Mixtures Of Poly Research Articles

Alendronic acid bearing acrylic monomer to produce heat resistant polyacrylonitrile copolymer and nanofibers

ABSTRACT A new bisphosphonate-bearing acrylic monomer was synthesized with the Aza-Michael addition reaction from sodium alendronate and polyethylene glycol diacrylate. The PAN copolymer of the new monomer and acrylonitrile was heat resistant. In TGA analysis, the char yield of the copolymer at 650°C was higher than that of PAN and the commercial poly(acrylonitrile-co-methyl acrylate) while poly(acrylonitrile-co-PEGDA-Ald) copolymers started to decompose at a lower temperature. Tg of the copolymers was considerably lower than PAN. Nanofibers were produced successfully by the electrospinning method from the mixture of poly(acrylonitrile-co-PEGDA-Ald) and poly(acrylonitrile-co-methyl acrylate). The poly(acrylonitrile-co-PEGDA-Ald) was also used to extract the copper ion from water.

Micellization and clouding singularity amid the mixture of EO-PO-based star-block copolymer and cationic surfactants in aqueous solution

We herein report the micellization study on mixtures of poly(ethylene oxide)-poly(propylene oxide) (PEO-PPO) star-block copolymer, Tetronics®1304 (T1304) with several cationic conventional and Gemini surfactants (GS) using plethora of physicochemical techniques viz. cloud point (CP), tensiometry, fluorescence, dynamic light scattering (DLS) and small angle neutron scattering (SANS). The results indicate resilient interactions of T1304 with GS in comparison to the conventional analogues with similar alkyl chain length. The presence of cationic surfactants, at lower temperature, induces micellization. Hence, a significant drop can be noted in the critical micellization temperature (CMT) of T1304 as observed from the spectral study. However, in the post-micellar regime, the presence of cationic surfactants enhance the surface charge on the copolymeric micelle which leads to the micellar breakdown resulting into the formation of mixed micelles. Addition of salt, on the contrary, compensated the effect of surfactants and counteracted the hydrophilicity generated in the presence of surfactants.

Fabrication and characterization of functionalized nano-silica based transparent superhydrophobic surface

Current work is focused on the fabrication and characterization of super-hydrophobic transparent thin-film coating to enhance the long-term mechanical and chemical stability and durability of the surface. Silica nanoparticles (Si-NPs) were first synthesized by the Stober process and then were functionalized to create a super-hydrophobic surface with trichloro (methyl) silane (TCMS) as the coupling agent. The modified Si-NPs were then associated with a mixture of poly(vinyl alcohol) (PVA) and methylethyleketone (MEK). The Si-NPs were used for the coating of selected substrate materials i.e., plastic and hemp fabric surfaces, using dip-coating and paintbrush methods. Topographical and morphological characteristics of the developed functionalized Si-NPs coatings on plastic and fabric surfaces were investigated through scanning electron microscopy (SEM) and atomic force microscopy (AFM). The morphological analysis showed that the thin-film coatings of Si-NPs were homogeneously applied. X-ray diffraction (XRD) revealed the existence of Si-NPs on the surface. The surface hydrophobicity was measured experimentally through water contact angle (WCA) and water sliding angle (WSA) analysis. The largest WCA on fabric and the plastic slab was measured as 176.79° ± 3° and 171.91° ± 4° while the measured WSA for these substrates were 5° ± 1° and 3° ± 0.5°, respectively. The maximum optical transmittance was achieved 89 % for the plastic slab. The coatings associated with PVA showed the best results for superhydrophobicity and durability.

