Luminescent Ink Based on Upconversion of NaYF4:Er,Yb@MA Nanoparticles: Environmental Friendly Synthesis and Structural and Spectroscopic Assessment.

NaYF4:Er,Yb upconversion luminescent nanoparticles (UCNPs) were prepared by hydrothermal methods at 180 °C for 24 h. The X-ray diffraction (XRD) and TEM (transmission electron microscopy) images show that the resulting 60 nm UCNPs possess a hexagonal structure. In this work, maleic anhydride (MA) was grafted on the surface of UCNPs to induce hydrophilic properties. The photoluminescence spectra (PL) show upconversion emissions centered around 545 nm and 660 nm under excitation at 980 nm. The luminescent inks, including UCNPs@MA, polyvinyl alcohol (PVA), deionized water (DI), and ethylene glycol (EG), exhibit suitable properties for screen printing, such as high stability, emission intensity, and tunable dynamic viscosity. The printed patterns with a height of 5 mm and a width of 1.5 mm were clearly observed under the irradiation of a 980 nm laser. Our strategy provides a new route for the controlled synthesis of hydrophilic UCNPs, and shows that the UCNPs@MAs have great potential in applications of anti-counterfeiting packing.

Phase Transfer and DNA Functionalization of Quantum Dots Using an Easy-to-Prepare, Low-Cost Zwitterionic Polymer.

Small, stable, and bright quantum dots (QDs) are of interest in many biosensing and biomedical imaging applications, but current methodologies for obtaining these characteristics can be highly specialized or expensive. We describe a straightforward, low-cost protocol for functionalizing poly(isobutylene-alt-maleic anhydride) (PIMA) with moieties that anchor to the QD surface (histamine), impart hydrophilicity [(2-aminoethyl)trimethylammonium chloride (Me3N+-NH2)], and provide a platform for biofunctionalization via click chemistry (dibenzocyclooctyne (DBCO)). Guidelines to successfully use this polymer for QD ligand exchange are presented, and an example of biofunctionalization with DNA is shown. Stable QD-DNA conjugates are obtained with high yield and without requiring additional purification steps.

Comparative assessment of the interface between poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and fish scales in composites: Preparation, characterization, and applications.

Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) composites containing fish scales (FSs) were prepared and used in the fabrication of three-dimensional printing filaments. Maleic anhydride (MA)-grafted polyhydroxyalkanoate (PHBV-g-MA) and FS were used to improve the compatibility of FS within a PHBV matrix. Mechanical and morphological characterization indicated that improved adhesion between FS and PHBV-g-MA enhanced the tensile strength of the composite compared with that of PHBV/FS. The PHBV-g-MA/FS composites were also more water-resistant than the PHBV/FS composites. Human foreskin fibroblasts (FBs) were seeded on two series of these composites to assess cytocompatibility. FB proliferation was greater on PHBV/FS composites than on PHBV-g-MA/FS composites. Cell-cycle assays with FBs on PHBV/FS and PHBV-g-MA/FS series composites were unaffected. Moreover, FS enhanced the antioxidant and antimicrobial properties of PHBV-g-MA/FS and PHBV/FS composites, demonstrating the potential of PHBV-g-MA/FS and PHBV/FS composites for biomedical material applications.

Assessment of novel maleic anhydride copolymers prepared via nitroxide-mediated radical polymerization as CaSO4 crystal growth inhibitors.

Calcium sulfate is one of the dominant scales which, unlike carbonate scale, are not easily removable by acid. To inhibit CaSO4 scale formation in artificial cooling water systems, well-defined low molecular weight maleic anhydride and n-alkylacrylamide copolymers (YMR-S series) were synthesized via nitroxide-mediated radical polymerization initiated by benzoyl peroxide in the presence of 2,2,6,6-tetramethyl-1-piperidinyloxy at varying concentrations. These polymerizations exhibit living polymerization characteristics; that is, they show linear growth in chain length as a function of monomer conversion, and have narrow molecular weight distributions. Resultant polymers were characterized by means of 1H-NMR and 13C-NMR. The inhibition behavior of these YMR-S series polymers against CaSO4 was evaluated using the static scale inhibition method and a dynamic tube block test. The inhibition ability on the CaSO4 scale is 99.5% with 9 ppm dosage level at pH 10.45 and temperature 70°C. Scanning electronic microscope analysis proved the morphological changes of the CaSO4 scales due to the strong inhibition action of YMR-S polymers. It is also observed that the antiscaling effect of the copolymers greatly depends on the molecular weight, and the optimum range is below 20,000 and approximately in the range 500-2000.

Integrated testing and assessment approaches for skin sensitization: a commentary.

A Bayesian integrated testing strategy (ITS) approach, aiming to assess skin sensitization potency, has been presented, in which data from various types of in vitro assays are integrated and assessed in combination for their ability to predict in vivo skin sensitization data. Here we discuss this approach and compare it to our quantitative mechanistic modeling (QMM) approach based on physical organic chemistry. The main findings of the Bayesian study are consistent with our chemistry-based approach and our previously published assessment of the key determinants of sensitization potency, in particular the relatively high predictive value found for chemical reactivity data and the relatively low predictive value for bioavailability parameters. As it stands at present the Bayesian approach does not utilize the full range of predictive capability that is already available, and aims only to assign potency categories rather than numerical potency values per se. In contrast, for many chemicals the QMM approach can already provide numerical potency predictions. However, the Bayesian approach may have potential for those chemicals where a chemistry modeling approach cannot provide a complete answer (e.g. pro-electrophiles whose in cutaneo activation cannot currently be modeled confidently). Nonetheless, our main message is of the importance of leveraging chemistry insights and read-across approaches to the fullest extent possible.

