Cationic Counterparts Research Articles

Enhancing adoptive T-cell therapy with fucoidan-based IL-2 delivery microcapsules.

Adoptive cell therapy (ACT) with antigen-specific T cells is a promising treatment approach for solid cancers. Interleukin-2 (IL-2) has been utilized in boosting the efficacy of ACT. However, the clinical applications of IL-2 in combination with ACT is greatly limited by short exposure and high toxicities. Herein, a complex coacervate was designed to intratumorally deliver IL-2 in a sustained manner and protect against proteolysis. The complex coacervate consisted of fucoidan, a specific IL-2 binding glycosaminoglycan, and poly-l-lysine, a cationic counterpart (FPC2). IL-2-laden FPC2 exhibited a preferential bioactivity in ex vivo expansion of CD8+T cells over Treg cells. Additionally, FPC2 was embedded in pH modulating injectable gel (FPC2-IG) to endure the acidic tumor microenvironment. A single intratumoral administration of FPC2-IG-IL-2 increased expansion of tumor-infiltrating cytotoxic lymphocytes and reduced frequencies of myeloid populations. Notably, the activation and persistency of tumor-reactive T cells were observed only in the tumor site, not in the spleen, confirming a localized effect of FPC2-IG-IL-2. The immune-favorable tumor microenvironment induced by FPC2-IG-IL-2 enabled adoptively transferred TCR-engineered T cells to effectively eradicate tumors. FPC2-IG delivery system is a promising strategy for T-cell-based immunotherapies.

The in vitro photo-sonodynamic combinatorial therapy activity of cationic and zwitterionic phthalocyanines on MCF-7 and HeLa cancer cell lines

The syntheses and characterization studies of zwitterionic 2,9,16,23-tetrakis-(N-propane sultone-morpholino) zinc(II) (4) and 2,9,16,23-tetrakis-(2,5-dimethyl-4-(N-propane sultone-morpholinomethyl))-phenoxy zinc(II) (6) phthalocyanines are reported in this work. The photophysical properties, reactive oxygen species (ROS) generation and in vitro anticancer photodynamic (PDT), sonodynamic (SDT), and photo-sonodynamic combination (PSDT) therapy activities of the Pcs were studied and compared to their cationic counterparts: (2,9,16,23-tetrakis-(N-methyl-morpholino) Zn(II)Pc, 3), (2,9,16,23-tetrakis-(2,5-dimethyl-4-(N-methylmorpholine)-phenoxy) Zn(II)Pc, 5). The cationic Pcs maintained higher anticancer activity for all treatment types and had higher ROS generation compared to the zwitterionic Pcs. Singlet oxygen and hydroxyl radicals were generated during ultrasound and combination irradiations of the Pcs. The zwitterionic Pcs also generated carbon radicals under ultrasound and combination irradiations. The ability of the Pcs to generate ROS is essential for PDT, SDT and PSDT, thus making these Pcs potential anticancer probes for these treatment types. Furthermore, the Pcs demonstrated the ability to bind to bovine serum albumin protein.

Above 23% Efficiency by Binary Surface Passivation of Perovskite Solar Cells Using Guanidinium and Octylammonium Spacer Cations

One of the important factors in the performance of perovskite solar cells (PSCs) is effective defect passivation. Dimensional engineering technique is a promising method to efficiently passivate non‐radiative recombination pathways in the bulk and surface of PSCs. Herein, a passivation approach for the perovskite/hole transport layer interface is presented, using a mixture of guanidinium and n‐octylammonium cations introduced via GuaBr and n‐OABr. The dual‐cation passivation layer can provide an open‐circuit voltage of 1.21 V with a power conversion efficiency of 23.13%, which is superior to their single cation counterparts. The mixed‐cation passivation layer forms a 1D/2D perovskite film on top of 3D perovskite, leading to a more hydrophobic and smoother surface than the uncoated film. A smooth surface can diminish non‐radiative recombination and enhance charge extraction at the interface making a better contact with the transport layer, resulting in improved short‐circuit current. In addition, space charge‐limited current measurements show a three times reduction in the trap‐filled limit voltage in the mixed‐cation passivated sample compared with unpassivated cells, indicating fewer trapped states. The shelf‐life stability test in ambient atmosphere with 60% relative humidity as well as light‐soaking stability reveal the highest stability for the dual‐cation surface passivation.