DLP printing of hydrogel/calcium phosphate composites for the treatment of bone defects

In this work, biocomposites based on hydrogels filled with calcium phosphates were fabricated using DLP method of 3D printing for the treatment of bone defects. The possibility to tune the functional properties of hydrogels such as degradation, swelling, and mechanical behavior by using a mixture of monomers with different functionality and different calcium phosphates was shown. Mechanical properties, photopolymerization, swelling behavior, and microstructure of hydrogels based on a mixture of poly(ethylene glycol) methacrylate/poly(ethylene glycol) diacrylate (PEGMA/PEGDA) monomers with different composition were studied. It was found that the usage of α-tricalcium phosphate (α-TCP) powder as a filler for hydrogels allowed to increase the filler fraction up to 60 ​wt% in comparison with octacalcium phosphate (OCP) and brushite (10 ​wt%) without significant thickening of photosuspension for DLP printing. Finally, the main parameters of DLP printing for biocomposites based on PEGMA/PEGDA hydrogels were found, and the macroporous biocomposite filled with 60 ​wt% α-TCP with gyroid structure was obtained.

A facile design of EGF conjugated PLA/gelatin electrospun nanofibers for nursing care of in vivo wound healing applications

Nano (or) microfiber structures made from biodegradable polymers offer many benefits for biomedical applications, including the tissue engineering system. In this study, a mixture of poly (lactic acid) (PLA)/gelatin (GEL) conjugated epidermal growth factor (EGF) electrospun nanofiber scaffolds, which may have potential applications for nursing care of diabetic wound healing. The amount of EGF conjugation on the PLA/GEL nanofibers was quantitated by X-ray photoelectron spectroscopy. A morphological examination of the electrospun nanofibers was performed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which has bead-free morphology nanofibers. After characterizing, the PLA/GEL and PLA/GEL/EGF scaffolds were selected for further investigation based on their superior mechanical properties, including tensile strength, maximum elongation, and tensile modulus. We evaluated the antibacterial activity, cell proliferation and the efficiency of diabetic wound healing in vivo. The antibacterial effect of EGF present in the PLA/GEL nanofibers was assessed using the zone inhibition test against S. aureus and E. coli. In vitro cell proliferation activity was well maintained after the PLA/GEL conjugation and was compared to that of EGF with L929 fibroblast cells. The nanofiber PLA/GEL conjugated with EGF exerted greater curative activities in vivo compared to the control groups or EGF solutions. This study showed that the nanofiber PLA/GEL in combination with EGF could potentially be used as a novel material for nursing care of wound healing by antibacterial, increasing inflammatory cell, and re-epithelialization.

Optimizing crystallinity of engineered poly(lactic acid)/poly(butylene succinate) blends: The role of single and multiple nucleating agents

AbstractThis work deals with the design and experimental development of formulations based on bioplastic materials optimized for the production processes of high‐performance packaging products, suitable for food contact and characterized by high thermo‐mechanical stability. For this purpose, mixtures of poly (L‐lactic acid) (PLLA)/poly (butylene succinate) (PBS) (PLA/PBS) containing micro‐lamellar talc as reinforcing agent and inorganic nucleating agent have been obtained on a pre‐industrial scale. Through the addition in formulation of two organic nucleating agents, ethylene (bis)stereamide (EBS) and poly (D‐lactic acid) (PDLA), evaluated separately and in combination with each other, four different PLA/PBS formulations were produced by means of a co‐rotating twin screw extruder. The effects on the crystallinity of the materials obtained first in the form of pre‐dried pellets, then in the form of films by casting extrusion and, finally, as thermoformed items were compared, according to the variation of the chosen nucleation system. The effect on the crystallinity of the materials was assessed by differential scanning calorimetry (DSC) and by Fourier transform infrared analysis in attenuated total reflection mode (ATR‐FTIR). This approach aims to provide data for the further investigation on the processability and the thermo‐mechanical properties of end‐goods achievable by converting processes (melt processing) of the bioplastic compounds.

Three-Step Synthesis of a Redox-Responsive Blend of PEG-block-PLA and PLA and Application to the Nanoencapsulation of Retinol.

