Cationic Polymer Research Articles

Syntheses, characterizations and photochromic properties of 1D→2D polycatenated cationic coordination polymers based on the flexible tripodal zwitterionic ligand

Two new coordination compounds, namely, {[ZnBr(µ3-tazna)]NO3·4H2O}n (1) and {[CdBr(µ3-tazna)]ClO4·2H2O}n (2) were solvothermally synthesized from the 1,1′,1′′-(((1,3,5-triazin-2,4,6-triyl)tris(benzene-4,1-diyl))tris(methylene))tris(3-carboxypyridin-1-ium) bromide (H3taznaBr3) ligand and characterized by IR spectroscopy, elemental analysis, X-ray single-crystal diffraction, X-ray powder diffraction (PXRD), and thermal analyses techniques. Single-crystal X-ray diffraction analysis reveals that compounds 1 and 2 crystallize in the triclinic system, P-1 space group. In 1 and 2, Zn(II) and Cd(II) centers are bridged by tazna ligands, displaying a rare 1D → 2D structure formed by the catenation of a 1D double chain. The photochromic behavior of compound 2 was investigated under 365 nm UV light, exhibiting a color change from white to yellow. Furthermore, the thermal and optical absorption properties of compounds 1 and 2 were investigated.

Co-delivery of retinoic acid and miRNA by functional Au nanoparticles for improved survival and CT imaging tracking of MSCs in pulmonary fibrosis therapy

Mesenchymal stem cells (MSCs) have emerged as promising candidates for idiopathic pulmonary fibrosis (IPF) therapy. Increasing the MSC survival rate and deepening the understanding of the behavior of transplanted MSCs are of great significance for improving the efficacy of MSC-based IPF treatment. Therefore, dual-functional Au-based nanoparticles (Au@PEG@PEI@TAT NPs, AuPPT) were fabricated by sequential modification of cationic polymer polyetherimide (PEI), polyethylene glycol (PEG), and transactivator of transcription (TAT) penetration peptide on AuNPs, to co-deliver retinoic acid (RA) and microRNA (miRNA) for simultaneously enhancing MSC survive and real-time imaging tracking of MSCs during IPF treatment. AuPPT NPs, with good drug loading and cellular uptake abilities, could efficiently deliver miRNA and RA to protect MSCs from reactive oxygen species and reduce their expression of apoptosis executive protein Caspase 3, thus prolonging the survival time of MSC after transplantation. In the meantime, the intracellular accumulation of AuPPT NPs enhanced the computed tomography imaging contrast of transplanted MSCs, allowing them to be visually tracked in vivo. This study establishes an Au-based dual-functional platform for drug delivery and cell imaging tracking, which provides a new strategy for MSC-related IPF therapy.

Cationic lipid-coated bPEI/pDNA complexes: Correlation between physicochemical and morphological properties

Cationic lipid–polymer hybrid nanoparticles (cLPHNPs) complexed with nucleic acids, also named lipopolyplexes, have been developed as an alternative to nonviral vectors. These core/shell structures have been introduced to mitigate the limitations of cationic liposomes and biodegradable polymeric nanoparticles (NPs). The colloidal study of hybrid structures opens interesting perspectives for developing novel carriers for drug and gene delivery applications. Morphology aspects (size, lamellarity, and nucleic acid localization) and physicochemical properties of nonviral vectors influence gene delivery. Unraveling the structure of lipopolyplexes can enable their rational design toward enhanced gene delivery. Herein, we investigated the cationic LPHNPs loading plasmid DNA (pDNA) structure using dynamic light scattering, cryo-TEM, and pDNA accessibility assay. This study used pDNA as a genetic cargo for association with a cationic polymer, branched polyethylenimine (bPEI). It was found that the morphology of cationic LPHNP structures is influenced mainly by the formation process. Cationic LPHNPs formulated with EPC, DOPE, and cationic lipid DOTAP showed various degrees of multilamellarity depending on the production method. The addition of lipid dispersion to bPEI-pDNA anionic polyplex induced multilamellarity, while the preformed cationic liposome induced core/shell-like structures. Also, cLPHNPs showed better mechanical stability than polyplexes in a centrifugal vacuum concentrator (CVC) process. The physicochemical properties of cLPHNPs, formed in the presence of CL, were kept constant without significant changes. We believe these obtained colloidal data may be used to investigate hybrid-gene nanocarriers and their production process.

