Nanoscale Particle Size Research Articles

Recent Advances on Alloyed Quantum Dots for Photocatalytic Hydrogen Evolution: A Mini-Review

Hydrogen is becoming a promising eco-friendly energy carrier to replace traditional nonrenewable fossil fuels. In this context, photocatalytic water splitting photosystems are considered a green tactic. Alloyed quantum dots (QDs) are considered as earth abundant, low cost, and environmentally friendly photocatalysts to be utilized effectively in photocatalytic H2 evolution. H2 production efficiency greatly depends upon tunable optical and electronic properties associated with chemical composition as well as nanoscale particle sizes of alloyed QDs. Recent efforts toward the fabrication of various alloyed QDs by varying the surface atomic ratio and ligand exchange for photocatalytic hydrogen production has been presented and appraised here. Furthermore, in this review, we presented the microstructure and optical properties of alloyed QDs with their advantages and the construction of efficient cadmium-bound and cadmium-free alloyed QDs toward a photocatalytic hydrogen evolution reaction. At last, the challenges as well as critical issues of alloyed QDs and alloyed QDs-based photocatalysts for H2 evolution has been proposed, with the hope that this mini-review will give a superior perceptive of different alloyed QDs.

Construction of Surface-Modified Polydopamine Nanoparticles for Sequential Drug Release and Combined Chemo-Photothermal Cancer Therapy.

Single chemotherapy often causes severe adverse effects and drug resistance to limit therapeutic efficacy. As a noninvasive approach, photothermal therapy (PTT) represents an attractive option for cancer therapy due to the benefits of remote control and precise treatment methods. Nanomedicines constructed with combined chemo-photothermal properties may exert synergistic effects and improved antitumor efficacy. In this study, we developed polydopamine (PDA)-coated nanoparticles grafted with folic acid (FA) and polyethylene glycol to transport doxorubicin (DOX) for targeted cancer therapy. The results showed that this delivery vehicle has a nanoscale particle size and narrow size distribution. No particle aggregation or significant drug leakage was observed during the stability test. This system presented excellent photothermal conversion capability under near-infrared light (NIR) laser irradiation due to the PDA layer covering. In vitro dissolution profiles demonstrated that sequential and triggered DOX release from nanoparticles was pH-, NIR irradiation-, and redox level-dependent and could be best fitted with the Ritger-Peppas equation. FA modification effectively promoted the intracellular uptake of nanoparticles by HepG2 cells and therefore significantly inhibited cell recovery and induced tumor cell apoptosis. Compared to the free DOX group, nanoparticles reduced the DOX concentration in the heart to avoid drug-related cardiotoxicity. More importantly, the in vivo antitumor efficacy results showed that compared with the single chemotherapy strategy, the nanoparticle group exerted combined and satisfactory tumor growth inhibition effects with good biocompatibility. In summary, this nanocarrier delivery system can organically combine chemotherapy and PTT to achieve effective and precise cancer treatment.

Preparation, stabilisation, isolation and tableting of valsartan nanoparticles using a semi-continuous carrier particle mediated process

This work investigated the technical feasibility of preparing, stabilizing and isolating poorly water-soluble drug nanoparticles via a small-scale antisolvent precipitation process operating in semi-continuous mode. Specifically, a novel semi-continuous process was demonstrated for the carrier particle mediated production, stabilization and isolation of valsartan nanoparticles into a solid form using montmorillonite clay particles as the carrier. The semi-continuous process operated robustly for the full duration of the experiment (~16 min) and steady-state conditions were reached after ~5 min. Nanoparticles of valsartan (51 ± 1 nm) were successfully prepared, stabilized and isolated with the help of montmorillonite (MMT) or protamine functionalized montmorillonite (PA-MMT) into the dried form by this semi-continuous route. The dissolution profile of the isolated valsartan nanocomposite solids was similar to that of valsartan nanocomposite solids produced via the corresponding laboratory scale batch mode process, indicating that the product quality (principally the nanoscale particle size and solid-state form) is retained during the semi-continuous processing of the nanoparticles. Furthermore, tablets produced via direct compression of the isolated valsartan nanocomposite solids displayed a dissolution profile comparable with that of the powdered nanocomposite material. PXRD, DSC, SSNMR and dissolution studies indicate that the valsartan nanoparticles produced via this semi-continuous process were amorphous and exhibited shelf-life stability equivalent to > 10 months.

