Shahgaldian, Patrick

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Shahgaldian
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Patrick
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Shahgaldian, Patrick

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Gerade angezeigt 1 - 10 von 14
  • Publikation
    Immobilisation and stabilisation of glycosylated enzymes on boronic acid-functionalised silica nanoparticles
    (Royal Society of Chemistry, 2021) Nazemi, Seyed; Olesinska, Magdalena; Pezzella, Cinzia; Varriale, Simona; Lin, Chia-Wei; Corvini, Philippe; Shahgaldian, Patrick [in: Chemical Communications]
    We report a method of glycosylated enzymes’ surface immobilisation and stabilisation. The enzyme is immobilised at the surface of silica nanoparticles through the reversible covalent binding of vicinal diols of the enzyme glycans with a surface-attached boronate derivative. A soft organosilica layer of controlled thickness is grown at the silica surface, entrapping the enzyme and thus avoiding enzyme leaching. We demonstrate that this approach results not only in high and durable activity retention but also enzyme stabilisation.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Publikation
    Hydrophobicity-responsive engineered mesoporous silica nanoparticles: application in the delivery of essential nutrients to bacteria combating oil spills
    (Royal Society of Chemistry, 06/2019) Corvini, Nora; Corvini, Philippe; Shahgaldian, Patrick; El Idrissi, Mohamed; Dimitriadou, Eleni [in: Chemical Communications]
    Facile chemical modification of mesoporous silica particles allows the production of gated reservoir systems capable of hydrophobicity-triggered release. Applied to the delivery of nutrients specifically to an oil phase, the systems developed have been shown to reliably assist the bacterial degradation of hydrocarbons. The gated system developed, made of C18 hydrocarbon chains, is demonstrated to be in a closed collapsed state in an aqueous environment, yet opens up through solvation by lipophilic alkanes and releases its content on contact with the oil phase.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Publikation
    Cyclodextrin-based polymeric materials for the specific recovery of polyphenolic compounds through supramolecular host-guest interactions
    (Springer, 06/2017) El Idrissi, Mohamed; Molina Bacca, Aurora E.; Frascari, Dario; Corvini, Philippe; Shahgaldian, Patrick [in: Journal of Inclusion Phenomena and Macrocyclic Chemistry]
    While the specific recovery of valuable chemicals from waste streams represents an environmentally-friendly and potentially economically-relevant alternative to synthetic chemical productions, it remains a largely unmet challenge. This is partially explained by the complexity of designing sorption materials able to target one specific compound and able to function in complex matrices. In this work, a series of cyclodextrin-based polymers (CDPs) were designed to selectively extract phenolic compounds from a complex organic matrix that is olive oil mill wastewater (OMW). In order to endow these polymers with selective adsorption properties, several monomers and cross-linkers were screened and selected. The adsorption properties of the CDPs produced were first tested with selected phenolic compounds commonly found in OMW, namely syringic acid, p-coumaric acid, tyrosol and caffeic acid. The selected CDPs were subsequently tested for their ability to adsorb phenolic compounds directly from OMW, which is known to possess a high and complex organic content. It was demonstrated through high-performance liquid chromatography-mass spectroscopy analyses that efficient removal of phenolic compounds from OMW could be achieved but also that two compounds, namely tyrosol and hydroxytyrosol, could be selectively extracted from OMW.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Publikation
    Enzyme Armoring by an Organosilica Layer: Synthesis and Characterization of Hybrid Organic/Inorganic Nanobiocatalysts
    (Academic Press, 02/2017) Correro, Maria Rita; Sykora, Sabine; Corvini, Philippe; Shahgaldian, Patrick [in: Methods in Enzymology]
    The availability of highly stable and reusable enzymes is one of the main challenges in bio-based industrial processes. Enzyme immobilization and encapsulation represent promising strategies to reach this goal. In this chapter, the synthetic strategy to produce hybrid organic/inorganic nanobiocatalysts (NBC) is reported. This strategy is based on the sequential immobilization of an enzyme on the surface of silica nanoparticles followed by the growth, at the surface of the nanoparticles, of a shielding layer which serves as an armor to protect the enzyme against denaturation/degradation. This armor is produced through a thickness-controlled organosilane poly-condensation onto the nanoparticle surface around the enzyme to form a protective organosilica layer. The armored nanobiocatalysts present enhanced catalytic activity and improved stability against heat, pH, chaotropic agents, proteases, and ultrasound. The method is versatile in that it can be successfully adapted to a number of different enzymes.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Publikation
    A Biocatalytic Nanomaterial for the Label-Free Detection of Virus-Like Particles
    (Wiley, 2017) Sykora, Sabine; Correro, Maria Rita; Moridi, Negar; Belliot, Gaël; Pothier, Pierre; Dudal, Yves; Corvini, Philippe; Shahgaldian, Patrick [in: ChemBioChem]
    The design of nanomaterials that are capable of specific and sensitive biomolecular recognition is an on-going challenge in the chemical and biochemical sciences. A number of sophisticated artificial systems have been designed to specifically recognize a variety of targets. However, methods based on natural biomolecular detection systems using antibodies are often superior. Besides greater affinity and selectivity, antibodies can be easily coupled to enzymatic systems that act as signal amplifiers, thus permitting impressively low detection limits. The possibility to translate this concept to artificial recognition systems remains limited due to design incompatibilities. Here we describe the synthesis of a synthetic nanomaterial capable of specific biomolecular detection by using an internal biocatalytic colorimetric detection and amplification system. The design of this nanomaterial relies on the ability to accurately grow hybrid protein-organosilica layers at the surface of silica nanoparticles. The method allows for label-free detection and quantification of targets at picomolar concentrations.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Publikation
