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- ItemDetection of Protein Glycosylation Using Tip-Enhanced Raman Scattering(Columbus, Ohio : American Chemical Society, 2016) Cowcher, David P.; Deckert-Gaudig, Tanja; Brewster, Victoria L.; Ashton, Lorna; Deckert, Volker; Goodacre, RoystonThe correct glycosylation of biopharmaceutical glycoproteins and their formulations is essential for them to have the desired therapeutic effect on the patient. It has recently been shown that Raman spectroscopy can be used to quantify the proportion of glycosylated protein from mixtures of native and glycosylated forms of bovine pancreatic ribonuclease (RNase). Here we show the first steps toward not only the detection of glycosylation status but the characterization of glycans themselves from just a few protein molecules at a time using tip-enhanced Raman scattering (TERS). While this technique generates complex data that are very dependent on the protein orientation, with the careful development of combined data preprocessing, univariate and multivariate analysis techniques, we have shown that we can distinguish between the native and glycosylated forms of RNase. Many glycoproteins contain populations of subtly different glycoforms; therefore, with stricter orientation control, we believe this has the potential to lead to further glycan characterization using TERS, which would have use in biopharmaceutical synthesis and formulation research.
- ItemStimuli-responsive nanogel composites and their application in nanomedicine(Cambridge : Royal Society of Chemistry, 2015) Molina, Maria; Asadian-Birjand, Mazdak; Balach, Juan; Bergueiro, Julian; Miceli, Enrico; Calderón, MarceloNanogels are nanosized crosslinked polymer networks capable of absorbing large quantities of water. Specifically, smart nanogels are interesting because of their ability to respond to biomedically relevant changes like pH, temperature, etc. In the last few decades, hybrid nanogels or composites have been developed to overcome the ever increasing demand for new materials in this field. In this context, a hybrid refers to nanogels combined with different polymers and/or with nanoparticles such as plasmonic, magnetic, and carbonaceous nanoparticles, among others. Research activities are focused nowadays on using multifunctional hybrid nanogels in nanomedicine, not only as drug carriers but also as imaging and theranostic agents. In this review, we will describe nanogels, particularly in the form of composites or hybrids applied in nanomedicine.
- ItemNickel cobalt oxide hollow nanosponges as advanced electrocatalysts for the oxygen evolution reaction(Cambridge : Soc., 2015) Zhu, Chengzhou; Wen, Dan; Leubner, Susanne; Oschatz, Martin; Liu, Wei; Holzschuh, Matthias; Simon, Frank; Kaskel, Stefan; Eychmüller, AlexanderA class of novel nickel cobalt oxide hollow nanosponges were synthesized through a sodium borohydride reduction strategy. Due to their porous and hollow nanostructures, and synergetic effects between their components, the optimized nickel cobalt oxide nanosponges exhibited excellent catalytic activity towards oxygen evolution reaction.
- ItemHybrid nanostructured particles via surfactant-free double miniemulsion polymerization([London] : Nature Publishing Group UK, 2018) Zhao, Yongliang; Liu, Junli; Chen, Zhi; Zhu, Xiaomin; Möller, MartinDouble emulsions are complex fluid systems, in which droplets of a dispersed liquid phase contain even smaller dispersed liquid droplets. Particularly, water-in-oil-in-water double emulsions provide significant advantages over simple oil-in-water emulsions for microencapsulation, such as carrier of both aqueous and oily payloads and sustained release profile. However, double emulsions are thermodynamically unstable systems consisting typically of relatively large droplets. Here we show that nanoscale water-in-oil-in-water double emulsions can be prepared by adding a silica precursor polymer, hyperbranched polyethoxysiloxane, to the oil phase without any additional surfactants. The resulting double miniemulsions are transformed to robust water@SiO2@polymer@SiO2 nanocapsules via conversion of the precursor to silica and polymerization of the oil phase. Other intriguing nanostructures like nanorattles and Janus-like nanomushrooms can also be obtained by changing preparation conditions. This simple surfactant-free double miniemulsion polymerization technique opens a promising avenue for mass production of various complex hybrid nanostructures that are amenable to numerous applications.
- ItemHighly sensitive and specific detection of E. coli by a SERS nanobiosensor chip utilizing metallic nanosculptured thin films(Cambridge : Soc., 2015) Srivastava, Sachin K.; Hamo, Hilla Ben; Kushmaro, Ariel; Marks, Robert S.; Grüner, Christoph; Rauschenbach, Bernd; Abdulhalim, IbrahimA nanobiosensor chip, utilizing surface enhanced Raman spectroscopy (SERS) on nanosculptured thin films (nSTFs) of silver, was shown to detect Escherichia coli (E. coli) bacteria down to the concentration level of a single bacterium. The sensor utilizes highly enhanced plasmonic nSTFs of silver on a silicon platform for the enhancement of Raman bands as checked with adsorbed 4-aminothiophenol molecules. T-4 bacteriophages were immobilized on the aforementioned surface of the chip for the specific capture of target E. coli bacteria. To demonstrate that no significant non-specific immobilization of other bacteria occurs, three different, additional bacterial strains, Chromobacterium violaceum, Paracoccus denitrificans and Pseudomonas aeruginosa were used. Furthermore, experiments performed on an additional strain of E. coli to address the specificity and reusability of the sensor showed that the sensor operates for different strains of E. coli and is reusable. Time resolved phase contrast microscopy of the E. coli-T4 bacteriophage chip was performed to study its interaction with bacteria over time. Results showed that the present sensor performs a fast, accurate and stable detection of E. coli with ultra-small concentrations of bacteria down to the level of a single bacterium in 10 μl volume of the sample.