Alginate nanogels-based thermosensitive hydrogel to improve antidepressant-like effects of albiflorin via intranasal delivery

Depression is a primary public health problem. However, current antidepressants work slowly, and together with side effects. Herein, the alginate nanogels were constructed to load albiflorin (albiflorin nanogels), which further formed albiflorin nanogel loaded self-assembled thermosensitive hydrogel system (albiflorin-NGSTH) and were used to improve its antidepressant effects. The nanogel showed a nano-scaled particle size and stronger antioxidant activity. Rheological studies showed that albiflorin-NGSTH had a sol-gel transition at approximately 28 °C. Albiflorin-NGSTH quickly entered the brain by intranasal delivery, and had a continuously release for albiflorin. Preliminary results of mice behavioral despair tests found that albiflorin-NGSTH had no effects on independent exploratory behavior and anxiety of the mice, and significantly decreased immobility duration of the mice in tail suspension test (TST). Moreover, the intranasally administrated albiflorin-NGSTH at a low dose improved depressive behavior, decreased levels of proinflammatory cytokines, and repaired neuronal damage of chronic unpredictable mild stress (CUMS) rats, which indicated an excellent potential for depression therapy. The treatment of albiflorin-NGSTH on depressive disorder was achieved by regulating signal pathway related to depression. Therefore, albiflorin-NGSTH has an excellent potential for clinical application in intranasal drug delivery systems.

Cheap Nano-Adsorbents Based on Zno/Mineral Nanocomposites for Removal of Chloroform from Water Solution

Background: Chloroform, as a hazardous chemical, can contaminate water resources via the reaction of chlorine as an antiseptic chemical with humic acids resulted from agricultural activities. In humans, chloroform may cause dizziness, heart disorders, and disorders of the nervous system. Hence, its removal is of crucial importance. Objectives: The current study aimed to propose cheap and efficient adsorbents to remove chloroform from water. Methods: Four different nanomaterials (ZnO, ZnO/graphene oxide (ZnO/GO), ZnO/GO/Zeolite, and GO/Zeolite nanocomposites) were prepared and characterized with X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) images. Textural properties of the nano- adsorbents were evaluated using Brunauer Emmet Teller (BET) and Barrett-Joyner-Halenda (BJH) techniques. Different isotherms and kinetic models were studied. The effect of pH on the removal efficiency of the nano-adsorbents was tested. Regenerability of the nano-adsorbents towards the removal of the chloroform was also evaluated. Results: XRD patterns and FESEM images of the nanocomposites confirmed lattice structures and nanoscale particle size of the prepared nanocomposites. According to the BET and BJH models, all samples had mesoporous structures. The BJH cumulative surface area of pores of ZnO, ZnO/GO, ZnO/GO/Zeolite, and GO/Zeolite nanocomposites were 8.5, 26.4, 17.2, and 20.8 m2/g, respectively. The best removal speed and efficiency were obtained according to the different isotherm and kinetic models for the removal of chloroform ZnO/GO nanocomposites. All adsorbents revealed characteristic adsorption in the pH range of 7 to 8. Conclusion: The ZnO/GO, a cheap and efficient nanocomposite, showed the best performance to remove chloroform from water samples due to its superior textural property. Hence, it can be used to remove chloroform from water for up to 5 cycles.

Folic Acid-Modified Erythrocyte Membrane Loading Dual Drug for Targeted and Chemo-Photothermal Synergistic Cancer Therapy.

