Amine End Groups Research Articles

Insights into molecular interactions at organic-MBene heterointerfaces for efficient Zn-ion storage

The intercalation of organic molecules is a promising approach to modulate the structure of 2D transition metal borides (MBenes), aiming to enhance charge transport and improve electrochemical performance in energy storage applications. However, key questions remain regarding how organic molecules with diverse functionalities penetrate and align between the MBene layer, as well as the mechanism of charge redistribution during intercalation. Addressing these questions is crucial for guiding the design of Organic-MBene heterostructures. To this end, a comprehensive approach combining theoretical calculations and experimental analyses was employed to explore the self-assembly mechanisms of organic molecules featuring N, O, S and tertiary amine end groups on the MoB-MBene surface. Experimental characterizations confirm that the interaction between MoB and organic compounds depends on the end groups. First principles calculations demonstrate that organic molecules tend to adopt a flat configuration on the MoB surface during molecular assembly. Calculations also reveal that the binding and charge transfer processes from organic molecules to MoB are highly dependent on the specific end groups, consistent with experimental observations. Furthermore, the effect of combining organic molecules with MoB on battery performance was further discussed, offering new insights for advancing the research and development of MBenes in aqueous battery systems.

Surface modification of expanded polytetrafluoroethylene to reinforced composite membranes for proton exchange membrane fuel cells

The study reports on the fabrication of reinforced composite membranes via hydrophilic surface modification of highly hydrophobic and porous expanded polytetrafluoroethylene (ePTFE) using argon plasma treatment and silane coupling. These processes create amine end group, functionalized onto ePTFE surface, thus improving hydrophilicity. It enables impregnation of Nafion ionomer dissolved in a polar aprotic solvent as well as water/alcohol mixture solvent. The optimal silane coupling concentration is systematically determined and facilitates uniform grafting of amine-functionalized silane without the pore blockage of ePTFE. The resulting reinforced composite membranes show improved mechanical, chemical, and dimensional stabilities and comparable proton conductivity. However, their membrane ohmic resistance is slightly higher than that of a commercial Nafion membrane (N211), leading to slightly reduced fuel cell performance. Note, the processes of this study prove versatile, accommodating partially fluorinated polymers in aprotic polar solvents with ePTFE, holding its potential for creating alternative reinforced composite.

Synthesis and behavior in aqueous solution of carboxymethyl pullulan-graft-poly(N-isopropylacrylamide-co-methacrylamide)

Stimuli-responsive polymers are fascinating materials because they mimic the behavior of living systems. This ability to respond to the action of certain stimuli makes them interesting both from the point of view of the theoretical study of their behavior in solution and of biomedical applications. In this regard, semitelechelic oligomers of N-isopropylacrylamide-co-methacrylamide (thermosensitive) with amine end groups were grafted onto previously synthesized carboxymethyl pullulan (sensitive to pH). The oligomers as well as the graft copolymer were characterized in terms of composition, molecular mass, number of grafts on the pullulan macromolecule, grafting density, and Kuhn segment length. Thermoresponsiveness of the grafted copolymer was studied in wide concentration and pH ranges. The onset temperature of phase separation proved to be independent of concentration and influenced by pH in highly basic solutions.The time of the copolymer response to abrupt change in temperature was analyzed.

β-Cyclodextrin Nanophotosensitizers for Redox-Sensitive Delivery of Chlorin e6.

