Cationic Properties Research Articles

Submission for Special Issue: The Role of Platelet Activation in the Pathophysiology of HIV, Tuberculosis, and Pneumococcal Disease. Bedaquiline Suppresses ADP-Mediated Activation of Human Platelets In Vitro via Interference With Phosphatidylinositol 3-Kinase.

Although bedaquiline has advanced the treatment of multidrug-resistant tuberculosis (TB), concerns remain about the cardiotoxic potential of this agent, albeit by unexplored mechanisms. Accordingly, we have investigated augmentation of the reactivity of human platelets in vitro as a potential mechanism of bedaquiline-mediated cardiotoxicity. Platelet-rich plasma (PRP) or isolated cells prepared from the blood of healthy, adult humans were treated with bedaquiline (0.625–10 µg/ml), followed by activation with adenosine 5’-diphosphate (ADP), thrombin or the thromboxane A2 receptor agonist (U46619). Expression of platelet CD62P (P-selectin), platelet aggregation, Ca2+ fluxes and phosphorylation of Akt1 were measured using flow cytometry, spectrophotometry, fluorescence spectrometry, and by ELISA procedures, respectively. Exposure to bedaquiline caused dose-related inhibition of ADP-activated, but not thrombin- or U46619-activated, expression of CD62P by platelets, achieving statistical significance at a threshold concentration of 5 µg/ml and was paralleled by inhibition of aggregation and Ca2+ mobilization. These ADP-selective inhibitory effects of bedaquiline on platelet activation were mimicked by wortmannin, an inhibitor of phosphatidylinositol 3-kinase (PI3-K), implicating PI3-K as being a common target of both agents, a contention that was confirmed by the observed inhibitory effects of bedaquiline on the phosphorylation of Akt1 following activation of platelets with ADP. These apparent inhibitory effects of bedaquiline on the activity of PI3-K may result from the secondary cationic amphiphilic properties of this agent. If operative in vivo, these anti-platelet effects of bedaquiline may contribute to ameliorating the risk of TB-associated cardiovascular disease, but this remains to be explored in the clinical setting.

Fructose-functionalized polymers to enhance therapeutic potential of p-boronophenylalanine for neutron capture therapy

In boron neutron capture therapy (BNCT), boron drugs should accumulate selectively within a tumor and be quickly cleared from blood and normal organs. However, it is usually challenging to achieve the efficient tumor accumulation and the quick clearance simultaneously. Here we report the complex composed of a fructose-modified poly(ethylene glycol)-poly(l-lysine) block copolymer and p-boronophenylalanine, termed PEG-P[Lys/Lys(fructose)]-BPA, as a boron delivery system permitting selective accumulation within the target tumor with quick clearance from normal organs as well as blood. Our PEG-P[Lys/Lys(fructose)]-BPA could be internalized into tumor cells through LAT1 amino acid transporter-mediated endocytosis and retain in the targeted cells, thereby accomplishing more efficient accumulation and retention in a subcutaneous tumor than clinically used fructose-BPA complexes. Importantly, the moderately cationic property of the polymer facilitated renal clearance and PEG-P[Lys/Lys(fructose)]-BPA exhibited high accumulation contrast between the target tumor and the blood/normal organ. Finally, upon thermal neutron irradiation, PEG-P[Lys/Lys(fructose)]-BPA significantly inhibited the tumor growth in mice. PEG-P[Lys/Lys(fructose)]-BPA may be a promising boron delivery system for BNCT.

Recyclable Iron Oxide Loaded Poly (Methyl Methacrylate) Core/Polyethyleneimine Shell Nanoparticle as Antimicrobial Nanomaterial for Zoonotic Pathogen Controls

In this study, a recyclable antimicrobial agent against infectious pathogens in contaminated water was proposed. Iron oxide (IO) loaded poly (methyl methacrylate) (PMMA) core/polyethyleneimine (PEI) shell nanoparticles (PMMA/PEI-IO) was fabricated. The PMMA/PEI-IO showed a cationic surface charge property which is reflected by the protonation behavior of PEI. IO content in PMMA/PEI was evaluated by TGA and indicated that the residue incorporation of IO was 50% by dried weight. The existing of IO in PMMA/PEI was confirmed by the vibrating-sample magnetometer (VSM) showing a superparamagnetic property. The antibacterial ability was confirmed in waterborne bacteria, Escherichia coli and Staphylococcus aureus. The disturbance of the cell membrane integrity occurred after 20 min post-incubation of PMMA/PEI-IO with bacteria. Antimicrobial activity and recycling ability was further confirmed in an infectious, zoonotic and waterborne pathogen, Streptococcus agalactiae. Antiviral activity of PMMA/PEI-IO was observed and proved in an avian flu virus H3N2, a virus that has the potential to contaminate water reservoirs. The result showed that PMMA/PEI-IO nanoparticles were effective in killing H3N2. This study proposes a novel nanoparticle-based antimicrobial agents with recycle ability. Moreover, PMMA/PEI-IO nanoparticle is a potent bactericidal and virucidal agents when tested with waterborn zoonotic pathogens.