Plasma-Assisted Dinitrogen Activation via Dual Platinum Cluster Catalysis: A Strategy for Ammonia Synthesis under Mild Conditions

Plasma-Assisted Dinitrogen Activation via Dual Platinum Cluster Catalysis: A Strategy for Ammonia Synthesis under Mild Conditions

Synthesis and characterization of carnitine-based ionic liquids and their evaluation as additives in cyclodextrin-electrokinetic chromatography for the chiral separation of thiol amino acids

In this study, new chiral ionic liquids based on the non-protein amino acid L-carnitine as cationic chiral counterpart and several anions (bis(trifluoromethane)sulfonimide (NTf2−), L-lactate− or Cl−) as counterions were synthesized. Moreover, three different salts based on L-carnitine were also synthesized and the other three were commercially acquired and used for comparison. The synthesized ionic liquids and salts were characterized by nuclear magnetic resonance, fourier transform infrared spectroscopy, high-performance liquid chromatography-mass spectrometry, and elemental analysis. Subsequently, they were used as additives to establish a γ-CD-based dual system for the enantiomeric separation of cysteine and homocysteine (previously derivatized with fluorenylmethoxycarbonyl chloride) by capillary electrokinetic chromatography. The effect of the nature of the anionic counterions and the presence of different substituents on the L-carnitine molecule on the chiral separation of both amino acids was investigated. The enantioseparations obtained with each dual system studied were compared in terms of the enantiomer effective mobilities (μeff) and the effective electrophoretic selectivity (αeff). Practically, all the dual systems evaluated exhibited substantially improved enantioseparations for the two amino acids compared with the single γ-CD system.

Influence of co‐neutralization by sodium and zinc on the ethylene ionomer structure and properties

AbstractThis study investigates the properties and structure of poly(ethylene‐co‐methacrylic acid) (EMAA) ionomers co‐neutralized by zinc and sodium, and compares them with ionomers neutralized by a single metal: zinc (EMAA‐Zn) and sodium (EMAA‐Na). The bending stiffness and the degree of crystallization for the co‐neutralized ionomer (Na:Zn = ~1:1 on a molar basis) gives 16.5% and 9.8% increase compared to the simple average of their single cation counterparts. Such unusual properties are seen in mechanical, thermal, and rheological properties and water uptake rate in this study. Infrared spectra of the co‐neutralized ionomer shows changes at the carboxylate antisymmetric stretching band, which correspond to the formation of carboxylates bridging zinc and sodium ions. X‐ray scattering identified that the number density of ionic multiplets for the co‐neutralized ionomers are equivalent to EMAA‐Na and ~ 1.7 times higher than EMAA‐Zn. The fraction of side groups forming ionic multiplets, β, in co‐neutralized ionomers were 0.7–0.8, close to EMAA‐Na (1.0) and higher than EMAA‐Zn (0.3), indicating that sodium promote zinc to form ionic multiplets. The synergistic properties induced by co‐neutralization are ascribed not only to a formation of new ionic multiplets where both cations are included but also to the change in the number density of ionic multiplets.

Rapid Synthesis of Metal Nanoparticles Using Low-Temperature, Low-Pressure Argon Plasma Chemistry and Self-Assembly.