The aim of this study is to prepare redox-sensitive nanophotosensitizers for the targeted delivery of chlorin e6 (Ce6) against cervical cancer. For this purpose, Ce6 was conjugated with β-cyclodextrin (bCD) via a disulfide bond, creating nanophotosensitizers that were fabricated for the redox-sensitive delivery of Ce6 against cancer cells. bCD was treated with succinic anhydride to synthesize succinylated bCD (bCDsu). After that, cystamine was attached to the carboxylic end of bCDsu (bCDsu-ss), and the amine end group of bCDsu-ss was conjugated with Ce6 (bCDsu-ss-Ce6). The chemical composition of bCDsu-ss-Ce6 was confirmed with 1H and 13C NMR spectra. bCDsu-ss-Ce6 nanophotosensitizers were fabricated by a dialysis procedure. They formed small particles with an average particle size of 152.0 ± 23.2 nm. The Ce6 release rate from the bCDsu-ss-Ce6 nanophotosensitizers was accelerated by the addition of glutathione (GSH), indicating that the bCDsu-ss-Ce6 nanophotosensitizers have a redox-sensitive photosensitizer delivery capacity. The bCDsu-ss-Ce6 nanophotosensitizers have a low intrinsic cytotoxicity against CCD986Sk human skin fibroblast cells as well as Ce6 alone. However, the bCDsu-ss-Ce6 nanophotosensitizers showed an improved Ce6 uptake ratio, higher reactive oxygen species (ROS) production, and phototoxicity compared to those of Ce6 alone. GSH addition resulted in a higher Ce6 uptake ratio, ROS generation, and phototoxicity than Ce6 alone, indicating that the bCDsu-ss-Ce6 nanophotosensitizers have a redox-sensitive biological activity in vitro against HeLa human cervical cancer cells. In a tumor xenograft model using HeLa cells, the bCDsu-ss-Ce6 nanophotosensitizers efficiently accumulated in the tumor rather than in normal organs. In other words, the fluorescence intensity in tumor tissues was significantly higher than that of other organs, while Ce6 alone did not specifically target tumor tissue. These results indicated a higher anticancer activity of bCDsu-ss-Ce6 nanophotosensitizers, as demonstrated by their efficient inhibition of the growth of tumors in an in vivo animal tumor xenograft study.

The Investigation of Copolymer Composition Sequence on Non-Isothermal Crystallization Kinetics of Bio-Based Polyamide 56/512.

A new bio-based polyamide 56/512 (PA56/512) has been synthesized with a higher bio-based composition compared to industrialized bio-based PA56, which is considered a lower carbon emission bio-based nylon. In this paper, the one-step approach of copolymerizing PA56 units with PA512 units using melt polymerization has been investigated. The structure of the copolymer PA56/512 was characterized using Fourier-transform infrared spectroscopy (FTIR) and Proton nuclear magnetic resonance (1H NMR). Other measurement methods, including relative viscosity tests, amine end group measurement, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), were used to analyze the physical and thermal properties of the PA56/512. Furthermore, the non-isothermal crystallization behaviors of PA56/512 have been investigated with the analytical model of Mo's method and the Kissinger method. The melting point of copolymer PA56/512 exhibited a eutectic point at 60 mol% of 512 corresponding to the typical isodimorphism behavior, and the crystallization ability of PA56/512 also displayed a similar tendency.

High impact strength of aliphatic polyketone/polyamide 6 blends induced by a chemical reaction

Compatibility and physical properties of aliphatic polyketon (PK)/polyamide 6 (PA6) blend were investigated. The PK and PA6 showed high adhesion strength and thus impact strength of PK/PA6 blends was very high. It was observed that PK-PA6 copolymers are formed by a chemical reaction between the two polymers and the copolymers act as a reactive compatibilizer in the PK/PA6 blends. The presence of the PK-PA6 copolymer was confirmed by FTIR analysis. The adhesion strength between PK and PA6 was very high compared to a typical incompatible polymer pair. PA6 investigated herein has two end groups, NH2 and carboxylic acid. We also adopted end-capped PA6 that has two carboxylic acid end groups. The adhesion strength and impact strength of the PK/end-capped PA6 blends was much lower than that of PK/PA6 blends. More importantly, the PK-PA6 copolymer was not formed in the PK/end-capped PA6 blends. Thus, it was concluded that the chemical reaction occurs between the carbonyl of PK and the primary amine end group of PA6. Due to the high impact strength of PK/PA6 blends, possible applications could be automotive parts where higher impact strength is required.

Peptide condensation and hydrolysis mechanisms from a proton-transfer network perspective.

