Polymeric Stabilizer Research Articles

Efficient perovskite solar cells based on polyoxyethylene bis(amine) and NaPF6 modified SnO2 layer with high open-circuit voltage

The electron transport layer (ETL) of SnO2 with a rough surface, low conductivity, and poor wettability has limited its application in perovskite solar cells (PSCs). To address this issue, we propose a strategy that involves the simultaneous use of bulk dopant NaPF6 and polymer stabilizer NH2-PEG-NH2 in SnO2. NH2-PEG-NH2 is compatible with both SnO2 and NaPF6, resulting in a homogeneous distribution. Additionally, the intrinsic hydrophilicity of the polymer facilitates the formation of a continuous and ordered ETL with improved wettability. The inclusion of NaPF6 as a bulk dopant enhances conductivity and promotes upper perovskite growth. As a result, optimized morphology, aligned energy levels, improved crystallinity, and reduced bottom defects are achieved in the fabricated perovskite layer. The champion device exhibits a power conversion efficiency (PCE) of ∼23.36%, which is ∼11.88% higher than that of the pristine device (PCE = 20.88%). Notably, the VOC reaches ∼1.2 V with only ∼0.08 V of VOC loss, which is among the highest report one. Furthermore, the PCE of the modified unpackaged PSC was only attenuated by 25% after 250 h of maximum power point tracking in the environment. These results present an alternative and effective approach for preparing high-quality SnO2 ETL for efficient PSCs.

Photomediated synthesis of stabilizer-free silver nanoprisms with a tunable plasmon wavelength for enhanced catalytic activity

Herein, we introduce a simplified photomediated method for fabricating silver nanoprisms (AgNPrs) with controllable surface plasmon resonance. The Ag nanoparticles (Ag seeds), Ag+, and citrate ions were used to control AgNPrs growth. Citrate ions served as a reducing agent and a stabilizer. The optimized [citrate]/[Ag+] ratio of 10 was sufficient to stabilize the final AgNPrs. Sodium borohydride (NaBH4) was used as a strong reducing agent to generate the initial Ag seed amount, then controlled by the [BH4−]/[Ag+] ratio. A ratio of 0.0005–0.005 ([BH4−]/[Ag+]) yielded a 545–702 nm plasmon band of AgNPrs. AgNPrs displayed an irregular plate shape in their morphological structure, featuring lateral dimensions spanning from 30.7 ± 4.3 to 51.0 ± 10.8 nm and a thickness ranging from 7.2 ± 0.8 to 10.7 ± 1.3 nm. The synthesized AgNPrs exhibited excellent stability in the dark at 4 °C without any additional polymeric stabilizer and presented negligible variations in their absorbance UV–visible spectra for at least 1 month. They demonstrated an enormous (111) facet potentially serving as an active catalytic site for reducing 4-nitrophenol to 4-aminophenol. With synthesized AgNPrs, the rate constant of the reduction reaction increased to 0.2440 min−1, which was 120 times greater than that without the catalyst or with spherical Ag nanoparticles. These AgNPrs can be reutilized for at least five catalytic cycles without losing their catalytic efficiency.

Size Control and Antioxidant Properties of Sulfur-Rich Polymer Colloids from Interfacial Polymerization.

High sulfur content polymeric materials, known for their intriguing properties such as high refractive indices and high electrochemical capacities, have garnered significant interest in recent years for their applications in optics, antifouling surfaces, triboelectrics, and electrochemistry. Despite the high interest, most high sulfur-content polymers reported to date are either bulk materials or thin films, and there is a general lack of research into sulfur-rich polymer colloids. Water-dispersed, sulfur-rich particles are anticipated to broaden the range of applications for sulfur-containing materials. In this study, the preparation and size control parameters are presented of an aqueous dispersion of sulfur-rich polymers with the sulfur content of dispersed particles exceeding 75wt%. Employing polymeric stabilizers with varying hydrophilic-lipophilic balance (HLB), along with changing the rank of inorganic polysulfides, allow for the control of particle size in the range of 360nm - 1.8µm. The sulfur-rich colloid demonstrates antioxidant properties in water, demonstrating the potential for the use of sulfur-rich polymeric materials readily removable, heterogeneous radical scavengers.

