Epoxy functionalized polymethacrylates based on various multifunctional d‐glucopyranoside acetals

The synthesis of acetal‐derived d ‐glucopyranosides with a various number of hydroxyl groups (the first step, acetalization) and their modified forms with bromoester groups (the second step, esterification) are presented here. The latter, due to the type of functional groups, can be used to initiate the controlled atom transfer radical polymerization. The copolymerizations of equimolar feed of methacrylate monomers, namely, methyl methacrylate and glycidyl methacrylate, were initiated by prepared new glycoinitiators, based on methyl α‐d ‐glucopyranoside (Meαd Glu) or 2‐(hydroxymethyl)phenyl‐β‐d ‐glucopyranoside (salicin), in the presence of the catalyst system CuCl/dNbpy in anisole at 30 °C. The conditions were sufficient for successful synthesis of well‐defined copolymers with sugar cores sheltered by two‐, three‐, four‐, or six‐polymethacrylate segments with various polymerization degrees (DP_arm = 15 – 70) and low dispersity indices (Ð = 1.15–1.30). Because of the presence of oxirane groups, the star‐copolymers can be functionalized in further steps by biologically active compounds or modified to amphipilics. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2483–2494     

A microfluidic system to study the cytotoxic effect of drugs: the combined effect of celecoxib and 5-fluorouracil on normal and cancer cells

We have investigated the response of normal and cancer cells to exposure a combination of celecoxib (Celbx) and 5-fluorouracil (5-FU) using a lab-on-a-chip microfluidic device. Specifically, we have tested the cytotoxic effect of Celbx on normal mouse embryo cells (Balb/c 3T3) and human lung carcinoma cells (A549). The single drugs or their combinations were adjusted to five different concentrations using a concentration gradient generator (CGG) in a single step. The results suggest that Celbx can enhanced the anticancer activity of 5-FU by stronger inhibition of cancer cell growth. We also show that the A549 cancer cells are more sensitive to Celbx than the Balb/c 3T3 normal cells. The results obtained with the microfluidic system were compared to those obtained with a macroscale in vitro cell culture method. In our opinion, the microfluidic system represents a unique approach for an evaluation of cellular response to multidrug exposure that also is more simple than respective microwell plate assays.

Low‐Energy Electron‐Induced Transformations in Organolead Halide Perovskite

Methylammonium lead iodide perovskite (MAPbI₃), a prototype material for potentially high‐efficient and low‐cost organic–inorganic hybrid perovskite solar cells, has been investigated intensively in recent years. A study of low‐energy electron‐induced transformations in MAPbI₃ is presented, performed by combining controlled electron‐impact irradiation with X‐ray photoelectron spectroscopy and scanning electron microscopy. Changes were observed in both the elemental composition and the morphology of irradiated MAPbI₃ thin films as a function of the electron fluence for incident energies from 4.5 to 60 eV. The results show that low‐energy electrons can affect structural and chemical properties of MAPbI₃. It is proposed that the transformations are triggered by the interactions with the organic part of the material (methylammonium), resulting in the MAPbI₃ decomposition and aggregation of the hydrocarbon layer.     

Electrospun poly(3‐hexylthiophene)/poly(ethylene oxide)/graphene oxide composite nanofibers: effects of graphene oxide reduction

In this article, we report on the production by electrospinning of P3HT/PEO, P3HT/PEO/GO, and P3HT/PEO/rGO nanofibers in which the filler is homogeneously dispersed and parallel oriented along the fibers axis. The effect of nanofillers' presence inside nanofibers and GO reduction was studied, in order to reveal the influence of the new hierarchical structure on the electrical conductivity and mechanical properties. An in‐depth characterization of the purity and regioregularity of the starting P3HT as well as the morphology and chemical structure of GO and rGO was carried out. The morphology of the electrospun nanofibers was examined by both scanning and transmission electron microscopy. The fibrous nanocomposites are also characterized by differential scanning calorimetry to investigate their chemical structure and polymer chains arrangements. Finally, the electrical conductivity of the electrospun fibers and the elastic modulus of the single fibers are evaluated using a four‐point probe method and atomic force microscopy nanoindentation, respectively. The electrospun materials crystallinity as well as the elastic modulus increase with the addition of the nanofillers while the electrical conductivity is positively influenced by the GO reduction. Copyright © 2016 John Wiley & Sons, Ltd.     