To overcome the challenges of systemic toxicity and weak tumor selectivity caused by traditional antitumor drugs, numerous nanocarrier systems have been developed in recent decades, and their therapeutic effect has been improved to varying degrees. However, because of the drug resistance effect and metastasis involved in tumor recurrence, a single chemotherapy can no longer satisfy the diversified treatment needs. Recently, the application of chemotherapy in combination with thermotherapy as a synergistic approach has been proven to be more effective, and it provides a new strategy for cancer therapy. In this work, by utilizing the unique properties of erythrocytes, a surface-modified erythrocyte membrane was constructed as a novel nanocarrier system (DOX and ICG-PLGA@RBC nanoparticles, DIRNPs for short) for the simultaneous transportation of chemotherapeutic drugs (doxorubicin, DOX) and photothermal agents (indocyanine green, ICG) to achieve the effects of long-term circulation, active tumor targeting, and triggered drug release. The results indicated that DIRNPs have a nanoscale particle size of 158.4 nm with a narrow size distribution and a negative surface charge of -5.79 mV. No particle aggregation or remarkable drug leakage was observed during the 30 day storage test, and because of the excellent photothermal conversion ability of ICG, the local temperature of DIRNPs could dramatically increase from 33.7 to 49.8 °C in 10 min under near-infrared (NIR) laser irradiation. The in vitro drug dissolution data demonstrated that the DOX release from the DIRNPs was pH-dependent and NIR-triggered. Folic acid modifications of the erythrocyte membrane effectively facilitated the intracellular uptake of DIRNPs by HepG2 cells and, as a result, it significantly inhibited tumor cell growth, promoted reactive oxygen species levels, induced cell apoptosis, and restricted cell recovery and migration. In vivo pharmacokinetics and biodistribution studies indicated that the DIRNPs prolonged the half-life of DOX from 6.03 to 17.6 h and remarkably reduced the DOX level in the heart to avoid drug-related cardiotoxicity. More importantly, the DIRNPs exerted excellent in vivo antitumor efficacy against H22 tumors with superior safety. In conclusion, utilizing the advantageous properties of erythrocytes to construct a tumor-targeted biomimetic nanocarrier for codelivery of chemotherapeutics and photothermal agents to produce synergistic effects is considered an effective method for cancer therapy.

Na10SnSb2S12: A nanosized air-stable solid electrolyte for all-solid-state sodium batteries

• Na 10 SnSb 2 S 12 with nanoscale particle size is synthetized by liquid phase process. • Na 10 SnSb 2 S 12 shows ion conductivity of 0.52 mS cm −1 . • Excellent air stability is achieved by replacing phosphorus with antimony. • All-solid-state sodium batteries display excellent cycling stability and rate capability. All-solid-state sodium batteries are attractive for large-scale energy storage due to their low cost, wide variety of cathode materials and high safety. And sulfide sodium solid electrolytes are key to enable room-temperature all-solid-state sodium batteries. Herein, we report the quaternary nanosized solid electrolyte Na 10 SnSb 2 S 12 synthetized through liquid phase process. The crystalline structure and diffusion path of Na 10 SnSb 2 S 12 are investigated through the first principles calculations. The Na 10 SnSb 2 S 12 electrolyte presents a room temperature conductivity of 0.52 mS cm −1 at 25 °C and very low activation energy of 0.23 eV as well as excellent air stability by replacing phosphorus with antimony. Moreover, the small particle size of the solid electrolytes enhances the contact between solid electrolyte and electrode, reducing the interfacial contact resistance. Consequently, the TiS 2 /Na 10 SnSb 2 S 12 /Na all-solid-state sodium batteries show excellent cycling stability and exhibit a capacity of 119.6 mAh g −1 after cycling for 100 cycles at 100 mA g −1 .

In vitro antioxidant and antidiabetic activity of essential oils encapsulated in gelatin-pectin particles against sugar, lipid and protein oxidation and amylase and glucosidase activity.