Polymer Coatings Affect Transport and Remobilization of Colloidal Activated Carbon in Saturated Sand Columns: Implications for In Situ Groundwater Remediation.

Colloidal activated carbon (CAC) is an emerging technology for the in situ remediation of groundwater impacted by per- and polyfluoroalkyl substances (PFAS). In assessing the long-term effectiveness of a CAC barrier, it is crucial to evaluate the potential of emplaced CAC particles to be remobilized and migrate away from the sorptive barrier. We examine the effect of two polymer stabilizers, carboxymethyl cellulose (CMC) and polydiallyldimethylammonium chloride (PolyDM), on CAC deposition and remobilization in saturated sand columns. CMC-modified CAC showed high mobility in a wide ionic strength (IS) range from 0.1 to 100 mM, which is favorable for CAC delivery at a sufficient scale. Interestingly, the mobility of PolyDM-modified CAC was high at low IS (0.1 mM) but greatly reduced at high IS (100 mM). Notably, significant remobilization (release) of deposited CMC-CAC particles occurred upon the introduction of solution with low IS following deposition at high IS. In contrast, PolyDM-CAC did not undergo any remobilization following deposition due to its favorable interactions with the quartz sand. We further elucidated the CAC deposition and remobilization behaviors by analyzing colloid-collector interactions through the application of Derjaguin-Landau-Verwey-Overbeek theory, and the inclusion of a discrete representation of charge heterogeneity on the quartz sand surface. The classical colloid filtration theory was also employed to estimate the travel distance of CAC in saturated columns. Our results underscore the roles of polymer coatings and solution chemistry in CAC transport, providing valuable guidelines for the design of in situ CAC remediation with maximized delivery efficiency and barrier longevity.

A nonlinear elastic-strain hardening model for frozen improved sandy soil under uniaxial compression loading condition

Artificial freezing is one of the most effective methods in the excavation of water-rich soils. This work aims at investigating the influence of cement‑sodium silicate grout (C-S grout) and organic polymer stabilizer (OPS) on the uniaxial compressive strength (UCS), stress-strain curve, and unfrozen water content of frozen sandy soil. A series of uniaxial compression tests and nuclear magnetic resonance (NMR) tests were conducted on the saturated frozen sandy soils improved by C-S grout and OPS (“C-S grout-improved soil” and “OPS-improved soil”) under different negative temperatures (i.e., −5 °C, −10 °C, −15 °C, and −20 °C). Based upon the experiment results and existing stress-strain models, including improved Duncan-Chang model and elastic-strain hardening model, a nonlinear elastic-strain hardening constitutive model for improved soils was proposed, in which each parameter has well-defined physical meaning. The results showed that, as the temperature decreases, the strengths of frozen improved soils gradually increase. The strength of OPS-improved soil first increases and then decreases with the increase of OPS dosage. Contrary to the UCS, the unfrozen water content of two improved soils was observed to gradually decrease with the decrease of temperature. As the OPS dosage increases, the unfrozen water content of improved soils decreases first and then increases. When the strain is <0.2, the stress-strain curves of frozen C-S grout-improved soil exhibits a behavior of yielding first and then hardening after the nonlinear elastic stage, while OPS-improved soil exhibits continuous strain hardening behavior. With temperature and unfrozen water content given, the new nonlinear elastic-strain hardening model can accurately predict the stress-strain behavior of frozen improved soils. This study is helpful to the stability analysis of artificial frozen walls and pre-control of environmental deformation during the excavation of water-rich sandy soils.

Bayesian Optimization of Environmentally Sustainable Graphene Inks Produced by Wet Jet Milling.