Biomimetic mineralized hybrid scaffolds with antimicrobial peptides

Infection in hard tissue regeneration is a clinically-relevant challenge. Development of scaffolds with dual function for promoting bone/dental tissue growth and preventing bacterial infections is a critical need in the field. Here we fabricated hybrid scaffolds by intrafibrillar-mineralization of collagen using a biomimetic process and subsequently coating the scaffold with an antimicrobial designer peptide with cationic and amphipathic properties. The highly hydrophilic mineralized collagen scaffolds provided an ideal substrate to form a dense and stable coating of the antimicrobial peptides. The amount of hydroxyapatite in the mineralized fibers modulated the rheological behavior of the scaffolds with no influence on the amount of recruited peptides and the resulting increase in hydrophobicity. The developed scaffolds were potent by contact killing of Gram-negative Escherichia coli and Gram-positive Streptococcus gordonii as well as cytocompatible to human bone marrow-derived mesenchymal stromal cells. The process of scaffold fabrication is versatile and can be used to control mineral load and/or intrafibrillar-mineralized scaffolds made of other biopolymers.

Direct entry of cell-penetrating peptide can be controlled by maneuvering the membrane curvature

A biomembrane's role is to be a barrier for interior cytosol from an exterior environment to execute the cell's normal biological functions. However, a water-soluble peptide called cell-penetrating peptide (CPP) has been known for its ability to directly penetrate through the biomembranes into cells (cytolysis) without perturbating cell viability and expected to be a promising drug delivery vector. Examples of CPP include peptides with multiple arginine units with strong cationic properties, which is the key to cytolysis. Here we show the conclusive evidence to support the mechanism of CPP’s cytolysis and way to control it. The mechanism we proposed is attributed to biomembrane’s physicochemical nature as lamellar liquid crystal (Lα). Cytolysis occurs as the temporal and local dynamic phase transitions from Lα to an undulated lamellar with pores called Mesh1. We have shown this phase transfer of Lα composed of dioleoyl-phosphatidylcholine (DOPC) with water by adding oligo-arginine (Rx) as CPP at the equilibrium. Using giant unilamellar vesicle composed of DOPC as a single cell model, we could control the level of cytolysis of CPP (FITC-R8) by changing the curvature of the membrane through osmotic pressure modulation. The cytolysis of CPP utilizes biomembrane's inherent topological and functional flexibility corresponding to the stimuli.

Injectable in situ forming hydrogel gene depot to improve the therapeutic effect of STAT3 shRNA.

Down-regulation of the signal transducer and activity of transcription 3 (Stat3) plays a crucial role in suppression of many solid tumors. Intratumoral injection of a gene carrier applying Stat3-small hairpin RNA (St3-shRNA) is a potential therapeutic strategy. To our knowledge, this is the first report of the intratumoral injection of St3-shRNA using a gene carrier. We herein designed biodegradable (methoxy)polyethylene glycol-b-(polycaprolactone-ran-polylactide) copolymer (MP) derivatized with a spermine group with cationic properties at the pendant position of the MP chain (MP-NH2). The designed MP-NH2 can act as a gene carrier of St3-shRNA by forming an electrostatic complex with cationic spermine. This can increase the stability of the complexes because of protection of PEG in biologic environments and can exhibit a sol-gel phase transition around body temperature for the formation of intratumorally injected MP-NH2 hydrogel depot for St3-shRNA. MP-NH2 was observed to completely condense with St3-shRNA to form St3-shRNA/MP-NH2 complexes. These complexes were protected for a relatively long time (≥72 h) from external biologic molecules of the serum, DNase, and heparin. St3-shRNA/MP-NH2 complexes in in vitro tumor cell experiments can enhance transfection of St3-shRNA, correspondingly enhance Stat3 knockdown efficiency, and inhibit tumor cell growth. St3-shRNA/MP-NH2 complexes and St3-shRNA/MP-NH2 complex-loaded hydrogel were intratumorally injected into the tumor as new efficient delivery carriers and depots of St3-shRNA. The intratumoral injection of St3-shRNA/MP-NH2 complexes and St3-shRNA/MP-NH2 complex-loaded hydrogel showed effective anti-tumor effect for an extended period of time due to the effect of Stat3 knockdown. Collectively, the development of MP-NH2 as a carrier and depot of St3-shRNA provides a new strategy for St3-shRNA therapy through intratumoral injection with high efficacy and minimal adverse effects.