Smart polymeric nanocarriers have been developed to deliver therapeutic agents directly to the intended site of action, with superior efficacy. Herein, a mixture of poly(lactide) (PLA) and redox-responsive poly(ethylene glycol)–block–poly(lactide) (PEG–block–PLA) containing a disulfide bond was synthesized in three steps. The nanoprecipitation method was used to prepare an aqueous suspension of polymeric nanocarriers with a hydrodynamic diameter close to 100 nm. Retinol, an anti-aging agent very common in cosmetics, was loaded into these smart nanocarriers as a model to measure their capacity to encapsulate and to protect a lipophilic active molecule. Retinol was encapsulated with a high efficiency with final loading close to 10% w/w. The stimuli-responsive behavior of these nanocarriers was demonstrated in vitro, in the presence of l-Glutathione, susceptible to break of disulfide bond. The toxicity was low on human keratinocytes in vitro and was mainly related to the active molecule. Those results show that it is not necessary to use 100% of smart copolymer in a nanosystem to obtain a triggered release of their content.

Antibacterial electrospun nanofibers from poly (vinyl alcohol) and Mikania micrantha with augmented moisture properties: formation and evaluation

The present study depicts the formation and characterization of electrospun nanofibrous mat generated from the mixture of poly (vinyl alcohol) (PVA) and Mikania Micrantha extract to incorporate the inherent medicinal properties of this natural herb for biomedical application. The nano mats were produced by the solution electrospinning technique with different mixing ratio under the optimum electrospinning conditions. The morphological structure, bonding behavior and moisture management properties of the developed mats were investigated by SEM, FTIR and moisture management test (AATCC 195-2009) respectively. The SEM analysis showed the homogenous and smooth fiber formation with average diameter of 75.85 ± 21.70 nm and the presence of compounds of PVA and Mikania Micrantha extracts were confirmed in by FTIR characteristic peaks at particular wave number. Results of moisture management test revealed that the developed nanomat exhibited better moisture management properties as the ratio of leaf extract is increased in comparison with PVA nanofiber alone. Aside from this, the bacterial resistance was evaluated against Gram-positive (S.aureus- ATCC 6538) bacteria using disc diffusion method for the sample developed at maximum mixing ratio of Mikania Micrantha extract (80%) which shows the formation of inhibition zone up to 12 mm due to the antibacterial constituents of Mikania Micrantha extract. Thus, the developed mats have a great potential to be used as biodegradable, biobased and antibacterial one in biomedical applications.

Hybrid Beads Bearing Immobilized Bacteria as Advanced Means for the Removal of Acid Blue 93 Dye

This paper describes the preparation of three- component hybrid copolymer beads, with water purification features. These newly developed hybrid beads were prepared starting from a mixture of poly(acrylonitrile- co- methacrylic acid) (PAN-co-PMAA), polyvinyl alcohol (PVA) and magnetite (Fe3O4), respectively. The preparation itself involved a Wet Phase Inversion (WPI) process. A Pseudomonas sp. strain was immobilized onto previously mentioned beads, before and after activation of the beads surface with glutardialdehyde, and afterwards used for the amendment of simulated water bearing an azo- blue dye, i.e. Acid Blue 93. In order to highlight the immobilization of Pseudomonas sp. strain, FTIR spectra and TGA results were recorded. CFU measurements as well as SEM images further provided evidence towards the occurrence of immobilization. The biodegradation studies of Acid Blue 93were carried out by means of UV spectroscopy at various contact times (24; 72 and 144 h) of the hybrid beads with the targeted dye.

Concept: fluorescent and waterlock-expansion material to detect potential of corrosion on metal substrate

