Search Results (654)

With the increasing exploration and development of deep shale gas resources, water-based fracturing fluids face multiple challenges, including high-temperature resistance, salt tolerance, and efficient proppant transport. In this study, a zwitterionic polymer (polyAMASV) is synthesized via aqueous two-phase dispersion polymerization, using acrylamide (AM), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), acrylic acid (AA), stearyl methacrylate (SMA), and 4-vinylpyridine propylsulfobetaine (4-VPPS) as monomers. The introduction of hydrophobic alkyl chains effectively adjusts the viscoelasticity of the emulsion, while the incorporation of zwitterionic units provides salt tolerance through their intrinsic anti-polyelectrolyte effect. As a result, the solutions of such copolymers exhibit stable apparent viscosity in both NaCl and CaCl₂ solutions and under high temperatures. Meanwhile, polyAMASV outperforms conventional samples across various saline environments, reducing proppant settling rates by approximately 20%. Moreover, the solutions exhibit rapid gel-breaking and low residue characteristics, ensuring effective reservoir protection. These results highlight the promising potential of polyAMASV for deep shale gas fracturing applications. Full article

(1) Background: gold nanoparticles (AuNPs) are of particular interest in biomedical research because they possess unique optical properties. In particular, its localized surface plasmon resonance is widely used for photothermal therapy and for detecting molecular interactions at nanoparticle surfaces. To enhance circulation time and biocompatibility, nanoparticles are often coated to shield their hydrophobic character. (2) Methods: we explored the seed-growth method to coat AuNPs with phospholipids to improve colloidal stability. (3) Results: various charged phospholipids were tested, and particle size and zeta potential were characterized. The monodispersity of the coated nanoparticles strongly depends on the narrow size distribution of both gold nanoparticles seeds and lipid vesicles. Achieving stable coated AuNPs with zwitterionic lipids such as phosphatidylcholine was challenging, whereas coatings containing phosphatidylglycerol did not compromise nanoparticle stability. (4) Conclusions: coating AuNPs with phospholipids via the seed-growth method has potential but requires further optimization to improve reproducibility and achieve stable nanoparticles with near-neutral surface charge. Full article

In order to form a solid electrolyte interphase (SEI) layer using aqueous processes, a graphite anode called MG-AQP was designed by wrapping and crosslinking graphite particles with aqueous composites (AQCs), which contained zwitterionic polymer, zwitterion molecules, and lithium salts. First, MG-AQP was used to fabricate a full lithium-ion battery (LIB) cell with Li[Ni_0.8Mn_0.1Co_0.1]O₂ (NMC811) as the cathode, denoted as LIB-MG-AQP//NMC811, to demonstrate its performance via a 0.5 C-rate break-in and 1 C-rate cycling. Accordingly, this showed that LIB-MG-AQP exhibits outstanding cyclic stability. To evaluate its electrochemical performance, MG-AQP and lithium metal were used to fabricate a half cell named LIBs-MG-AQP. According to the initial cyclic voltammetry curve, almost no surface reaction for forming an SEI layer exists in LIBs-MG-AQP, illustrating its high initial coulombic efficiency of 92% at a 0.5 C-rate break-in. These outstanding results are due to the fact that the AQC has fewer cracks, thus blocking solvent molecules from passing from the electrolyte into the graphite anode. This study provides new insights to optimize graphite anodes via 0.5 C-rate break-in rather than conventional SEI formation to save time and energy. Full article

Poly(carboxybetaine methacrylate)s (PCBMA) belongs to a class of zwitterionic polymers that offer promising alternatives to polyethylene glycol (PEG) in biomedical applications. This review highlights how the unique zwitterionic structure of PCBMA dictates its strong antifouling behavior, low immunogenicity, and sensitivity to environmental stimuli such as pH and ionic strength. These features make PCBMA promising for designing advanced systems suited for complex biological environments. This review describes PCBMA-based materials—ranging from hydrogels, nanogels, and surface coatings to drug carriers and protein conjugates—and critically evaluates their performance in drug delivery, tissue engineering, diagnostics, and implantable devices. Comparative studies demonstrated that PCBMA consistently outperformed other zwitterionic polymers and PEG in resisting protein adsorption, maintaining bioactivity of conjugated molecules, and ensuring long circulation times in vivo. Molecular dynamics simulations provide additional information into the hydration shells and conformational behaviors of PCBMA in aqueous dispersions. These insights underscore PCBMA’s broad potential as a promising high-performance material for next generation healthcare technologies. Full article