Real-Space Visualization of Charged Polymer Network of Hydrogel by Double Network Strategy and Mineral Staining.

Hydrogels consist of three-dimensional (3D) and complicated polymer networks that determine their physical properties. Among the methods for structural analyses of hydrogels, the real-space imaging of a polymer network of hydrogels on a nanometer scale is one of the optimal methods; however, it is highly challenging. In this study, we propose a direct observation method for cationic polymer networks using transmission electron microscopy (TEM). By combining the double network strategy and the mineral staining technique, we overcame the challenges of polymer aggregation and the low electron density of the polymer. An objective cationic network was incorporated into a neutral skeleton network to suppress shrinkage during subsequent staining. Titania mineralization along the cationic polymer strands provided sufficient electron density for the objective polymer network for TEM observation. This observation method enables the visualization of local structures in real space and plays a complementary role to scattering methods for soft matter structure analysis.

Monitoring of the Homogeneity of Primer Layers for Ink Jet Printing on Polyester Fabrics by Hyperspectral Imaging.

Untreated polyester films and fibers can be hardly printed or coated, in particular if aqueous inks or lacquers have to be applied. Therefore, an adequate primer layer has to be applied first. A cationic polymer formulation based on poly(dimethylamine-co-epichlorohydrin-co-ethylenediamine) (PDEHED) was used as primer layer for digital printing on polyester fabrics. Because of the exceedingly high requirements on the homogeneity of such layers, hyperspectral imaging was used for qualitative and quantitative monitoring of the distribution of the primer layer on the textiles. Multivariate data analysis methods based on the PLS algorithm were applied for quantification of the NIR reflection spectra using gravimetry as a reference method. Optimization of the calibration method resulted in various models with prediction errors of about 1.2 g/m2. The prediction performance of the models was proven in external validations using independent samples. Moreover, a special ink jet printing technology was tested for application of the aqueous primer formulation itself. Since possible clogging of jet nozzles in the print head might lead to inhomogeneity in the coatings such as missing tracks, the potential of hyperspectral imaging to detect such defects was investigated. It was demonstrated that simulated missing tracks can be clearly detected. Consequently, hyperspectral imaging has been proven to be a powerful analytical tool for in-line monitoring of the quality of printability improvement layers and similar systems.

Nonviral CRISPR/Cas9 mutagenesis for streamlined generation of mouse lung cancer models

Functional analysis in mouse models is necessary to establish the involvement of a set of genetic variations in tumor development. A modeling platform to facilitate and cost-effectively analyze the role of multiple genes in carcinogenesis would be valuable. Here, we present an innovative strategy for lung mutagenesis using CRISPR/Cas9 ribonucleoproteins delivered via cationic polymers. This approach allows the simultaneous inactivation of multiple genes. We validate the effectiveness of this system by targeting a group of tumor suppressor genes, specifically Rb1, Rbl1, Pten, and Trp53, which were chosen for their potential to cause lung tumors, namely small cell lung carcinoma (SCLC). Tumors with histologic and transcriptomic features of human SCLC emerged after intratracheal administration of CRISPR/polymer nanoparticles. These tumors carried loss-of-function mutations in all four tumor suppressor genes at the targeted positions. These findings were reproduced in two different pure genetic backgrounds. We provide a proof of principle for simplified modeling of lung tumorigenesis to facilitate functional testing of potential cancer-related genes.

Copper-Free Synthesis of Cationic Glycidyl Triazolyl Polymers.

Copper-free synthesis of cationic glycidyl triazolyl polymers (GTPs) is achieved through a thermal azide-alkyne cycloaddition reaction between glycidyl azide polymer and propiolic acid, followed by decarboxylation and quaternization of the triazole unit. For synthesizing nonfunctionalized GTP (GTP-H), a microwave-assisted method enhances the decarboxylation reaction of carboxy-functionalized GTP (GTP-COOH). Three variants of cationic GTPs with different N-substituents [N-ethyl, N-butyl, and N-tri(ethylene glycol) monomethyl ether (EG3)] are synthesized. The molecular weight of GTP-H is determined via size exclusion chromatography. Thermal properties of all GTPs are characterized using differential scanning calorimetry and thermogravimetric analysis. The ionic conductivities of these cationic GTPs are assessed by impedance measurements. The conducting ion concentration and mobility are calculated based on the electrode polarization model. Among three cationic GTPs, the GTP with the N-EG3 substituent exhibits the highest ionic conductivity, reaching 6.8 × 10-6 S cm-1 at 25°C under dry conditions. When compared to previously reported reference polymers, the reduction of steric crowding around the triazolium unit is considered to be a key factor in enhancing ionic conductivity.