PurposeThis paper aims to discuss the use of the sensor material in coating to detect defects which can cause corrosion on metal substrate. This coating consists of sodium polyacrylate (SP) to detect the presence of water and fluorescence substance 2-[4-(piperidin-1-yl)-5H-chromeno-[2,3-d]pyrimidin-2-yl]phenol [benzopyranopyrimidine (BPP)] to detect crack formation.Design/methodology/approachThe coating resin is a mixture of poly(methyl methacrylate) (PMMA) and poly (methyl vinyl ether-alt-maleic anhydride). The additives are used to provide a visual indicator to the observer for when the coating exhibits any defects, so that quick action can be taken before corrosion develops further. SP has absorbent properties and expand when in contact with water, while BPP exhibits high luminous intensity in its solid form that is easily perceivable when exposed to UV. PVM/MA was used as the binder with ethanol as the solvent. The resistance of this coating towards water penetration was investigated using electrochemical impedance spectroscopy (EIS). The coating’s performance was observed in terms of visible optical appearance.FindingsThe sensor coating developed in this project serves as visual aid to the observer through the expansion of SP and high fluorescence of BPP material after the top coat is physically damaged. These findings are in provision of preventive measures that can be taken in case of top coat failure.Research limitations/implicationsThe resistance of the coating that contained SP could not be investigated with EIS due to its ability to expand immediately when in contact with liquids.Practical implicationsThe coating developed in this study may be to detect corrosion.Originality/valueThe sensor material used has not been previously studied in applications to detect the presence of water or used to detect crack formation.

Shape Memory Polymer Foam with Programmable Apertures

In this work, a novel type of polyester urethane urea (PEUU) foam is introduced. The foam was produced by reactive foaming using a mixture of poly(1,10–decamethylene adipate) diol and poly(1,4–butylene adipate) diol, 4,4′-diphenylmethane diisocyanate, 1,4–butanediol, diethanolamine and water as blowing agent. As determined by differential scanning calorimetry, the melting of the ester-based phases occurred at temperatures in between 25 °C and 61 °C, while the crystallization transition spread from 48 °C to 20 °C. The mechanical properties of the foam were simulated with the hyperplastic models Neo-Hookean and Ogden, whereby the latter showed a better agreement with the experimental data as evidenced by a Pearson correlation coefficient R² above 0.99. Once thermomechanically treated, the foam exhibited a maximum actuation of 13.7% in heating-cooling cycles under a constant external load. In turn, thermal cycling under load-free conditions resulted in an actuation of more than 10%. Good thermal insulation properties were demonstrated by thermal conductivities of 0.039 W·(m·K)−1 in the pristine state and 0.052 W·(m·K)−1 in a state after compression by 50%, respectively. Finally, three demonstrators were developed, which closed an aperture or opened it again simply by changing the temperature. The self-sufficient material behavior is particularly promising in the construction industry, where programmable air slots offer the prospect of a dynamic insulation system for an adaptive building envelope.

Ultrastrong adhesion of fluorinated graphene on a substrate: In situ electrochemical conversion to ionic-covalent bonding at the interface

Graphene shows unique properties such as high mechanical strength and high thermal and chemical stability, making it promising for versatile applications. However, the lack of either interlayer or interface covalent bonds causes this type of 2D materials assembled via van der Waals forces to suffer from weak adhesion with the underlying substrates, thus hindering their application. In this study, a novel method based on a hydrothermal reaction was proposed to synthesize fluorinated graphene (FG) through a facile, scalable, and highly safe process, where a mixture of poly(perfluorosulfonic acid) (C7HF13O5S·C2F4, PFSA) and graphene oxide (GO) as the precursor was employed. The FG sheets prepared by the electrophoretic deposition (EPD) method exhibit superior conformity layered structure on a metal foil. Due to the in situ formation of ionic-covalently bonded F–Cu–F and Cu–F–C between fluorine on the FG sheets and dissolved Cu ions from the copper foil, the deposited film shows ultrastrong adhesion that can sustain up to 3 MPa of shear force. Furthermore, by changing the parameters in the EPD process, such as the EPD duration and applied voltage, the thickness and hydrophobicity of the film can be well controlled from 0.20 μm to 2.51 μm with a contact angle from 93.03° to 122.44°. This study provides a new strategy to prepare a robust film for the assembly of 2D materials, not limited to graphene, with ultrastrong adhesion on substrates, which could solve the long-reported issue of weak adhesion and low durability of graphene-/2D-based functional composites and coatings.

