Search Results (225)

A new sensor system for the determination of nitrogen-containing pharmaceutical substances has been proposed. It is based on the use of an ion association complex formed between cationic polyacrylamide (CPAA) and sulfonephthalein dye as a reagent. Bromocresol purple (BCP) interacts with CPAA to form a complex through hydrophobic interaction as well as electrostatic interaction. In the pH range from 3.5 to 5.5, this leads to an increase in the intensity of the dianionic form BCP band at 590 nm. The interaction between the polymer and the dye leads to an increase in the acidic properties of BCP, causing its pK_a2 to shift from 6.3 to 3.75. Subsequently, when loratadine (LOR) is added to the CPAA/BCP system, the strong electrostatic interaction between the BCP monoanion and the protonated form of LOR leads to a decrease in the intensity of the band at 590 nm and an increase in the absorbance of the band at 432 nm, which is related to the dye monoanion. Here, we have demonstrated that this facile methodology can enable the rapid, reliable, and selective determination of LOR with a detection limit of 1.6 mg L⁻¹ and a linear range from 5.0 to 120 mg L⁻¹. The environmental friendliness of the developed method was assessed using the AGREE metric and is characterized by a high score of 0.83. The developed method represents a new approach to the creation of extraction-free spectrophotometric methods based on ionic associates of anionic dyes with protonated forms of nitrogen-containing medicinal compounds. The method was successfully applied to the determination of LOR in pharmaceutical preparations with satisfactory precision and accuracy. Overall, the results obtained indicate that this method has great potential for application in pharmaceutical analysis. Full article

Background/Objectives: Lyotropic liquid crystalline nanoparticles are promising drug delivery nanocarriers, exhibiting significant technological advantages, such as their extended internal morphology. In this study, cationic non-lamellar lyotropic–lipidic liquid crystalline nanoparticles were formulated by phytantriol lipid. Methods: The poly(2-(dimethylamino)ethyl methacrylate)-b-poly(lauryl methacrylate) block copolymer carrying tri-phenyl-phosphine cations (TPP-QPDMAEMA-b-PLMA), was employed as a stabilizer co-assisted by other polymeric guests. The exact qualitative and quantitative formulation of the systems was investigated. Their physicochemical profile was depicted from a variety of light scattering techniques, while their microenvironmental parameters were determined by fluorescence spectroscopy using adequate probe molecules. The effect of environmental conditions was monitored, confirming stimuli-responsiveness properties. Their morphology was illustrated by cryo-TEM, revealing expanded internal assemblies. Resveratrol was incorporated into the nanoparticles and the entrapment efficiency was calculated. Results: Their properties were found to be dependent on the formulation characteristics, such as the lipid used, as well as the architecture of the polymeric stabilizer, also being found to be stealth toward proteins, exhibiting stimuli responsiveness and high entrapment efficiency. Conclusions: The studied liquid crystalline nanoparticles, being stimuli-responsive, with high cationic potential, high loading capacity and showing intriguing 3D structures, are suitable for pharmaceutical applications. Full article

In this study, we present a novel and straightforward approach for the synthesis of copolymers and nanocomposites based on α- and β-pinene, employing an eco-friendly and cost-effective nano-reinforcing filler. The copolymers (α-co-β-P) were produced through cationic copolymerization, using AlCl₃ as a catalyst. The structural characterization of the resulting copolymer was validated through FT-IR, ¹H-NMR spectroscopy, and differential scanning calorimetry (DSC). The molecular weight of the obtained polymer is determined by Gel Permeation Chromatography (GPC) analysis and is about 4500 g/mol. Nanocomposites (α-co-β-P/Clay 2, 5, 8, and 10% by weight of nano-clay) were synthesized by combining clay and α-co-β-P copolymer in solution using ultrasonic irradiation. This ultrasound-assisted method was employed to enhance and assess the structural, morphological, and thermal properties of the pure copolymer. The morphology of the resultant nanocomposites was characterized using infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Thermogravimetric analysis (TGA) revealed that the nanocomposites exhibit a higher degradation temperature compared to the pure copolymer. The analyses provided evidence of the chemical modification of nano-clay layers and their uniform dispersion in the α-co-β-P copolymer matrix. Exfoliated structures were achieved for lower clay concentration (2% by weight), while intercalated structures and immiscible regions were observed for higher clay concentrations (5, 8, and 10% by weight). The antioxidant activity of α-pinene, β-pinene, and the obtained nanocomposites were studied using DPPH (2,2-diphenyl-1-picrylhydrazyl) as a model free-radical. The results demonstrate a significant antioxidant potential of the nanocomposites, showcasing their ability to effectively neutralize free-radicals. Finally, a novel procedure was devised for the rapid synthesis of copolymers and nanocomposites using α- and β-pinene. Full article

