguished it as a potent weapon in combating the growing threat of problematic multidrug-resistant bacterial infections.

Poly(oligoethylene glycol methacrylate) Star‐Shaped Copolymers with Hydroxypropyl Methacrylate Cores

AbstractStar‐shaped copolymers with crosslinked hyperbranched cores, varying in both number and length of the arms, are prepared by the reversible addition‐fragmentation chain transfer (RAFT) polymerization technique. Star synthesis is conducted via a simple, “core‐first” method. Hydroxypropyl methacrylate monomer is used for the formation of the hyperbranched/crosslinked core, with ethylene glycol dimethacrylate used as a bifunctional monomer in the role of the cross‐linker. Two different cross‐linker/chain transfer agent ratios are chosen to manipulate the number of the arms in the final star nanostructure. Oligoethylene glycol methacrylate (OEGMA500) is used as a biocompatible and hydrophilic component for the creation and extension of the arms. Arm length is controlled by the amount of OEGMA monomer used in the second polymerization step. Molecular characterization of the four synthesized stars is achieved via size exclusion chromatography and nuclear magnetic resonance, which provides information regarding the molar mass, dispersity, and composition of each star‐shaped copolymer. Dynamic light scattering (DLS) studies of copolymers in N,N‐dimethyl formamide solutions provide sizes of individual copolymer molecules in the size range of 8–20 nm. Aqueous dispersions of copolymers are investigated by DLS, cryogenic transmission electron microscopy, and atomic force microscopy, which show the formation of spherical aggregates with diameters of 60–350 nm, dependent on the arm number and length of star copolymers. The obtained sizes and size distributions, along with the hydroxyl‐group‐bearing cores, indicate that the star copolymer can be used as potential nanocarriers for drugs or bioimaging agents.

Synthesis of the hyper-branched core tetrasaccharide motif of chloroviruses.

Chemical synthesis of complex oligosaccharides, especially those possessing hyper-branched structures with one or multiple 1,2-cis glycosidic bonds, is a challenging task. Complementary reactivity of glycosyl donors and acceptors and proper tuning of the solvent/temperature/activator coupled with compromised glycosylation yields for sterically congested glycosyl acceptors are among several factors that make such syntheses daunting. Herein, we report the synthesis of a semi-conserved hyper-branched core tetrasaccharide motif from chloroviruses which are associated with reduced cognitive function in humans as well as in mouse models. The target tetrasaccharide contains four different sugar residues in which l-fucose is connected to d-xylose and l-rhamnose via a 1,2-trans glycosidic bond, whereas with the d-galactose residue is connected through a 1,2-cis glycosidic bond. A thorough and comprehensive study of various accountable factors enabled us to install a 1,2-cis galactopyranosidic linkage in a stereoselective fashion under [Au]/[Ag]-catalyzed glycosidation conditions en route to the target tetrasaccharide motif in 14 steps.

Comparative study of enzyme-catalyzed biodegradation and crystallization behavior of PCL-PTEGMA amphiphilic hypergraft copolymers

This work aims to systematically elucidate the biodegradation and crystallization behaviors of the model hypergraft systems made of poly(ε-caprolactone) (PCL) and poly[tri(ethylene glycol) methyl ether acrylate] (PTEGMA) blocks. A series of hyperbranched PCL (HB-PCLn) with varied subchain lengths were synthesized using AB2-type macromonomers with different degrees of polymerization (DPs). The HB-PCLs were grafted with linear PTEGMA chains to prepare amphiphilic hypergraft copolymers (HB-PCLn-g-PTEGMAm) to eventually get self-assembled structures through micellization. The DP of PTEGMA was also varied to get two sets of samples with varied sub-chain lengths of the hyperbranched core and the linear corona within each individual set to systematically study the crystallization and biodegradation behaviors of PCL. Differential scanning calorimetric (DSC) measurements of both hypergrafts and linear precursors were compared in order to get insights into the crystallization pattern of PCL. We found that the degree of crystallization in PCL can be controlled from ~0 (lowest limit) to ~52% (highest limit) by structural regulation. Biodegradation studies were performed in aqueous medium with Lipase from Pseudomonas using dynamic light scattering (DLS). A model was proposed to correlate the sub-chain length of core, the chain length of corona with the biodegradation rate of PCL, which reveals that an increase of PCL content in HB-PCLn-g-PTEGMAm increases the crystallinity while decreases the rate of biodegradation in a predictable manner.