Ultrathin single and multiple layer electrospun fibrous membranes of polycaprolactone and polysaccharides

Electrospinning was used to produce fibrous membranes, in single and multiple layers, from poly(ε-caprolactone), pullulan, and from mixtures of poly(ε-caprolactone) with potato modified starch and β-glucan. It was possible to obtain single-layer membranes from solutions of pullulan in water, poly(ε-caprolactone) in chloroform, and from mixtures of poly(ε-caprolactone)/β-glucan and poly(ε-caprolactone)/potato modified starch in chloroform. Scanning electron microscopy images showed the formation of ultrathin homogeneous fibers from electrospun poly(ε-caprolactone) and pullulan, whereas the fibers obtained from mixtures of poly(ε-caprolactone)/ β -glucan and poly(ε-caprolactone)/potato modified starch had different sizes and morphologies, as well as irregular microstructures, characterized by the presence of beads. Contact angle analyses showed that pullulan membranes were extremely hydrophilic, while poly(ε-caprolactone) membranes were predominantly hydrophobic. Subsequently, poly(ε-caprolactone)-pullulan-poly(ε-caprolactone) multilayer membranes, with intermediate wettability, were prepared by successive electrospinning steps. Infrared spectroscopy and calorimetric analyses showed the presence of both polymers and the absence of changes in their structure and stability due to electrospinning, indicating adequate compatibility between the two polymers. We foresee that the polyester-polysaccharide multilayer membrane might be used as a biodegradable vehicle for active agents with different hydrophobicity, with applications as food packaging and biocompatible scaffold materials.

CHARACTERIZATION OF NON-STEROIDAL ANTI-INFLAMMATORY DRUGS IN TABLETS BY DIRECT ANALYSIS IN REAL TIME/TIME OF FLIGHT/MASS SPECTROMETRY (DART/TOF/MS) WITHOUT SAMPLE PREPARATION

This powerful mass spectrometric technique was used to investigate four profen drugs which are widely used as non-steroidal anti-inflammatory drugs for treating pain, fever and inflammation: Ibuprofen (M = 206), Flurbiprofen (M = 244), Naproxen (M = 230) and Ketoprofen (M = 254). The DART ion source was operated in positive ion mode with helium as the ionizing medium heated to 250°C. A solution containing a mixture of poly (ethylene glycol) standards PEG 600 and PEG 200 was used for mass calibration. A standard solution of each pure standard was manually introduced by using a small glass rod. The high resolution mass spectra of Ibuprofen, Flurbiprofen, Naproxen and Ketoprofen showed the presence of an intense protonated molecular ion [M + H]+ at 207.13860, 245.09776, 231.10632 and 255.09966 Da, respectively. Moreover, a non-protonated molecular ion M+ was also observed except for Ketoprofen. On the other hand, an intense adduct ion [M + H2O]+ was also present in the four mass spectra. Since these profens are 2-arylpropionic acid derivatives they have a known tendency to form dimers; indeed, an intense protonated ion corresponding to this dimer [2M + H]+ was present in the spectrum of Ibuprofen, Flurbiprofen, Naproxen and Ketoprofen at 413.27102, 489.19944, 461.19266 and 509.19662 Da, respectively. The presence of profens as active ingredients was then investigated in various pharmaceutical tablets collected from the local market. A small piece of each solid tablet was submitted to the DART ion source without any sample preparation. The obtained mass spectrum showed the characteristic peaks corresponding to each profen as active principle, as well as the other ingredients of the tablet.

