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Nuclear medicine specialty involves the administration of unsealed radioactive substances to patients to allow specific diagnostics and treatments using radiopharmaceuticals, radiotracers, and materials. Developing a radiopharmaceutical must involve considering and addressing some limitations such as its retention by unintended organs, which can influence patient and worker safety, imaging findings, and diagnostic and therapeutic accuracy. This paper presents data on the changing biodistribution, localization, stability, and accuracy patterns of radiopharmaceuticals by liposome encapsulation., Methods: Data are presented for 5 male New Zealand white rabbits. They were injected intravenously with the 99m Tc-liposomes encapsulated MIBI through a marginal ear vein, and whole-body images were acquired using a dual-head gamma camera. Cationic PEGylated liposomes were prepared using the conventional thin-film-hydration method. The liposomes were tested for particle size, zeta potential, high-performance-liquid-chromatography (HPLC), and toxicity., Results: The liver activity was slightly greater than or equivalent to heart uptake, using 99m Tcsestamibi, MIBI, without liposome as a reference. The absorbed doses in myocardium cells after injecting rabbits with 99m Tc-MIBI labeled with free positive lower pH liposomes was greater than in the liver, whereas 99m Tc labeled with encapsulated MIBI within positive liposomes showed a significantly higher heart-to-liver ratio. The heart-to-spleen activity uptake ratio in 99m Tc-MIBI was higher than or equal to one but increased in 99m Tc labeled with MIBI and free positive liposomes. Injecting rabbits with 99m Tc labeled with encapsulated MIBI raised myocardium uptake to 2-4 times more than the spleen. Heart-to-bowel activity began to rise with 99m Tc-labeld-MIBI and liposomes., Conclusion: This study provides findings in radiopharmaceutical biodistribution using liposomal agents. Adding free liposomes using a pH gradient technique enhanced the uptake and localization of the radiotracer. However, tracer encapsulation during the formation of the liposomes showed even better specificity., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

This study presents a novel flocculant for harvesting Chlorella vulgaris as model species for freshwater microalgae based on cellulose nanocrystals (CNCs), thus synthesized from a renewable and biodegradable resource. Cationic pyridinium groups were grafted onto CNCs by two separate one-pot simultaneous esterification and nucleophilic substitution reactions. Both types of modified CNCs were positively charged in the pH range 4–11. Both reactions yielded CNCs with a high degree of substitution (up to 0.38). A maximum flocculation efficiency of 100% was achieved at a dosage of 0.1 g g −1 biomass. In contrast to conventional polymer flocculants, cationic CNCs were relatively insensitive to inhibition of flocculation by algal organic matter. The present results highlight the potential of these new type of nanocellulose-based flocculants for microalgae harvesting. [ABSTRACT FROM AUTHOR]

Previously we reported the synthesis and in vitro evaluation of four novel, short-chain cationic lipid gene delivery vectors, characterized by acyclic or macrocyclic hydrophobic regions composed of, or derived from, two 7-carbon chains. Herein we describe a revised synthesis of an expanded library of related cationic lipids to include extended chain analogues, their formulation with plasmid DNA ( p DNA) and in vitro delivery into Chinese hamster ovarian (CHO-K1) cells. The formulations were evaluated against each other based on structural differences in the hydrophobic domain and headgroup. Structurally the library is divided into four sets based on lipids derived from two 7- or two 11-carbon hydrophobic chains, C7 and C11 respectively, which possess either a dimethylamine or a trimethylamine derived headgroup. Each set includes four cationic lipids based on an acyclic or macrocyclic, saturated or unsaturated hydrophobic domain. All lipids were co-formulated with the commercial cationic lipid 1,2-dimyristoyl- sn -glycero-3-ethylphosphocholine (EPC) in a 1:1 molar ratio, along with one of two distinct neutral co-lipids, cholesterol or 1,2-dioleoyl- sn -glycero-3-phosphoethanolamine (DOPE) in an overall cationic-to-neutral lipid molar ratio of 3:2. Binding of lipid formulations with DNA, and packing morphology associated with the individual lipid–DNA complexes were characterized by gel electrophoresis and small angle X-ray diffraction (SAXD), respectively. As a general trend, lipoplex formulations based on mismatched binary cationic lipids, composed of a shorter C7 lipid and the longer lipid EPC (C14), were generally associated with higher transfection efficiency and lower cytotoxicity than their more closely matched C11/EPC binary lipid formulation counterparts. Furthermore, the cyclic lipids gave transfection levels as high as or greater than their acyclic counterparts, and formulations with cholesterol exhibited higher transfection and lower cytotoxicity than those formulated with DOPE. A number of the lipid formulations with cholesterol as co-lipid performed as well as, or better than Lipofectamine 2000™ and EPC, the two positive controls employed in these studies. These results suggest that our novel cyclic and acyclic cationic lipid vectors are effective nonviral gene transfer agents that warrant further investigation. [ABSTRACT FROM AUTHOR]