Liquid phase exfoliation (LPE) of graphene is a potentially scalable method to produce conductive graphene inks for printed electronic applications. Among LPE methods, wet jet milling (WJM) is an emerging approach that uses high-speed, turbulent flow to exfoliate graphene nanoplatelets from graphite in a continuous flow manner. Unlike prior WJM work based on toxic, high-boiling-point solvents such as n-methyl-2-pyrollidone (NMP), this study uses the environmentally friendly solvent ethanol and the polymer stabilizer ethyl cellulose (EC). Bayesian optimization and iterative batch sampling are employed to guide the exploration of the experimental phase space (namely, concentrations of graphite and EC in ethanol) in order to identify the Pareto frontier that simultaneously optimizes three performance criteria (graphene yield, conversion rate, and film conductivity). This data-driven strategy identifies vastly different optimal WJM conditions compared to literature precedent, including an optimal loading of 15wt% graphite in ethanol compared to 1wt% graphite in NMP. These WJM conditions provide superlative graphene production rates of 3.2ghr-1 with the resulting graphene nanoplatelets being suitable for screen-printed micro-supercapacitors. Finally, life cycle assessment reveals that ethanol-based WJM graphene exfoliation presents distinct environmental sustainability advantages for greenhouse gas emissions, fossil fuel consumption, and toxicity.

Impact of polymeric stabilizers on the transformation and sustainable recovery of silver microstructures from spent button batteries

This paper presents a simple, rapid, highly efficient, and environmentally friendly technique for recovering silver microstructures from spent button batteries. The technique exploits the reducing ability of H2O2 to convert silver sources into high-purity silver at the microscopic scale. The influence of polymeric stabilizers (PVP and PVA) on the formation of silver microstructures was elucidated. The results revealed that polymeric stabilizers play a crucial role in controlling the growth of silver particles at the microscopic level. Specifically, PVP affords a homogeneous silver microplate, whereas PVA facilitates the formation of isotropic spherical microparticles. Additionally, the effect of the molecular weight (Mw) of the stabilizers on the silver particles was examined. The Mw of PVP significantly impacts its anti-aggregation properties. Similarly, the Mw of PVA affects the formation of silver microstructures. The high purity of the recovered silver microstructures was verified by EDX and XRD. Finally, the optimal recovery conditions involving 360,000 and 150,000 g/mol for PVP and PVA, respectively with 0.5 % w/v) were implemented to recover silver from button batteries. These battery residues were successfully transformed into highly pure silver microplates and microspheres using those respective polymeric stabilizers. The developed synthesis approach will facilitate the sustainable recovery of silver from spent button batteries, addressing the environmental, and resource challenges associated with battery waste.

Tunable templating of photonic microparticles via liquid crystal order-guided adsorption of amphiphilic polymers in emulsions

Multiple emulsions are usually stabilized by amphiphilic molecules that combine the chemical characteristics of the different phases in contact. When one phase is a liquid crystal (LC), the choice of stabilizer also determines its configuration, but conventional wisdom assumes that the orientational order of the LC has no impact on the stabilizer. Here we show that, for the case of amphiphilic polymer stabilizers, this impact can be considerable. The mode of interaction between stabilizer and LC changes if the latter is heated close to its isotropic state, initiating a feedback loop that reverberates on the LC in form of a complete structural rearrangement. We utilize this phenomenon to dynamically tune the configuration of cholesteric LC shells from one with radial helix and spherically symmetric Bragg diffraction to a focal conic domain configuration with highly complex optics. Moreover, we template photonic microparticles from the LC shells by photopolymerizing them into solids, retaining any selected LC-derived structure. Our study places LC emulsions in a new light, calling for a reevaluation of the behavior of stabilizer molecules in contact with long-range ordered phases, while also enabling highly interesting photonic elements with application opportunities across vast fields.

Traditional and green approaches to the synthesis of copper-containing nanoparticles using chemical reduction

The problem of obtaining copper-containing nanoparticles by chemical reduction has been studied. A comparison is made of traditional and “green” approaches to synthesis. The experimental data obtained during the synthesis of copper nanoparticles in the presence of a polymer stabilizer (polyvinylpyrrolidone) and a reducing agent (tert-butylamine-borane), as well as literature data on the synthesis of nanoparticles using plant and conditionally “green” substances (glucose, extracts of Ocimum sanctum and Celastrus paniculatus leaves, Sarcostemma acidum stem). The advantages and disadvantages of these approaches are identified and discussed. It is noted that the industrial applicability of “green” methods is limited due to the need to create completely new production of reagents for synthesis. In addition, the application of green synthesis is difficult due to scalability and standardization issues. Environmental pollution associated with the production of plant extracts also requires additional assessment. It has been established that traditional synthesis methods remain relevant for modern industry, and “green” methods have prospects for use in the distant future.