The in vitro antioxidant and antidiabetic activities of Oliveria decumbens, Thymus kotschyanus, Trachyspermum ammi, and Zataria multiflora essential oils incorporated into gelatin‐pectin composite were investigated. The gas chromatography–mass spectrometry characterization revealed that thymol (1.2%–86.4%), carvacrol (3.2%–52.4%), gamma‐terpinene (0.0%–12.7%), para‐cymene (3.2%–5.2%), geraniol (0.0%–14.5%), and spathulenol (0.0%–13.6%) are the major constituents of the essential oils. Gelatin‐pectin composite incorporated with the essential oils exhibited acidic pH (2.40–3.04), low conductivity (265–278 µS/cm), low surface tension (19.0–23.5 mN/m), low Newtonian viscosity (23.7–28.5 mPa.s), negative zeta‐potential (14.2–16.9 mV), and nanoscale particle size (313–336 nm). These rheological properties result in the production of globular gelatin‐pectin nanoparticles with a size range of 500–700 nm. The FTIR spectra of gelatin‐pectin and gelatin‐pectin‐essential oils to some extent were similar, suggesting the noncovalent interactions between them. Gelatin‐pectin composite incorporated with the essential oils displayed antiglucose oxidation (130–150 µg/ml) antilipid peroxidation (120–130 µg/ml), antiprotein oxidation (150–168 µg/ml), and antiprotein glycation (145–170 µg/ml) as well as antiamylase (216–230 µg/ml), and antiglucosidase (212–238 µg/ml) activity. The essential oils strongly improved the antioxidant capacity of the gelatin‐pectin composite so strongly which can be recommended as a natural compound for oxidative stress management.

In vitro and ex vivo anti-diabetic and anti-hyperglycemic properties of Zataria multiflora essential oil.

The underlying mechanism involved in the onset of many diseases such as diabetes is oxidative stress. Zataria multiflora has a very high antioxidant power that can be used in the antioxidant therapy of the diabetes symptom. The in vitro antioxidant and anti-diabetic capacity of Zataria multiflora essential oil (ZMEO) incorporated in dendrosome against glucose oxidation, lipid oxidation, protein oxidation, and protein glycation was analyzed. The ex vivo antioxidant capacity of dendrosomal ZMEO were explored against hyperglycemia (HG)-induced oxidative stress. Inhibition of oxidative stress markers; NADH oxidase (NOX), nuclear respiratory factor 2 (NRF2) and nuclear factor kappa B (NF-kB) were examined. Dendrosomal-ZMEO displayed low conductivity, low surface tension, low zeta-potential, nanoscale particle size and low viscosity that suggest dendrosomal-ZMEO could remain stable in biological fluids. FTIR spectra of dendrosomal-ZMEO indicated the non-covalent interactions between dendrosome and ZMEO and the entrapment of ZMEO droplets in the dendrosome network. Dendrosomal-ZMEO displayed good anti-glucose oxidation, anti-lipid peroxidation, anti-protein oxidation, and anti-protein glycation activity. Dendrosomal ZMEO strongly reduced intracellular hydrogen peroxide and NOX expression and activity in HG-treated macrophages while increased superoxide dismutase (SOD) and catalase (CAT) expression and activity in a synergistic manner. HG-treated murine macrophages showed an increased level of NF-kB expression while the decreased level of NRF2 expression compared to controls. The anti-diabetic activity of ZMEO by sequestering hydrogen peroxide and down-regulation of NOX activity is a recommended mechanism for diabetes and oxidative stress. The effect of ZMEO on decreasing NF-kB and increasing in NRF2, transcription factors involved in oxidative stress and hyperglycemia, may imply its clinical application.

Preparation of Nanosilica Powder Using Rice Husk via Precipitation Method

Silica in nanoscale has various superior properties which leads to a wide range of applications. Most researches used and metal alkoxides as the sources but very few researches attempted at preparing nanosilica powder from the agricultural waste which environmental friendly and inexpensive. This research is presented as the studies of optimization of parameters involved during preparation, aimed to improve the purity of silica produced. In this work, rice husk ash (RHA) precursor was subjected to precipitation method in order to produce nanosilica powder. Acid leaching and thermal treatment were done as a pre-synthesis process. The process parameters that have been studied were the refluxed NaOH concentration, heating time, and temperature, in which the properties were then evaluated during characterization process. The results from X-Ray Flourescence (XRF) confirmed that it is possible to extract 100% purity of silica from RHA treated by the combination of thermal treatment, acid leaching, refluxed with 2.5 M of NaOH and heated at 50°C for 48 hours. X-Ray Diffraction (XRD) illustrated that the produced silica is in amorphous state. Meanwhile, the mean particle size of the spherical shape of silica obtained ranging from 44.7 nm to 1.23 μm. Therefore, the best mean particle size obtained was by using the sample refluxed with 2.5 M NaOH and heated at 50°C for 48 hours, which were confirmed by Scanning Electron Microscope (SEM) and Field Emission Scanning Electron Microscope (FESEM). These findings on the optimum parameters indicate the successful production of highest purity of nanosilica powder with nanoscaled particle size.