Steady-shear rheology and surface activity of surfactant–polymer solutions were investigated experimentally. Four different polymers were studied as follows: cationic hydroxyethyl cellulose, nonionic hydroxyethyl cellulose, nonionic guar gum, and anionic xanthan gum. The influence of the following four surfactants on each of the polymers was determined: nonionic alcohol ethoxylate, anionic sodium lauryl sulfate, cationic hexadecyltrimethylammonium bromide, and zwitterionic cetyl betaine. The interaction between cationic hydroxyethyl cellulose and anionic sodium lauryl sulfate was extraordinarily strong, resulting in dramatic changes in rheological and surface-active properties. The consistency increased initially, reached a maximum value, and then fell off with the further addition of surfactant. The surface tension of surfactant–polymer solution dropped substantially and exhibited a minimum value. Thus, the surfactant–polymer solutions were much more surface-active compared with pure surfactant solutions. The interaction between anionic xanthan gum and cationic hexadecyltrimethylammonium bromide was also strong, resulting in a substantial decrease in consistency. The surfactant–polymer solution became less surface-active compared with pure surfactant solution due to the migration of surfactant from solution to polymer. The interactions between other polymers and surfactants were weak to moderate, resulting in small to modest changes in rheological and surface-active properties. Surface activity of surfactant–polymer solutions often increased due to the formation of complexes more surface-active than pure surfactant molecules. Full article

Background/Objectives: Chikungunya virus (CHIKV), a mosquito-borne single-stranded RNA virus belonging to the genus Alphavirus (family Togaviridae), causes large-scale outbreaks. However, no specific treatment for CHIKV infections is currently available. Berberine and emodin are plant-derived compounds with anti-CHIKV activities. This study aimed to evaluate the antiviral efficacy of liposomes containing berberine (LB) or emodin (LE) against CHIKV in vitro, since nanocarriers incorporating zwitterionic polymers are known to enhance the biostability, biocompatibility, and therapeutic efficacy of drug candidates. Methods: Liposomes were synthesized and characterized, and cell viability was assessed to determine appropriate concentrations for subsequent assays. Confocal microscopy, antiviral assays, and western blotting were performed in BHK-21 and Huh7 cells. Results: In BHK-21 and Huh7 cells, LB and LE were well tolerated at concentrations of 5 and 10 µM, respectively. In both cell types, liposomes were internalized; LE was predominantly localized in the cytoplasm, whereas LB was also detected in the nucleus. EGCG, used as a standard drug against CHIKV in antiviral assays, exhibited virucidal activity and inhibited RNA replication and multiple stages of the CHIKV replication cycle in BHK-21 and Huh7 cells. Both the nanoformulations and EGCG consistently suppressed the expression of CHIKV replicase and virion proteins. Conclusions: These findings highlight the potential of berberine- and emodin-loaded liposomes as antiviral agents against CHIKV infection. Full article

Adhering to the principles of green analytical chemistry (GAC) is crucial for advancing sample pretreatment. In this work, we developed a green in-tube solid-phase microextraction (IT-SPME) material utilizing non-toxic cyclodextrin and zwitterionic polymers as co-functioning monomers. The hybrid monolithic material was synthesized within 38 min via an efficient epoxy ring-opening reaction and free radical polymerization. Comprehensive characterization confirmed a rigid framework with strong anti-swelling properties, good permeability, and high enrichment efficiency on the polymers. When coupled with HPLC-UV, the optimized IT-SPME method enabled highly sensitive detection of polypeptides (vancomycin and teicoplanin) in aqueous matrices, achieving detection limits as low as 15.0–20.0 μg L⁻¹, a wide linear range (60–800 μg L⁻¹, R² > 0.99), and good precision (RSDs = 5.9–8.2%). The prepared material demonstrated remarkable performance in real complex water samples, achieving recovery rates of up to 95.4%. Density functional theory (DFT) calculations indicated that the adsorption mechanism primarily involves hydrogen bonding and electrostatic interactions. This study presents an effective approach for the development of green chemical synthesis of extraction materials and offers a sustainable platform for monitoring trace contaminants in environmental waters. Full article