Synthesis and characterization of maleic anhydride esterified corn starch by the dry method.

Maleic anhydride esterified starch was synthesized by a dry method using corn starch as the material and maleic anhydride as the esterifying agent. The esterified starch (ES) was analyzed by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), which confirmed that there was a successful esterification reaction between the maleic anhydride and corn starch. The effects of reaction temperature and time on the degree of substitution of esterified starch were studied, where the results showed that 80 °C of reaction temperature and 3h of reaction time were optimal conditions. The result of XPS testing demonstrated that the esterification reaction led to increase of ester bonds in starch. The scanning electron microscopy (SEM) and laser particle size analyzer results showed that esterification led to roughness on the surface of the starch particle, and the particle size and distribution rate of esterification starch became larger. X-ray diffraction (XRD) analysis demonstrated that esterification reaction did not change the crystalline type of native starch. The differential scanning calorimeter (DSC) and thermo gravimetric analysis (TGA) confirmed that destruction of the crystal structure resulted in improved thermoplasticity of the starch, decreased the gelatinization temperature and increased the thermogravimetric rate of esterification starch.

Synthesis, characterization, and assessment of cytotoxic, antiproliferative, and antiangiogenic effects of a novel procainamide hydrochloride-poly(maleic anhydride-co-styrene) conjugate.

Poly(maleic anhydride-co-styrene) (MAST) was synthesized by a free-radical polymerization reaction. A bioactive molecule, procainamide hydrochloride (PH), was then conjugated to MAST. The conjugation product was named as MAST/PH. Structural characterization of MAST and MAST/PH was carried out by Fourier Transform Infrared and Nuclear Magnetic Resonance spectroscopy. Their molecular weights were determined by size-exclusion chromatography. A mechanism was then suggested for the conjugation reaction. The results of the cytotoxicity assay, employing a mouse fibroblast cell line (L929), indicated that MAST/PH had no cytotoxicity at concentrations [Formula: see text] 62 µg mL(-1) (p > 0.05). Antiproliferative activities of MAST/PH and PH were determined by the BrdU cell proliferation ELISA assay, using C6 and HeLa cell lines. In the experiment, two anticancer chemotherapy drugs, cisplatin and 5-fluorouracil, were included as positive control. Antiproliferative activity results demonstrated that MAST/PH yielded the highest suppression profile (approximately 42%) at 20 µg/ml, while free PH exerted the same activity at 100 µg/ml. Interestingly, both MAST/PH and PH suppressed the proliferation of only one of the cell lines, C6 cells. Both cisplatin and 5-fluorouracil yielded approximately 60% antiproliferative activity on C6 cells at 20 and 100 µg/ml concentrations. Antiangiogenic capacity of both MAST and MAST/PH was also investigated by using the chicken chorioallantoic membrane assay. Results obtained indicated that while MAST/PH could be included into the category of good antiangiogenic substances, the activity score of MAST was within the weak category.

Electrospun mats from styrene/maleic anhydride copolymers: modification with amines and assessment of antimicrobial activity.

New antimicrobial microfibrous electrospun mats from styrene/maleic anhydride copolymers were prepared. Two approaches were applied: (i) grafting of poly(propylene glycol) monoamine (Jeffamine® M-600) on the mats followed by formation of complex with iodine; (ii) modification of the mats with amines of 8-hydroxyquinoline or biguanide type with antimicrobial activity. Microbiological screening against S. aureus, E. coli and C. albicans revealed that both the formation of complex with iodine and the covalent attachment of 5-amino-8-hydroxyquinoline or of chlorhexidine impart high antimicrobial activity to the mats. In addition, S. aureus bacteria did not adhere to modified mats.

Metabolic enzyme microarray coupled with miniaturized cell-culture array technology for high-throughput toxicity screening.

Due to poor drug candidate safety profiles that are often identified late in the drug development process, the clinical progression of new chemical entities to pharmaceuticals remains hindered, thus resulting in the high cost of drug discovery. To accelerate the identification of safer drug candidates and improve the clinical progression of drug candidates to pharmaceuticals, it is important to develop high-throughput tools that can provide early-stage predictive toxicology data. In particular, in vitro cell-based systems that can accurately mimic the human in vivo response and predict the impact of drug candidates on human toxicology are needed to accelerate the assessment of drug candidate toxicity and human metabolism earlier in the drug development process. The in vitro techniques that provide a high degree of human toxicity prediction will be perhaps more important in cosmetic and chemical industries in Europe, as animal toxicity testing is being phased out entirely in the immediate future.We have developed a metabolic enzyme microarray (the Metabolizing Enzyme Toxicology Assay Chip, or MetaChip) and a miniaturized three-dimensional (3D) cell-culture array (the Data Analysis Toxicology Assay Chip, or DataChip) for high-throughput toxicity screening of target compounds and their metabolic enzyme-generated products. The human or rat MetaChip contains an array of encapsulated metabolic enzymes that is designed to emulate the metabolic reactions in the human or rat liver. The human or rat DataChip contains an array of 3D human or rat cells encapsulated in alginate gels for cell-based toxicity screening. By combining the DataChip with the complementary MetaChip, in vitro toxicity results are obtained that correlate well with in vivo rat data.