Ceramic-Doped in Cross-Linked Solid Polymer Electrolyte for Solid-State Batteries

Replacing liquid electrolytes with solid-state Li-ion conductors is one way to achieve safe rechargeable batteries with high energy density. Semi-interpenetrating polymer network (s-IPN) was synthesized from the mixture of poly(propylene carbonate), poly(ethylene glycol) methyl ether acrylate, poly(ethylene glycol) diacrylate (PEGDA), and lithium bis(trifluoromethane)sulfonamide salt via one-pot thermal curing method. The crosslinker PEGDA content and salt concentration were optimized and the best result was abtained at a molar ratio of EO:Li ∼ 14:1. The electrolyte with higher salt concentration had lower ionic conductivity, consistent with higher glass transition temperature of poly(ethylene glycol) chain. Differential scanning calorimetry has shown a low degree of crystallinity when lithium lanthanum zirconate doped tantalum (LLZTO) was added to the s- IPN electrolyte which corresponds to an increase in ionic conductivity, 4.5 x 10-4 S/cm at 40°C. The resulting composite polymer electrolyte (CPE) showed high electrochemical stability up to 5.5 V. Lithium plating and stripping at 0.1 mA/cm2 at room temperature revealed a stable Li/electrolyte interface and no dendrite formation. Cycling performance of a full solid-state cell made with the CPE using LiFePO4 as the cathode will be discussed. Figure 1

A heatproof electrospun PES/PVDF composite membrane as an advanced separator for lithium‐ion batteries

AbstractIn the present paper, the physicochemical properties of a novel composite fibrous membrane, based on a mixture of poly(aryl ether sulfone) (PES) and poly(vinylidene fluoride) (PVDF), as separators for lithium‐ion batteries are reported and discussed. Compared with the pure PVDF fibrous membrane, the introduction of PES can decrease the PVDF crystallinity while increasing the proportion of α‐phase. Meanwhile, the initial thermal decomposition temperature is enhanced by 24°C. Heat shrinkage tests and thermomechanical analyzers indicate the composite membrane has significantly improved thermal‐dimensional stability. The shrinkage rate of the composite membrane after heat‐treated at 180°C for 2 hr is only 4.8%, which is far below the Celgard separator (82%) and the pure PVDF fibrous membrane (75%). The composite membrane with excellent wettability demonstrates a high ionic conductivity (1.69 × 10−3 S cm−1) at room temperature as well as high electrolyte uptake (595%). The cells assembled with the composite membrane exhibit more stable cycle performance, capacity retention, and C‐rate capability than that with polyolefin separator. These results suggest that PES/PVDF composite fibrous membrane is an effective separator for high‐performance Lithium‐ion batteries.

Thin dielectric-layer-enabled low-voltage operation of fully printed flexible carbon nanotube thin-film transistors

The quality of printable dielectric layer has become one of the major obstacles to achieving high-performance fully printed transistors. A thick dielectric layer will require high gate voltage to switch the transistors on and off, which will cause high power dissipation in printed devices. In response to this challenge, fully printed carbon nanotube (CNT)-based thin-film transistors (TFTs) have been fabricated on flexible membranes such as polyimide and liquid crystal polymer using aerosol jet printing. These devices can be operated at bias voltages below ±10 V (drain/gate voltages around ±6 V). This is much smaller than the previously reported values for fully printed CNT-TFTs because of using xdi-dcs (mixture of poly(vinylphenol)/poly (methylsilsesquioxane)) as the dielectric and using a single printing method. The lower voltage is a consequence of a thin dielectric layer (∼300 nm) and good uniformity in the printed CNT network. The printed CNT-TFTs show on/off ratio >105, and mobility >5 cm2V−1s−1. Layer-by-layer deposition of CNT allows highly uniform and dense network formation, and the optimization of the xdi-dcs concentration using natural butyl alcohol provides high-yield printing of a thin dielectric layer. Collectively, this work shows the potential of using fully printed CNT-TFTs in various flexible electronic applications such as wearable sensors, actuators, artificial skin, displays and wireless tags and antennas.