Oil‐in‐water Pickering emulsion stabilization with oppositely charged polysaccharide particles: chitin nanocrystals/fucoidan complexes

Chitin nanocrystals (ChN) are insoluble particles that can be used as stabilizers for Pickering emulsions. Their unique cationic properties and antibacterial activity have generated considerable interest among researchers. However, ChN have remained largely underexplored. Furthermore, the droplets of the emulsions stabilized by ChN are as large as 10-100 μm, and their physical stability requires further improvement. Some studies have shown that the spontaneous reaction of oppositely charged particles can effectively stabilize the emulsions. Positively charged ChN and negatively charged fucoidan (F) were therefore compounded to stabilize Pickering emulsions, and the stability of these emulsions was analyzed qualitatively. The results showed that the composite particles comprising two polysaccharides in a mass ratio of 1:1 and at a pH of 2 (ChN1 -F1 -pH 2) possessed the lowest sulfate content (20.1%) and almost zero potential (-3 mV), indicating a high degree of neutralization of the positively charged amino group in ChN and the negatively charged sulfate group in F. Meanwhile, ChN1 -F1 -pH 2 displayed a dense network structure that improved the dispersibility and wettability (contact angle = 9.3°). Fourier transform infrared spectroscopy results confirmed that ChN and F were effectively combined through electrostatic interaction or neutralization to produce a polyelectrolyte complex. Furthermore, the particle size of the Pickering emulsion stabilized by ChN-F was significantly reduced, and the maximum size did not exceed 10 μm; the physical and storage stability also improved. The ChN1 -F1 -pH 2 emulsion presented excellent storage stability; in particular, the emulsions stabilized by ChN1 -F1 -pH 5 and ChN1 -F1 -pH 6 exhibited excellent flocculation stabilities. The size of the emulsion droplets stabilized by the oppositely charged polysaccharide particles (ChN-F complexes) reduced significantly. Furthermore, by changing the mass ratio and pH, the microstructure and binding degree of the complexes can be adjusted, thereby promoting their adsorption on the oil-water interface and improving the stability of the Pickering emulsion. © 2020 Society of Chemical Industry.

X-ray structurally characterized quinoline based fluorescent probes for pH sensing: Application in intracellular pH imaging; DFT calculations and fluorescent labelling

Quinoline based fluorescent probes QNOH-MO and QNOH-OME were synthesized, and their photo-physical properties were carefully investigated. The probes were well characterized by 1H-NMR, 13C-NMR, ESI-MS, and single-crystal X-ray structure analysis. QNOH-MO and QNOH-OME can identify small changes in pH by colorimetric and fluorescence methods. In low pH range, these probes display a red fluorescence in both live and fixed cells. However, with increasing pH, the observed red fluorescence decreased with a simultaneous increase in green fluorescence. The pH-dependent switching from red to green fluorescence is well supported by theoretical calculations and 1H NMR titration experiments. Furthermore, the ability of these probes to image pH changes in live cells was also scrutinized. Moreover, QNOH-OME was successfully utilized for fluorescent labelling of cholesterol molecule which is an important component of biological membranes and is used in the liposomal formulation for drug delivery applications. Additionally, QNOH-MO was quaternized to induce an intrinsic cationic property to the molecule. The cationic probe QNOH-MO-CA exhibited improved water solubility and pH sensing efficiency.

