Search

A non-linear reduction in percolation threshold from 0.46 to 0.19 vol% by transforming the phase into lamellar structures.

Herein, we have reported the facile para-fluoro thiol click reaction to control microphase separation and the dielectric properties of poly(pentafluorostyrene-b-acrylic acid) copolymers. The block copolymer of pentafluorostyrene and acrylic acid was synthesized resulting in high block incompatibility by Nitroxide Mediated Polymerisation. By using the para-fluoro thiol reaction, 1-dodecanethiol was precisely clicked to block copolymers in various ratios. The microphase structures were observed in cylindrical geometry and their directionality was changed from parallel to perpendicular with increasing click ratio, besides domain size was recorded as low as 5.5 nm. The dielectric constant of the copolymers decreases with increasing click ratio due to the low dielectric constant of dodecane pendant groups and reaches κ=2.4 (at 1000 Hz). This study provides insights on one-step control over phase and dielectric properties by using a facile and very effective click reaction strategy that can simplify the fabrication of novel polymers for next-generation capacitor films for use in directed energy and advanced integrated circuits with smaller feature sizes.

Polymers does not only show phase transition in aqueous solutions but they also do in organic solvents, which is the focus of this review article.

Degradable polymers are considered to present a promising solution to combat plastic pollution.

Gene delivery is a powerful technique that is often exploited in the treatment of several diseases.

Access to a wide range of plastic materials has been rationalized by the increased demand from growing populations and the development of high-throughput production systems. Plastic materials at low costs with reliable properties have been utilized in many everyday products. Multibillion-dollar companies are established around these plastic materials, and each polymer takes years to optimize, secure intellectual property, comply with the regulatory bodies such as the Registration, Evaluation, Authorisation and Restriction of Chemicals and the Environmental Protection Agency and develop consumer confidence. Therefore, developing a fully sustainable new plastic material with even a slightly different chemical structure is a costly and long process. Hence, the production of the common plastic materials with exactly the same chemical structures that does not require any new registration processes better reflects the reality of how to address the critical future of sustainable plastics. In this review, we have highlighted the very recent examples on the synthesis of common monomers using chemicals from sustainable feedstocks that can be used as a like-for-like substitute to prepare conventional petrochemical-free thermoplastics.

Hyaluronic acid (HA), the only non-sulphated glycosaminoglycan, serves numerous structural and biological functions in the human body, from providing viscoelasticity in tissues to creating hydrated environments for cell migration and proliferation. HA is also involved in the regulation of morphogenesis, inflammation and tumorigenesis through interactions with specific HA-binding proteins. Whilst the physicochemical and biological properties of HA have been widely studied for decades, the exact mechanisms by which HA exerts its multiple functions are not completely understood. Glycopolymers offer a simple and precise synthetic platform for the preparation of glycan analogues, being an alternative to the demanding synthetic chemical glycosylation. A library of homo, statistical and alternating HA glycopolymers were synthesised by reversible addition–fragmentation chain transfer polymerisation and post-modification utilising copper alkyne–azide cycloaddition to graft orthogonal pendant HA monosaccharides (N-acetyl glucosamine: GlcNAc and glucuronic acid: GlcA) onto the polymer. Using surface plasmon resonance, the binding of the glycopolymers to known HA-binding peptides and proteins (CD44, hyaluronidase) was assessed and compared to carbohydrate-binding proteins (lectins). These studies revealed potential structure-binding relationships between HA monosaccharides and HA receptors and novel HA binders, such as Dectin-1 and DEC-205 lectins. The inhibitory effect of HA glycopolymers on hyaluronidase (HAase) activity was also investigated suggesting GlcNAc- and GlcA-based glycopolymers as potential HAase inhibitors., Glycopolymers based on hyaluronan (HA) were synthesised as homopolymers and alternating copolymers and used as probes to study the interactions with known HA-binding proteins and peptides.