Star‐Shaped Conjugated Molecules with Oxa‐ or Thiadiazole Bithiophene Side Arms

Star‐shaped conjugated molecules, consisting of a benzene central unit symmetrically trisubstituted with either oxa‐ or thiadiazole bithiophene groups, were synthesized as promising molecules and building blocks for application in (opto)electronics and electrochromic devices. Their optical (E_g(opt)) as well as electrochemical (E_g(electro)) band gaps depended on the type of the side arm and the number of solubilizing alkyl substituents. Oxadiazole derivatives showed E_g(opt) slightly below 3 eV and by 0.2 eV larger than those determined for thiadiazole‐based compounds. The presence of alkyl substituents in the arms additionally lowered the band gap. The obtained compounds were efficient electroluminophores in guest/host‐type light‐emitting diodes. They also showed a strong tendency to self‐organize in monolayers deposited on graphite, as evidenced by scanning tunneling microscopy. The structural studies by X‐ray scattering revealed the formation of supramolecular columnar stacks in which the molecules were organized. Differences in macroscopic alignment in the specimen indicated variations in the self‐assembly mechanism between the molecules. The compounds as trifunctional monomers were electrochemically polymerized to yield the corresponding polymer network. As shown by UV/Vis‐NIR spectroelectrochemical studies, these networks exhibited reversible electrochromic behavior both in the oxidation and in the reduction modes.     

Assembly of highly aligned DNA strands onto Si chips

This paper reports a robust and efficient approach to assemble highly aligned DNA strands onto Si chips. The method combines advantages from molecular combing and microcontact printing to realize controlling both the density and direction of DNA strands on the Si chip. In addition, it also can be utilized to prepare stretched DNA structures on solid surfaces. Compared to approaches that use molecular combing directly on silanated surfaces, the stretched single-chain DNA structures are straighter. Furthermore, by exploiting the hydrophobic property of the intrinsic poly(dimethylsiloxane) stamp, this study also describes a simple way to produce straight bundled DNA arrays on Si and other substrates.     

Effect of Resveratrol Treatment on Human Pancreatic Cancer Cells through Alterations of Bcl-2 Family Members

Pancreatic cancers are among of the most lethal types of neoplasms, and are mostly detected at an advanced stage. Conventional treatment methods such as chemotherapy or radiotherapy often do not bring the desired therapeutic effects. For this reason, natural compounds are increasingly being used as adjuvants in cancer therapy. Polyphenolic compounds, including resveratrol, are of particular interest. The aim of this study is to analyze the antiproliferative and pro-apoptotic mechanisms of resveratrol on human pancreatic cells. The study was carried out on three human pancreatic cancer cell lines: EPP85-181P, EPP85-181RNOV (mitoxantrone-resistant cells) and AsPC-1, as well as the normal pancreatic cell line H6c7. The cytotoxicity of resveratrol in the tested cell lines was assessed by the colorimetric method (MTT) and the flow cytometry method. Three selected concentrations of the compound (25, 50 and 100 µM) were tested in the experiments during a 48-h incubation. TUNEL and Comet assays, flow cytometry, immunocytochemistry, confocal microscopy, real-time PCR and Western Blot analyses were used to evaluate the pleiotropic effect of resveratrol. The results indicate that resveratrol is likely to be anticarcinogenic by inhibiting human pancreatic cancer cell proliferation. In addition, it affects the levels of Bcl-2 pro- and anti-apoptotic proteins. However, it should be emphasized that the activity of resveratrol was specific for each of the tested cell lines, and the most statistically significant changes were observed in the mitoxantrone-resistant cells.     