Evaluation of Sub-Lethal Toxicity of Benzethonium Chloride in Cyprinus carpio Liver

Benzenthonium chloride (BEC, Hyamine 1622) is a quaternary ammonium surfactant with cationic properties widely used in cleaning, sanitation, and medical products that can become harmful to humans and also to the environment. This study aimed to evaluate its acute effects on Cyprinus carpio fish in terms of oxidative stress and morphological changes on hepatic tissue in order to show the sub-lethal toxicity of BEC. Fish were exposed to 1 mg/L BEC for 24, 48, and 96 h, and the liver samples were collected. The most significant changes were noticed after 96 h of exposure when the entire antioxidant enzyme system was affected. The activities of catalase, glutathione peroxidase, glutathione reductase, and glutathione S-transferase decreased by 44%, 31%, 30%, and 45%, respectively, compared to control. Glucose-6-phosphate dehydrogenase activity decreased by 29% after 96 h of control, inducing a reduction of NADPH formation which decreased by half the level of reduced glutathione, the main non-enzymatic antioxidant. These effects correlated with the raised value of lipid peroxidation after 96 h and the morphology changes on hepatic tissue, such as cytoplasmic vacuolization and nuclear hypertrophy that could affect the normal function of the liver. All of these results showed acute toxicity of BEC on C. carpio after 96 h of exposure, causing oxidative stress response at the hepatic level.

Versatile Battery Insertion Materials: Crystal Structure and Electrochemistry

Rechargeable battery technologies became the spotlight of global scientific research in the quest to address growing energy demand. Currently, Li-ion batteries are unanimously occupied consumer electronic sector. These are mostly depending on only two transition elements such as Cobalt (Co) and Nickel (Ni) in popular cathodes LiCoO2 and LiNi1/3Mn1/3Co1/3O2 (NMC). The resource constraints of Co and Ni have paved away for alternate redox chemistry. In this scenario, manganese and vanadium-based layered materials are promising to owe their low-cost, resource-friendly nature with high operational safety. Moreover, the multiple redox states associated with these transition metals are promising to design high energy density cathodes.Here, we worked on the A2M3O7 (M= V, Mn) class of cathode materials. This family of materials exhibits polymorphism and multiple cationic redox properties. Further, bond valence sum energy calculations (BVSE) discovered a very low migration barrier of the alkali-ion (A) site. It inspired us to examine the intercalation properties of different ions including Li, Na, K and Zn. In each case, we observed interesting crystal chemistry with self-ion exchange property. The residual ions after self-ion exchange acted as pillars to lash out structural collapse during (de)intercalation. The ternary layered Na-Mn-O based metal oxide (Na2Mn3O7) was synthesized using different synthetic routes to tune the size and morphology of Na2Mn3O7 particles. The phase pure Na2Mn3O7 crystallizes in a triclinic layered structure (s.g. P-1). It consists of Mn in major +IV and minor +III oxidation states with electrochemically active Mn4+/Mn3+ redox center. The as-synthesized powder material worked as a versatile cathode for the Li, Na, K and Zn-ion batteries1-4. The systematic electrochemical studies were carried in both the aqueous and non-aqueous electrolytes. It delivered a reversible capacity of ~160, ~140, ~134 and ~330 mA h g-1 respectively with Li, Na, K and Zn metal foil as an anode in half-cell architectures. The detailed (de)intercalation mechanism along with diffusional studies of the various alkali-ions (Li/Na/K) along with Zn-ion will be described to present Na2Mn3O7 as a versatile cathode material.

Sorting hidden patterns in nanoparticle performance for glioblastoma using machine learning algorithms

Cationic compounds have been described to readily penetrate cell membranes. Assigning positive charge to nanosystems, e.g. lipid nanoparticles, has been identified as a key feature to promote electrostatic binding and design ligand-based constructs for tumour targeting. However, their intrinsic high cytotoxicity has hampered their biomedical application. This paper seeks to establish which cationic compounds and properties are compelling for interface modulation, in order to improve the design of tumour targeted nanoparticles against glioblastoma. How can intrinsic features (e.g. nature, structure, conformation) shape efficacy outcomes?In the quest for safer alternative cationic compounds, we evaluate the effects of two novel glycerol-based lipids, GLY1 and GLY2, on the architecture and performance of nanostructured lipid carriers (NLCs). These two molecules, composed of two alkylated chains and a glycerol backbone, differ only in their polar head and proved to be efficient in reversing the zeta potential of the nanosystems to positive values. The use of unsupervised and supervised machine learning (ML) techniques unraveled their structural similarities: in spite of their common backbone, GLY1 exhibited a better performance in increasing zeta potential and cytotoxicity, while decreasing particle size. Furthermore, NLCs containing GLY1 showed a favorable hemocompatible profile, as well as an improved uptake by tumour cells. Summing-up, GLY1 circumvents the intrinsic cytotoxicity of a common surfactant, CTAB, is effective at increasing glioblastoma uptake, and exhibits encouraging anticancer activity. Moreover, the use of ML is strongly incited for formulation design and optimization.