Novel cationic hydrido complexes [RuH(1,5-cod)(NH 3 )(NH 2 NMe 2 ) 2 ](X) (X = PF 6 , BPh 4 ) and chlorido-ammine complexes [RuCl(1,5-cod)(NH 3 ) 2 (NH 2 NMe 2 )](X) (X = PF 6 , BPh 4 ), were isolated from the reaction of the polymeric [RuCl 2 (1,5-cod)] x with NH 2 NMe 2 . Reaction of the hydrido complexes with the phosphine ligands PMe 3 , PMe 2 Ph, P(OMe) 2 Ph resulted in the formation of monohydrido-phosphine complexes, whereas reaction with the bulkier PMePh 2 ligand gave dihydrido-phosphine complexes. Similar reactions of the chlorido-ammine complexes with the phosphine ligands PMe 3 , PMe 2 Ph, P(OMe) 2 Ph, and PMePh 2 all sequentially substituted the NH 2 NMe 2 and the 1,5-cod ligands to give the chlorido-ammine phosphine complexes. All complexes were fully characterised and the single crystal X-ray structures were determined for [RuH{P(OMe) 2 Ph} 5 ](BPh 4 ), [RuH 2 (PMePh 2 ) 4 ], [{Ru(PMe 2 Ph) 3 } 2 (μ-F) 3 ](PF 6 ), fac -[RuCl(NH 3 ) 2 (PMe 2 Ph) 3 ](PF 6 ), and [RuCl(NH 3 )(PMe 2 Ph) 4 ](PF 6 ). Intramolecular strain between coordinated σ-donor ligands in the Ru(II)-NH 2 NMe 2 precursor complexes as well as the relative steric bulk of incoming σ-donor ligands were found to be chemically directing in the formation of monohydrido-, bishydrido-, mono-ammine, and bis-ammine ruthenium(II) complexes. [ABSTRACT FROM AUTHOR]

Effective delivery of drugs to alveoli in a controlled manner using hydrophobic polymers as carriers has already been reported. Preclinical studies revealed that toxicity and hydrophobicity are related to each other in pulmonary delivery. Here, we are reporting a chemically modified dextran having amphiphilicity and cationicity achieved by controlled grafting of stearyl amine. Two proportions of lipopolymers were synthesized and physico-chemical characterization was carried out. In vivo evaluation of sub-acute toxicity of the synthesized lipopolymer in Sprague–Dawley rats was carried out for three months. This was followed by a histological evaluation of the sacrificed animal’s lung. Further, the synthesized lipopolymer was formulated with drug (Rifampicin) loaded inhalable microparticles through spray drying. The final drug formulation was tested for toxicity and proinflammatory responses in human cell lines. Dose deposition efficiency of the formulation was determined using Anderson Cascade Impactor. [ABSTRACT FROM AUTHOR]

The methyl acrylamide propyl dimethyl butyl ammonium chloride (DMAPMA-C) and allyl-β-cyclodextrin (A-β-CD) were synthesized separately and then jointly copolymerized with acrylamide (AM) to form a novel cationic acrylamide polymer P(AM/A-β-CD/DMAPMA-C) through aqueous redox free-radical polymerization. The structure of the copolymer was characterized using Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) and scanning electron microscopy (SEM). Subsequently, a series of experiments were carried out to investigate its comprehensive performances, including temperature resistance, salt tolerance, aqueous stability, and sandpack flooding experiments. In addition, the rheological properties of P(AM/A-β-CD/DMAPMA-C) were also tested and calculated. The results showed that P(AM/A-β-CD/DMAPMA-C) possessed higher salt tolerance, temperature resistance, and aqueous stability than polyacrylamide (PAM). The rheological properties also indicated its applicability for enhanced oil recovery. The copolymer could significantly increase the oil recovery of 15.47%, which indicated its potential application for enhancing oil recovery in the oilfield. [ABSTRACT FROM AUTHOR]

A novel cationic asphalt emulsifier N, N-dimethyl- N-(oxiran-2-ylmethyl)octadecan-1-aminium chloride was synthesized by reaction of epichlorohydrin and N, N-dimethyloctadecylamine. The optimum reaction condition was obtained. The yield and epoxy group value reached 98.0 and 41.8 %, respectively, at the optimum conditions: reaction temperature of 50 °C, reaction time of 5 h, and feedstock mole ratio of epichlorohydrin to N, N-dimethyloctadecylamine of 1.2. The chemical structure of the emulsifier was confirmed by Fourier-transform infrared (FTIR), H nuclear magnetic resonance (NMR), and elemental analysis. The synthesis process was monitored by the online FTIR technique. The by-product was detected by online FTIR analysis. Based upon the experimental data, a plausible reaction mechanism is proposed for the reaction. The critical micelle concentration (CMC) of the emulsifier has a lower value of 4.35 × 10 mol/L. The surface tension at CMC is 28.51 mN/m. The emulsifier exhibits satisfactory emulsification. The prepared bituminous emulsion showed higher storage stability. The emulsifier belongs to the class of medium-set asphalt emulsifiers. [ABSTRACT FROM AUTHOR]