Validating experimental data for attenuation coefficients of developed polymer composites in shielding applications through Monte Carlo simulation

Abstract The widespread use of composites in an ionizing environment raises durability concerns, particularly when performance is required over a longer period, in a radiation environment. The goal of this study was to measure the attenuation coefficient for the polymer composite developed for the radiation shielding application and validate it with the well-known Monte Carlo simulation. A radiation-hardened epoxy resin was developed in the laboratory by utilizing various compositions which is capable of being employed as a shielding material in a nuclear environment. To develop a radiation-hardened layer, to some extent, raised the density of the material, using suitable fillers. Polymer stabilizers were used single or in combination. The specimens were irradiated to determine the developed material’s shielding properties. The prepared composites’ radiation absorption is evaluated using an absorption coefficient. Experiments with gamma radiation using an Am Be Neutron source were conducted to determine the linear absorption coefficient. Monte Carlo simulation was utilized to predict the absorption coefficient for developed composites and the results were compared with experimental data.

Tailoring Morphology and Size of Silver Nanoparticles Prepared by Polyol Method by Changing the Structure of Silver Carboxylate Precursor

AbstractSilver nanoparticles are synthesized by reducing silver alkyl carboxylates at their high concentrations with ethylene and propylene glycol without a common use of polymeric dispersants and stabilizers. The effects of alkyl chain structure on the morphology and size of silver particles have been studied by scanning electron microscopy, transmission electron microscopy, powder X‐ray diffraction, differential scanning calorimetry, and thermogravimetric analyses. The carboxylates that have been investigated are silver caprylate, laurate, 2‐butyloctanoate, and 2‐ethylhexanoate. It was found that the reduction temperature of straight‐chain alkyl carboxylates is in the 110–120 °C range. The particles prepared under these conditions are perfectly spherical in shape and their average size varies from 20 to 40 nm. In the case of the branched structure, the reduction process starts at around 80 °C and produces irregularly shaped silver particles with a size of 150 to 450 nm. Possible ways of controlling the parameters of the synthesized nanoparticles are proposed. This study proposes a simple and easily scalable method to prepare silver nanoparticles stabilized by a non‐polymeric stabilizer. The as‐synthesized silver particles may have applications as metallic fillers in ink and paste formulations for 2D and 3D printing to fabricate functional components and devices.

Integration of Lipid-Functionalized Epigallocatechin-3-gallate into PLGA Matrix as a Novel Polyphenol-Based Nanoantioxidant.

The search for polyphenol-based materials with antioxidant activity is a growing research area in the biomedical field. To obtain an efficient and stable nanoantioxidant, a novel biosystem was designed by integrating a lipophilic derivative of epigallocatechin-3-gallate (named EGCG-C18) on the surface of poly(lactic-co-glycolic acid) (PLGA). Poly(vinyl alcohol) (PVA) and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-poly(ethylene glycol) (DSPE-PEG2000) were selected as polymeric and lipidic stabilizers, respectively, and their influence on both physical properties and the antioxidant activity of nanoantioxidant was investigated by a combined in silico and experimental approach. Full-atom molecular dynamics (MD) simulations were carried out to describe the different self-assembly processes of all components and the interactions that guided the EGCG-C18 insertion inside the PLGA matrix. Together with infrared spectroscopy results, the formation of an antioxidant lipid shell on the PLGA surface was clear. Dynamic light scattering and transmission electron microscopy showed that in the presence of DSPE-PEG2000, NPs were smaller than those treated with PVA. In addition, the different stabilizers used strongly influenced the ROS-scavenging ability of nanomaterials and this effect was strictly related to the molecular organization of EGCG-C18. MD showed that the apolar interaction between the alkyl chains of DSPE-PEG2000 and EGCG-C18 oriented the phenolic groups of the polyphenol toward the solvent, providing an ability of NP to scavenge hydroxyl radicals over to free EGCG-C18 and PLGA/PVA NPs. Finally, the ability of nanoantioxidants to protect human dermal fibroblasts from cell death induced by oxidative stress has been tested, revealing the high potential of these novel NPs as polyphenol-based materials.