A clickable initiator, pentafluoro benzyl bromide, has been investigated for the cationic ring opening polymerization of poly(2-oxazolines). Additionally, the clickable alpha end group was then utilized in a para-fluoro-thiol click reaction to synthesise linear diblock, tetrablock, multiblock copolymers as well as star shaped poly(2-oxazoline)s using dithiol compounds as terminating agents. Thus, a one-pot approach combining the para-fluoro-thiol click reaction and direct termination of the poly(2-oxazoline) living chain end with 4,4-thiobisbenzenethiol has been performed to prepare multiblock copolymers of poly(2-ethyl-2-oxazoline) (PEtOx) and poly((2-ethyl-2-oxazoline)-b-(2-methyl-2-oxazoline) (PEtOx-mb-PMeOx). All obtained polymers were characterized by Size Exclusion Chromatography (SEC), 1H Nuclear Magnetic Resonance (NMR) and Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-ToF) mass spectrometry. Last but not least, the self-assembly properties of prepared amphiphilic polymers were studied with DLS and TEM. Nanoparticles with a diameter ranging from 184 nm to 250 nm were observed in TEM for PEtOx-mb-PMeOx copolymers.

To combine the advantages of poly(2-oxazoline)s (POx) and controlled radical polymerization (CRP) techniques, the cationic ring-opening polymerization (CROP) of 2-methyl-2-oxazoline (MeOx), 2-ethyl-2-oxazoline (EtOx), and 2-n-nonyl-2-oxazoline (NonOx) were terminated with a carboxylic acid functionalized chain transfer agent (CTA). The obtained PEtOx with a high degree of functionalization (DF) was used as macro-CTA for the reversible addition–fragmentation chain transfer (RAFT) polymerization of various vinylic monomers (styrene (St), methyl acrylate (MA), tert-butyl acrylate (tBuA), acrylic acid (AA), N,N-dimethyl acrylamide (DMAAm), and N,N-dimethylaminoethylacrylate (DMAEA)) resulting in well-defined block copolymers. Thus, in this work we report a versatile route to combine poly(2-oxazoline)s prepared via CROP with RAFT polymerization for the synthesis of novel block copolymers.

Layer-by-layer (LBL) assembly of concanavalin A (Con A), peanut agglutinin (PNA) plant lectins, and well-defined synthetic glycopolymers via their biological affinities have been prepared using a quartz crystal microbalance with dissipation monitoring (QCM-D). We demonstrate the use of mannose/galactose glycopolymers as lectin binders due to their selective binding to Con A/PNA, respectively. A detailed analysis of the adsorption processes and the adsorbed layer are provided and tuning the composition of multilayers using a series of well-defined glycopolymers differing only in the pendant sugar ratio is discussed.

Many cell types in Nature are covered by glycans with a sugar shell on their surface. Synthetic glycopolymer-based materials can mimic these glycans in terms of their variety of biological processes, such as cell growth regulation, adhesion, inflammation by bacteria and viruses, and immune responses. However, the complexity of glycans is still very challenging to be mimicked completely to obtain specific and selective binding ability. Therefore, in this study we aimed to understand how the complexity in the sense of the effect of number of arms and lengths in star-shaped glycopolymers affect the binding activity with different lectins. The Cu-mediated reversible deactivation radical polymerization (Cu-RDRP) technique was employed for the synthesis of mannose containing star-shaped glycopolymers with varying arm number and length. Two sets of star-shaped glycopolymers with on average 1, 3, 7, 8, and 15 arms were successfully synthesized and characterized via

Multiblock copolymers (MBCs) are an emerging class of synthetic polymers that exhibit different macromolecular architectures and behaviours to those of homopolymers or di/triblock copolymers. Owing to the rapidly expanding field of synthetic methodologies applied in the field of polymer chemistry, sequenced controlled MBCs are becoming the new functional materials of this decade. MBCs can now be synthesised with precision and control unlike before and yet some of the synthetic limitations remain a challenge. In this review article, we summarise the various synthetic methodologies that have been reported to date with recent advances in different polymerisation techniques and applications.

Cyclodextrins (CDs) are a family of cyclic oligosaccharides with a hydrophilic exterior surface and a nonpolar cavity interior, therefore, CDs can form inclusion complexes through noncovalent interactions with a broad range of hydrophobic guests. CD derivatives and CD-based polymers find important uses in different fields such as pharmacy, cosmetics, biomedicine, textiles, and food domain due to their unique properties during the past decade. Hence, in this review, functionalised CDs and CD-based polymers are classified and discussed according to their synthetic approaches comprehensively to help polymer chemists for the development of new CD-based materials for different types of applications.