Lauroylated Histidine-Enriched S413-PV Peptide as an Efficient Gene Silencing Mediator in Cancer Cells.

This study aimed to endow the cell-penetrating peptide (CPP) S413-PV with adequate features towards a safe and effective application in cancer gene therapy. Peptide/siRNA complexes were prepared with two new derivatives of the CPP S413-PV, which combine a lauroyl group attached to the N- or C-terminus with a histidine-enrichment in the N-terminus of the S413-PV peptide, being named C12-H5-S413-PV and H5-S413-PV-C12, respectively. Physicochemical characterization of siRNA complexes was performed and their cytotoxicity and efficiency to mediate siRNA delivery and gene silencing in cancer cells were assessed in the absence and presence of serum. Peptide/siRNA complexes prepared with the C12-H5-S413-PV derivative showed a nanoscale (ca. 100nm) particle size, as revealed by TEM, and efficiently mediated gene silencing (37%) in human U87 glioblastoma cells in the presence of 30% serum. In addition, the new C12-H5-S413-PV-based siRNA delivery system efficiently downregulated stearoyl-CoA desaturase-1, a key-enzyme of lipid metabolism overexpressed in cancer, which resulted in a significant decrease in the viability of U87 cells. Importantly, these complexes were able to spare healthy human astrocytes. These encouraging results pave the way for a potential application of the C12-H5-S413-PV peptide as a promising tool in cancer gene therapy.

A low temperature MgH2-AlCl3-SiO2 system to synthesize nano-silicon for high-performance Li-ion batteries

Nano-silicon is a star anode material for the next generation Li-ion batteries with the merits of high theoretical capacity and low voltage plateau. To date, it remains a great challenge to efficiently convert low-cost silica (SiO2) into nano-Si at a low temperature due to the solid Si-O band (the bond energy is 460 kJ mol−1). Herein, a low temperature MgH2-AlCl3-SiO2 melt system is developed to synthesize nano-Si through the reduction of SiO2 by MgH2 in the molten AlCl3. It is confirmed to be a controllable liquid-solid process with no side reactions and high Si yield of 97.6%. The battery grade nano-Si product can be obtained by suitable post-treatment without undesirable HF etching. This reaction can be initiated at as low as 150 °C, which is much lower than mostly reported synthesis routes of nano-Si. The nano-Si product with an average particle size of 22.4 nm exhibits superior electrochemical storage capacity of 1185 mA h g−1 over 300 cycles at 0.2 A g−1 and a low increased thickness of 14.5% at 2 A g−1 over 500 cycles. We believe that this low temperature melt system not only paves the new path of synthesizing nano-Si, but also gives a new insight into the effects of nanoscale particle size on the electrochemical performance of Si anode.

Effects of Nanoscale Surface Lithium Depletion on the Optical Properties and Electronic Band Structures of Lithium Transition-Metal Phosphates

The optical absorption properties of lithium transition-metal phosphates (LiTMPO4, TM = Mn, Fe, Co, Ni) with nanoscale particle sizes (300–500 nm in diameter) have been measured. The measured edges...

Liquid crystalline nanodispersion functionalized with cell-penetrating peptides improves skin penetration and anti-inflammatory effect of lipoic acid after in vivo skin exposure to UVB radiation.