The synthesis of metal nanoparticles has become a priority for the advancement of nanotechnology. In attempts to create these nanoparticles, several different methods: chemistry, physics, and biology, have all been used. In this study, we report the reduction of cations using argon plasma chemistry to produce nanoparticles of gold (AuNPs), silver (AgNPs), and copper (CuNPs). Although other groups have used plasma-reduction methods to synthesize metal nanoparticles from their cation counterparts, these approaches often require plasma|liquid state interactions, high temperature, specific combinations of gases, and extended treatment times (>10 minutes), for which only specific cations (noble or non-noble) may be reduced. As a result, we have developed a non-thermal, low-pressure argon-plasma|solid state approach for the reduction of both noble and non-noble cations. More specifically, when 50-μL droplets of 2-mM solutions of gold(III) chloride, silver nitrate, or copper(II) sulfate are exposed to vacuum, they undergo an evaporation process. As the pressure in the chamber decreases to 220 mtorr, the droplets become completely evaporated, leaving behind a metal precursor. Nucleation and growth studies reveal that when the metal precursors of gold(III) chloride, silver nitrate, and copper(II) sulfate are treated with 80 watts of argon plasma for 5, 60, and 150 seconds, respectively, nanoparticles could be synthesized with efficiency rates of upwards of 98%. The size of nanoparticles synthesized in this work was studied using Scanning Electron Microscopy, and the scattering properties of the nanoparticles was studied using UV/Vis spectroscopy. Transmission Electron Microscopy with corresponding elemental analysis was also very useful in confirming the identity of the synthesized nanoparticles. The results from this study reveal that we have synthesized metal nanoparticles with distinct chemical and physical properties. Scanning Electron Microscopy depicts AgNPs with a round-shape and diameters from 40 - 80 nm, while AuNPs were hexagonal, with sizes from 40 - 80 nm, and CuNPs were rod-shaped, with dimensions 40 by 160 nm. Our findings demonstrate that the argon plasma approach used in this study is a rapid, green, and versatile reduction method for the synthesis of both noble and non-noble metal nanoparticles.

Zero area thermal expansion of honeycomb layers via double distortion relaxation in (PPh4)[Cu2(CN)3

The zero area TE of cyanide-bridged honeycomb layers occurs by complementary structural changes in the cation and anion counterparts.

Be2H3L2− (L=CH3 and F–I): Hyperhalogen anions with ultrashort beryllium-beryllium distances

The superalkali cations and superhalogen anions commonly have different type of core moieties. Based on the previous reports that Be2H3L′2+ (L′=NH3 and noble gases Ne–Xe) are superalkali cations, in the present work, we designed the superhalogen anions Be2H3L2− (L=CH3 and halogens F–I), and both superalkali cations and superhalgen anions can be constructed using Be2H3 as the core moiety. The newly designed Be2H3L2− species are much more stable than their isoelectronic cationic counterparts Be2H3L′2+, as can be reflected by the highly exergonic substitution reaction of L′ ligand in Be2H3L′2+ with isoelectronic L− to give Be2H3L2−. These anionic species possess the well-defined electronic structure, which can be proven by their large HO-MO–LUMO gaps of 4.69 eV to 5.38 eV. It is remarkable that Be2H3L2− can be regarded as the hyperhalogen anions due to the extremely high vertical detachment energies (5.38 eV to 6.06 eV) and the Be–Be distances in these species (1.776 Å to 1.826 Å) are short in ultrashort metal-metal distances (defined as dM–M<1.900 Å) between main group metals. In the designed five small model species, three of them, i.e. Be2H3L2− (L=CH3, Cl, and Br), are kinetical viable global energy minima, which are the promising target for generation and characterization in anion photoelectron spectroscopy. The analogue molecule [t-Bu–Be2H3–t-Bu]− with bulky protecting tert-butyl (t-Bu) groups is designed as a possible target for synthesis and isolation in condensed states.

Zwitterionic Phospholipidation of Cationic Polymers Facilitates Systemic mRNA Delivery to Spleen and Lymph Nodes.

Polymers represent a promising therapeutic platform for extrahepatic messenger RNA (mRNA) delivery but are hampered by low in vivo efficacy due to polyplex serum instability and inadequate endosomal escape following systemic administration. Here, we report the rational design and combinatorial synthesis of zwitterionic phospholipidated polymers (ZPPs) via cationic polymer postmodification by alkylated dioxaphospholane oxides to deliver mRNA to spleen and lymph nodes in vivo. This modular postmodification approach readily produces tunable zwitterionic species for serum resistance and introduces alkyl chains simultaneously to enhance endosomal escape, thereby transforming deficient cationic polymers to efficacious zwitterionic mRNA carriers without the need to elaborately synthesize functional monomers. ZPPs mediated up to 39 500-fold higher protein expression than their parent cationic counterparts in vitro and enabled efficacious mRNA delivery selectively in spleen and lymph nodes following intravenous administration in vivo. This zwitterionic phospholipidation methodology provides a versatile and generalizable postmodification strategy to introduce zwitterions into the side chains of cationic polymers, extending the utility of cationic polymer families for precise mRNA delivery and demonstrating substantial potential for immunotherapeutic applications.