Peptide bond formation is a fundamental organic chemical reaction; however, despite numerous recent reports, the computationally predicted barriers remain contradictory to experimental results. Incompleteness of the molecular mechanism for either the peptide bond formation or the reverse hydrolysis reactions is also highlighted by our lack of understanding of the seemingly equilibrium nature of the reaction that favors dipeptide formation over longer peptide chains under hydrothermal conditions. In this work, we first completed an assessment of levels of theory and evaluated chemical models that range from the neutral glycine condensation reaction in gas phase to explicitly solvated zwitterionic amino acids that are embedded in a polarizable continuum at neutral pH. Ultimately, we identified a six-step 'ping-pong' mechanism with the involvement of both zwitterions and neutral species. The carboxylate and amine end-groups of the diglycine intermediates play critical roles in the proton transfer and condensation processes. The experimental condensation barrier of 98 kJ mol-1 was approximated to be 118-129 kJ mol-1 at the MN15/def2TZVPP|SMD(water) level of theory for the rate determining step, when using the most complete model for the solvation environment. Condensed phase free energy correction employed to the rate limiting step reduced the barrier height to 106 kJ mol-1. These results have fundamental implications for understanding enzyme catalyzed peptide bond formation, peptide/protein stability, and "metabolism first" emergence of life scenarios.

Lab-on-Paper Strip Chemical Sensor: Reversible Visible Sensor for Detection of Acids Using Naphthalenediimide Derivative

Naphthalenediimide derivatives have shown applications in the area of chemical sensors for anions due to their special optical and electrical properties. In the current work, NDI derivative having phenyl amine end group (PPD-NDI) has been synthesized and tested for sensitivity towards trifluoroacetic acid (TFA), hydrochloric acid (HCl), nitric acid (HNO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) and sulfuric acid (H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> SO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> ) for 1-65 mM concentrations. PPD-NDI displays reversible optical and visible sensitivity for detection of acids, specially, for HCl and TFA. PPD-NDI shows charge transfer band in the range of 500-600 nm in absorption spectra along with color change in presence of acid. To understand the mechanism of sensitivity, an exclusion method has been applied by analyzing other reference NDI molecules with different end groups and linkers. PPD-NDI shows selective sensitivity for TFA present in low concentration (1 mM) and HCl at all other concentrations. Binding constants for the association between PPD-NDI and acids are obtained from the Benesi Hildebrand plot and highest value is observed in case of TFA. The sensitivity of NDI derivatives can be very helpful in detection of acids in various industrial effluents from cloth, paper, refineries and in smelting industries. We have demonstrated the reversible lab-on paper strip testing experiment for detection of HCl acid by naked eye in low and high concentrations without need of any excitation light source.

Structure Property Relationships in PA 6 and PP Copolymers Blended by Single and Twin Screw Extrusion

AbstractPolyamides such as polycaprolactam (PA 6) and poly(hexamethylene adipamide) (PA 6.6), are generally classified as pseudo-ductile materials. Fracture behaviour of PA can be changed by melt compounding with modified olefinic elastomers such as Ethylene-propylene copolymers (EPM and EPDMs) and nitrile rubbers (NBRs). Often, small amounts of a compatibilizer are added to the polymer blend in order to assure good dispersion, morphology stability and consistent end-use properties. Maleated polypropylene (PP-MAH) has been used as compatibilizer in blends of polyamides with polyolefins as they tend to react with amine end groups in the polyamide molecules and also interact by molecular entanglement with non-funcionalized polypropylene chains. This work was intended to optimise stiffness-toughness balance in polyamide/ polypropylene blends by reactive processing of PA 6 with polypropylene heterophase copolymers using the PP-MAH as a compatibilizer. Effects of processing conditions on the blend morphology and mechanical properties were investigated by comparing compatibilized and non-compatibilized blends prepared by single and twin screw extrusion. Such approach was intended to investigate whether blend morphology and its response to processing steps can be controlled by blend composition, changes in rheology and interfacial tension during reactive processing. Viscosity measurements by torque rheometry and particle coalescence in-situ observations were performed in order to provide additional evidence of mechanisms relating to phase morphology definition in such systems.

Influence of Small Amounts of ABS and ABS-MA on PA6 Properties: Evaluation of Torque Rheometry, Mechanical, Thermomechanical, Thermal, Morphological, and Water Absorption Kinetics Characteristics.