Successful cytosolic delivery enables opportunities for improved treatment of various genetic disorders, infectious diseases and cancer. Cationic nanoemulsions were designed using alternative excipients and evaluated for particle size, charge, effect of sterilization on its stability, DNA condensation potential and cellular uptake efficiency. Various concentrations of non-ionic and ionic stabilizers were evaluated to design formula for colloidally stable cationic nanoemulsion. The nanoemulsion comprised of 5% Capmul MCM, 0.5% didodecyldimethylammonium bromide (DDAB), 1% phospholipid, 1% Poloxamer 188 and 2.25% glycerol and possessed particle size of 81.6 ± 3.56 nm and 137.1 ± 1.57 nm before and after steam sterilization, respectively. DNA condensation studies were carried out at various nanoemulsion: DNA ratios ranging from 1:1 to 10:1. Cell uptake studies were conducted on human embryonic kidney (HEK) cell lines which are widely reported for transfection studies. The nanoemulsions showed excellent cellular uptake as evaluated by fluorescence microscopy and flow cytometry. Overall, a colloidally stable cationic nanoemulsion with good DNA condensation ability was successfully fabricated for efficient cytosolic delivery and potential for in vivo effectiveness. [ABSTRACT FROM AUTHOR]

Ligands 2,6-dimethyl-N-(pyridin-2-ylmethylene)aniline C 14 H 14 N 2 ( L1 ), 2,6-dimethyl-N-(1-(pyridin-2-yl)ethylidene)aniline C 15 H 16 N 2 ( L2 ) and 2,6-diisopropyl-N-(1-(pyridin-2-yl)ethylidene)aniline C 19 H 24 N 2 ( L3 ) were obtained by condensation reactions. The reactions of CoCl 2 ·6H 2 O with the corresponding ligands L1 – L3 in the presence of the new salt methoxytris(dimethylamino)phosphonium hexafluorophosphate [CH 3 OP(NMe 2 ) 3 ] + PF 6 − afford in good yields, the complexes bis[2,6-dimethyl-N-(pyridin-2-ylmethylene)aniline]chloro cobalt(II) hexafluorophosphate C 28 H 28 ClCoF 6 N 4 P ( C1 ), bis[2,6-dimethyl-N-(1-(pyridin-2-yl)ethylidene)aniline]chlorocobalt(II) hexafluorophosphate C 30 H 32 ClCoF 6 N 4 P ( C2 ) and bis-[2,6-diisopropyl-N-(1-(pyridin-2-yl)ethylidene)aniline]chlorocobalt(II) hexafluorophosphate C 38 H 48 ClCoF 6 N 4 P ( C3 ). All new complexes C1 – C3 have been characterized by CHN analyses, 1 H, 13 C, 31 P NMR and IR spectroscopy. Solid state and electronic structures of complex C1 have been determined. [ABSTRACT FROM AUTHOR]

Surfactants with amine groups are often used in the nanoparticle synthesis due to the high affinity with Au atoms. The match of charges of a capping reagent with Au has significant influence on structures in nanoparticle synthesis. Thus we studied the adsorption of a catanionic surfactant system on Au surface. The surfactants used in the study are bis[[(amidoethyl)carbamoyl]ethyl]octadecylamine (C18N3) and arachidic acid. Three combinations of the surfactants were studied with regard to the protonation state of the amine groups and the match of charges of the surfactant headgroup. The morphology of the surfactant mixtures changes from high-curvature aggregates to low-curvature with increasing the molar ratio of arachidic acid in the mixtures or the pH of the surfactant solutions. The adsorption of the mixed surfactant systems was studied by means of scanning electron microscopy (SEM), quartz crystal microbalance (QCM) and cyclic voltammetry (CV). The results revealed that the homogeneity and the compactness of the adsorbed layer on a gold surface were increased with the molar ratio of arachidic acid in the complexes. Furthermore, we may obtain the construction of the film of the mixed surfactant on gold surface using the result obtained by QCM. [ABSTRACT FROM AUTHOR]