Cationization to boost both type I and type II ROS generation for photodynamic therapy

The pursuing of photosensitizers (PSs) with efficient reactive oxygen species (ROS) especially type I ROS generation in aggregate is always in high demand for photodynamic therapy (PDT) and photoimmunotherapy but remains to be a big challenge. Herein, we report a cationization molecular engineering strategy to boost both singlet oxygen and radical generation for PDT. Cationization could convert the neutral donor-acceptor (D-A) typed molecules with the dicyanoisophorone-triphenylamine core (DTPAN, DTPAPy) to their A-D-A′ typed cationic counterparts (DTPANPF6 and DTPAPyPF6). Our experiment and simulation results reveal that such cationization could enhance the aggregation-induced emission (AIE) feature, promote the intersystem crossing (ISC) processes, and increase the charge transfer and separation ability, all of which work collaboratively to promote the efficient generation of ROS especially hydroxyl and superoxide radicals in aggregates. Moreover, these cationic AIE PSs also possess specific cancer cell mitochondrial targeting capability, which could further promote the PDT efficacy both in vitro and in vivo. Therefore, we expect this delicate molecular design represents an attractive paradigm to guide the design of type I AIE PSs for the further development of PDT.

Cucurbit[7]uril-threaded flexible organic frameworks: Quantitative polycatenation through dynamic covalent chemistry

A three-dimensional flexible organic framework FOF-1 has been synthesized from the condensation of a tetratopic acylhydrazine and a rigid 4,4′-diphenyl-4,4′-bipyridinium dialdehyde in water through the quantitative formation of hydrazone bond. FOF-1 is further applied to construct a polycatenane framework FOF-pc-1 through the quantitative cucurbit[7]uril encapsulation for the diphenylbipyridinium subunits of the framework by making use of the dynamic nature of the hydrazone bond in water. The bipyridinium subunits in both frameworks can be reduced their radical cation counterparts to produce conjugated radical cation-linked dynamic organic frameworks rc-FOF-1 or rc-FOF-pc-1. Polycatenation is revealed to enhance the stability of the dynamic frameworks in water, whereas depolycatenation can be reached for both FOF-pc-1 and rc-FOF-pc-1 by using a ferrocene guest to form a more stable complex with CB[7].

Transport properties and solvation state of magnesium salts dissolved in propylene carbonate and [formula omitted]-butyrolactone: A comparison with monovalent cation counterparts

We experimentally measured the conductivity and viscosity of non-aqueous solutions of magnesium electrolytes; Mg(TFSA)2 (TFSA = bis(trifluoromethanesulfonyl) amide) and Mg(ClO4)2 dissolved in propylene carbonate (PC) and γ-butyrolactone (GBL) up to the concentration of m/molkg-1=1.4-1.7 in the temperature range 288⩽T/K⩽328. With the previously obtained results, the matrix of experimental data, comprising three cations (Mg2+, Li+, Na+), two anions (ClO4-, TFSA−) and two solvents (PC, GBL), enables a systematic comparison of their transport properties. Raman spectra of Mg(TFSA)2, LiTFSA, and NaTFSA dissolved in GBL yield the solvation state of each cation, suggesting that the GBL molecules solvating Mg2+ are classified into tightly and less tightly bound states. The lattice gas Monte-Carlo simulation of conductivity quantitatively explains well the reason why the divalent cation systems are less conductive than the monovalent ones; namely, the negative effect of the strong inter-ionic interaction of Mg2+ overwhelms the positive effect of the high valence, because the former effect exponentially attenuates the conductivity while the latter is merely proportional to the harmonic mean valence of the salt. The simulation revealed that, in a hypothetical scenario wherein the long-range interactions are absent, the conductivity is dominantly determined by the solvent. Consequently, the solvent-specific upper limit of the conductivity is predicted for PC and GBL.