In this work, polyamide 6 (PA6) properties were tailored and improved using a maleic anhydride-grafted acrylonitrile-butadiene-styrene terpolymer (ABS-MA). The PA6/ABS-MA blends were prepared using a co-rotational twin-screw extruder. Subsequently, the extruded pellets were injection-molded. Blends were characterized by torque rheometry, the Molau test, Fourier transform infrared spectroscopy (FTIR), impact strength, tensile strength, Heat Deflection Temperature (HDT), Differential Scanning Calorimetry (DSC), Thermogravimetry (TG), Contact Angle, Scanning Electron Microscopy (SEM), and water absorption experiments. The most significant balance of properties, within the analyzed content range (5, 7.5, and 10 wt.%), was obtained for the PA6/ABS-MA (10%) blend, indicating that even low concentrations of ABS-MA can improve the properties of PA6. Significant increases in impact strength and elongation at break have been achieved compared with PA6. The elastic modulus, tensile strength, HDT, and thermal stability properties of the PA6/ABS-MA blends remained at high levels, indicating that maleic anhydride interacted with amine end-groups of PA6. Torque rheometry, the Molau test, and SEM analysis suggested interactions in the PA6/ABS-MA system, confirming the high properties obtained. Additionally, there was a decrease in water absorption and the diffusion coefficient of the PA6/ABS-MA blends, corroborating the contact angle analysis.

CD44 Receptor-Mediated/Reactive Oxygen Species-Sensitive Delivery of Nanophotosensitizers against Cervical Cancer Cells.

Stimulus-sensitive, nanomedicine-based photosensitizer delivery has an opportunity to target tumor tissues since oxidative stress and the expression of molecular proteins, such as CD44 receptors, are elevated in the tumor microenvironment. The aim of this study is to investigate the CD44 receptor- and reactive oxygen species (ROS)-sensitive delivery of nanophotosensitizers of chlorin e6 (Ce6)-conjugated hyaluronic acid (HA) against HeLa human cervical cancer cells. For the synthesis of nanophotosensitizers, thioketal diamine was conjugated with the carboxyl group in HA and then the amine end group of HA-thioketal amine conjugates was conjugated again with Ce6 (Abbreviated as HAthCe6). The HAthCe6 nanophotosensitizers were of small diameter, with sizes less than 200. Their morphology was round-shaped in the observations using a transmission electron microscope (TEM). The HAthCe6 nanophotosensitizers responded to oxidative stress-induced changes in size distribution when H2O2 was added to the nanophotosensitizer aqueous solution, i.e., their monomodal distribution pattern at 0 mM H2O2 was changed to dual- and/or multi-modal distribution patterns at higher concentrations of H2O2. Furthermore, the oxidative stress induced by the H2O2 addition contributed to the disintegration of HAthCe6 nanophotosensitizers in morphology, and this phenomenon accelerated the release rate of Ce6 from nanophotosensitizers. In a cell culture study using HeLa cells, nanophotosensitizers increased Ce6 uptake ratio, ROS generation and PDT efficacy compared to free Ce6. Since HA specifically bonds with the CD44 receptor of cancer cells, the pretreatment of free HA against HeLa cells decreased the Ce6 uptake ratio, ROS generation and PDT efficacy of HAthCe6 nanophotosensitizers. These results indicated that intracellular delivery of HAthCe6 nanophotosensitizers can be controlled by the CD44 receptor-mediated pathway. Furthermore, these phenomena induced CD44 receptor-controllable ROS generation and PDT efficacy by HAthCe6 nanophotosensitizers. During in vivo tumor imaging using HeLa cells, nanophotosensitizer administration showed that the fluorescence intensity of tumor tissues was relatively higher than that of other organs. When free HA was pretreated, the fluorescence intensity of tumor tissue was relatively lower than those of other organs, indicating that HAthCe6 nanophotosensitizers have CD44 receptor sensitivity and that they can be delivered by receptor-specific manner. We suggest that HAthCe6 nanophotosensitizers are promising candidates for PDT in cervical cancer.