Background/Objectives: Biodegradable and pH-responsive nanocarriers using zwitterionic moieties represent a promising avenue for targeted delivery of chemotherapeutics. The present study addresses this by developing zwitterionic nanoparticles based on polylactic acid/poly(ethylene adipate) (PLA/PEAd) copolymers grafted with SBMA, designed to combine acid-triggered drug release with stealth-like biocompatibility. Methods: A series of polylactic acid/poly(ethylene adipate) (PLA/PEAd) copolymers with varying compositions (95/5, 90/10, and 75/25 w/w) were synthesized via ring-opening polymerization, followed by controlled radical grafting of the zwitterionic monomer [2-(Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA), which was then successfully grafted upon their backbone. The resulting zwittenionic copolymers were thoroughly characterized for their structural and physicochemical properties, displaying tunable molecular weights of 3200–4900 g/mol, enhanced hydrophilicity and controlled degradation, with mass loss ranging from 8% to 83% over 30 days, depending on PEAd content and pH. Paclitaxel-loaded nanoparticles of spherical shape with sizes ranging from 220 to 565 nm were then fabricated. Drug release was pH-dependent with significantly higher release at pH 5.0 (up to ~79% for PLAPEAd7525-SBMA) compared to pH 7.4 (~18–35%). Hemolysis assays demonstrated excellent hemocompatibility, and cytotoxicity studies showed strong anticancer activity (>80% cell death in MDA-MB-231) with lower toxicity toward iMEFs, especially for PEAd-rich formulations. Conclusions: Our findings underline the potential of SBMA-functionalized PLA/PEAd nanoparticles as effective nano-carriers for tumor-targeted chemotherapy. Full article

This paper comprehensively reports experimental proof of parity violation in the ground and photoexcited states of three mirror-symmetric Si–Si bond polymers in homogeneous solutions of achiral molecules under non-stirring conditions by analyzing 370 chiroptical datasets relating to multiple second-order helix–helix transitions in the circular dichroism (CD) of poly(di-i-butylsilane) (iBS), poly(di-i-pentylsilane) (iPS), and poly(di-i-hexylsilane) (iHS) in achiral alkanols and p-dioxane-h₈/-d₈. Particularly large (–)-CD of g_abs = −3.1 × 10⁻² at 290 nm was found for iBS in i-pentanol at 25 °C. Notably, iPS in n-propanol at −5 °C generated (–)-CD with g_abs = −0.48 × 10⁻² at 300 nm, but (+)-circularly polarized luminescence (CPL) with g_lum = +0.84 × 10⁻² at 326 nm. In contrast, iHS in n-octanol at 0 °C showed only very weak (–)-CD of g_abs ~−0.03 × 10⁻² at 310 nm. The H/D isotopes of p-dioxane-h₈/-d₈ weakly affected the helix–helix transition characteristics of iBS. (–)-Sign vibrational CD signals assigned to the handed symmetric and asymmetric bending modes of the CH₃ and CH₂ groups of the solvents and other achiral molecules were observed. We assumed (i) three ¹H nuclear-spin-1/2 induced handed motions of CH₃ rotors at i-alkyl side chains and achiral alkanols, and (ii) helical main-chain Si atoms (δ⁺) coordinated by handed lone pairs at oxygen (δ⁻) in gauche-containing n- and i-alkanols induced by the CH₃ rotors. A possible origin of biomolecular handedness is proposed based on the first observation of far-UV CD and UV spectra of zwitterionic glycine bearing H₃N⁺ rotor in neutral H₂O. Full article