Confining polyoxometalates in porphyrin-based porous cationic polymer toward boosting visible-light-driven synthesis of sulfoxides and detoxification of mustard gas simulants

Visible-light-driven oxidation of sulfides has attracted the profound attention to synthesize sulfoxides and purify mustard gas simulant. In this work, a series of visible-light-responsive polyoxometalate-based porous cationic polymers, i.e. SiW12-PCP 1, PW12-PCP 2, SiW11-PCP 3, SiW10-PCP 4, SiW9-PCP 5 (PCP = porphyrin-based porous cationic polymer), were synthesized by ion exchange process. These POM-PCPs exhibit excellent ability of trapping visible light due to their built-in porphyrin units, which can rapidly oxidize sulfides and degrade 2-chloroethyl ethyl sulfide (CEES) in the presence of a 10 W white LED light and O2. Benefiting from the synergistic effect between [SiW12] and PCP, hybrid 1 has the highest photocatalytic efficiency, attaining 99 % conversion of sulfides within 16 min and 99 % CEES purification in 8 min, much higher than PCP precursor. The reaction mechanism reveals that both O2•− and 1O2 are involved in the photocatalytic process. What's more, hybrid 1 has remarkable applicability to numerous sulfides and robust six-round recycling with no reduction in catalytic efficiency.

Self-Assembled Borneol-Guanidine-Based Amphiphilic Polymers as an Efficient Antibiofilm Agent.

Biofilm-associated infections remain a tremendous obstacle to the treatment of microbial infections globally. However, the poor penetrability to a dense extracellular polymeric substance matrix of traditional antibacterial agents limits their antibiofilm activity. Here, we show that nanoaggregates formed by self-assembly of amphiphilic borneol-guanidine-based cationic polymers (BGNx-n) possess strong antibacterial activity and can eliminate mature Staphylococcus aureus (S. aureus) biofilms. The introduction of the guanidine moiety improves the hydrophilicity and membrane penetrability of BGNx-n. The self-assembled nanoaggregates with highly localized positive charges are expected to enhance their interaction with negatively charged bacteria and biofilms. Furthermore, nanoaggregates dissociate on the surface of biofilms into smaller BGNx-n polymers, which enhances their ability to penetrate biofilms. BGNx-n nanoaggregates that exhibit superior antibacterial activity have the minimum inhibitory concentration (MIC) of 62.5 μg·mL-1 against S. aureus and eradicate mature biofilms at 4 × MIC with negligible hemolysis. Taken together, this size-variable self-assembly system offers a promising strategy for the development of effective antibiofilm agents.

Cationic Polymer Binder for Simultaneously Propelling Ion Transfer and Promoting Polysulfide Conversion in Lithium–Sulfur Batteries

Cationic Polymer Binder for Simultaneously Propelling Ion Transfer and Promoting Polysulfide Conversion in Lithium–Sulfur Batteries

Branching in poly(amine-co-ester) polyplexes impacts mRNA transfection

Branching is a key structural parameter of polymers, which can have profound impacts on physicochemical properties. It has been demonstrated that branching is a modulating factor for mRNA delivery and transfection using delivery vehicles built from cationic polymers, but the influence of polymer branching on mRNA delivery remains relatively underexplored compared to other polymer features such as monomer composition, hydrophobicity, pKa, or the type of terminal group. In this study, we examined the impact of branching on the physicochemical properties of poly(amine-co-esters) (PACE) and their efficiency in mRNA transfection in vivo and in vitro under various conditions. PACE polymers were synthesized with various degrees of branching ranging from 0 to 0.66, and their transfection efficiency was systemically evaluated. We observed that branching improves the stability of polyplexes but reduces the pH buffering capacity. Therefore, the degree of branching (DB) must be optimized in a delivery route specific manner due to differences in challenges faced by polyplexes in different physiological compartments. Through a systematic analysis of physicochemical properties and mRNA transfection in vivo and in vitro, this study highlights the influence of polymer branching on nucleic acid delivery.