Effect of Polymeric Agent on the Strength and Water Stability of Cement-Stabilized Construction Waste Soil

Due to the large output of construction waste soils, it has become an enormous challenge for human society and the ecological environment. The purpose of this paper is to discuss the possibility of using a stabilized waste soil in road engineering. Cement and polymer stabilizers were added to the waste soil, and the effect of the stabilizer on the strength and water stability of the stabilized soil was studied. The structure and morphology of the specimens were analyzed using an X-ray diffractometer (XRD) and a scanning electron microscope (SEM). The results show that the unconfined compressive strength increases by 25.0% and the 28-day water stability coefficient, K increases by 59.6% after the addition of the stabilizer. The XRD curve shows that the addition of the new stabilizer does not produce a new characteristic peak, but the diffraction peak strength of some minerals can be improved. SEM shows that the surface of stabilized soil particles is covered by materials, and the particles show obvious agglomeration, forming a network structure, which improves the strength and water stability of the soil.

TEMPO oxidized cellulose nanocrystal (TOCNC) scaffolded nanoscale zero-valent iron (nZVI) for enhanced chromium removal

The conventional carboxymethyl cellulose (CMC) stabilization hampered available active sites of adsorption and reduction, due to irregular shape of nanoscale zero-valent iron (nZVI) particles with augmented average size and passivated surface, leading to insufficient removal and poor resistance against complex environmental conditions. Herein, we presented (2,2,6,6-Tetramethylpiperidine-1-oxyl)-mediated (TEMPO-mediated) oxidation of cellulose nanocrystal (TOCNC) scaffolded nZVI (nZVI@TOCNC) with enhanced efficiency for chromium removal in comparison with CMC stabilized nZVI (nZVI@CMC). The anchoring of nZVI at the functional sites of TOCNC was initiated by liquid-phase chemical reduction method. The nZVI@TOCNC showed improved nZVI distribution with uniform particle size and thinner shell (∼1 nm). Characterizations using FT-IR, XPS and XRD demonstrated that bindings between TOCNC and nZVI were through hydrogen bonds, electrostatic attractions, coordination-covalent bonds and bidentate chelation. TOCNC with shorter branch-chain (–COC–) surrounding the nZVI could potentially form a porous and compact “mesh” to rigidly encapsulate nZVI, while CMC wrapped around nZVI in the way of traditional polymeric stabilizers. Thus, 0.5 g/L nZVI@TOCNC achieved 99.96% Cr (Ⅵ) removal efficiency (20 mg/L) at pH = 7 and the removal capacity were up to 55.86 mg/g. The nZVI@TOCNC consistently presented higher removal efficiency than nZVI@CMC under wide pH range (3–7). Cr (Ⅵ) was reduced to Cr (Ⅲ) by nZVI@TOCNC with deposition of CrxFe1-x (OH)3 and Cr2O3. The predominant mechanisms of removal probably consisted of electrostatic attractions, reduction, co-precipitation and surface complexation. The pseudo-second-order kinetic model well-fitted the sorption kinetic, indicating TOCNC scaffold stabilized nZVI for efficient reduction of Cr (Ⅵ) through multi-layer adsorption. As a template and delivery carrier, TOCNC shows promising potential to further improve the capability and practice of nZVI for in situ treatment of industrial waste water with heavy metal pollution.