Background/Objectives: The growing threat of antibiotic resistance necessitates the development of novel antimicrobial agents that effectively target pathogenic microorganisms while minimizing toxicity. Methods: Two series DABCO-based cationic homopolymers (D-subs 1kDa, D-subs 5kDa, D-subs 15kDa) and DABCO–pyridinium-based copolymers (PyH-subs 5kDa_Dsubs 5kDa, PyH-subs 7kDa_Dsubs 3kDa, PyH-subs 3kDa_Dsubs 7kDa) were synthesized to mimic to host-defense cationic peptides via ring-opening metathesis polymerization (ROMP). The antimicrobial activities of these polymers were determined by their minimum inhibitory concentrations (MICs) against E. coli (Gram-negative bacteria), P. aeruginosa (Gram-negative bacteria), S. aureus (Gram-positive bacteria), and C. albicans (fungus). In vitro cytotoxicity assays revealed selective toxicity towards bacterial cells, with high selectivity indices for several copolymers. To gain insight into the mechanism of action, morphological changes in S. aureus upon exposure to D-subs 1kDa were examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results: The D-subs 15kDa homopolymer demonstrated the highest overall antimicrobial activity, particularly against S. aureus (MIC: 8 µg/mL), with all polymers exhibiting minimal hemolytic activity (HC₅₀ ≥ 1024 µg/mL). SEM and TEM results revealed membrane disruption indicative of polymer–bacteria interactions. Additionally, stability studies confirmed polymer integrity under physiological conditions for at least 28 days. Conclusions: These results support the potential of DABCO-based cationic polymers as a promising platform for next-generation antimicrobial therapeutics. Full article

Because of their potential “smart” applications, multifunctional stimuli-responsive polymers are gaining increasing scientific interest. The present work explores the possibility of developing such materials based on the hydrolytically stable N-3-dimethylamino propyl methacrylamide), DMAPMA. To this end, the properties in aqueous solution of the homopolymer PDMAPMA and copolymers P(DMAPMA-co-MMA_x) of DMAPMA with the hydrophobic monomer methyl methacrylate, MMA, were explored. Two copolymers were prepared with a molar content x = 20% and 35%, as determined by Proton Nuclear Magnetic Resonance (¹H NMR). Turbidimetry studies revealed that, in contrast to the homopolymer exhibiting a lower critical solution temperature (LCST) behavior only at pH 14 in the absence of salt, the LCST of the copolymers covers a wider pH range (pH > 8.5) and can be tuned within the whole temperature range studied (from room temperature up to ~70 °C) through the use of salt. The copolymers self-assemble in water above a critical aggregation Concentration (CAC), as determined by Nile Red probing, and form nanostructures with a size of ~15 nm (for P(DMAPMA-co-MMA₃₅)), as revealed by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The combination of turbidimetry with ¹H NMR and automatic total organic carbon/total nitrogen (TOC/TN) results revealed the potential of the copolymers as visual CO₂ sensors. Finally, the alkylation of the copolymers with dodecyl groups lead to cationic amphiphilic materials with an order of magnitude lower CAC (as compared to the unmodified precursor), effectively stabilized in water as larger aggregates (~200 nm) over a wide temperature range, due to their increased ζ potential (+15 mV). Such alkylated products show promising biocidal properties against microorganisms such as Escherichia coli and Staphylococcus aureus. Full article

This study focuses on the synthesis and characterization of a cationic ion-exchange sorbent derived from vermiculite and epoxy acrylate copolymers, designed to address freshwater scarcity by removing toxic metal ions from aqueous environments. The sorbent was engineered to preserve the chemical integrity of freshwater while adhering to environmental safety standards. Vermiculite served as the base material, modified with glycidyl methacrylate (GMA), acrylonitrile (ACN), and orthophosphoric acid (H₃PO₄) in a mass ratio of 1:0.35:0.15:3. Optimization experiments explored varying H₃PO₄ proportions (two- and threefold increases) to refine the synthesis conditions. The materials underwent microwave irradiation at 300 W for 10 min. Infrared (IR) spectroscopy confirmed the presence of functional groups (P=O, P−O−C), enhancing sorption capacity, while scanning electron microscopy (SEM) revealed a porous structure crucial for adsorption. Sorption properties, assessed via atomic emission spectroscopy, demonstrated capacities of 39.80 mg/g for MoO₄²⁻ and 39.06 mg/g for ReO₄⁻, with extraction efficiencies of 79% and 78%, respectively. Chemical stability tests indicated the sorbent retained up to 90% of its functionality in aggressive environments, highlighting its robustness. The developed sorbent offers a high-performance, cost-effective solution for heavy metal removal from wastewater, advancing sustainable water purification technologies. Full article