Recycled Red Mud–Decorated Porous 3D Graphene for High‐Energy Flexible Micro‐Supercapacitor

AbstractFlexible micro‐supercapacitors, with high energy and power density, and using materials with a low environmental impact are attractive for next‐generation energy storage devices. Carbon‐based materials are widely used for supercapacitors but can be increased in energy density via combination with metal oxides. Red mud is an iron‐oxide‐rich by‐product of aluminum production, which needs to be more widely utilized to reduce its environmental damage. To achieve a flexible micro‐supercapacitor device with increased energy density, a laser‐induced graphene (LIG) supercapacitor is realized from a polyimide substrate, decorated with red‐mud nanoparticles (LIG‐RM), employing a solid‐state ionic liquid electrolyte with a mixture of poly(vinylidene fluoride) (PVDF), 1‐ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMI][TFSI]), and 1‐ethyl‐3‐methylimidazolium tetrafluoroborate ([EMIM][BF4]). The fabricated two‐electrode flexible device, in an interdigitated planar design, with inkjet‐printed silver current collectors, has a high energy of 0.018 mWh cm−2 at a power of 0.66 mW cm−2, with 81% of capacitance retained after 4000 cycles and good resistance to bending and flexing. The high energy storage performance, brought about through the combination of graphene and red‐mud nanoparticles, which would—if not utilized—be an environmental liability, shows a promise as a material for future energy storage with low environmental impact.

Continuum Description of the Role of Negative Transference Numbers on Ion Motion in Polymer Electrolytes

New experimental techniques such as electrophoretic NMR (eNMR) are emerging as powerful methods for directly measuring ion velocities in electrolytes under applied electric fields. The aim of this theoretical study is to predict the spatial- and temporal-dependence of these velocities of ions as a function of the magnitude of the applied field and salt concentration. It has recently been shown that mixtures of poly(ethylene oxide)-based (PEO) and lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) electrolytes exhibit negative cation transference numbers in a certain salt concentration range. In this range, the cation motion at early times is directed to the positive electrode at all locations in the cell; ion migration dominates in this regime. As time progresses, the cation velocity in finite zones near both the electrodes changes sign. These zones grow rapidly with time, reflecting the increasing importance of diffusion, and a point in time is reached beyond which the cation velocity in the entire cell is directed toward the negative electrode. Our work reveals the limited time window over which the results of eNMR can be used to determine the transference number. More importantly, it shows how to account for the effect of diffusional flux in such experiments.

Prominent Enhancement of Cisplatin Efficacy with Optimized Methoxy Poly(ethylene glycol)-Polycaprolactone Block Copolymeric Nanoparticles.

Chemotherapy has been one of the major standard treatments for a variety of cancers. cis-Dichlorodiamminoplatiunum (II) (cisplatin, CDDP), as one of the anticancer agents, demonstrated excellent efficacy against tumor and has been an indispensable component in chemotherapy, chemoradiation, chemo-molecular targeted therapy and chemo-immunotherapy. However, its therapeutic concentration was limited since its inevitable toxicity. Previously, we have constructed CDDPloaded nanoparticles (NPs) with mixture of poly(ethyleneglycol)-polycaprolactone (PEG-PCL) and polycarprolactone (HOPCL) by a facile method. The most optimal proportion of the two copolymers was selected through a series of physical, chemical, cytological and histological evaluations. In the present study, we explored the mechanisms of NPs and observed the in vivo antitumor effect after administrating CDDP-loaded PEG-PCL NPs. Positron emission tomography as well as computed tomography (PET/CT) were adopted for detecting tumoral metabolic activity. Images from fluorescence microscope revealed superior cellular uptake of CDDP-loaded NPs with rhodamine B aggregated intracellularly in cancer cells. Similar apoptotic rates between free CDDP group and CDDP-loaded NPs group was measured by flow cytometry. Tumor volumes and murine weights confirmed the superiority of CDDP-loaded NPs in therapeutic efficacy as compared with free CDDP. Blood tests showed milder side effects in CDDP-loaded nanoparticle group. PET/CT images illustrated less uptake intensity of FDG in mice received CDDP-loaded NPs than free CDDP. Our results suggest that PEG-PCL/PCL NPs could be a promising antitumor drug carrier for CDDP delivery with solid efficacy and minor side effects.