Chitosan Modified Cationic Polyacrylamide Initiated by UV-H2O2 for Sludge Flocculation and New Insight on the Floc Characteristics Study.

In the present study, a novel graft modified flocculant CTS-g-PAMD was synthesized and applied to conduct sludge conditioning and dewatering. CTS-g-PAMD was copolymerized with AM, DMC and chitosan (CTS) under UV-H2O2 initiation. In addition, the effects of single factor experiments on the molecular weight (MW) CTS grafting efficiency (GE) of CTS-g-PAMD were determined and the optimal copolymerization conditions were achieved. The GE of CTS-g-PAMD reached 91.1% and the MW was 4.82 × 106 Da. As revealed from the characterized results of Fourier-transform infrared spectra (FT-IR), 1H/ NMR, X-ray diffraction (XRD), scanning electron microscopic (SEM) and X-ray photoelectron spectroscopy (XPS), the successful synthesis of CTS-g-PAMD was confirmed, which is considered to be conducive to explaining sludge dewatering performance. Under the optimal conditions (pH = 7.0, flocculant dosage = 35 mg/L), the best flocculating performance (FCMC: 73.7%; SRF: 4.7 × 1012 m·kg−1, turbidity: 9.4 NTU) and large and dense sludge flocs (floc size d50 = 379.142 µm, floc fractal dimension Df = 1.58) were formed. The DMC and CTS chain segments exhibiting cationic properties significantly improved the positive charge density and enhanced the electrical patching effect of CTS-g-PAMD. The long molecular chain of CTS-g-PAMD exhibited superior extensibility, which enhanced bridging effect on adsorption. Moreover, the sludge floc after undergoing CTS-g-PAMD conditioning exhibited robust shear resistance and regeneration ability. After the sludge floc was crushed and broken, a large and dense sludge floc was formed, helping significantly reduce the sludge specific resistance (SRF), turbidity and cake moisture content (FCMC) and enhance the sludge dewatering effect. The novel CTS-g-PAMD flocculant shows promising practical applications and high market value.

Synthesis and characterization both micellization and thermodynamic parameter of cationic surfactant mixture derived from vegetable oil

The imidazolinium chloride salts have improved as a potential new material for a wide variety of industrial operations, due to their exceptional structures and properties. Therefore, recognition of the surface proprieties and thermodynamic criteria of this product is extremely important for fundamental and industrial operations. In this investigation a mixture of fatty imidazolinium chlorides was synthesized dealing with a novel method using sunflower oil as a promoter of fatty acids. The reaction of ethane-1,2 diamine with a fatty acid yields a fatty imidazoline molecule. Hydrochloric acid was used to obtain fatty imidazolinium hydrochlorides with cationic surfactant properties. A FT-IR and NMR spectroscopic technique was using to establish the synthetic structure. The surface tension and conductivity as a function of the surfactant concentration in aqueous solution were measured at distinct temperatures, to figure out the micellization, adsorption and aggregation characteristics in aqueous solutions. Formerly the effect of temperature on the CMC was investigated. The HLB values were assumed for our surfactant and the results achieved indicate that it is O/W emulsifier. The Krafft point was identified at 288.45 K. All Surface adsorption parameters like, the maximum surface excess concentration (Γmax), minimum area per molecule (Amin), effectiveness (πCMC), and efficiency of surface tension reduction (pC20) were calculated using Gibb’s equation. Finally, an attentive study of the thermodynamic aspects of air-ionic surfactant aqueous system reveals that the process of both micellization and adsorbtion was spontaneous and that adsorption is more favored than micellization.