In this study, the development and the performance of a new targeted liquid crystalline nanodispersion (LCN) by the attachment of cell-penetrating peptides (CPP) onto their surfaces to improve skin delivery of lipoic acid (LA) were evaluated. For that, the synthesis and characterization of this new platform as well as its spatiotemporal analysis from in vitro and in vivo topical application were explored and extensively discussed in this paper. The TAT or D4 peptides were chosen as CPP due to specific target strategies by the charge grouping on the skin surface or target the overexpressed epidermal growth factor receptor (EGFR) of cell membrane of keratinocytes, respectively. Thus, the nanoparticle characterization results when taken together suggested that designed LCNs maintained their hexagonal phase structure, nanoscale particle size, and low polydispersity index even after drug, lipopolymers, and peptide additions, which are proved to be favorable for topical skin delivery. There were no statistical differences among the LCNs investigated, except for superficial charge of LCN conjugated with TAT which may have altered the LCN zeta potential due to cationic charge of TAT amino acid sequence compared with D4. The cumulative amounts of LA retained into the skin were determined to be even higher coming from the targeted LCNs. Moreover, the exogenous antioxidant application of the LA from the LCNs can prevent ROS damage, which was demonstrated by this study with the less myeloperoxidase (MPO) activity and decrease in cytokine levels (TNF-alpha and IL-1β) generated by the oxidative stress modulation. Together, the data presented highlights the potential of these targeted LCNs, and overall, opens new frontiers for preclinical trials.

Evaluating the In vitro anti-cancer potential of estragole from the essential oil of Agastache foeniculum [Pursh.] Kuntze

Estragole is a particular metabolite which belongs to the class of phenylpropanoids that can be found in the essential oil of Agastache foeniculum . Estragole with lipophilic nature was emulsified in glycerol monostearate (GMS) emulsifier. The rheological properties of GMS/estragole emulsion including; conductivity, viscosity, surface tension, zeta-potential, and particle size was determined. The cytotoxicity effects of GMS/estragole have been evaluated using 3- (4, 5-dimethylthiazol-2-yl) −2, 5-diphenyltetrazolium Bromide (MTT) assay on MCF-7 cell line followed by apoptosis assay using ethidium bromide (EB)/acridine orange (AO) staining , Annexin-fluorescein isothiocyanate (FITC)/propidium iodide (PI) staining and caspase-3 assay. The main component of A. foeniculum essential oil was estragole (97%). GMS/estragole elusion displayed low conductivity (234 μS/cm), low surface voltage (1.86 mN/m), low zeta-potential (−4.63 mV), nanoscale particle size (232 nm) and low viscosity (2.56 mPa s). Estragole exhibited a dose-dependent cytotoxic activity in the monolayer culture of MCF7 cell line with the IC 50 values of 74 μg/mL. Staining with EB/AO showed apparent apoptotic morphological changes such as nuclear fragmentation, chromatin condensation , and destruction of cell membrane integrity in cells treated with estragole. Flow cytometry confirms that estragole significantly triggered apoptosis in the MCF-7 cell line. Estragole increased the activity of caspase-3 compared to the control untreated cells.

Glycodendron/pyropheophorbide-a (Ppa)-functionalized hyaluronic acid as a nanosystem for tumor photodynamic therapy

To enhance the drug delivery efficiency of hyaluronic acid (HA), we designed and prepared glycodendron and pyropheophorbide-a (Ppa)-functionalized HA (HA-Ppa-Dendron) as a nanosystem for cancer photodynamic therapy. Linear Ppa-modified HA (HA-Ppa) was also prepared as a control. Cellular uptake of both polymers by MDA-MB-231 cells led to mitochondrial dysfunction and generation of reactive oxygen species under the irradiation of a laser. Compared to the linear polymer, HA-Ppa-Dendron had higher molecular weight, a more compact nanoscale particle size, and a dendritic structure, resulting in a much longer blood circulation time and higher tumor accumulation. HA-Ppa-Dendron outperformed HA-Ppa in inhibiting cell growth, with 60 % of tumors was eradicated under laser irradiation. Tumor growth inhibition (TGI) up to 99.2 % was achieved from HA-Ppa-Dendron, which was much higher than that of HA-Ppa (50.6 %). Therefore, glycodendron-functionalized HAs by integration of HA and dendritic polymers may act as efficient anti-cancer nanomedicine.

Nanostructured lipid carriers as oral delivery systems for improving oral bioavailability of nintedanib by promoting intestinal absorption.