Efficient polycation non-viral gene delivery system with high buffering capacity and low molecular weight for primary cells: Branched poly(β-aminoester) containing primary, secondary and tertiary amine groups

Gene transfer studies, preferred in many biotechnology studies such as in vitro transgenic cell modeling systems, gene therapy, transgenic animal production by cloning, etc., are quite limited due to transfection difficulties on primary cell lines. The main purpose of this study is on the production of biocompatible gene carrier systems with high transfection efficiency for Primary Ovine Fibroblast cell lines (POF). To achieve this goal, the synthesis of the branched poly(β-aminoester) (PBAE) containing primary, secondary and tertiary amino groups in their molecular structures was carried out via step-growth polymerization by a typical Michael addition reaction between bisphenol A-ethoxylate diacrylate (BPAEDA) and ethylenediamine (EDA) for the first time. PBAEs were characterized using FTIR and NMR techniques. GPC-SEC system was used to determine the molecular weight of these polymers. Proton buffering capacity of the PBAE was also determined. In order to optimize the preparation of the PBAE nanoparticles (nPBAE), two different methods, which are solvent evaporation and solvent displacement techniques, were used. Their physicochemical properties such as particle size, polydispersity index (PDI), zeta potential and stability were identified. nPBAE-gene complexes (gnPBAE) were obtained according to the adsorption or encapsulation mechanisms and their properties were evaluated by comparative surface charge and gel electrophoresis. In vitro studies including gene binding capacity, cytotoxicity and the transfection efficiency for primary ovine fibroblast (POF) cell lines were also realized. Consequently, (egnPBAE)dw formulation, which is obtained from PBAEEDA with the lowest Mw by encapsulation method in this study, have very high in vitro transfection efficiency up to 78.3% in POF cells and it was also exhibited almost 1.5 times more transfection efficiency against commercial product Lipofectamine because of its low Mw and the presence of the secondary and tertiary amine structures as well as primary amine end groups in its backbone.

Laser sintering of coated polyamide 12: a new way to improve flammability

In this study coatings of kaolin and talc particles were successfully applied on the surface of polyamide 12 powder intended for laser sintering (LS). Microscopic observations revealed that using carboxymethyl cellulose (CMC) as surface modifier for fillers led to a better coverage of polymer grains with a surface coverage between 6 and 16% as a function of filler type and content. Differential scanning calorimetry measurements showed that the addition of talc and kaolin led to an increase in the crystallization temperature of PA12, but at the expense of processability. Process parameters were optimized in order to manufacture LS samples with the different coated powders. Fire behavior assessed by cone calorimetry showed that the use of CMC resulted in a significant decrease in the peak of heat release rate depending on the filler type and content. This behavior can be partially explained by an interaction between CMC, fillers and polymer, with the formation of amide linkage between carboxyl part of CMC and amine end groups of polyamide, resulting in an increase in the complex viscosity of materials.

Designing of quaternized hyperbranched polyamidoamines dendrimers: Surface activity, pharmaceutical efficacy, and safety approach

The low solubility of the drug considers a major challenge for pharmaceutical formulation of both oral and parenteral products. In this work various generations of cationic hyperbranched polyamidoamine (PAMAM) quaternary ammonium salt dendrimers terminated with amine end groups were synthesized. The pharmaceutical application of these quaternized cationic surfactants ended with amine end groups and those ended with ester end groups which prepared in an earlier study were investigated. These dendrimers were compared as solubilizing agents for coenzyme Q10 (poorly soluble drug) and the dendrimers that showed high solubilizing potential (G2.5 C8, G2.5 C12) were selected to be evaluated as a dendrimer in dissolution study for coenzyme Q10 or Ledipasvir drug. In our investigation a comparison between four dissolution media with different surfactants namely, G2.5 C8, G2.5 C12, CTAB and Labrasol used for the dissolution test of Q10 was carried out. The results revealed that % Q10 released after 4 h was 86.7, 70.5, 43 and 10.5% for these dissolution media, respectively. These results indicated the priority of the synthesized cationic surfactants than the known commercial cationic surfactant (CTAB) or than Labrasol as recommended surfactant in previous lectures. Therefore, the profiles of the ledipasvir dissolution in the three-dissolution media (G2.5 C8, G2.5 C12 and FDA surfactant (1.5% tween 80 and 0.0075 mg/ml Butylated Hydroxytoluene (BHT)) are similar. The obtained results emphasized that the new surfactants can be used as alternative to FDA surfactant in the dissolution media of Ledipasvir.Eventually, the toxicity study was performed for two selected compounds from the prepared dendrimers, and these compounds were proved to be safe.