Quantitative Account of the Bonding Properties of a Rubredoxin Model Complex [Fe(SCH3)4]q, q = −2, −1, +2, +3

Iron-sulfur clusters play important roles in biology as parts of electron-transfer chains and catalytic cofactors. Here, we report a detailed computational analysis of a structural model of the simplest natural iron-sulfur cluster of rubredoxin and its cationic counterparts. Specifically, we investigated adiabatic reduction energies, dissociation energies, and bonding properties of the low-lying electronic states of the complexes [Fe(SCH3)4]2-/1-/2+/3+ using multireference (CASSCF, MRCISD), and coupled cluster [CCSD(T)] methodologies. We show that the nature of the Fe-S chemical bond and the magnitude of the ionization potentials in the anionic and cationic [Fe(SCH3)4] complexes offer a physical rationale for the relative stabilization, structure, and speciation of these complexes. Anionic and cationic complexes present different types of chemical bonds: prevalently ionic in [Fe(SCH3)4]2-/1- complexes and covalent in [Fe(SCH3)4]2+/3+ complexes. The ionic bonds result in an energy gain for the transition [Fe(SCH3)4]2- → [Fe(SCH3)4]- (i.e., FeII → FeIII) of 1.5 eV, while the covalent bonds result in an energy loss for the transition [Fe(SCH3)4]2+ → [Fe(SCH3)4]3+ of 16.6 eV, almost half of the ionization potential of Fe2+. The ionic versus covalent bond character influences the Fe-S bond strength and length, that is, ionic Fe-S bonds are longer than covalent ones by about 0.2 Å (for FeII) and 0.04 Å (for FeII). Finally, the average Fe-S heterolytic bond strength is 6.7 eV (FeII) and 14.6 eV (FeIII) at the RCCSD(T) level of theory.

Neutral Re(I) Complex Platform for Live Intracellular Imaging.

Luminescent metal complexes are a valuable platform for the generation of cell imaging agents. However, many metal complexes are cationic, a factor that can dominate the intracellular accumulation to specific organelles. Neutral Re(I) complexes offer a more attractive platform for the development of bioconjugated imaging agents, where charge cannot influence their intracellular distribution. Herein, we report the synthesis of a neutral complex (ReAlkyne), which was used as a platform for the generation of four carbohydrate-conjugated imaging agents via Cu(I)-catalyzed azide-alkyne cycloaddition. A comprehensive evaluation of the physical and optical properties of each complex is provided, together with a determination of their utility as live cell imaging agents in H9c2 cardiomyoblasts. Unlike their cationic counterparts, many of which localize within mitochondria, these neutral complexes have localized within the endosomal/lysosomal network, a result consistent with examples of dinuclear carbohydrate-appended neutral Re(I) complexes that have been reported. This further demonstrates the utility of these neutral Re(I) complex imaging platforms as viable imaging platforms for the development of bioconjugated cell imaging agents.

Electron binding energies and Dyson orbitals of OnH2n+1 +,0,- clusters: Double Rydberg anions, Rydberg radicals, and micro-solvated hydronium cations.

Ab initio electron propagator methods are employed to predict the vertical electron attachment energies (VEAEs) of OH3 +(H2O)n clusters. The VEAEs decrease with increasing n, and the corresponding Dyson orbitals are diffused over exterior, non-hydrogen bonded protons. Clusters formed from OH3 - double Rydberg anions (DRAs) and stabilized by hydrogen bonding or electrostatic interactions between ions and polar molecules are studied through calculations on OH3 -(H2O)n complexes and are compared with more stable H-(H2O)n+1 isomers. Remarkable changes in the geometry of the anionic hydronium-water clusters with respect to their cationic counterparts occur. Rydberg electrons in the uncharged and anionic clusters are held near the exterior protons of the water network. For all values of n, the anion-water complex H-(H2O)n+1 is always the most stable, with large vertical electron detachment energies (VEDEs). OH3 -(H2O)n DRA isomers have well separated VEDEs and may be visible in anion photoelectron spectra. Corresponding Dyson orbitals occupy regions beyond the peripheral O-H bonds and differ significantly from those obtained for the VEAEs of the cations.

CO2 Chemisorption Behavior of Coordination-Derived Phenolate Sorbents.