Bioaccessibility of Antioxidants in Blackcurrant Juice after Treatment Using Supercritical Carbon Dioxide

Blackcurrant juice (Ribes nigrum L.) was subjected to supercritical carbon dioxide (SCCD) at 10, 30, and 60 MPa for 10 min at 45 °C, as well as thermally treated at 45 and 85 °C for 10 min to determine the stability, antioxidant capacity (AC), and bioaccessibility (BAc) of vitamin C, total anthocyanins, and their individual monomers. An in vitro gastrointestinal digestion model completed with dialysis was used to assess BAc. The use of SCCD at each of the pressures applied improved the stability of vitamin C, total anthocyanins, and AC before in vitro digestion. As a result of digestion, the total content of vitamin C, anthocyanins, and AC decreased. The highest BAc of vitamin C was noted in fresh juice (FJ) (40%) and after mild heat treatment at 45 °C (T45) (46%). The highest BAc of total anthocyanins was also noted in the FJ (4.4%). The positive effect of the application of SCCD on the BAc of the delphinidin-3-O-glycosides was observed compared to T45 and thermal pasteurization at 85 °C (T85). Although SCCD did not significantly improve the BAc of vitamin C and total anthocyanins, the higher AC of SCCD samples after intestinal digestion (ABTS+• and DPPH•) and in dialysate (ABTS+•) compared to thermally treated was observed. The protocatechuic acid was detected by UPLC-PDA-MS/MS as the major metabolite formed during the digestion of delphinidin-3-O-rutinoside. This may indicate the influence of SCCD on improvement of the accessibility of antioxidants for digestion, thanks to which more metabolites with high antioxidant activity were released.     

Biofortification of Three Cultivated Mushroom Species with Three Iron Salts—Potential for a New Iron-Rich Superfood

Mushrooms fortified with iron (Fe) can offer a promising alternative to counter the worldwide deficiency problem. However, the factors that may influence the efficiency of fortification have not yet been fully investigated. The aim of this study was to compare the effects of three Fe forms (FeCl₃ 6H₂O, FeSO₄ 7H₂O, or FeHBED) in three concentrations (5, 10, or 50 mM) for three mushroom species (Pleurotus eryngii, P. ostreatus, or Pholiota nameko) on their chemical composition, phenolic compounds, and organic acid production. The most effective metal accumulation of all the investigated species was for the 50 mM addition. FeCl₃ 6H₂O was the most favorable additive for P. eryngii and P. nameko (up to 145 and 185% Fe more than in the control, respectively) and FeHBED for P. ostreatus (up to 108% Fe more than in control). Additionally, P. nameko showed the highest Fe accumulation among studied species (89.2 ± 7.51 mg kg⁻¹ DW). The creation of phenolic acids was generally inhibited by Fe salt supplementation. However, an increasing effect on phenolic acid concentration was observed for P. ostreatus cultivated at 5 mM FeCl₃ 6H₂O and for P. eryngii cultivated at 5 mM FeCl₃ 6H₂O and 5 mM FeSO₄ 7H₂O. In the case of organic acids, a similar situation was observed. For P. ostreatus, FeSO₄ 7H₂O and FeHBED salts increased the formation of the determined organic acids in fruiting bodies. P. eryngii and P. nameko were characterized by a much lower content of organic acids in the systems supplemented with Fe. Based on the obtained results, we recommend starting fortification by preliminarily indicating which form of the element is preferred for the species of interest for supplementation. It also seems that using an additive concentration of 50 mM or higher is most effective.     

Study on the Incorporation of Oat and Yeast β-Glucan into Shortbread Biscuits as a Basis for Designing Healthier and High Quality Food Products

According to international health and food organizations and authorities, people should limit fat intake since fat is the most caloric component of food and it is often a source of unsafe saturated fatty acids (FA) and trans isomers. The greatest health benefits come from replacing shorts with dietary fiber molecules. The aim of the study was to determine the possibility of reducing shortening content, which has an undesirable profile of FA, by addition of β-glucan molecules in shortbread biscuits. The effect of oat and yeast β-glucan supplementation on physical and sensory quality of products with reduced fat content (max 15%) were studied. It was shown that the substitution of shortening by β-glucan in shortbread biscuits is possible to a limited extent. Reduction in product energy value (up to 36 kcal/100 g) and content of undesirable FA (maximum 2.1 g/100 g) and increased of β-glucan content, regardless of the type, caused deterioration of biscuits quality and affected changes during storage. The substitution of shortening by β-glucan in food is a good way to improve nutritional value by increasing the amount of dietary fiber molecules, reducing calories, and amount of SFA in diets.