An inimer approach is presented here for the formation of bottlebrush copolymers consisting of a poly(2-oxazoline) backbone and acrylate branches. A hydroxyl group containing 2-oxazoline (2-n-pentanol-2-oxazoline) was synthesized from e-caprolactone, which is a sustainable starting material. 2-n-Pentanol-2-oxazoline was then further functionalized with a bromoisobutyrate group, which was used to initiate a Cu(0)-mediated reversible-deactivation radical polymerisation (RDRP) of acrylates. This compound is termed an “inimer” because it contains both a monomer (2-oxazoline) and an initiator (the RDRP initiator in this study). Herein, we report the use of an inimer to form 2-oxazoline-based polymer backbones through cationic ring opening polymerisation, and further polymerisation via the Cu(0)-mediated RDRP of acrylates was achieved by initiating from the RDRP-initiator sites embedded within the poly(2-oxazoline) backbone. Furthermore, statistical copolymers of 2-ethyl 2-oxazoline and the inimer were also formed leading to statistically distributed radical initiating sites, which were then used to form graft copolymers of varying densities.

From drug delivery to nanoreactors and protocells, polymersomes have gained considerable interest from researchers due to their novel applications. However, one of the main challenges is the selection of the most appropriate synthetic route. It is crucial to consider factors such as desired application, functionalisation, and environment of the polymersome when designing a synthetic route. This review will explore the current scope of polymersome synthesis and preparation methods, and will conclude by highlighting the most recent reports on polymersome related systems such as virus-like nanoparticles. From the choice of monomers, to polymerisation techniques, and to preparation methods used, we aim for this review to be utilised as a tutorial guide for the synthesis of a range of polymersomes, each with varying characteristics and applications.

One long-standing challenge in polymer science is the development of transformation reactions, in which the conversion of a specific functional group to another is targeted. For this purpose, a thioester polymer consisting of thioacrylate monomers has been prepared via nitroxide-mediated polymerization and its kinetics has been studied for the first time. The copolymerization behavior of butyl thioacrylate with PFS was investigated in detail and compared to the copolymerization of butyl acrylate and PFS. Finally, a series of modification reactions were carried out using different amines and alcohols, in an attempt to transform the thioacrylate monomer into an acrylamide or acrylate, respectively. The established conditions allowed one to obtain poly(acrylamide)s via post polymerization functionalization in a versatile and efficient way, which is why this process is believed to be widely used by polymer chemists.

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.

Core cross-linked star shaped polymers possess unique physical properties that can be utilized as drug transporters for biomedical applications. However, detailed analysis of these polymer structures is not straightforward. Herein, we employ multi-detector gel permeation chromatography (GPC) to elucidate structural features of cross-linked stars prepared from the polymerisation of NIPAM via Cu(0)-mediated Reversible Deactivation Radical Polymerisation. Furthermore, we aim to show how varying the arm length and the core size of the star polymers can not only affect their structural properties but also their capacity to encapsulate drug-like molecules.\ud \ud

Carbohydrate-binding proteins (lectins) play vital roles in cell recognition and signaling, including pathogen binding and innate immunity. Thus, targeting lectins, especially those on the surface of immune cells, could advance immunology and drug discovery. Lectins are typically oligomeric; therefore, many of the most potent ligands are multivalent. An effective strategy for lectin targeting is to display multiple copies of a single glycan epitope on a polymer backbone; however, a drawback to such multivalent ligands is they cannot distinguish between lectins that share monosaccharide binding selectivity (e.g., mannose-binding lectins) as they often lack molecular precision. Here, we describe the development of an iterative exponential growth (IEG) synthetic strategy that enables facile access to synthetic glycomacromolecules with precisely defined and tunable sizes up to 22.5 kDa, compositions, topologies, and absolute configurations. Twelve discrete mannosylated "glyco-IEGmers" are synthesized and screened for binding to a panel of mannoside-binding immune lectins (DC-SIGN, DC-SIGNR, MBL, SP-D, langerin, dectin-2, mincle, and DEC-205). In many cases, the glyco-IEGmers had distinct length, stereochemistry, and topology-dependent lectin-binding preferences. To understand these differences, we used molecular dynamics and density functional theory simulations of octameric glyco-IEGmers, which revealed dramatic effects of glyco-IEGmer stereochemistry and topology on solution structure and reveal an interplay between conformational diversity and chiral recognition in selective lectin binding. Ligand function also could be controlled by chemical substitution: by tuning the side chains of glyco-IEGmers that bind DC-SIGN, we could alter their cellular trafficking through alteration of their aggregation state. These results highlight the power of precision synthetic oligomer/polymer synthesis for selective biological targeting, motivating the development of next-generation glycomacromolecules tailored for specific immunological or other therapeutic applications.