The development of high-performance sensing materials is critical for advancing bioelectronics. Conductive hydrogels, with their unique flexibility, are promising candidates for biomedical sensors. However, traditional conductive hydrogels often suffer from excessive swelling and undesirable antibacterial activity, limiting their practical use. To overcome these challenges, anti-swelling, antibacterial, and ionically conductive hydrogels were built through free radical polymerization. The preparation was conducted using a monomer mixture comprising acrylic acid (AA), the antibacterial zwitterionic compound [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA), and the hydrophobic monomer lauryl methacrylate (LMA). The protonation of SBMA by AA enables electrostatic repulsion, thereby imparting anti-swelling properties to the hydrogel. The introduction of hydrophobic LMA components further enhances the anti-swelling and mechanical performance of hydrogel. The resulting hydrogel exhibits excellent anti-swelling property with a swelling ratio of 59.36% after 120 h and good mechanical performance with a tensile strength of 158 kPa, an elongation at break of 176%, and a compressive strength of 0.37 MPa at 80% strain. In addition, hydrogels possess superior sensing performance for strain sensing with a gauge factor of 1.315 within 40–60% of strain, 330 ms of response time, and 177 ms of recovery time. Furthermore, the hydrogel is capable of monitoring human motion and physiological signals. These attributes make it highly suitable for wearable sensors and biomedical monitoring applications. Full article

Sulfur-containing heterocyclic structures play an important role in modern biotechnology. Their synthesis is made possible by means of the hetero Diels–Alder reaction involving unsaturated sulfur compounds. In the framework of this paper, the molecular mechanism of the cycloaddition reactions between tioanalogs of the butadiene generated in situ with the participation of the Lawesson reagent and the E-2-phenyl-1-nitroethene was evaluated on the basis of the DFT quantum chemical calculations. It was found that the most favored reaction path is realized according to a stepwise mechanism with the participation of the zwitterionic intermediate. To study this further, the molecular mechanism of the deamination process of the primary cycloadducts was also analyzed. It was found that this mechanism is substantially different to the case of other known β-elimination processes and is achieved via a stepwise scheme. In addition to these investigations, the LA catalysis of the deamination process was also explored. Full article

Building on the early investigation by Sidney W. Fox that dry-heated amino acids can spontaneously form microspheres, this research studies the self-organization of glycine and alanine with hydrogen in a liquid system. This study aimed to investigate the spontaneous formation of membraneless, microscale amino acid assemblies under simulated prebiotic hydrothermal conditions, such as hot mineral sources and ponds. Aqueous solutions of glycine and alanine were prepared in a hydrogen-rich mineral buffer and thermally incubated at 75 °C. Phase-contrast microscopy, transmission electron microscopy (TEM), and molecular modeling were employed to analyze the morphology and internal organization of the resulting structures. Microscopy revealed that zwitterionic glycine and alanine spontaneously self-organize into spherical microspheres (~12 µm), in which the charged –NH₃⁺ and –COO⁻ groups orient outward, while the hydrophobic methyl groups of alanine point inward, forming a stabilized internal core. The primary studies were performed with hot mineral water from Rupite, Bulgaria, at 73.4 °C. The resulting osmotic pressure difference Δπ ≈ 2490 Pa, derived from the van’t Hoff equalization. This suggests a chemically asymmetric system capable of sustaining directional water flux and passive molecular enrichment. The zwitterionic nature of glycine and alanine, which possesses both –NH₃⁺ and –COO⁻ groups, supports the formation of microspheres in our experiments. Under conditions with hot mineral water and hydrogen acting as a reducing agent in the primordial atmosphere, these amino acids self-organized into dense interfacial microspheres. These findings support the idea that thermally driven, zwitterion-mediated aggregation of simple amino acids, such as glycine and alanine, with added hydrogen, could generate membraneless, selectively organized microenvironments on the early Earth. Such microspheres may represent a plausible intermediate between dispersed organisms and microspheres. Full article

Addressing the challenge of sulfonated lignite (SL) removal from oilfield wastewater, this study introduces a novel hierarchical MgFe-layered double hydroxide (LDH) adsorbent. The material was fabricated via in situ co-precipitation, utilizing a template formed by the NaCl-induced co-assembly of oleylaminopropyl betaine (OAPB) and sodium dodecyl sulfate (SLS) into zwitterionic, anionic, shear-responsive viscoelastic gels. This gel-templating approach yielded an LDH structure featuring a hierarchical pore network spanning 1–80 nm and a notably high specific surface area of 199.82 m²/g, as characterized by SEM and BET. The resulting MgFe-LDH demonstrated exceptional efficacy, achieving a SL removal efficiency exceeding 96% and a maximum adsorption capacity of 90.68 mg/g at neutral pH. Adsorption kinetics were best described by a pseudo-second-order model (R² > 0.99), with intra-particle diffusion identified as the rate-determining step. Equilibrium adsorption data conformed to the Langmuir isotherm, signifying monolayer uptake. Thermodynamic analysis confirmed the process was spontaneous (ΔG < 0) and exothermic (ΔH = −20.09 kJ/mol), driven primarily by electrostatic interactions and ion exchange. The adsorbent exhibited robust recyclability, maintaining over 79% of its initial capacity after three adsorption–desorption cycles. This gel-directed synthesis presents a sustainable pathway for developing high-performance adsorbents targeting complex contaminants in oilfield effluents. Full article