A single-center, open-label study consisting of two visits over the course of approximately 2 weeks was conducted to evaluate the efficacy of Retaine™ ophthalmic emulsion in improving the signs and symptoms of dry eye. Forty-two subjects were enrolled and received 1-2 drops twice daily of Retaine™ beginning at the first visit (day 1) and ending at the second visit. Subjects were instructed to complete a symptomatology diary twice daily prior to drop instillation through the morning of the second visit. Ocular sign and symptom assessments, visual acuity procedures, and comfort assessments were conducted during both visits. A statistically significant reduction was observed in mean breakup area on the second visit between the predose time and the postdose time (P=0.026). On the second visit, subjects had significantly less corneal fluorescein staining in the superior (P=0.002), central (P=0.017), corneal sum (P=0.011), and all ocular regions combined (P=0.038) than on the first visit. On the second visit, statistically significant reductions in dryness (P<0.001), grittiness (P=0.0217), ocular discomfort (P=0.0017), and all symptoms (P<0.001) were also seen as measured by the Ora Calibra™ Ocular Discomfort and 4-Symptom Questionnaire (0-5 scale). Subjects reported a statistically significant improvement in their abilities to work with a computer at night (P=0.044). Mean drop comfort scores ranged from 1.29-1.81 on the Ora Calibra™ 0-10 Drop Comfort Scale, on which 0 is very comfortable and 10 is very uncomfortable. Retaine™ demonstrates promising results as a novel artificial tear option for individuals suffering from dry eye. The unique mechanism of action of Retaine™ provides enhanced comfort and improves the quality of life of dry eye subjects while reducing the ocular signs of dry eye. [ABSTRACT FROM AUTHOR]

The acyclic diene metathesis (ADMET) polymerization of 6-hydroxy-1,10-undecadiene ( M1) and 6-acetoxy-1,10-undecadiene ( M2) by the action of two different catalysts, i.e., the second-generation Grubbs-Hoveyda system ([RuCl2(IMesH2)(CH-2-(2-PrO-C6H4)]) ( 1) and the dicationic ruthenium alkylidene [Ru(DMF)3(IMesH2)(CH-2-(2-PrO-C6H4)] ( 2, IMesH2 = 1,3-dimesitylimidazolin-2-ylidene) is reported. Biphasic conditions using 1-butyl-2,3-dimethylimidazolium tetrafluoroborate ([BDMIM+BF4−]) and 1,2,4-trichlorobenzene (TCB) are applied. Under the chosen conditions ( T = 75 °C, 20 mbar), the use of catalyst 1 results only in the formation of low-molecular-weight polymers ( [ABSTRACT FROM AUTHOR]

Pulmonary immunization enhances local humoral and cell-mediated mucosal protection, which are critical for vaccination against lung-specific pathogens such as influenza or tuberculosis. A variety of nanoparticle (NP) formulations have been tested preclinically for pulmonary vaccine development, yet the role of NP surface charge on downstream immune responses remains poorly understood. We used the Particle Replication in Non-Wetting Templates (PRINT) process to synthesize hydrogel NPs that varied only in surface charge and otherwise maintained constant size, shape, and antigen loading. Pulmonary immunization with ovalbumin (OVA)-conjugated cationic NPs led to enhanced systemic and lung antibody titers compared with anionic NPs. Increased antibody production correlated with robust germinal center B-cell expansion and increased activated CD4+ T-cell populations in lung draining lymph nodes. Ex vivo treatment of dendritic cells (DCs) with OVA-conjugated cationic NPs induced robust antigen-specific T-cell proliferation with ~100-fold more potency than soluble OVA alone. Enhanced T-cell expansion correlated with increased expression of surface MHCII, T-cell coactivating receptors, and key cytokines/chemokine expression by DCs treated with cationic NPs, which were not observed with anionic NPs or soluble OVA. Together, these studies highlight the importance of NP surface charge when designing pulmonary vaccines, and our findings support the notion that cationic NP platforms engender potent humoral and mucosal immune responses. [ABSTRACT FROM AUTHOR]

Polyarginine, a cell-penetrating peptide, has been shown to aid cellular penetration of bioactives into cells. We utilized a novel approach of using a histidine linker to produce poly(ethyl-cyanoacrylate) (PECA) nanoparticles tagged with oligoarginine and investigated cellular uptake. MALDI TOF/TOF (tandem) analysis revealed that di-arginine-histidine (RRH) covalently bound to PECA nanoparticles to form cationic particles (+18 mV), while longer oligoarginine peptides did not co-polymerize with PECA nanoparticles. Although RRH-tagged nanoparticles had similar size and FITC-dextran entrapment efficiency compared to unmodified nanoparticles, RRH-tagging of nanoparticles resulted in a greater release of FITC-dextran. As the nanoparticles were found to aggregate in Hanks Balanced Salt Solution (HBSS), the effect of phosphate on the zeta-potential of nanoparticles was studied. Treating the nanoparticles with poloxamer-407 prevented aggregation. RRH-tagged PECA nanoparticles increased cellular uptake by a further 30% compared to unmodified PECA nanoparticles and was concentration dependent. We suggest that enhanced cell uptake can be achieved using a di-arginine-histidine construct as opposed to the previously published findings that a minimum of hexa-arginine is necessary. Further, the cationic zeta-potential of the cell-penetrating peptide may not be needed to enhance uptake. [ABSTRACT FROM AUTHOR]

