Ultra‐low‐fouling poly[N‐(2‐hydroxypropyl) methacrylamide] (poly(HPMA)) brushes have been synthesized for the first time. Similar to the so far only ultra‐low‐fouling surface, poly(carboxybetaine acrylamide), the level of blood plasma fouling was below the detection limit of surface plasmon resonance (SPR, 0.03 ng · cm−2) despite being a hydrogen bond donor and displaying a moderate wettability, thus challenging the currently accepted views for the design of antifouling properties. The antifouling properties were preserved even after two years of storage. To demonstrate the potential of poly(HPMA) brushes for the preparation of bioactive ultra‐low fouling surfaces a label‐free SPR immunosensor for detection of G Streptococcus was prepared.
Thionins belong to a family of cysteine‐rich, low‐molecular‐weight (～5 KDa) biologically active proteins in the plant kingdom. They display a broad cellular toxicity against a wide range of organisms and eukaryotic cell lines. Thionins protect plants against different pathogens, including bacteria and fungi. A highly selective solid‐phase extraction method for plant thionins is reported deploying aluminum silicate (3:2 mullite) powder as a sorbent in extraction columns. Mullite was shown to considerably improve selectivity compared to a previously described zirconium silicate embedded poly(styrene‐co‐divinylbenzene) monolithic polymer. Due to the presence of aluminum(III), mullite offers electrostatic interactions for the selective isolation of cysteine‐rich proteins. In comparison to zirconium(IV) silicate, aluminum(III) silicate showed reduced interactions towards proteins which resulted into superior washings of unspecific compounds while still retaining cysteine‐rich thionins. In the presented study, European mistletoe, wheat and barley samples were subjected to solid‐phase extraction analysis for isolation of viscotoxins, purothionins and hordothionins, respectively. Matrix‐assisted laser desorption/ionization time of flight mass spectroscopy was used for determining the selectivity of the sorbent toward thionins. The selectively retained thionins were quantified by colorimetric detection using the bicinchoninic acid assay. For peptide mass‐fingerprint analysis tryptic digests of eluates were examined. 相似文献
The first simultaneous quantification of neomycin and bacitracin using liquid chromatography evaporative light scattering detection as an alternative to MS detection and pre-/post-column derivatisation, respectively, was the aim of this study. The developed method was validated for two strength of neomycin and one strength of bacitracin in sterile pharmaceutical formulation and is a fast and efficient tool for content uniformity tests in quality control. With this method the separation of neomycin from sulfate and the base line separation of the four major components of bacitracin (bacitracin A, B1, B2 and B3) was achieved. These four components are responsible for 96% of the microbiological activity. A Phenomenex Synergi POLAR analytical column (250 mm × 4.6 mm, 4 μm I.D.) in combination with 0.5% perfluoropropionic acid and acetonitrile in gradient mode, the peaks of interest could be separated with high efficiency within 14 min. The calibration was performed using a second order regression with an R2 = 0.9999 for neomycin (B and C) sulfate and R2 = 0.9996 for bacitracin A, B1, B2 and B3. The results of the accuracy evaluation were 99.2 and 99.7%, respectively, for neomycin and 100.8% for bacitracin. Injection precision results are 0.4–1.5 RSD% recorded for six injections. The established method has a high potential for routine high-throughput analyses in the pharmaceutical industry.
Microdroplets in microfluidics offer a great number of opportunities in chemical and biological research. They provide a compartment in which species or reactions can be isolated, they are monodisperse and therefore suitable for quantitative studies, they offer the possibility to work with extremely small volumes, single cells, or single molecules, and are suitable for high‐throughput experiments. The aim of this Review is to show the importance of these features in enabling new experiments in biology and chemistry. The recent advances in device fabrication are highlighted as are the remaining technological challenges. Examples are presented to show how compartmentalization, monodispersity, single‐molecule sensitivity, and high throughput have been exploited in experiments that would have been extremely difficult outside the microfluidics platform. 相似文献
We address the problem of determining finite subsets of Delone sets Λ⊂ℝd with long-range order by X-rays in prescribed Λ-directions, i.e., directions parallel to nonzero interpoint vectors of Λ. Here, an X-ray in direction u of a finite set gives the number of points in the set on each line parallel to u. For our main result, we introduce the notion of algebraic Delone sets Λ⊂ℝ2 and derive a sufficient condition for the determination of the convex subsets of these sets by X-rays in four prescribed Λ-directions. 相似文献