CO2 chemisorption via C-O bond formation is an efficient methodology in carbon capture especially using phenolate-based ionic liquids (ILs) as the sorbents to afford carbonate products. However, most of the current IL systems involve alkylphosphonium cations, leading to side reactions via the ylide intermediate pathway. It is important to figure out the CO2 chemisorption behavior of phenolate-derived sorbents using inactive and easily accessible cation counterparts without active protons. Herein, phenolate-based systems were constructed via coordination between alkali metal cations with crown ethers to avoid the participation of active protons in CO2 chemisorption. Reaction pathway study revealed that CO2 uptake could be achieved by O-C bond formation to afford carbonate. CO2 uptake capacity and reaction enthalpy were significantly influenced by the coordination effect, alkali metal types, and alkyl groups on the benzene ring.

An insight into the supramolecular interactions in two linear polyvanadates

Two polymeric [VO3]nn− metavanadate chain complexes have been synthesized and characterized by spectral and elemental analysis. The X-ray data of only complex 2 has been reported in this work. Both the complexes have a linear vanadate chain, countered by appropriately charged organic amine moieties. The simplest units of the chains contain a linear [V3O9]3− and [V2O6]2− anionic moieties in complexes 1 and 2, respectively. The charge neutralizing cationic counterparts are triprotonated tren {tris(2-aminoethyl)amine} and a diprotonated N-ethylethylenediamine in complexes 1 and 2, respectively. Complex 2 is unique in the sense that its crystal lattice contains the divanadate [V2O6]2− repeat unit and protonated N-ethylethylenediamine as the charge compensating and space filling moiety which is not reported in any other literature till now. The individual units are assembled to form a 2D supramolecular network. DFT calculations (PBE0-D3/def2-TZVP) have been used in combination to QTAIM and NCI plot computational tools to analyze the strong N–H···O charge assisted hydrogen bonding interactions in both complexes. Phenoxazinone synthase like activity (i.e. oxidative conversion of o-aminophenol to 2-aminophenoxazine-3-one) of complex 2 was evaluated.

Loading and Release of Charged and Neutral Fluorescent Dyes into and from Mesoporous Materials: A Key Role for Sensing Applications.

The aim of this study is to determine the efficiency of loading and release of several zwitterionic, neutral, anionic and cationic dyes into/from mesoporous nanoparticles to find the optimum loading and release conditions for their application in detection protocols. The loading is carried out for MCM-41 type silica supports suspended in phosphate-buffered saline (PBS) buffer (pH 7.4) or in acetonitrile, involving the dyes (rhodamine B chloride, rhodamine 101 chloride, rhodamine 101 perchlorate, rhodamine 101 inner salt, meso-(4-hydroxyphenyl)-boron–dipyrromethene (BODIPY), sulforhodamine B sodium salt and fluorescein 27). As a general trend, rhodamine-based dyes are loaded with higher efficiency, when compared with BODIPY and fluorescein dyes. Between the rhodamine-based dyes, their charge and the solvent in which the loading process is carried out play important roles for the amount of cargo that can be loaded into the materials. The delivery experiments carried out in PBS buffer at pH 7.4 reveal for all the materials that anionic dyes are more efficiently released compared to their neutral or cationic counterparts. The overall best performance is achieved with the negatively charged sulforhodamine B dye in acetonitrile. This material also shows a high delivery degree in PBS buffer.

DNA-Chitosan Hydrogels: Formation, Properties, and Functionalization with Catalytic Nanoparticles.

DNA-chitosan (DNA-CS) hydrogels were prepared on the basis of interpolyelectrolyte complexes (IPEC) in a co-assembled regime by in situ charging of the polysaccharide in a DNA solution. In contrast to poorly controlled coacervates formed upon mixing of DNA and CS solutions, stable DNA-CS IPEC hydrogels are formed at near-stoichiometric ratios of DNA and chitosan ionogenic groups. Structure, stability, and ion absorption properties of such hydrogels depended strongly on the ratio between cationic (CS) and anionic (DNA) counterparts in hydrogels. Abundant amino- and nitrogen-containing aromatic groups of co-assembled DNA and CS make their hydrogel an efficient, multitarget absorbent toward metal ions. Such strong affinity of both DNA and CS to Au3+ cation was used to entrap Au3+ ions into the DNA-CS hydrogels. Subsequent reduction of Au3+ ion inside hydrogels resulted in the formation of ∼2-3 nm size Au nanoparticles on DNA-CS scaffolds. Metallized hydrogels demonstrated catalytic activity in reduction of various nitroaromatics that depended on the ratio between CS and DNA in the hydrogel.