The reaction of the bulky ligand 1,2-bis-(di-tert-butylphosphinomethyl)benzene, 1 with [Ni(DME)Cl₂], 3, DME = 1,2-dimethoxyethane, at room temperature over extended periods, affords the new blue Zwitterionic complex [2-(C₆H₄-CH₂P(H)^tBu₂-1-(CH₂P^tBu₂NiCl₃)], 4, which contains a phosphonium group and an anionic nickel trichloride. This complex decomposes in alcohols such as methanol and the solution turns yellow. A discussion of the possible mechanism leading to the observed product is presented. Key to this is identification of the source of the phosphonium proton, which we speculated to arise from trace water in the initial nickel complex. To prove that trace water was present in [Ni(DME)Cl₂], a sample of this precursor was reacted under similar condition with anhydrous DMF alone. In addition to the known complex [Ni(DMF)₆)]²⁺[NiCl₄]²⁻, 5, we identified the trans-diaqua complex [Ni(Cl)₂(H₂O)₂(DMF)₂], 6, which proved the presence of trace water. Interestingly in dimethylformamide, [2-(C₆H₄-CH₂P(H)^tBu₂-1-(CH₂P^tBu₂NiCl₃)] exhibits thermochromic properties: an solution that is pale blue at ambient temperature reversibly changes colour to yellow upon cooling. This behaviour is specific to DMF and is related to the solvato-chromic behaviour exhibited by related DMF–nickel complexes. A discussion of the NMR spectra of compound 4 in a range of solvents is presented. The structures of the previously prepared molybdenum complex, [1,2-(C₆H₄-CH₂P^tBu₂)₂Mo(CO)₄] and the bis-(phosphine sulphide) of the ligand, [1,2-(C₆H₄-H₂P(S)^tBu₂)₂], 5, are described for structural comparative purposes. Full article

Background/Objectives: Army Liposome Formulation with QS21 (ALFQ) is a vaccine adjuvant formulation consisting of liposomes that contain saturated zwitterionic and anionic phospholipids, 55 mol% cholesterol, and small molar amounts of monophosphoryl lipid A (MPLA) and QS21 saponin as adjuvants. A unique aspect of ALFQ is that after addition of QS21 to nanoliposomes (<100 nm), the liposomes self-assemble through fusion to form giant (≥1000 nm) unilamellar vesicles (GUVs). The purpose of this study was to introduce and investigate new intermediate structures in the fusion process that we term tethered incomplete microspheres (TIMs), which were discovered by us incidentally as structures that were visible by phase contrast microscopy. Methods: Differential centrifugation; phase contrast microscopy; confocal microscopy of vesicles or TIMs which contain fluorescent chromophores linked to phospholipids or cholesterol; ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis of lipid components of liposomes and TIMs; and dynamic light scattering were all used for the characterization of TIMS. Results and Conclusions: (A) Sizes of TIMs range from overall aggregated structural sizes of ~1 µm to mega sizes of ≥200 µm. (B) Stable TIM structures occur when a fusion process is stopped by depletion of a fusogenic lipid during an evolving fusing of a lipid bilayer membrane. (C) TIMs consist of long-term stable (>2 years), but also metastable, tightly aggregated tear-drop or spherical incomplete GUVs tethered to visible masses of underlying vesicles that are not individually visible. (D) The TIMs and GUVs all contain phospholipid and cholesterol (when present) as bulk lipids. (E) Lyophilized liposomes lacking QS21 saponin, but which still contain MPLA (ALF55lyo), also self-assemble to form GUVs and TIMs. (F) Cholesterol is a required component in nanoliposomes for generation of GUVs and TIMs by addition of QS21. (G) Cholesterol is not required for production of GUVs and TIMs in ALFlyo, but cholesterol greatly reduces and narrows the polydisperse vesicle distribution. Full article