The novel platinum (II) dimethyl complexes Pt(κ 2 -L1)Me 2 and Pt(κ 2 -L1)Me 2 ( 1 ), Pt(κ 2 -L2a)Me 2 ( 2a ) and Pt(κ 2 -L2b)Me 2 ( 2b ) bearing the functionalised N -heterocyclic carbenes (NHCs), L1 = 1-(2-diphenylphosphinoethyl)-3-(2,6-di iso propyl-phenyl)-imidazol-2-ylidene, L2a = 1-(2-pyridyl)-3-(2,6-di iso propyl-phenyl)-imidazol-2-ylidene, L2b = 1-(2-(3-picolinyl))-3-(2, 6-di iso propyl-phenyl)-imidazol-2-ylidene, react with the acid [H(Et 2 O) 2 + B(Ar F ) 4 − ], Ar F = 3, 5-(CF 3 ) 2 C 6 H 3 , in the presence of various neutral donors ( Dn ) to give the salts [{Pt(κ 2 -L)(Me)(Dn)} + {B(Ar F ) 4 } − ], where Dn occupies specifically the site trans to the P and the C NHC donor atoms of the coordinated ligands L1 and L2a , L2b , respectively. Spectroscopic data give evidence that the same selectivity prevails when other acids are employed. Activation of the Cl–CH 2 Cl bond by 2b led to [Pt(κ 2 -L2b)(Me)Cl], while reaction of CH 3 I with the dimethyl complexes led to isolable [Pt(κ 2 -L)Me 3 I] species. [ABSTRACT FROM AUTHOR]

Fluorinated surfactants are usually composed of a perfluorinated chain and a hydrophilic group. Academic surveys have reported that straight chain fluorinated surfactants have the lowest surface tension in a relatively high concentration while the branched fluorinated surfactants show more efficient in a relatively low concentration. Introducing branch is one of effective strategies for synthesis of non-bioaccumulable fluorinated surfactants. Three novel branched fluorinated surfactants were designed and prepared through a five-step route using perfluoro-2-methyl-2-pentene as starting material. The surface activities of them were investigated and found that they exhibited excellent surface activities. FCS can reduce the surface tension of water to below 20 mN/m, and the cmc value of FAS in water is about 1.04 × 10 −4 mol/L at 298 K. All the values of surface properties of FCS, FGS and FAS are lower than that of sodium perfluorooctanoate. [ABSTRACT FROM AUTHOR]

Ligands (pyridin-2-ylmethylene)anilines ( L1 – L4 ) and (1-(pyridin-2-yl)ethylidene)anilines ( L5 – L6 ) were obtained by condensation reactions. These ligands react with Pd(dba) 2 in the presence of methallyloxytris(dimethylamino)phosphonium hexafluorophosphate [C 4 H 7 OP(NMe 2 ) 3 ] + PF 6 − to give the corresponding monometallic cationic η 3 -methallylpalladium complexes C1–C6 in high yields. All new complexes C1–C6 have been characterized by CHN analyses, 1 H, 13 C, 31 P NMR and IR spectroscopy. Solid state and electronic structures of complex C5 have been determined. [ABSTRACT FROM AUTHOR]

A range of antimicrobial peptides (AMP) exhibit activity on malaria parasites, Plasmodium spp., in their blood or mosquito stages, or both. These peptides include a diverse array of both natural and synthetic molecules varying greatly in size, charge, hydrophobicity, and secondary structure features. Along with an overview of relevant literature reports regarding AMP that display antiplasmodial activity, this review makes a few considerations about those molecules as a potential new class of antimalarial drugs. [ABSTRACT FROM AUTHOR]

The partitioning of corrosion inhibitor (CI) products is a measure of their potential to protect oilfield pipelines. In this paper the hydrophilic-lipophilic deviation (HLD) model is first used to quantify their partitioning in terms of the characteristic curvature ( C) of a series of anionic (alkoxylated phosphate esters) and cationic (alkoxylated amines, aromatic amines, imidazoline acetates and quaternary amines) actives. This parameter is expressed over a range of pHs within which pipeline corrosion occurs. The HLD model is next used to predict the partitioning of each active from water into toluene at increased salinities. Linear mixing rules are lastly used to predict the characteristic curvature of Product A ( C) as a function of the C of a subset of actives. [ABSTRACT FROM AUTHOR]

Functional star-shaped 4-arm poly(ethylene glycol)- b-poly[( ε-caprolactone- co- γ-amino- ε-caprolactone)] (4-arm PEG- b-P(CL- co-ACL) was synthesized through ring-opening polymerization. The structure of the copolymer was confirmed by H NMR, Fourier transform infrared spectroscopy (FTIR), and gel permeation chromatography (GPC). To further understand the copolymers, the difference of the conversion rate between ε-caprolactone (CL) and γ-(carbamic acid benzyl ester)- ε-caprolactone (CABCL) and the detailed deprotection condition were studied. The thermal property of the copolymer was analyzed by WAXR and differential scanning calorimetry (DSC), which demonstrated that the thermal property could be well adjusted. The pH-responsive behavior of the copolymers was studied in detail by dynamic light scattering (DLS), pH titration, and pyrene fluorescence methods, which indicated that it could form micelles and exhibit pH responsibility. Moreover, the copolymer was nontoxic and had good biocompatibility according to the results by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assay. [ABSTRACT FROM AUTHOR]