Hatice Mutlu, Filip Du Prez and Remzi Becer present the Polymer Chemistry themed collection on synthetic methodologies for complex macromolecular structures in honour of Prof. Yusuf Yagci's 70th birthday.

2-oxazoline based polymers are attracting more and more attention in the last decade owing to their unique properties not only in biomedical applications but also in lubrication. Their combination with widely used polymers that are usually synthesized via controlled/“living” polymerisation techniques allows the design of novel polymer architectures and further increases the range of properties accessible from poly(2-oxazoline) based materials. However, there are several synthetic challenges to achieve a successful combination of these polymers and various techniques, such as click reactions, macromonomers, and heterobifunctional initiators have been reported in the literature to overcome these challenges. In this review, various synthetic methods to combine poly(2-oxazoline)s with vinyl based polymers have been discussed including the pros and cons of each method.

Supramolecular polymer-based biomaterials play a significant role in current biomedical research. In particular, peptide amphiphiles (PAs) represent a promising material platform for biomedical applications given their modular assembly, tunability, and capacity to render materials with structural and molecular precision. However, the possibility to provide dynamic cues within PA-based materials would increase the capacity to modulate their mechanical and physical properties and, consequently, enhance their functionality and broader use. In this study, we report on the synthesis of a cationic PA pair bearing complementary adamantane and β-cyclodextrin host-guest cues and their capacity to be further incorporated into self-assembled nanostructures. We demonstrate the possibility of these recognition motifs to selectively bind, enabling noncovalent cross-linking between PA nanofibers and endowing the resulting supramolecular hydrogels with enhanced mechanical properties, including stiffness and resistance to degradation, while retaining in vitro biocompatibility. The incorporation of the host-guest PA pairs in the resulting hydrogels allowed not only for macroscopic mechanical control from the molecular scale, but also for the possibility to engineer further spatiotemporal dynamic properties, opening opportunities for broader potential applications of PA-based materials.

Multi-block copolymers offer a plethora of exciting properties, easily tuned by modulating parameters such as monomer composition, block length, block number and dispersity. Here, we demonstrate a highly efficient one-pot synthesis of such materials by combining copper-mediated reversible-deactivation radical polymerisation (Cu-RDRP) with thiol-bromo post-polymerisation modification. Specifically, the use of bifunctional bromo initiators and bisthiol compounds furnishes hydrophilic, hydrophobic and amphiphilic architectures in less than 10 minutes via a step growth-type mechanism. Furthermore, the degradation characteristics of the obtained polymers are demonstrated in oxidative, methylating and high temperature environments. The rate of degradation and nature of the end-group is shown to vary with the choice of bisthiol linker and other reaction conditions.

Thioacrylates are a novel class of monomers that have been shown to be polymerisable. However, knowledge of their polymerisation behaviour in metal mediated radical polymerisation is limited, although the thioester functionality allows efficient post modifications. In this report, findings on the polymerisation of thioacrylates via SET-LRP conditions are presented. In a set of carefully monitored optimisation reactions, low conversions were observed when CuBr2 was employed, which is due to the complexation of the thioester with Cu catalyst. Nevertheless, once CuBr2 is replaced with an iron based deactivator, full conversion for the homopolymerisation of ethyl thioacrylate is achieved. In a next step, the polymerisation conditions for an ethyl thioacrylate and a methyl acrylate block copolymer are optimised. The obtained block copolymer was subjected to an amidation reaction to obtain an all-acrylic copolymer, consisting of an acrylate, a thioacrylate and an acrylamide.