The aim of this study was to fabricate nanostructured lipid carriers, NLCs, of nintedanib (BIBF) to improve its oral bioavailability. Two types of NLCs loaded with BIBF (BIBF-NLCs-1 and BIBF-NLCs-2) were prepared by the melt-emulsification technique. BIBF-NLCs-1 and BIBF-NLCs-2 showed nanoscale particle sizes of 142.70±0.85nm and 7.99±0.06nm, and both were positive zeta potential. Study on Caco-2 cells showed that BIBF-NLCs-1 exhibited distinct advantages at the cytological level. The oral bioavailability of BIBF-NLCs-1 and BIBF-NLCs-2 was extremely improved 3.13-fold and 2.39-fold respectively compared with BIBF solution (BIBF-Sol). And in vivo anti-tumor efficiency study in mice bearing LLC lung tumor indicated that BIBF-NLCs-1 and BIBF-NLCs-2 had excellent tumor inhibition. Besides, the two NLCs did not increase the risk of liver damage and can even reduce the incidence of gastrointestinal irritation of BIBF to some extent. In summary, NLCs are a potential oral delivery system to improve the bioavailability of BIBF by promoting intestinal absorption.

Folic acid-modified methotrexate-conjugated gold nanoparticles as nano-sized trojans for drug delivery to folate receptor-positive cancer cells

Methotrexate (MTX), an analog of folic acid (FA), is a drug widely used in cancer treatment. To prevent its potential toxicity and enhance therapeutic efficacy, targeted drug delivery systems, especially nanotechnology–folate platforms, are a central strategy. Gold nanoparticles (AuNPs) are promising candidates to be used as drug delivery systems because of their small particle sizes and their inertness for the body. In this study, glutathione (GSH)-coated FA-modified spherical AuNPs (5.6 nm) were successfully synthesized, and the anticancer activity of novel MTX-loaded (MTX/Au-GSH-FA) NPs (11 nm) was examined. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) results showed that MTX/AuNPs possess spherical morphology, nanoscaled particle size, narrow size distribution, and good stability. In vitro studies showed that cytotoxicity of MTX/Au-GSH-FA to folate receptor-positive (FR+) human brain (U-87 MG) and cervical (HeLa) cancer cells enhanced significantly (∼3 and ∼10 fold, respectively) compared to free MTX while there was no significant effect in FR−negative human cell lines A549 (lung carcinoma), PC3 (prostate carcinoma), HEK-293 (healthy embryonic kidney). Moreover, the receptor specificity of the conjugate was shown by fluorescent microscopic imaging. In conclusion, these results indicate that the synthesized novel MTX/Au-GSH-FA NP complex seems to be a good candidate for effective and targeted delivery in FR+ cancer therapy.

Catalytic Activity of Nanosized Ruthenium Oxide-Coated Titanium Anodes Prepared by Thermal Decomposition for Oxygen Evolution in Sulfuric Acid Solutions

The effects of the nanoscale particle size of RuO2 in thermally prepared RuO2-coated Ti anodes on electrochemical kinetic parameters such as the active surface area and Tafel slope for oxygen evolution in sulfuric acid solutions were investigated. RuO2/Ti anodes with four different average sizes of RuO2 particles—5.6 nm, 6.8 nm, 14.6 nm, and 21.2 nm—were prepared. The double-layer charge corresponding to the active surface area for oxygen evolution of the anodes was shown to increase with decreasing average RuO2 particle size. The polarization curves of the anodes showed that the oxygen evolution current density at a certain potential increased with decreasing average RuO2 particle size, meaning that oxygen evolution, especially in the high-current-density region, where it mainly depends on the mass transfer rate, accelerated with decreasing RuO2 particle size. The Tafel slope obtained for the anodes was shown to decrease with decreasing average RuO2 particle size, indicating that the change in particle size affected the electron transfer rate for oxygen evolution. The present study reveals that changes in the nanoscale size of RuO2 affect not only the mass transfer process but also the electron transfer process for oxygen evolution in sulfuric acid solutions.

Abstract withdrawn: Formation and Oxidation Stability of Tea Polyphenols-Loaded W/O Microemulsion with Eucommia Ulmoides Oliver Seed Oil as an Alternative to α-linolenic Acid.

[This retracts the article DOI: 10.1093/cdn/nzab071.].