Conceptual stabilizer selection for nanomilling based on dispersibility parameters

The choice of stabilizers to prevent particle agglomeration during nanomilling is an elaborate process which is often based on empirical rules and experience. Usually, extensive screening studies are required to find an appropriate stabilizing additive. The present study shows how the selection of polymeric stabilizers can be narrowed down to a couple of additives based on Hansen solubility parameters. The stabilizing capability was found to be a function of the difference between solubility parameters of additive and particulate species. Solubility parameters of different additives and two particle species were determined by inverse gas chromatography and the stabilization performance was evaluated by nanomilling experiments conducted with a stirred media mill. It is shown that a certain difference of solubility parameters between particle and additive is necessary in order to provide colloidal stability of small particles after milling. On the one hand, the additive needs a certain affinity to the particle surface, while on the other hand it also has to be compatible with the solvent. Based on experimental data, a solubility parameter difference in the range of 7.5–10 MPa0.5 was identified as a good measure for a proper stabilizer selection. The approach was proved for two organic particle species and represents a promising tool for a more efficient formulation development of drug nanosuspensions.

Research on strength improvement and stabilization mechanism of organic polymer stabilizer for clay soil of subgrade

Soil stabilizer can improve the physical and chemical properties of clay and improve the bearing capacity of subgrade soil. A kind of liquid polymer soil stabilizer of vinyl acetate-ethylene was used in this paper. First of all, the effects of stabilizer content and curing time on the unconfined compressive strength (UCS) and the water stability were studied to clarify the strength evolution of stabilized soil. Furthermore, the pH test, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), X-Ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR) were performed to study mineralogy, morphology, and chemistry of clay minerals and polymer stabilizer, as well as the potential interaction of the both. The results show that the stabilized soil has a quick strength growth before 14d that reaches about 89% of the final strength, then followed by a decreasing growth rate. Extending the curing time and increasing stabilizer content contribute to the dense agglomeration structure and homogenous skeleton structure. When immersed in the water, the strength has the largest reduction amplitude within the first day. The pore-filling effect, physicochemical bonds, and surface wrapping for clay particles are dominating roles of the polymer stabilizer. The formed fine colloidal particles could fill micro-pores distributed in the matrix. In addition, the polar functional group of carbonyl could create a strong electrostatic attraction and hydrogen bond with the clay minerals, further improving the adhesion, while there are no other new function groups generated. The polymers containing hydrophobic groups are recommended in consideration of water stability.

Comparative study on the degradation of HDPE, LLDPE and LDPE during multiple extrusions

Stricter regulations of plastics waste and the enforcement of higher recycling quotas has led to an increasing interest in recycling. One of the most prominent recycling strategies is mechanical recycling, which is based on sorting, pre-treatment and remelting of plastics waste. As repeated reprocessing, may be associated with a reduced quality of the obtained recyclates, approaches for the characterization of these materials by analytical techniques need to be developed. These should help to identify recyclates that will not fulfil the requirements but also to provide data allowing to take countermeasures (such as addition of a certain percentage of virgin material and/or polymer stabilizers). Three different polyethylene (PE) types (high-density (HDPE), linear low-density (LLDPE) and low-density (LDPE)) were subjected to long-time extrusion experiments in order to gain a better understanding of degradation occurring during multiple recycling steps (as expected in a circular economy). Unstabilized material as well as PE with two different stabilizers, Irganox 1010 (IX1010) and Irgafos 168 (IF168) were investigated, employing high temperature gel permeation chromatography with infrared spectroscopic detection (HT-GPC-IR), thermo desorption gas chromatography-mass spectrometry (TD-GC-MS) and high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (HPLC-qTOF-MS) (the latter primarily used for analysing stabilizer degradation). The direct comparison of the PE types revealed significant differences regarding the degradative behaviour. One main conclusion is the possible use of short n-alkanes (below 30 carbon atoms) as a quality markers in the recycling process, as unique trends in the breakdown of polymer chains were found for each PE type. Both HDPE and LLDPE showed an increase in odd numbered n-alkanes, but only HDPE showed a constant decrease in the even numbered ones. For LDPE odd and the even numbered n-alkanes were increasing during extrusion. Focusing on the effect of the added stabilizers, IF168 alone had little to no impact, whereas the presence of IX 1010 showed a beneficial influence on polymer degradation – a trend that was even intensified when both stabilizers were combined. Also, in this case differences between the three PE types could be observed. In HDPE and LDPE stabilizers were consumed during extrusion to a higher extent than in LLDPE.