Evidence of incompatibility for topical anionic agents used in conjunction with chlorhexidine gluconate: A systematic review

<p>Chlorhexidine gluconate (CHG) is a widely used antiseptic agent for skin and wound disinfection. The cationic properties of CHG may allow its inactivation and precipitation by anionic agents in commonly used topical agents. We conducted a systematic review by searching through PubMed, Cochrane Library, and Web of Science databases and selected original research articles reporting on CHG incompatibility, defined as inactivation or precipitation. The search yielded 22 publications that demonstrated CHG incompatibility via: 1) reduced antibacterial activity (carbomer, acrylates/C10-C30 alkyl acrylate crosspolymer, dentin, bovine serum albumin, copolymer M239144, sodium lauryl sulfate, heat-killed microbes, triethanolamine, and bark cork); and 2) visible precipitate formation (sodium hypochlorite, EDTA, saline, ethanol, andnystatin). Only three publications reported on CHG incompatibility in dermatology, specifically for carbomer, triethanolamine, and acrylates/C10-C30 alkyl acrylate crosspolymer. Although limited evidence linking CHG incompatibility and anionic agents exists, clinicians should carefully consider the nature of topical agents used if CHG is concurrently applied. Increased awareness of CHG incompatibility may result in better antibacterial activity thus ensuring optimal patient management.</p>

Cationic and anionic concentration dependent elastic properties of zinc blende specimens within CdxZn1-xSySe1-y quaternary system: Calculations with density functional theory

Elastic properties of zinc blende CdxZn1-xSySe1-y quaternary alloys have been calculated with density functional theory oriented FP-LAPW scheme. Elastic stiffness constants and hardness of specimens have been increased almost linearly with increasing sulphur composition at each fixed cadmium composition, while their decrease have been observed with increasing cadmium composition at each fixed sulphur composition in any binary-ternary/ternary-quaternary system. Mechanical and dynamical stability, elastic anisotropy, compressibility, ductility and fair plasticity have been calculated as the key features of each specimen. Mixture of covalent and ionic bonding with dominant role of covalent, central nature of interatomic forces and bending over stretching in chemical bonds have been observed in each compound. Calculated Debye temperature suggests ZnS as the stiffest and CdSe as the softest among all compounds. Calculated Gruneisen parameter has confirmed anharmonic nature of interaction between the atoms. Thermal conductivities and melting temperatures of all the specimens have also been computed.

In silico prediction of silver nitrate nanoparticles and Nitrate Reductase A (NAR A) interaction in the treatment of infectious disease causing clinical strains of E. coli

BackgroundThe interaction of specially designed nanoparticles with proteins is the basis of formation of a nanoparticle-protein corona. Silver nanoparticles and molecules have been used in many fields due to their strong antimicrobial activity against pathogenic microorganisms such as bacteria, yeast and fungi. E. coli is a Gram-negative bacteria that has the genome completely sequenced and determined majority of its protein 3D structures. Nitrate Reductase A is a cellular protein often found in many bacteria that uses nitrate as an electron acceptor during anaerobic growth. The enzyme is composed of three different chains α, β and γ, all having properties of metal binding regions and domains. MethodsBioinformatics tools were used to investigate the structure, domains, interactomes, and docking sites of E. coli Nitrate Reductase A in order to predict the possible site of interaction of silver nitrate AgNO3 with the protein. The 3D structure of the NAR A protein was predicted with the Phyre2 protein modeling software. The generated structures from Phyre2 were validated and evaluated by analysis of Ramachandran plots using RAMPAGE online software. To understand the evolutionary relationships between the subunits of Nitrate Reductase A, a phylogenetic tree was constructed using Phylogeny.fr. ResultsAll cysteine and histidine residues in amino acid sequences were identified; 3D structure of subunits predicted together with Ramachandran plots, and the electrostatic potential was computed using various bioinformatics tools. The reactive cationic property of silver ion leads to attachment to specific anionic regions and active sites of the three subunits causing in many prokaryotic cells deactivation of nitrate reductase. Obtained results showed the possible sites of attachment of silver ions and their reactivity with domains that have metal bonding properties. In silico analysis of silver nanoparticles and nitrate reductase is helpful to treat various infections diseases caused by E. coli.

Comparative Nanofabrication of PLGA-Chitosan-PEG Systems Employing Microfluidics and Emulsification Solvent Evaporation Techniques.