Five cationic CH-CF hybrid surfactants, each of which has a hydrocarbon chain (CnH2n+1, n = 8, 10, 12, 14, 16) and a fluorocarbon one (C6F13), have been synthesized. Taking the advantage of the Grignard reaction and the subsequent quaternization, the hybrid surfactants were obtained with high synthetic yields over 65%. Their structures have been unambiguously confirmed by FTIR, ¹H NMR, 19F NMR, 13C NMR and MS measurements. 19F NMR revealed that the presence of the chiral carbon center induced a nonequivalent magnetic resonance of the adjacent fluorine nuclei. The aggregation behavior of the hybrid surfactants were investigated by surface tension, conductivity and steady-state fluorescence measurements. Surface tension measurements revealed that the hybrid surfactants exhibited high surface activity. With increasing hydrocarbon chain length, the critical micellar concentration (cmc) decreased while the surface tension at the cmc (γcmc) increased. Both the results of conductivity and surface tension measurements showed there exists a stepwise aggregation behavior for the hybrid surfactants with n = 8 and 10. Steady-state fluorescence measurements showed fairly good agreement with the results obtained from conductivity and surface tension measurements. Evaluation of the thermodynamic parameters (ΔGm0, ΔHm0, ΔSm0showed that the aggregate formation of the hybrid surfactants with n < 16 is enthalpy-driven at low temperature, which turns to entropy-driven at high temperature. While the aggregate formation of the hybrid surfactant with n = 16 is entropy-driven within all the investigated temperature ranges. [ABSTRACT FROM AUTHOR]

Host-defense antimicrobial peptides (AMPs) are a promising lead in the search for novel antibiotics. Many of these peptides exhibit broad-spectrum antibacterial ability, low toxicity toward human cells, and little susceptibility to induction of bacterial resistance. Our research focuses on the development of synthetic polymers that are able to mimic the amphiphilic and cation-rich characteristics of AMPs. This derives bioactive polymers that retain the activity profile of AMPs while utilizing a construct that is less expensive and easier to produce and manipulate chemically. This review details structure-activity relationships (SARs) of a new class of arginine-rich, synthetic AMP mimicking polymers (SAMPs), the guanylated polymethacrylates. These are contrasted with those of amine-based polymers that are mimics of lysine-rich AMPs. The ideal composition for candidates for practical applications was identified as those containing guanidines as a cation source, having a low molecular weight and a low level of lipophilicity. This gave polymers with high potency against Gram-positive strains of bacteria (e.g., Staphylococcus epidermidis MIC = 10 μg/mL) and low toxicity towards human red blood cells (<4% hemolysis at given MIC). This work emphasizes the need to rationalize observed biological activities based not purely on the global lipophilic and cationic character of polymers but rather to consider the profound effect that specific pendant functional groups may have on the potency, selectivity, and mechanisms behind the action of antimicrobial polymers. [ABSTRACT FROM AUTHOR]

A novel foam single-face pretreatment was used to modify silk fabrics for improving inkjet printing performance without any washing process. The foams used in pretreatment process were prepared by foaming agent, as Tween 80 and Sodium dodecyl sulfate (SDS). The compatibilities of the cationic modifier ethylene base-double octadecyl dimethyl ammonium chloride (EBODAC) agent with Tween 80 and SDS were investigated by comparing the foam properties at different EBODAC concentrations. The results show that Tween 80 is more compatible with EBODAC. The silk fabric surface is adhered with cationic groups after foam-treated with EBODAC, which improves the inkjet printing performances. The K/S values enhance from 5.84 to 8.21 with the increasing EBODAC concentrations. The printing images of treated fabrics perform more vivid than those of the controlled silk fabrics. The width and edges of practical printing lines become smaller and more definite, respectively. All these indicate that higher color yield and definition are achieved. The hand feeling after foam pretreatment is superior to that after pad pretreatment. The fastnesses are hardly affected after pretreatment. The foam-pretreatment provides a new pathway to improve the inkjet printing performance. [ABSTRACT FROM AUTHOR]

Hydrophobically modified polysaccharides that contain amine and amide groups possess valuable features for drug delivery and other applications. These chemical groups are known to play a fundamental role in the biological activity of important polysaccharides. Pullulan is known for its non-toxicity and biocompatibility, therefore, we have applied the versatile Staudinger reaction for the synthesis of regioselectively substituted pullulan derivatives containing amine or amide groups with promise for biomedical applications. The synthesis began with the regioselective bromination of pullulan at C-6 with N-bromosuccinimide and triphenylphosphine, providing 6-bromo-6-deoxy-pullulan, which is soluble in a range of organic solvents and therefore is a dynamic intermediate for the synthesis of other pullulan derivatives. Azide displacement of bromide from 6-bromo-6-deoxy-pullulan esters yielded the corresponding 6-azido-6-deoxy-pullulan esters. Staudinger reduction of these azides efficiently and chemoselectively afforded the corresponding amino- or amidopullulans. [ABSTRACT FROM AUTHOR]