Solid electrolyte membranes based on polybenzimidazole containing graphitic carbon nitride moiety (PBICN) for high-temperature fuel cell applications

Polybenzimidazole containing graphitic carbon nitride moiety (PBICN) is prepared by in situ polymerization of 3,3′-diaminobenzidine (DAB), isophthalic acid (IPA), and graphitic carbon nitride (g-CN) for the application in high-temperature fuel cell membrane. Since g-CN has a nanosheet structure and lots of amine end groups, it can be involved in the polymerization process producing PBI-grafted g-CN. The PBICN membrane shows much improved thermal property, oxidative stability, mechanical strength, and proton conductivity compared to pristine PBI membrane and the PBI composite membrane prepared simply by mixing PBI and g-CN. In addition, it is confirmed that the PBI-grafted g-CN structure formed during the in situ polymerization can contribute to the increase of the dimensional stability for the PBICN membrane. Especially, PBICN membrane prepared by the in situ polymerization using g-CN exhibits much improved fuel cell performance. For example, the power density value of the membrane electrode assembly (MEA) fabricated using PBICN membrane prepared using 0.5 wt% of g-CN is 400 mW cm−2, which is much larger than those of MEA fabricated using PBI membrane (241 mW cm−2) and the PBI composite membrane containing 0.5 wt% of g-CN (326 mW cm−2) membrane during the fuel cell performance test performed at 160 °C without humidification.

Mitigation of the Color Generated During Mechanical Recycling of PET/MXD6 blends

High oxygen barrier in Poly(ethylene terephthalate) (PET), a widely used packaging polyester, can be achieved by blending poly(m-xylene adipamide) (MXD6), a commercially available high-barrier polymer, with PET. This blend is used industrially to address the increasing demand for longer shelf-life PET packaging. However, the impact of color generation in PET/MXD6 blends during mechanical recycling on recycled PET (rPET) flake is an ongoing challenge to the PET recycling industry. This work demonstrates the effect of multiple recycles on the physical and chemical properties of PET/MXD6 blends. Through 2D NMR correlation spectroscopy, structure of color forming conjugated imines present in the PET/MXD6 blends was confirmed for the first time. Building on the prior art, a modified processing method is proposed to mitigate the color generation in the blend by scavenging the MXD6’s amine end groups by adding small amounts of terephthalic acid (TPA) in the melt. Colorimetric evaluation showed that the incorporation of 0.5% (w/w) TPA in the blends reduced the Yellowness Index by 21% in the blend and by 41% in the recycled products after two melt histories, due to lower conjugated imine concentration in the blended samples. This work demonstrates a potential pathway to reduce color generation typically observed in PET-MXD6 blends in order to reduce the need for separating MXD6 in the recycling processes and the costs associates with it.

Amphiphilic DTPA Multimer Assembled on Icosahedral Closo-Borane Motif as High-Performance MRI Blood Pool Contrast Agent

A multimeric MRI blood pool contrast agent based on the closo-borane motif is reported. Twelve copies of an amphiphilic DTPA chelate with amine end groups are appended on carbonate-functionalized closo-borane motif using carbamate linkages. The presence of peripheral phenyl groups on the modified DTPA chelates results in high human serum albumin binding, high relaxivity, and excellent contrast enhancement in vitro and in vivo.