Preparation and properties of UV-curable hyperbranched polyurethane acrylate hard coatings

In order to efficiently protect plastic cover of 5G mobile phones, a novel hyperbranched polyurethane acrylate-based hard coating (HBPUA) having highly rigid hyperbranched cores was prepared and used as the protective film. For purpose of researching the structure and property relationship, two more hyperbranched cores (Hyper-6OH) and corresponding HBPUA oligomers were also synthesized. The structures of Hyper-6OH and HBPUA were characterised by proton nuclear magnetic resonance, and the molecular weight of HBPUA was confirmed by gel permeation chromatography. To further enhance the crosslinking and lower the internal stress, pentaerythritol tetra(3-mercaptopropionate) (PETMP) was introduced into the film system. The curing behaviours of the prepared HBPUA coatings were determined by Fourier-transform infrared spectroscopy. The results indicated that the double bond conversion was associated with the rigidity of the hyperbranched core and the content of thiol groups. The properties of HBPUA-based films were characterized by the test of gel content, swelling ratio and water absorption and as well as dynamic mechanical property, mechanical property, thermogravimetry and surface property. The results reveal that the pencil hardness of the prepared coatings reaches 5H that is higher than the commercially available resin PUA-6, enabling potential application in the protection of plastic cover. The rigidity of the hyperbranched cores and the introduction of PETMP remarkably affect the Tg value of the films, and the addition of thiol groups increases the gel content, swelling ratio, toughness and adhesion of coatings, but decreases the water absorption and tensile strength. Moreover, all coatings exhibit good thermal properties.

Synthesis and Dispersion of Organic Pigments by Amphiphilic Hyperbranched Polyesteramides Dispersant

The amphiphilic hyperbranched polyesteramides (AHPAs) consisting of hydrophobic hyperbranched polyether cores and hydrophilic poly (ethyleneglycol) arms with urethane bonds in the molecular structure were synthesized by solution polymerization in chloroform using hexamethylene diisocyanate (HMDI) as a coupling agent. And their chemical structures were confirmed by FT-IR and and 13C NMR. Further, the AHPAs were applied to disperse organic pigments and their dispersibilities were investigated. The results showed that AHPAs had good dispersing effect on organic pigments. When the dosage of AHPA was 12% (on the weight of pigment), the dispersing effect of AHPA on phthalocyanine green was the best with the lowest relative settlement rate, viscosity and particle size. The dispersibilities of AHPA on organic pigments were phthalocyanine green > benzidine yellow G > pigment red F5R. AHPAs have the characteristics of high solubility, low viscosity, good rheological properties and no pollution and would be the ideal materials for using as the pigment dispersants.

Chain‐growth polymerization of azide–alkyne difunctional monomer: Synthesis of star polymer with linear polytriazole arms from a core

ABSTRACTThis article reports a chain‐growth coupling polymerization of AB difunctional monomer via copper‐catalyzed azide–alkyne cycloaddition (CuAAC) reaction for synthesis of star polymers. Unlike our previously reported CuAAC polymerization of AB n (n ≥ 2) monomers that spontaneously demonstrated a chain‐growth mechanism in synthesis of hyperbranched polymer, the homopolymerization of AB monomer showed a common but less desired step‐growth mechanism as the triazole groups aligned in a linear chain could not effectively confine the Cu catalyst in the polymer species. In contrast, the use of polytriazole‐based core molecules that contained multiple azido groups successfully switched the polymerization of AB monomers into chain‐growth mechanism and produced 3‐arm star polymers and multi‐arm hyperstar polymers with linear increase of polymer molecular weight with conversion and narrow molecular weight distribution, for example, Mw/Mn ~ 1.05. When acid‐degradable hyperbranched polymeric core was used, the obtained hyperstar polymers could be easily degraded under acidic environment, producing linear degraded arms with defined polydispersity. © 2019 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 84–90

AIE Supramolecular Assembly with FRET Effect for Visualizing Drug Delivery.

Here, we constructed a nanostructured pH/redox dual-responsive supramolecular drug carrier with both aggregation-induced emission (AIE) and Forster resonance energy transfer (FRET) effects, which enabled selective drug release and monitoring drug delivery and release processes. Taking the hyperbranched polyamide amine (H-PAMAM) with intrinsic AIE effects as the core, poly(ethylene glycol) (PEG) was bridged on its periphery by dithiodipropionic acid. Then, through the host-guest interaction of PEG and α-cyclodextrin, the supramolecular nanoparticles with AIE effects were constructed to load the anticancer drug doxorubicin (DOX). The supramolecular assembly has sufficiently large DOX loading due to the abundant cavities formed by branched structures. The hyperbranched core H-PAMAM has strong fluorescence, and the dynamic track of drug carriers and the dynamic drug release process can be monitored by the AIE and FRET effects between H-PAMAM and DOX, respectively. Furthermore, the introduction of disulfide bonds and the pH sensitivity of H-PAMAM enable the achievement of rapid selective release of loaded DOX at the tumor while remaining stable under normal physiological conditions. In vitro cytotoxicity indicates that the drug-loaded supramolecular assembly has a good therapeutic effect on cancer. In addition, the H-PAMAM core is different from the traditional AIE functional group, which has no conjugated structure, such as a benzene ring, thereby providing better biocompatibility. This technology will have broad applications as a new drug delivery system.