Reversible addition–fragmentation chain-transfer (RAFT) polymerization was used to synthesize novel thermoresponsive cationic molecular brushes with high yields—namely of copolymers of methoxyoligo(ethylene glycol) methacrylate, alkoxyoligo(ethylene glycol) methacrylate, and N-methacryloylaminopropyl-N,N-dimethyl-N-propylammonium bromide. Controlled polymerization yielded polymers with a molecular weight dispersity of ≤1.3 and conversions exceeding 80%. The influence of the cationic molecular brushes’ composition on their solubility in water and organic solvents, interfacial tension at the water–oil interface, and aggregation behavior in aqueous solutions was investigated. For the first time, we report the design of thermoresponsive cationic molecular brushes combining an antibacterial potential and tunable hydrophilic–hydrophobic properties, enabling highly precise control over their LCST behavior (17–68 °C) through composition tuning. The solubilization capacity of the hydrophobic compounds of brush micelles in water increased with the hydrophobic comonomer content. These polymers exhibited interfacial activity, significantly reducing the water–oil interfacial tension, with critical micelle concentrations (CMCs) of 3–10 mg/L. It was shown that the amphiphilic properties of the copolymers in aqueous solutions can be easily tuned in a desired direction by varying the content of the comonomer units. The obtained data indicate the potential of the polymers as micellar nanocarriers for controlled drug delivery. Full article

Designing conducting polymers with novel structures is essential for electrochemical energy storage devices. Here, copolymers of s-triazine and o-aminophenol are electropolymerized from an aqueous solution onto a carbon cloth substrate using the galvanostatic method. The poly(s-triazine-co-o-aminophenol) (PT-co-oAP) is characterized, and its charge storage properties are investigated in 1 M H₂SO₄ and in 1 M ZnSO₄. At 1 A g⁻¹, the specific capacities of PT-co-oAP reach 101.3 mAh g⁻¹ and 84.4 mAh g⁻¹ in 1 M H₂SO₄ and in 1 M ZnSO₄, respectively. The specific capacity of PT-co-oAP maintains 90.3% of its initial value after cycling at 10 A g⁻¹ for 2000 cycles in 1 M H₂SO₄. The high specific capacity achieved originates from abundant surface active sites, facile ion diffusion, with optimized active site structure achieved by forming copolymer. The charge storage mechanism involves the redox processes of amino/imino groups and hydroxyl/carbonyl groups in the copolymer, together with the insertion of cations. Two electrode devices using two PT-co-oAP and aqueous 1 M H₂SO₄ are assembled, and the maximum energy density reaches 63 Wh kg⁻¹ at 0.5 A g⁻¹ with a power density of 540 W kg⁻¹. The capacity retention of the device after 3000 cycles at 10 A g⁻¹ reaches 81.2%. Full article

Chiral molecules are integral to various biological and artificial systems, influencing processes from chemical production to optical activities. In this study, we explore the potential of chiral vinyl[2.2]paracyclophane (vinyl-PCP) as a monomer for the synthesis of homopolymers and copolymers with styrene. We achieved polymerization through anionic, cationic, and radical methods. The resulting polymers demonstrated significant chiral properties, even in copolymers with small fractions of the chiral monomer. Further, we developed a polymerizable vinyl emitter from 10-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-9,9-dimethyl-9,10-dihydroacridine (DMAC-TRZ) through a two-step synthesis with an overall yield of 48%. Copolymerization with chiral vinyl-PCP resulted in emissive polymers that demonstrated circularly polarized luminescence (CPL) properties. The inclusion of the chiral PCP monomer, acting both as a host material and the source of chirality for CPL, enhanced the photoluminescence quantum yield (PLQY) to 47.2% in N₂ at 5–10% emitter content, compared to 26.8% for the pure emitter polymer. CPL-active polymers show clear mirror-image Cotton effects at 240 nm and 267 nm and dissymmetry factors around +2 × 10⁻⁴ and −1 × 10⁻⁴. This self-hosting effect of PCP monomers underscores the potential of chiral vinyl-PCP for advanced functional materials in optical communication and bio-responsive imaging. Full article