Hardboards (HBs) (wet-process high-density fibreboards) were made in an industrial trial using a binder system consisting of cationic mimosa tannin and laccase or just cationic tannin without any thermosetting adhesive. The boards displayed superior mechanical strength compared to reference boards made with phenol–formaldehyde, easily exceeding the European standards for general-purpose HBs. The thickness swell of most of the boards was slightly greater than the standards would allow, so some optimisation is required in this area. The improved board properties appear to be mainly associated with ionic interactions involving quaternary amino groups in cationic tannin and negatively charged wood fibres rather than to cross-linking of fibres via laccase-assisted formation and coupling of radicals in tannin and fibre lignin. [ABSTRACT FROM AUTHOR]

Highlights: [•] Silk fibroin was decorated with tetracycline in aqueous solution to impart positive charge. [•] Cationic silk fibroin was deposited on titanium substrate as cathode via electrophoretic deposition. [•] Osteoblast-like cells achieved acceptable cell affinity on the cationic silk fibroin coatings. [•] Tetracycline was responsible for the antibacterial activity of cationic silk fibroin coatings. [ABSTRACT FROM AUTHOR]

Efficient delivery of siRNA to cancer cells after systemic administration poses a significant challenge. While many methods of nucleic acid delivery have been described, encapsulation of siRNA in lipid nanoparticles (LNPs) represents the most clinically advanced delivery approach. Currently, there are two siRNA-LNP-based treatments (ALN-VSP and TKM-PLK1) in clinical trials targeting solid tumors, with additional studies ongoing for noncancer diseases. The consensus from these clinical studies is that siRNA-LNP represents safe and potent silencing systems. Improvements in LNP technology through development of more potent and biocompatible ionizable cationic lipids along with targeting lipids to mediate delivery of LNPs specifically to cancer cells are on the horizon. In combination with genomic screening, it is possible that within the next 5 years the pathogenic drivers of individual cancers will be identified and siRNA-based personalized medicines will be formulated to achieve successful treatment of cancer and other genetic diseases. [ABSTRACT FROM AUTHOR]

Objectives Topical ocular administration is the most convenient route of administration of drugs for the treatment of eye diseases. However, the bioavailability of drugs following eye instillations of eye drops is very low. Over the past 20 years, extensive efforts have been put into research to improve drug bioavailability without compromising treatment compliance and patients' quality of life. Key findings One of the most efficient ways to improve drug bioavailability is to increase the precorneal residence time of the eye drop formulations. As a result, new eye drops, with bioadhesive properties, have been developed based on the cationic oil-in-water (o/w) nanoemulsion technology. These low viscosity eye drop nanoemulsions have improved precorneal residence time through the electrostatic interactions between the positively charged oil nanodroplets and the negatively charged ocular surface epithelium. Summary This review is the first to present the benefits of this new strategy used to improve ocular drug bioavailability. The roles of the cationic agent in the stabilization of a safe cationic o/w nanoemulsion have been discussed, as well as the unexpected benefits of the cationic o/w nanoemulsion for the protection and restoration of a healthy tear film and corneal epithelium. [ABSTRACT FROM AUTHOR]

Highlights: [•] Three intercalation regions of the bentonite interlayers according to the surfactant type. [•] Non-ionic surfactant inhibited intercalation and changed interlayer conformation. [•] Lecithin caused extensive bentonite intercalation and increased thermal stability. [ABSTRACT FROM AUTHOR]

Background and objectives: Vesicles, recently claimed as drug delivery carriers, were prepared by taking advantage of an electrostatic interaction between the carboxylic groups of fatty acids (FAs) and the amino groups of N-[3-(Dimethylamino)propyl]-Octadecanamide (DMAPODA). The study is to find out the effect of FAs' chain length on physicochemical properties of vesicles. Methods: Decanoic acid (DA), myristic acid (MA), stearic acid (SA) and behenic acid (BA) were used as FAs. Vesicles composed of them and DMAPODA were studied about formation on microscope, calorimetric analysis, size and zeta potential. Results: On microphotographs, all of FAs could form vesicles when mixed with DMAPODA in an equi-molar ratio. However, DA/DMAPODA vesicles were disintegrated during the homogenization. Due to the asymmetry of DA/DMAPODA associate, it seems to hardly form a stable and well-packed bilayer. On thermograms, the vesicles exhibited one strong peak, indicating that FAs can be homogeneously mixed with the cationic amphiphile. The sizes of the four kinds of vesicles suspended in an aqueous solution (final pH 7.5) were in the same order (hundreds of nanometer) on microphotographs. But, on a light scattering machine, the mean size of MA/DMAPODA vesicle was measured to be much greater than those of the other vesicles, possibly because of the low absolute value of the zeta potential. In addition, the medium pH value had a significant effect on the size of BA/DMAPODA vesicle possibly because the zeta potential was strongly dependent on the pH value. Conclusion: FAs' chain length would affect the physicochemical properties of vesicles composed of them and DMAPODA. [ABSTRACT FROM AUTHOR]