Synthesis and intracellular basic protein delivery of a polyanionic flexible organic framework

Although cationic porous polymers have been widely used for gene and drug delivery, the delivering function of anionic porous polymers has rarely been explored. Herein, we prepare a polyanionic flexible organic framework (pa-FOF) through the quantitative formation of the acylhydrazone bond from a tetraanionic tetraaldehyde and a tetraanionic diacylhydrazine. Pa-FOF is highly water-soluble and has a size of 26 to 51 nm, which depends on the concentration of the monomers, and an aperture of approximately 3.8 nm. Fluorescence, zeta potential, confocal laser scanning microscopic and flow cytometric experiments reveal that pa-FOF can adsorb basic proteins, including lysozyme, trypsin and cytochrome c, which is driven by intermolecular ion-pairing electrostatic attraction and hydrophobicity, and realizes efficient intracellular delivery of the adsorbed proteins. Confocal laser scanning microscopic imaging experiments further illustrate that the delivery of cytochrome c can significantly increase its ability of causing cell apoptosis.

Synergistic Polymer Blending Informs Efficient Terpolymer Design and Machine Learning Discerns Performance Trends for pDNA Delivery.

Cationic polymers offer an alternative to viral vectors in nucleic acid delivery. However, the development of polymer vehicles capable of high transfection efficiency and minimal toxicity has remained elusive, and continued exploration of the vast design space is required. Traditional single polymer syntheses with large monomer bases are very time-intensive, limiting the speed at which new formulations are identified. In this work, we present an experimental method for the quick probing of the design space, utilizing a combinatorial set of 90 polymer blends, derived from 6 statistical copolymers, to deliver pDNA. This workflow facilitated rapid screening of polyplex compositions, successfully tailoring polyplex hydrophobicity, particle size, and payload binding affinity. This workflow identified blended polyplexes with high levels of transfection efficiency and cell viability relative to single copolymer controls and commercial JetPEI, indicating synergistic benefits from copolymer blending. Polyplex composition was coupled with biological outputs to guide the synthesis of single terpolymer vehicles, with high-performing polymers P10 and M20, providing superior transfection of HEK293T cells in serum-free and serum-containing media, respectively. Machine learning coupled with SHapley Additive exPlanations (SHAP) was used to identify polymer/polyplex attributes that most impact transfection efficiency, viability, and overall effective efficiency. Subsequent transfections on ARPE-19 and HDFn cells found that P10 and M20 were surpassed in performance by M10, contrasting with results in HEK293T cells. This cell type dependency reinforced the need to evaluate transfection conditions with multiple cell models to potentially identify moieties more beneficial to delivery in certain tissues. Overall, the workflow employed can be used to expedite the exploration of the polymer design space, bypassing extensive synthesis, and to develop improved polymer delivery vehicles more readily for nucleic acid therapies.

Enhanced flotation removal of polystyrene nanoplastics by chitosan modification: Performance and mechanism

Nanoplastics are difficult to remove from water using conventional flotation processes due to their stability and resistance to biodegradation. Here, polystyrene nanoplastics (PSNPs) were selected as the object of study. In addition, chitosan (CTS), an environmentally friendly natural cationic polymer, was selected to modify the air flotation process to improve the separation of PSNPs using air flotation. Adding chitosan effectively enhanced the removal of PSNPs using air flotation from 3.1 % to 96.7 %. The residual concentration decreased from 9.69 mg/L to 0.33 mg/L. Removal of PSNPs by CTS-modified air flotation was maintained at 92.8 % even when the air flotation time was significantly shortened. The zeta potential alterations demonstrated robust electrostatic attraction within the CTS-modified air flotation process. The contact angle measurements indicated that incorporating CTS could enhance the hydrophobic interaction between bubbles and PSNPs. PSNPs particles around 100 nm agglomerated to form floating flocs with a particle size of more than 4500 nm. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) images confirmed the presence of tight adhesion between PSNPs and CTS, indicating the presence of bridging adsorption during the process. The major PSNPs removal mechanisms included electrostatic attraction, enhancement of hydrophobicity, and bridging adsorption. Increasing the aeration volume could improve the removal rate, but this improvement was finite. Weakly acidic and low ionic strength conditions favored PSNPs removal. The CTS-modified air flotation process showed great potential for PSNPs removal from real water bodies.