Effect of polymeric stabilizers on the size and stability of PLGA paclitaxel nanoparticles

The aim of this study is to formulate polymeric paclitaxel nanoparticles with various stabilizers to improve solubility, enhance stability, maximize therapeutic efficacy and minimize detrimental toxicities of paclitaxel. In this study, trastuzumab-guided poly lactic-co-glycolic acid (PLGA)-loaded paclitaxel nanoparticles were formulated with pluronic F-127, polyvinyl alcohol (PVA), poloxamer 407, Tween-80, span 20, sodium dodecyl sulfate (SDS), and sodium lauryl sulfate (SLS) at different concentrations (0.5, 1, 1.5 and 2%) using the solvent evaporation method. The nanoparticles were evaluated for physicochemical characteristics and short and long-term stability. The optimum particle size (190 nm ± 12.42 to 350 nm ± 11.1), PDI (0.13 ± 0.02 to 0.2 ± 0.01), surface charge (-19.1mv ± 1.5 to −40.4mv ± 1.6), drug loading (2.43 to 9.5 %) and encapsulation efficiency (greater than 80 %) were obtained with these stabilizers while keeping the polymer concentration, temperature, probe size, amplitude and sonication time constant. The nanoformulations were stably stored at 4 °C. The nanoformulations of paclitaxel with pluronic F-127, polyvinyl alcohol (PVA), and poloxamer 407 were found to be more soluble, stable, uniform in physicochemical properties, and efficient in drug loading and encapsulation for improved therapeutic effects.

Enhanced Cytotoxic Activity of 6-Mercaptopurine-Loaded Solid Lipid Nanoparticles in Hepatic Cancer Treatment.

6-Mercaptopurine (6-MCP) is an antiproliferative purine analog used in acute lymphoblastic leukemia, non-Hodgkin lymphoma, and inflammatory bowel disease (Crohn's disease, ulcerative colitis). Although 6-MCP has the great therapeutic potential for cancer and immunosuppressant-related diseases, 6-MCP is not readily soluble in water, presents a high first-pass effect, short half-life (0.5-1.5 h), and implies a low bioavailability (16%). On the contrary, solid lipid nanoparticles (SLNs) are prepared from solid lipids at room temperature and body temperature. In this study, SLNs were prepared w/o/w double emulsion-solvent evaporation method using Precirol ATO5 as matrix lipid. In the emulsion stabilization, surfactant (Tween 80) and polymeric stabilizer (polyvinyl alcohol [PVA]) were used. Two group formulations using Tween 80 and PVA were compared in terms of particle size, polydispersity index, zeta potential encapsulation efficiency%, and process yield%. Differential calorimetric analysis and release properties were examined for optimum formulation, and release kinetics were calculated. According to studies, sustained release was obtained with SLNs by the Korsmayer-Peppas kinetic model. The in vitro cytotoxicity studies were performed on the hepatocarcinoma (HEP3G) cell line. According to the results, successful SLN formulations were produced, and PVA was found best stabilizer. Optimum formulation exhibited significantly higher cytotoxic effects on HEP3G than on pure 6-MCP. These results demonstrated that solid lipid nanodrug delivery systems have great potential for formulation of 6-MCP.

Medicinal importance and chemosensing applications of Schiff base derivatives for the detection of metal ions: A review

Schiff bases, named after Hugo Schiff, are formed when primary amine reacts with carbonyl compounds (aldehyde or ketone) under specific conditions. Schiff bases are economical, simple synthetic routes, and easily accessible in laboratories. They have medicinal and biological applications such as antiviral, antioxidant, antifungal, anticancer, anthelmintic, antibacterial, antimalarial, anti-inflammatory, antiglycation, anti-ulcerogenic, and analgesic potentials. A number of Schiff bases are reported for the detection of various metal ions. They are also used as catalysts, polymer stabilizers, intermediates in organic synthesis, and corrosion inhibitors. In this review, we have highlighted the recent advancements in the development of bioactive Schiff base derivatives and their sensing applications for detecting metal cations. Additionally, various spectroscopic techniques for structural characterization, such as X-ray diffraction analysis (XRD), FT-IR, UV-vis, and NMR spectroscopy were also discussed.