Mechanically improved polymeric membranes with high ionic conductivity (IC) and good permeability are highly desired for next-generation anion exchange membranes (AEMs) in order to reduce Ohmic losses and enhance water management in alkaline membrane fuel cells. To move towards the fabrication of such high-performance membranes, the creation of hydrophilic ion-conducting double gyroid (DG) nanochannels within block copolymer (BCP) AEMs is a promising approach. However, this attractive solution remains difficult to implement due to the complexity of constructing a well-developed ion-conducting DG morphology across the entire membrane thickness. To deal with this issue, water permeable polystyrene-block-poly(2-vinylpyridine)-block-poly(ethylene oxide) membranes with ion-conducting DG nanochannels were produced by combining a solvent vapor annealing (SVA) treatment with a methylation process. Here, the SVA treatment enabled the manufacture of DG-forming BCP AEMs while the methylation process allowed for the conversion of pyridine sites to N-methylpyridinium (NMP⁺) cations via a Menshutkin reaction. Following this SVA-methylation method, the IC value of water-permeable (~384 L h⁻¹ m⁻² bar⁻¹) DG-structured BCP AEMs in their OH⁻counter anion form was measured to be of ~2.8 mS.cm⁻¹ at 20 °C while a lower IC value was probed, under the same experimental conditions, from as-cast NMP⁺-containing analogs with a non-permeable disordered phase (~1.2 mS.cm⁻¹). Full article

Herein, anionic (sodium dodecylbenzene sulfonate, SDBS) and cationic (cetyltrimethylammonium bromide, CTAB) surfactants are involved in the synthesis of a poly(acrylic acid-co-acrylamide) copolymer, p(AA-co-AM), containing nanoceria (CeO₂). The physicochemical and optical properties of CTAB-CeO₂@p(AA-co-AM) and SDBS-CeO₂@p(AA-co-AM) nanocomposites can be studied using different techniques. The physicochemical properties of nanoceria-immobilized p(AA-co-AM) are significantly developed when handled with SDBS. Compared to the CTAB-CeO₂@p(AA-co-AM) nanocomposite, SDBS-CeO₂@p(AA-co-AM) exhibits pronounced negatively charged mesoporous surfaces with Corel reef-like morphology. SDBS-CeO₂@p(AA-co-AM) contains ceria nano-cubes of ~30 nm size, evenly dispersed along a copolymeric moiety, displaying narrower energy bandgap. The photocatalytic efficiency of this nanocomposite is performed in activating persulfate-ions (PS) under visible light irradiation, yielding reactive oxygen species that effectively treat dye wastewater. Advanced SDBS-CeO₂@p(AA-co-AM)/PS/Vis photocatalytic oxidation system possesses ~100% methylene blue degradation efficiency within 2 h for five consecutive purification-cycles with thorough mineralization performance. Such superior photo-degradability consults efficacious synergistic combinations gathering the nanocomposite, persulphate-ions, and visible light radiation, yielding an escalated synergy-index value (SI = 6) with intensive generation of reactive-oxidizing species (SO₄^•−/h⁺ synergistic ratio 1:5.6). Including anionic-surfactant molecules in the synthesis of metal-containing copolymer nanocomposites is indispensably profitable in the future for the treatment of industrial wastewater. Full article

Background/Objectives: The endosomal escape of lipid nanoparticles (LNPs) is crucial for efficient mRNA-based therapeutics. Here, we present a cationic polymeric micelle (cPM) as a safe and potent co-delivery system with enhanced endosomal escape capabilities. Methods: We synthesized a cationic and ampholytic di-block copolymer, poly (poly (ethylene glycol)_4-5 methacrylate_a-co-hexyl methacrylate_b)_X-b-poly(butyl methacrylate_c-co-dimethylaminoethyl methacrylate_d-co-propyl acrylate_e)_Y (p(PEG_4-5MA_a-co-HMA_b)_X-b-p(BMA_c-co-DMAEMA_d-co-PAA_e)_Y), via reversible addition–fragmentation chain transfer polymerization. The cPMs were then formulated using the synthesized polymer by the dispersion–diffusion method and characterized by dynamic light scattering (DLS) and cryo-transmission electron microscopy (CryoTEM). The membrane-destabilization activity of the cPMs was evaluated by a hemolysis assay. We performed an in vivo functional assay of firefly luciferase (Fluc) mRNA using two of the most commonly studied LNPs, SM102 LNP and Dlin-MC3-DMA LNPs. Results: With a particle size of 61.31 ± 0.68 nm and a zeta potential of 37.76 ± 2.18 mV, the cPMs exhibited a 2–3 times higher firefly luciferase signal at the injection site compared to the control groups without cPMs following intramuscular injection in mice, indicating the high potential of cPMs to enhance the endosomal escape efficiency of mRNA-LNPs. Conclusions: The developed cPM, with enhanced endosomal escape capabilities, presents a promising strategy to improve the expression efficiency of delivered mRNAs. This approach offers a novel alternative strategy with no modifications to the inherent properties of mRNA-LNPs, preventing any unforeseeable changes in formulation characteristics. Consequently, this polymer-based nanomaterial holds immense potential for clinical applications in mRNA-based vaccines. Full article