Poor circulation stability and inadequate cell membrane penetration are significant impediments in the implementation of nanocarriers as delivery systems for therapeutic agents with low bioavailability. This research discusses the fabrication of a biocompatible poly(lactide-co-glycolide) (PLGA) based nanocarrier with cationic and hydrophilic surface properties provided by natural polymer chitosan and coating polymer polyethylene glycol (PEG) for the entrapment of the hydrophobic drug disulfiram. The traditional emulsification solvent evaporation method was compared to a microfluidics-based method of fabrication, with the optimisation of the parameters for each method, and the PEGylation densities on the experimental nanoparticle formulations were varied. The size and surface properties of the intermediates and products were characterised and compared by dynamic light scattering, scanning electron microscopy and X-ray diffraction, while the thermal properties were investigated using thermogravimetric analysis and differential scanning calorimetry. Results showed optimal particle properties with an intermediate PEG density and a positive surface charge for greater biocompatibility, with nanoparticle surface characteristics shielding physical interaction of the entrapped drug with the exterior. The formulations prepared using the microfluidic method displayed superior surface charge, entrapment and drug release properties. The final system shows potential as a component of a biocompatible nanocarrier for poorly soluble drugs.

Multi-responsive nanococktails with programmable targeting capacity for imaging-guided mitochondrial phototherapy combined with chemotherapy

The integration of multimodal functions into one nanoplatform holds great promise for enhancing anticancer drug action and mitigating adverse effects. Herein, we prepared hyaluronic acid-functionalized regenerated silk fibroin-based nanoparticles (NPs) loading with photosensitizer (NIR770) and doxorubicin (DOX). The resultant HNDNPs had a desirable diameter of 161.0 nm and a negative zeta-potential of −30.5 mV. Interestingly, they showed excellent responses when triggered with various stimuli (acidity, reactive oxygen species, glutathione, hyaluronidase, or hyperthermia). Cell experiments revealed that HNDNPs could be specifically internalized by A549 cells, and efficiently released the payloads into the cytoplasm. Moreover, NIR770 was preferentially retained in mitochondria due to its lipophilic and cationic properties, which exhibited highly efficient photothermal therapy and photodynamic therapy upon near infrared (NIR) irradiation. Meanwhile, DOX molecules were mainly accumulated in the nucleus. Intravenous injection of HNDNPs into mice followed by NIR irradiation provided excellent multimodal imaging (NIR, photothermal, and photoacoustic imaging), almost eliminated the entire tumor, and greatly prolonged mice survival time with no side effects. Our study demonstrates that this HNDNP, which integrates the functions of tumor targeting, on-demand drug release, multimodal imaging, mitochondrial phototherapy, and chemotherapy, can be exploited as a promising nanococktail for imaging-guided synergistic treatment of cancer.

Cationization of cotton fiber: an integrated view of cationic agents, processes variables, properties, market and future prospects

Anionic dyes are often used for conventional cotton dyeing. This process, however, has a moderate affinity and it is estimated that less than 70% of the dye interacts with the cotton fiber. Cationization of cellulose is a chemical treatment that modifies the cellulose molecule, making it strongly cationic. This pretreatment increases the affinity between cotton and anionic dyes. Therefore, cationic dyeing reduces water, time, energy and chemical consumption. In this scenario, there is a growing demand to develop new cleaner products, as well as to elucidate the reaction mechanism aiming to create a clean and low-cost process for cotton cationization. In the last decades, more than 800 documents were published, and this number continues to rise. Among the cationic agents, 3-chloro-2-hydroxypropyl trimethylammonium chloride is the most researched and has achieved niche markets. However, poly-diallyldimethylammonium chloride combines effectiveness with a cleaner process. These characteristics make this cationic agent promising for future research. This review reports the state of the art on the techniques used for cationization, with a brief description of the market available for cationic cotton and a critical evaluation of the future perspectives for cationization.

Mixed Anionic and Cationic Redox Chemistry in a Tetrathiomolybdate Amorphous Coordination Framework

AbstractWe report the electrochemistry of a hitherto unexplored Na2MoS4 phase as a conversion electrode material for Na‐ and Li‐ion batteries. The material adopts an amorphous coordination polymer structure with mixed Mo and S valences. XPS and XRD analysis reveal a complex interplay between Mo and S redox chemistry, while excluding the formation of free sulfur, lithium sulfide, or other crystalline phases. Na2MoS4 behaves as a mixed ionic–electronic conductor, with electronic conductivity of 6.1×10−4 S cm−1, that permits carbon‐free application in an electrochemical cell. A reversible capacity of up to 500 mAh g−1 was attained, corresponding to a five‐electron redox exchange, with species ranging from <Na<1MoS4> (highest oxidized state) to <Na>5MoS4> (lowest oxidized state). This study emphasizes the excellent charge‐storage performances of Na2MoS4 for Li‐ or Na‐ion batteries, and enriches the emerging library and knowledge of sulfide phases with mixed anionic and cationic redox properties.