Azido‐terminated Hyperbranched Multi‐arm Copolymer as Energetic Macromolecular Plasticizer

AbstractAzido‐terminated hyperbranched multi‐arm copolymer (POGA) with hyperbranched polyether core (PEHO‐c) and linear azido‐terminated glycidyl azide polymer arms (GAPA‐a) has been prepared. The structures of the polymers were characterized by FT‐IR, NMR, GPC and elemental analysis. The molecular weight of POGA was up to ca 17000 g mol−1, far higher than that of common plasticizers (200∼1000 g mol−1). The enthalpy of formation and high nitrogen content of POGA demonstrated its remarkable energy level, and low impact and friction sensitivities indicated its good safety performance in mechanical stimuli. The results of the kinetic and thermodynamic parameters, calculated from non‐isothermal DSC, denoted a fine thermal stability of POGA. Furthermore, the plasticizing effect of POGA, evaluated by plasticizer efficiency and viscosity, was superior to A3 but inferior to Bu‐NENA, however, its exudation was much slower than that of small molecular plasticizers, especially Bu‐NENA. Moreover, the plasticizing mechanism of POGA as energetic macromolecular plasticizer was established by analyzing its structure and performance characteristics.

Size-Transformable, Multifunctional Nanoparticles from Hyperbranched Polymers for Environment-Specific Therapeutic Delivery.

Hyperbranched polymer-derived drug nanocarriers have been synthesized that can change sizes selectively in response to pH. These constructs were composed of tertiary amine-conjugated polycarbonate blocks "grafted from" a hyperbranched polyester polyol core. At neutral pH, unprotonated polycarbonate arms stabilized the copolymer aggregates in the form of nanoparticles with hydrodynamic diameters ranging from 150 to 190 nm. Upon lowering of pH, these larger aggregates disassembled into smaller nanoparticles with diameters of 3-5 nm as directed by protonation of tertiary amine side-chains. The pH-dependent reduction of particle sizes was evident by titrimetric, spectroscopic, dynamic light scattering, transmission electron, and atomic force microscopy-based experiments. We observed that these copolymeric nanoparticles could be loaded with dye and drug molecules either by noncovalent encapsulation or by covalent conjugation. A pH-induced disassembly of the aggregates initiated rapid release of the encapsulated payload, but not of the conjugated ones, thus establishing a controlled rate of therapeutic delivery from the nanostructures over an extended period. We envision that such systems can be used for drug delivery applications where nanoparticle sizes critically govern therapeutic efficiency in a vasculature-poor disease microenvironment such as desmoplasia in pancreatic cancer. Hence, we tested the cellular uptake, cytotoxicity, and chemotherapeutic potential of the size-modifiable nanoaggregates using gemcitabine as a model drug in pancreatic cancer setting. We observed that assembled nanoparticles were biocompatible to noncancerous cells, showed pH-dependent effects on cellular uptake as well as promoted accumulation within cancer cells cultured as 3D spheroids. We also found that when conjugated with gemcitabine, the resulting drug-loaded nanoparticles suppressed proliferation of cancer cells. Collectively, the studies suggested that these synthesized, pH-disassembling nanoscale platform will find applications as biomaterials for constructing a size-transformable drug nanocarriers where reduction of size takes effect near localized disease targets in response to microenvironmental triggers.

Total Synthesis of a Hyperbranched N‐Linked Hexasaccharide Attached to ATCV‐1 Major Capsid Protein without Precedent

Summary of main observation and conclusionThe N‐glycans attached to some chloroviruses comprise a hyperbranched core structure without precedent. We are interested in the chemical synthesis of the hexasaccharide attached to ATCV‐1 (Acanthocystis turfacea Chlorella virus 1) for its distinct structure. After exploring four routes, the target hexasaccharide 2 was successfully synthesized for the first time in overall 10% yield over 8 steps from thioglycoside building blocks. This synthetic protocol is characterized by the three‐component one‐pot glycosylation and the regioselective glycosylation reactions. The disclosed synthetic approach to this new type of N‐glycans will facilitate the in‐depth understanding of their biological functions.