Recent advances in polymer science make it possible to create single chain polymer nanoparticles (SCNPs), which can mimic the folding of natural macromolecules, such as protein and nucleic acid, in terms of their native and functional state. Even though considerable progress has been done during the last years, the synthesis of relatively controlled SCNPs with a good folding accuracy is still challenging due to lack of appropriate chemical synthesis techniques. Different types of SCNPs are developed with enhanced properties and used for various applications, e.g., delivery systems, imaging agents, and nanomedicine. As it is believed that SCNPs are so crucial to elucidate single chain technology, in this review, recent developments in SCNPs are discussed comprehensively according to their synthetic approaches to keep readers updated on this important research field. First, selective point folding methods are classified and highlighted, and then repeat unit folding routes are discussed with exciting examples.

In this work, we describe the physicochemical characterization of amphiphilic glycopolymers synthesized via copper(0)-mediated reversible-deactivation radical polymerization (Cu-RDRP). Depending on the chemical composition of the polymer, these glycopolymers are able to form multi-chain or single-chain polymeric nanoparticles. The folding of these polymers is first of all driven by the amphiphilicity of the glycopolymers and furthermore by the supramolecular formation of helical supramolecular stacks of benzene-1,3,5-tricarboxamides (BTAs) stabilized by threefold hydrogen bonding. The obtained polymeric nanoparticles were subsequently evaluated for their lectin-binding affinity toward a series of mannose- and galactose-binding lectins via surface plasmon resonance. We found that addition of 2-ethylhexyl acrylate to the polymer composition results in compact particles, which translates to a reduction in binding affinity, whereas with the addition of BTAs, the relation between the nature of the particle and the binding ability system becomes more unpredictable.

Thermoresponsive behavior of polymers in aqueous solutions has been widely studied and utilized in various applications. However, the fundamental understanding on the use of oil soluble polymers in non-aqueous solutions is very limited. Herein, we report the synthesis of linear homo and copolymers as well as graft-copolymers based on 2-oxazoline monomers and the investigation of their solution behavior and thermal properties via turbidity measurements and thermal analyses (DSC and TGA). The homo and copolymers were synthetized via living cationic ring-opening polymerization (CROP) of 2-stearyl-2-oxazoline (SteOx) and 2-ethyl-2-oxazoline (EtOx) and their composition was varied in order to tune the thermoresponsive behavior in a commercially available base oil (Yubase-4). The graft-copolymers were obtained using the grafting-onto method. The backbone composed of a methacrylic acid and 2-ethylhexyl methacrylate copolymer was synthetized via reversible addition–fragmentation chain-transfer (RAFT) polymerization, while side chains consisting of SteOx–EtOx copolymers were obtained via CROP. Various polymerization parameters were evaluated in order to optimize the grafting efficiency and the solubility in oil of the synthetized graft-copolymers. It was seen that not only the overall hydrophobicity of the polymer chains but also the overall order of the system have significant effects on the upper critical solution temperature (UCST) in oil. Finally, a relationship between the crystallization temperature measured using DSC and the transition temperature (Ttrans) values obtained from the turbidity measurements was compared.

Star-shaped glycopolymers provide very high binding activities toward lectins. However, a straightforward synthesis method for the preparation of multi-arm glycopolymers in a one-pot approach has been challenging. Herein, we report a rapid synthesis of well-defined multi-arm glycopolymers via Cu(0)-mediated reversible deactivation radical polymerization in aqueous media. d-Mannose acrylamide has been homo- and copolymerized with NIPAM to provide linear arms and then core cross-linked with a bisacrylamide monomer. Thus, the arm length and core size of multi-arm glycopolymers were tuned. Moreover, the stability of multi-arm glycopolymers was investigated, and degradation reactions under acidic or basic conditions were observed. The binding activities of the obtained multi-arm glycopolymers with mannose-specific human lectins, DC-SIGN and MBL, were investigated via surface plasmon resonance spectroscopy. Finally, the encapsulation ability of multi-arm glycopolymers was examined using DHA and Saquinavir below and above the lower critical solution temperature (LCST) of P(NIPAM).

Lectins are omnipresent carbohydrate binding proteins that are involved in a multitude of biological processes. Unearthing their binding properties is a powerful tool toward the understanding and modification of their functions in biological applications. Herein, we present the synthesis of glycopolymers with a brush architecture via a "grafting from" methodology. The use of a versatile 2-oxazoline inimer was demonstrated to open avenues for a wide range of 2-oxazoline/acrylamide bottle brush polymers utilizing aqueous Cu-mediated reversible deactivation radical polymerization (Cu-RDRP). The polymers in the obtained library were assessed for their thermal properties in aqueous solution and their binding toward the C-type animal lectins dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN) and mannose-binding lectin (MBL) via surface plasmon resonance spectrometry. The encapsulation properties of a hydrophobic drug-mimicking compound demonstrated the potential use of glyco brush copolymers in biological applications.