Lipid-Polymer Nanoparticles Mediate Compartmentalized Delivery of Cas9 and sgRNA for Glioblastoma Vasculature and Immune Reprogramming.

Hypervascularized glioblastoma is naturally sensitive to anti-angiogenesis but suffers from low efficacy of transient vasculature normalization. In this study, a lipid-polymer nanoparticle is synthesized to execute compartmentalized Cas9 and sgRNA delivery for a permanent vasculature editing strategy by knocking out the signal transducer and activator of transcription 3 (STAT3). The phenylboronic acid branched cationic polymer is designed to condense sgRNA electrostatically (inner compartment) and patch Cas9 coordinatively (outer compartment), followed by liposomal hybridization with angiopep-2 decoration for blood-brain barrier (BBB) penetration. The lipid-polymer nanoparticles can reach glioblastoma within 2h post intravenous administration, and hypoxia in tumor cells triggers charge-elimination and degradation of the cationic polymer for burst release of Cas9 and sgRNA, accompanied by instant Cas9 RNP assembly, yielding ≈50% STAT3 knockout. The downregulation of downstream vascular endothelial growth factor (VEGF) reprograms vasculature normalization to improve immune infiltration, collaborating with interleukin-6 (IL-6) and interleukin-10 (IL-10) reduction to develop anti-glioblastoma responses. Collectively, the combinational assembly for compartmentalized Cas9/sgRNA delivery provides a potential solution in glioblastoma therapy.

Current Trends in Chitosan Functionalization Methods and Their Applications

AbstractGrowing concerns about the harmful impact of synthetic polymers on the environment and living organisms have shifted the attention towards biopolymers which are environment‐friendly and biocompatible. Biopolymers represent attractive sustainable and biodegradable alternatives for replacing commercial synthetic polymers. Chitosan is one of the most prevalent biopolymers available on Earth. Chitosan is an alkaline cationic polymer, the deacetylated form of chitin. Chitosan possesses excellent physicochemical properties such as biocompatibility, biodegradability, nontoxic, nonallergenic, and biologically active molecules. During recent years, there has been a surge in the demand for chitosan in various fields, however, due to poor water solubility and mechanical properties, chitosan applications are limited to some extent. Strong inter and intramolecular hydrogen bonds in the chitosan matrix make it highly crystalline, reducing its water solubility. Chemical modification of the chitosan matrix by various technologies is reported to improve its solubility and other physicochemical characteristics, expanding the application areas. Details on various chemical reactions involved in chemical modification and other available technologies have been focused in this paper. The role of chitin deacetylase enzyme in chitosan modification has been discussed. This review aims to provide insight into recent developments in chitosan functionalization, and the development of chitosan derivatives for various applications.

Protonation-triggered self-assembly of chiral copper nanoclusters: Chirality transfer and circularly polarized luminescence generation

Complex biological processes are inseparable from the transmission of chiral information, and the realization of chiral transfer in the process of designing and manufacturing chiral functional materials is conducive to explore sophisticated nature activities. The construction of chiral nanomaterials using self-assembly strategy can effectively constitute asymmetric molecular stacking pattern and occur hierarchical chirality transfer, but there are few studies on the chirality modulation or amplification of metal nanoclusters in self-assembled systems. Herein, we select a chiral glutathione-stabilized copper nanocluster (R-GSH-Cu NCs) as the chiral donor and introduced achiral cationic polymer poly (allylamine hydrochloride) (PAH) to self assembly to form R-GSH-Cu NCs/PAH nanoaggregates. Through thesynergistic effectof hydrogen bonding and electrostatic interaction. Through the synergistic effect of hydrogen bonding and electrostatic interaction, the optical properties of nanoaggregates were greatly regulated, especially in the supramolecular chirality and circularly polarized luminescence (CPL). Meanwhile, the addition of external proton source (hydrochloric acid, HCl) into the R-GSH-Cu NCs/PAH complexes increased the protonation degree of PAH, resulting in chiral inversion and CPL amplification. Regulating chiral properties of chiral metal NCs provides a nanoscale platform for understanding chiral transfer at organic–inorganic interface, which provided candidate in 3D display, biological probes, encrypted information transmission.