Synthesis of Multiarm Star Polymer Based on Hyperbranched Polyester Core and Poly(ε-caprolactone) Arms and Its Application in UV-Curable Coating.

Hyperbranched polymers have attracted much attention in the field of UV-curable coatings because of its low viscosity, highly branched structure, and rich functional moieties. However, hyperbranched polymers also have some limitations. For example, the spherical structure increases the crosslinking hindrance, resulting in surplus functional moieties. In this study, a multiarm star polymer with hyperbranched polyester core and linear polymer arms was synthesized and used as UV-curable coating. H40, the fourth generation of the hyperbranched polyester, was chosen as the core owing to its low viscosity and high chemical reactivity. Poly(ε-caprolactone) (PCL) arms were introduced to increase the content of flexible segments and reduce the cross-linking hindrance. The terminal hydroxyls were then replaced with methacrylate groups to endow the star polymer with UV curable ability, yielding HPCLn-M. This multiarm star polymer was considered as a promising candidate to make up for the shortcomings of UV-curable coating made from the hyperbranched polymer. The properties, such as hardness, adhesion, acid resistance, and alkali resistance of cured films were enhanced obviously after the grafting of PCL. Moreover, to further explore the effect of the length of PCL grafts on the coating, star polymers with different degree of polymerization (DP) were synthesized. Through the performance tests of cured films, it was found that the multiarm star polymer HPCLn-M could make up for the limitations of the hyperbranched polymer when the DP of PCL was suitable, and the comprehensive performance of cured film reached the best when the DP of PCL was 20. Overall, this multiarm star polymer could combine the advantages of the hyperbranched polymer and linear polymer and has the potential to be the next environmentally friendly UV-curable coating.

High Azide Content Hyperbranched Star Copolymer as Energetic Materials

A series of star azide copolymers (b-POBs) with hyperbranched polyether cores (HBPO-c) and short linear poly(3,3′-bis-azidomethyl oxetane) arms (PBAMO-a) have been prepared. The polymers were characterized with FT-IR, 1H NMR, quantitative 13C NMR, gel permeation chromatography, MALDI-TOF, and X-ray diffractometry. Due to hyperbranched structures, the crystallinity (Wc) of b-POBs was significantly decreased, and the processability was greatly improved. The enthalpy of formation, obtained by oxygen bomb calorimetric measurements, high azide content, and heats of decomposition of b-POBs demonstrated their remarkable energy level. Furthermore, b-POBs had good resistance to pyrolysis up to 230 °C (T5%), and their mechanical sensitivities were also obviously lower than that of the PBAMO homopolymer, showing their good safety properties. Moreover, the mechanism for sensitivity reduction of b-POBs was established by analyzing the relationship between the activation course in mechanical stimulus and its crystallin...

Star-Like Glycosaminoglycans with Superior Bioactivity Assemble with Proteins into Microfibers.

Here it is shown that glycosaminoglycans (GAGs) with high molecular weight can be grafted via their reducing end on hyperbranched synthetic cores by oxime condensation without the need of any previous functionalisation of the polysaccharide. The versatility of this reaction is demonstrated by the use of hyaluronan, chondroitin sulfate and heparin with up to 60 sugar units. The isothermal calorimetry analysis demonstrated that the generated star-like glycopolymers have superior bioactivity. Moreover, when mixed with positively charged proteins (e.g., fibroblast growth factor-2, FGF-2) they form microfiber structures instead of the spherical nanocomplexes described for linear GAGs. The results suggest that the described star-like GAG are closer mimics of the proteoglycans at the structural and functional level and therefore have huge potential in the development of tissue engineering platforms and therapeutics by modulating the activity and presentation of various proteins such as growth factors.

Glyco-pseudodendrimers on a Polyester Basis: Synthesis and Investigation of Protein-Pseudodendrimer Interaction.

Molar mass and end group number of a hyperbranched polyester are significantly increased by its transformation to a pseudodendrimer. Three generations of pseudodendrimers are obtained from hyperbranched aliphatic polyester core by modification with a protected AB*2 monomer. A sequence of protection and deprotection steps leads to OH-terminated pseudodendrimers. NMR studies confirm maximum degree of branching in the first generation, which slightly decreases in the next two generations. Uniform, dense molecular structure formation was confirmed by MD simulation. Further modification to glyco-pseudodendrimers was performed with α-D-mannose leading to high molar masses and dense distribution of sugar units. The interaction of these sugar units with a plant lectin concanavalin A (Con A) was investigated using dynamic light scattering and cryogenic transmission electron microscopy. The protein-interaction studies of the glyco-pseudodendrimers confirm a loose network with Con A. The interaction activity depends on the generation number and modification degree.