Brush-shaped macromolecular architectures provide unique material properties because of their dense branched structures. However, there are major challenges in obtaining brush-shaped macromolecules when the required functional monomers are not compatible for copolymerization using the same synthetic technique. Herein, we present an inimer molecule structure that has both an initiating group for Cu-mediated radical polymerization and a 2-oxazoline monomer ring for cationic ring-opening polymerization. Thus, various combinations of poly(2-oxazoline-brush-acrylate/acrylamide) copolymers could be obtained by grafting from a poly(2-oxazoline) backbone bearing radical initiator units. A simple two-step synthesis method for a novel 2-oxazoline inimer was established and used in the homo and block copolymerization with 2-ethyl-2-oxazoline to yield the brush initiator structure. Moreover, selected acrylates and acrylamides were utilized for Cu(0)-mediated reversible deactivation radical polymerization (RDRP) initiated through the brush initiator. Finally, because of the understanding obtained via optimization reactions, high/low density, block, and amphiphilic brush copolymers with narrow molecular weight distributions were successfully obtained.

We introduce visible light induced dynamic covalent chemistry as a powerful reversible ligation tool based on a wavelength-dependent photon efficiency analysis (WPEA). We demonstrate by a monochromatic wavelength scan of the reversible dimerization of styrylpyrene at constant photon count that the system is most effective in its forward reaction at 435 nm, while the highest reverse reaction efficiency is observed at 330 nm. Critically, these optimum wavelengths are not accessible by inspection of the UV/vis spectra of the monomer and the dimer. Application of the identified reaction conditions enabled an entirely λ-orthogonal photoreversible polymer ligation using visible light, including with readily available light sources. The current study thus makes a [2 + 2] reaction system applicable in the critical visible light regime based on quantitative wavelength resolved data for applications in recodeable surface design in biological environments as well as reprogrammable materials systems.

Becer, C. Remzi/0000-0003-0968-6662; Ozcelik, Serdar/0000-0003-2029-0108; Geyik, Caner/0000-0002-8382-2186; Guler Celik, Emine/0000-0003-2381-9775; YILMAZ, GOKHAN/0000-0002-1803-5397; Odaci Demirkol, Dilek/0000-0002-7954-1381, WOS: 000424988400014, Over the past decade, there has been a great deal of interest in the integration of nanotechnology and carbohydrates. The advances in glyconanotechnology have allowed the creation of different bioactive glyconanostructures for different types of medical applications, especially for drug delivery and release systems. Therefore, the use of more efficient biocompatible nanocarriers with high loading capacity, low overall toxicity and receptor-mediated endocytosis specificity is still in focus for the enhancement of the therapeutic effect. Conjugation of sugar derivatives onto gold nanoparticles presents unique properties that include a wide array of assembling models and size-related electronic, magnetic and optical properties. Here, pH-responsive drug-conjugated glycopolymer-coated gold nanoparticles were prepared by functionalization of gold nanoparticles with thiol-terminated glycopolymers and then subsequent conjugation of doxorubicin (DOX). Among the four different glycopolymers, their drug release, physicochemical characterization (spectroscopy, particle size and surface charge) and in vitro bioapplications with four different cell lines were compared. As a result, pH-sensitive drug delivery via sugar-coated AuNPs was performed thanks to hydrazone linkages between glycopolymers and DOX. Comparative viability tests also demonstrated the efficiency of glycopolymer-DOX conjugates by fluorescence cell imaging. The obtained results reveal that AuNP homoglycopolymer DOX conjugates (P4D) have significant potential, especially in human neuroblastoma cells in comparison to cervical cancer cells and lung cancer cells.