Optimizing the performance of sustainable nail gel compositions using a mixture experimental design methodology

This study presents the development of two major classes of oligomers extensively used in nail gel formulations – urethane acrylates and polyester acrylates – using sustainable routes. To this end, a series of non-isocyanate acrylic functional polyurethane oligomers (NIPU-ACs) were synthesized by the reaction of cyclic carbonates with a stoichiometric excess of amine, followed by reacting the amine-end groups with methacrylic anhydride (MAAH) to introduce the acrylate functionalities. Moreover, a series of different bio-renewable based polyester oligomers (BR-PS) were synthesized from ring-opening esterification of epoxidized soybean oil (ESO) with various mono/di acids such as rosin, benzoic acid, and itaconic acid.Next, the mixture experimental design methodology was used to formulate two categories of sustainable nail gels based on NIPU-ACs and BR-PS oligomers. The formulations were then evaluated for a set of screening tests, and Design-Expert® software was used to determine the most suitable correlation between the variable parameters and responses. In each category, the optimized formulation was selected based on the desired performance criteria and evaluated for complementary tests. Finally, three-layer nail gels systems were also developed and tested for durability and removability.The nail gel systems developed in this study not only have eco-friendly composition but meet critical requirements such as fast-curing (1−2 min), easy removability (in 5 min), high gloss (> 85 T 60°), and high durability (> 10,000 wet scrub cycles, acetone double rubs > 100, and abrasion resistance of < 20 mg after 500 cycles). The combination of these attributes makes these nail gels attractive alternatives to the incumbent products for commercial markets.

Nanophotosensitizers for Folate Receptor-Targeted and Redox-Sensitive Delivery of Chlorin E6 against Cancer Cells.

In this study, FA–PEG3500-ss-Ce6tri copolymer was synthesized to deliver photosensitizers via redox-sensitive and folate receptor-specific manner. Folic acid (FA) was attached to amine end of poly (ethylene glycol) (PEG3500) (FA–PEG3500 conjugates) and cystamine-conjugated chlorin e6 (Ce6) (Ce6-cystamine conjugates). FA–PEG3500 was further conjugated with Ce6-cystamine to produce FA–PEG3500-ss-Ce6 conjugates. To the remaining amine end group of Ce6-cystamine conjugates, Ce6 was attached to produce FA–PEG3500-ss-Ce6tri. Nanophotosensitizers of FA–PEG3500-ss-Ce6tri copolymer were smaller than 200 nm. Their shapes were disintegrated by treatment with GSH and then Ce6 released by GSH-dependent manner. Compared to Ce6 alone, FA–PEG3500-ss-Ce6tri copolymer nanophotosensitizers recorded higher Ce6 uptake ratio, reactive oxygen species (ROS) production and cellular cytotoxicity against KB and YD-38 cells. The in vitro and in vivo study approved that delivery of nanophotosensitizers is achieved by folate receptor-sensitive manner. These results indicated that FA–PEG3500-ss-Ce6tri copolymer nanophotosensitizers are superior candidate for treatment of oral cancer.

Synthesis of amphiphilic Janus dendrimer and its application in improvement of hydrophobic drugs solubility in aqueous media

Classic dendrimers are not used in many specific applications such as simultaneous loading of different drugs due to the existence of identical end groups. The possibility of designing the structure in dendrimers paves the way to synthesize more complicated dendrimers. This includes the creation of various types of peripheral groups on the surface of dendrimers to synthesize for example Janus dendrimers. Nowadays, three main methods are proposed for the synthesis of Janus dendrimers in which the high amount of conventional dendrimers is produced. The goal of this work is to develop a new method for synthesis of Janus dendrimers without production of conventional dendrimers. The present method has three main stages for the synthesis of Janus dendrimers including synthesis of 5th generation PPI dendrimer with cystamine core and hydrophobic surface, conversion of disulfide bonds to thiol group using a structure scission approach, and the formation of PAMAM hydrophilic dendrons with amine end groups. Different analyses including FT-IR, NMR, DLS, and GPC are used to prove the success of the synthesis route. Also, due to application of dendrimers in drug delivery including solubility improvement of hydrophobic drugs, Janus dendrimers are used to improve solubility of tetracycline and dexamethasone in presence of different generations of Janus dendrimers. Since the Janus dendrimers have both hydrophilic and hydrophobic ends, as well as having numerous terminal groups and numerous internal cavities, they have resulted in significant improvements in drug solubility. Also, solubility of the two hydrophobic drugs in water was increased by increasing concentration and generation of dendrimer.