Abstract: Peripherally tetra-substituted oxo-titanium(IV) phthalocyanines bearing (2-{2-[3-(dimethylamino)phenoxy]ethoxy}ethoxy) and (2-{2-[3-(diethylamino)phenoxy]ethoxy}ethoxy) groups and their cationic derivatives have been synthesized. Electrochemical properties of the complexes 5 and 6 were determined with cyclic voltammetry and square wave voltammetry techniques. Electrochemical studies reveal that metallophthalocyanines containing redox active metal center such as Ti(IV) extends the redox richness of the phthalocyanine ring. Although titanium phthalocyanines complexes give common reduction processes, titanium phthalocyanines electropolymerized on the working electrode during anodic and whole potential scans. Electropolymerization mechanism changes with changing the potential window of the electrolyte system. [Copyright &y& Elsevier]

Abstract: Antibiotic resistance is one of the main problems concerning public health or clinical practice. Antimicrobial peptides appear as good candidates for the development of new therapeutic drugs. In this study we de novo designed a group of cationic antimicrobial peptides, analyzed its physicochemical properties, including its structure by circular dichroism and studied its antimicrobial properties against a panel of clinical isolates expressing different mechanisms of resistance. Three cationic alpha helical peptides exhibited antimicrobial activity comparable to, or even better than the comparator omiganan (MBI-226). [Copyright &y& Elsevier]

Efficient gene transfer is a critical goal in retroviral transduction. Several peptides capable of forming amyloid fibrils, such as the 39-residue semen-derived infection-enhancing peptide (SEVI), have demonstrated the ability to boost retroviral gene delivery. Here, a 13-residue peptide P13 (Ac-671NWFDITNWLWYIK683) derived from the membrane-proximal external region of the human immunodeficiency virus type 1 (HIV-1) gp41 transmembrane protein, together with its 16-residue peptide derivative (P16) were found to enhance HIV-1 infection significantly. Both peptides, P13 and P16, could form amyloid fibril structures to potently enhance HIV-1 infectivity. Further investigations showed that both aromatic Trp residues and cationic Lys residues contributed to the enhancement of HIV-1 infection by these two active peptides. P16 could more effectively augment HIV-1 YU-2 infection than SEVI, implying its potential applications as a tool in the lab to improve gene transfer rates. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Microalgae biomass has been considered as one of the potential feedstocks in biofuel production. Yet, biomass harvesting poses a challenge to the overall production cost due to its low cell density. Flocculation has been marked as one of the promising processes in microalgae harvesting technology. In this study, the first screening of two anionic (A-230, and A-330E) and five cationic polymers (C-810E, C-810EL, C-810EB, C-810ELH, and C-810EMB) followed by gravity settling with the mixed microalgae concentration of 2.24 g TSS /L revealed that anionic polymers are less effective. Whereas all cationic polymers achieved above 90% harvesting efficiency. Therefore, the maximum mass recovery of 98.7% with 86.8 g TSS /L sediment content was achieved by adjusting pH to 6-0.6 mL/L (115.178 mg/g biomass ) of C-810E followed by 15-min settling. The cationic polymer addition followed by settling would enable cost-effective downstream processing of microalgal biomass., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Abstract With an increase in the number of isolates resistant to multiple antibiotics, infection control has become increasingly important to help combat the spread of multi-drug-resistant pathogens. An important component of this is through the use of disinfectants and antiseptics (biocides). Antibiotic resistance has been well studied in bacteria, but little is known about potential biocide resistance genes and there have been few reported outbreaks in hospitals resulting from a breakdown in biocide effectiveness. Development of increased tolerance to biocides has been thought to be more difficult due to the mode of action of biocides which affect multiple cellular targets compared with antibiotics. Very few genes which contribute towards increased biocide tolerance have been identified. However, the majority of those that have are components or regulators of different efflux pumps or genes which modulate membrane function/modification. This review will examine the role of efflux in increased tolerance towards biocides, focusing on cationic biocides and heavy metals against Gram-negative bacteria. As many efflux pumps which are upregulated by biocide presence also contribute towards an antimicrobial resistance phenotype, the role of these efflux pumps in cross-resistance to both other biocides and antibiotics will be explored.

Abstract: To gain access to prenylated hexahydroxanthenes, tandem cascade cyclization–electrophilic aromatic substitution reactions have been studied on substrates bearing allylic and propargylic substituents. Both BF3·OEt2 and TMSOTf can be used to initiate this reaction sequence, resulting in different ratios of the C-2 and C-6 substitution products. Even though allylic transposition is observed in some cases, the results of a crossover experiment are consistent with an intramolecular reaction sequence. Taken together, these studies now allow preparation of either the C-2 or C-6 prenylated hexahydroxanthene products. [Copyright &y& Elsevier]