Inspired by the uniqueness and ubiquity of thioesters in nature, much attention has been paid to thioester functionalized materials, yielding applications ranging from responsive polymers to bioconjugates and (bio)degradable polymers. This review focuses on various applications of thioesters in polymer science, covering the synthesis and polymerisation of thioester containing monomers, thioester generation via polymerization processes or the presence of thioesters in chain ends, such as initiators or chain transfer agents. Examples of post-polymerization modifications with various compounds (e.g. thiols, azides, amines and cysteine containing peptides) to enable modification via pathways such as ligation, amidation or exchange reactions are also presented.

Electrospun biodegradable membranes have attracted great attention for a range of tissue engineering applications. Among them, poly(e-caprolactone) (PCL) is one of the most widely used polymers, owing to its well-controlled biocompatibility and biodegradability. However, PCL also has a number of limitations, such as its hydrophobic nature and the lack of functional groups on its side chain, limiting its ability to interact with cells. Herein, we have designed and prepared a series of well-defined A2B-miktoarm copolymers with PCL and glycopolymer segments to address these limitations. Moreover, copolymers were electrospun to make membranes, which were studied in vitro to investigate cell affinity, toxicity, activity, and adhesion with these materials. The results indicate that incorporating glucose moieties into miktoarm polymers has improved the biocompatibility of the PCL while increasing the cellular interaction with the membrane material.

Glycopolypeptides with defined block sequences were prepared by sequential addition of two different N-carboxyanhydrides (NCAs), followed by selective deprotection and functionalization of predefined positions within the polypeptide backbone. The sequential arrangement of the galactose units and the block-sequence length have been systematically varied. All the glycopolypeptides have been obtained with a similar overall composition and comparable molecular weights. Circular dichroism measurements revealed some dependence of the secondary structure on the primary composition of the glycopolypeptides at physiological pH. While statistical, diblock, and tetrablock glycopolypeptides adopted a random coil conformation, the octablock glycopolypeptide was mostly α-helical. The ability to selectively bind to lectins was investigated by turbidity measurements as well as surface plasmon resonance (SPR) studies. It was found that the extent of binding was dependent on the position of the galactose units and thus the primary glycopolypeptide structure. The octablock glycopolypeptide favored interaction with lectin RCA120 while the tetrablock glycopolypeptide demonstrated the strongest binding activity to Galectin-3. The results suggest that different lectins are very sensitive to glyco coding and that precise control of carbohydrate units in synthetic polymeric glycopeptides will remain important.

Inorganic–organic co-networks prepared by a sol–gel method are a promising class of materials due to their unique physical and biological properties, especially when covalent bonds are formed between the networks. The polymer structure and composition can have a drastic effect on the synthesis and properties. Here, we compared reversible addition fragmentation chain-transfer (RAFT) with telomerisation (TL), for the synthesis of the polymer, to investigate whether refining the polydispersity of polymethacrylate could lead to better and more tailorable properties. 3-(Methoxysilyl)propyl methacrylate was used as a model and successfully synthesised by RAFT and TL using 2-cyano-2-propyl benzodithioate and thioglycerol as chain transfer agents, respectively. The polydispersity of the polymer had a significant effect on the sol–gel process with an increase in gelation time as the polydispersity decreased. Direct correlation was made between the gelation time and Mz, suggesting that the gelation of hybrids followed the percolation model. However, regarding the properties, it is a tie. No statistical difference in silica release and mechanical properties of the resulting hybrids was observed, regardless of the polydispersity of the polymer.

Correction for ‘Synthetic approaches for multiblock copolymers’ by Valentin P. Beyer et al., Polym. Chem., 2020, 11, 1271–1291.

Inflammatory conditions are frequently accompanied by increased levels of active proteases, and there is rising interest in methods for their detection to monitor inflammation in a point of care setting. In this work, new sensor materials for disposable single-step protease biosensors based on poly(2-oxazoline) hydrogels cross-linked with a protease-specific cleavable peptide are described. The performance of the sensor material was assessed targeting the detection of matrix metalloproteinase-9 (MMP-9), a protease that has been shown to be an indicator of inflammation in multiple sclerosis and other inflammatory conditions. Films of the hydrogel were formed on gold-coated quartz crystals using thiol-ene click chemistry, and the cross-link density was optimized. The degradation rate of the hydrogel was monitored using a quartz crystal microbalance (QCM) and showed a strong dependence on the MMP-9 concentration. A concentration range of 0-160 nM of MMP-9 was investigated, and a lower limit of detection of 10 nM MMP-9 was determined.