Biofilms are a well-known multifactorial virulence factor with a pivotal role in chronic bacterial infections. Their pathogenicity is determined by the combination of strain-specific mechanisms of virulence and the biofilm extracellular matrix (ECM) protecting the bacteria from the host immune defense and the action of antibacterials. The successful antibiofilm agents should combine antibacterial activity and good biocompatibility with the capacity to penetrate through the ECM. The objective of the study is the elaboration of biofilm-ECM-destructive drug delivery systems: mixed polymeric micelles (MPMs) based on a cationic poly(2-(dimethylamino)ethyl methacrylate)-b-poly(ε-caprolactone)-b-poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA₃₅-b-PCL₇₀-b-PDMAEMA₃₅) and a non-ionic poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO₁₀₀-b-PPO₆₅-b-PEO₁₀₀) triblock copolymers, loaded with ciprofloxacin or azithromycin. The MPMs were applied on 24 h pre-formed biofilms of Escherichia coli and Pseudomonas aeruginosa (laboratory strains and clinical isolates). The results showed that the MPMs were able to destruct the biofilms, and the viability experiments supported drug delivery. The biofilm response to the MPMs loaded with the two antibiotics revealed two distinct patterns of action. These were registered on the level of both bacterial cell-structural alterations (demonstrated by scanning electron microscopy) and the interaction with host tissues (ex vivo biofilm infection model on skin samples with tests on nitric oxide and interleukin (IL)-17A production). Full article

We introduce a novel concept in nucleic acid delivery based on the use of mixed polymeric micelles (MPMs) as platforms for the preparation of micelleplexes with DNA. MPMs were prepared by the co-assembly of a cationic copolymer, poly(1-(4-methylpiperazin-1-yl)-propenone)-b-poly(d,l-lactide), and nonionic poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) block copolymers. We hypothesize that by introducing nonionic entities incorporated into the mixed co-assembled structures, the mode and strength of DNA binding and DNA accessibility and release could be modulated. The systems were characterized in terms of size, surface potential, buffering capacity, and binding ability to investigate the influence of composition, in particular, the poly(ethylene oxide) chain length on the properties and structure of the MPMs. Endo–lysosomal conditions were simulated to follow the changes in fundamental parameters and behavior of the micelleplexes. The results were interpreted as reflecting the specific structure and composition of the corona and localization of DNA in the corona, predetermined by the poly(ethylene oxide) chain length. A favorable effect of the introduction of the nonionic block copolymer component in the MPMs and micelleplexes thereof was the enhancement of biocompatibility. The slight reduction of the transfection efficiency of the MPM-based micelleplexes compared to that of the single-component polymer micelles was attributed to the premature release of DNA from the MPM-based micelleplexes in the endo–lysosomal compartments. Full article

Here, we report a reprocessible, reusable, self-healing, and form-switching polymeric adsorbent for remediating fluorinated pollutants in water. The copolymer hydrogel is designed to contain fluorophilic segments and cationic segments to induce strong binding with perfluorinated pollutants. The sorption performance reveals rapid and quantitative removal of these pollutants, driven by the synergistic effect of fluorophilic and electrostatic interaction. Importantly, a disulfide-containing dynamic crosslinker plays a crucial role in imparting multifunctionality. This enables self-healing by the restoration of crosslinks at the cut surfaces by disulfide exchange reactions and allows for the repeated use of the adsorbent via multiple adsorption–desorption cycles. Furthermore, the adsorbent is reprocessible by cleaving the crosslinks to afford linear copolymers, which can be repolymerized into a hydrogel network on demand. Also, form-switching capability is showcased through the aqueous self-assembly of linear copolymers into a fluorinated micelle, serving as another form of adsorbent for pollutant removal. Full article