Chitosan: A Versatile Biomaterial Revolutionizing Endodontic Therapy.

Owing to their nanoscale dimensions, nanomaterials have special chemical and physical properties that set them apart from their bulk counterparts. The exterior dimensions of a minimum of half of the particles span several nanometers in their size distribution. Silver nanoparticles (AgNPs) are one type of nanomaterial that has been widely used because of their strong antibacterial properties, which can kill bacteria that are resistant to many drugs. Due to its potential for regulated release, localized retention, and safeguarding the active ingredients against environmental or enzymatic deterioration, nanoparticle technology has also emerged as a promising medication delivery method. The techniques for creating nanoparticles can be easily scaled up and used for a wide variety of medications. Since polymeric nanoparticles are biodegradable, biocompatible, and have more readily available formulation techniques than other nanoparticle drug delivery approaches, their range of applications has been expanding. Chitosan, also known as deacetylated polysaccharide, is a straight-chain cationic polymer that is typically a cationic copolymer. It can be generated naturally or by deacetylating chitin. Consequently, it contains an extensive array of biomedical applications, such as efficient healing of wounds, regeneration of tissues, regeneration of bone, and anti-infection. Because of its functional diversity, accessibility, and being both biodegradable and biocompatible, it has a wide spectrum of uses in dentistry. Recent research on chitosan-based nanoparticles is founded on the field's growing comprehension of the characteristics of chitosan and techniques for chemical or physical modification that are used to optimize the drug loading and release characteristics of the nanoparticles.

Module-combinatorial design and screening of multifunctional polymers based on polyaspartic acid for DNA delivery

It is crucial to develop non-viral gene vectors that can efficiently and safely transfect plasmid DNA into cells. Low transfection efficiency and high cytotoxicity of cationic polymers hinder their application as gene carriers. Modification of cationic polymers has emerged as an attractive strategy for efficient and safe nucleic acids delivery. In this study, a simple and rapid method is developed to synthesize a series of multifunctional polymers by utilizing biodegradable polyaspartic acid as the backbone and modifying it with three modules. This one-component polymer possesses capabilities for nucleic acid condensation, cellular uptake, and endosomal escape. Polymers containing imidazole, triazole, or pyridine group exhibited promising transfection activity. Substituted with dodecylamine or 2-hexyldecan-1-amine enhance cellular uptake and subsequent transfection. Furthermore, the influence of ionizable amine side chains on gene delivery is investigated. Two optimal polymers, combined with the avian encephalomyelitis virus (AEV) plasmid vaccine, induced robust specific antibody responses and cellular immune responses in mice and chickens. Through module-combination design and screening of polyaspartamide polymers, this study presents a paradigm for the development of gene delivery vectors.

Ion-Exchange Strategy Enabling Direct Reformation of Unreliable Perfluorinated Cationic Polymer for Robust Proton Exchange Membrane towards Hydrogen Fuel Cells

Perfluorosulfonated anionic ionomers are known for their robust ion conductivity and chemical and mechanical stability. However, the structure and transport property degradation of perfluorinated cationic polymers (PfCPs) are not well understood. Herein, we propose an ion-exchange strategy to identify the structural degradation, ion transport mechanisms, and architectural reformation of PfCPs. Particularly, we demonstrate that the utility of a –SO2–N+ strategy employing the Menshutkin reaction cannot yield reliable PfCPs and anion-exchange membranes, but can yield an unreliable zwitterionic intermediate (cations–anions molar ratio is approximately 7.6%). Moreover, the degradation products were efficiently reformed as proton exchange membranes (PEMs), and the as-reformed PEMs achieved an ion-exchange capacity (IEC) value (0.89 mmol g−1), meanwhile retaining more than 94.7% of their initial capacity. Furthermore, the fuel cell assembled with reformed PEMs displayed a power density of 0.91 Wcm−2 at 2.32 A cm−2, which was 90.1% of that of the robust perfluorosulfonic acid PEMs. Our combined findings shed some fresh light on the state of understanding of the structure–property relationship in PfCPs.