    Template-free hierarchical self-assembly of a pyrene derivative into supramolecular nanorods
    (Payame Noor University, 2017) El Idrissi, Mohamed; Teat, Simon J.; Corvini, Philippe; Paterson, Martin J.; Dalgarno, Scott J.; Shahgaldian, Patrick [in: Chemical Communications]
    The accurate molecular design of organic building blocks is of great importance for the creation of large supramolecular entities with precise dimensional organisation. Herein we report on the design of a new pyrene derivative that yields, through a hierarchical self-assembly process and in the absence of template, stable and well defined nanorods. X-ray diffraction studies allowed elucidation of the three dimensional packing of this pyrene derivative within the self-assembled nanorods.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Publikation
    Supramolecular enzyme engineering in complex nanometer-thin biomimetic organosilica layers
    (Royal Society of Chemistry, 09/2016) Correro, Maria Rita; Takacs, Michael; Sykora, Sabine; Corvini, Philippe; Shahgaldian, Patrick [in: RSC Advances]
    The use of enzymes in industrial processes is often hampered by their limited stability under operational conditions. As enzymes' function and stability are directly correlated to their three-​dimensional structure, numerous methods aiming at the preservation of this structure have been developed. While stabilization can be achieved using solid scaffolds for encapsulating the enzyme, it often results in loss of enzymic activity owing to a lack of conformational mobility of the biocatalyst. With the idea of mimicking protein-​protein interactions to create a network of weak force interactions between the surface of an immobilized enzyme and a synthetic protective layer, we have developed a chem. strategy allowing the use of complex mixts. of building blocks mimicking the lateral chain of natural amino acids. After crosslinking a model enzyme at the surface of silica nanoparticles, incubation with eight different organosilane mixts. allowed growing protective organosilica layers of controlled thicknesses. The nanoparticles produced were characterized by SEM and their biocatalytic activity was measured under a series of operational stress conditions. Our results clearly demonstrated that increasing the complexity and biomimetic nature of the protection layer allowed for relevant improvement of the protection effect. Indeed, when compared with the basic formulation, selected complex formulations allowed for an improvement of up to 100​% when treated at 50 °C for 60 min or in the presence of a denaturing detergent (SDS)​.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Publikation
    Production of superparamagnetic nanobiocatalysts for green chemistry applications
    (Springer, 23.04.2016) Gasser, Christoph; Ammann, Erik; Schäffer, Andreas; Shahgaldian, Patrick; Corvini, Philippe [in: Applied Microbiology and Biotechnology]
    Immobilization of enzymes on solid supports is a convenient method for increasing enzymatic stability and enabling enzyme reuse. In the present work, a sorption-assisted surface conjugation method was developed and optimized to immobilize enzymes on the surface of superparamagnetic nanoparticles. An oxidative enzyme, i.e., laccase from Trametes versicolor was used as model enzyme. The immobilization method consists of the production of superparamagnetic nanoparticles by co-precipitation of FeCl2 and FeCl3. Subsequently, the particle surface is modified with an organosilane containing an amino group. Next, the enzymes are adsorbed on the particle surface before a cross-linking agent, i.e., glutaraldehyde is added which links the amino groups on the particle surface with the amino groups of the enzymes and leads to internal cross-linking of the enzymes as well. The method was optimized using response surface methodology regarding optimal enzyme and glutaraldehyde amounts, pH, and reaction times. Results allowed formulation of biocatalysts having high specific enzymatic activity and improved stability. The biocatalysts showed considerably higher stability compared with the dissolved enzymes over a pH range from 3 to 9 and in the presence of several chemical denaturants. To demonstrate the reusability of the immobilized enzymes, they were applied as catalysts for the production of a phenoxazinone dye. Virtually, 100 % of the precursor was transformed to the dye in each of the ten conducted reaction cycles while on average 84.5 % of the enzymatic activity present at the beginning of a reaction cycle was retained after each cycle highlighting the considerable potential of superparamagnetic biocatalysts for application in industrial processes.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Publikation
    Immobilization of an artificial imine reductase within silica nanoparticles improves its performance
    (Royal Society of Chemistry, 2016) Hestericová, Martina; Correro, Maria Rita; Lenz, Markus; Corvini, Philippe; Shahgaldian, Patrick; Ward, Thomas R. [in: Chemical Communications]
    Silica nanoparticles equipped with an artificial imine reductase (biotinylated iridium complex conjugated with streptavidin) display marked redn. activity toward cyclic imines and NAD. The method, based on immobilization and protection of streptavidin on silica nanoparticles, shields the biotinylated metal cofactor against deactivation yielding >46,​000 turnovers in pure samples and 4000 turnovers in crude cellular exts.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Publikation
    Enzyme Shielding in an Enzyme-thin and Soft Organosilica Layer
    (Wiley, 2016) Correro, Maria Rita; Moridi, Negar; Schützinger, Hansjörg; Sykora, Sabine; Ammann, Erik; Peters, E. Henrik; Dudal, Yves; Corvini, Philippe; Shahgaldian, Patrick [in: Angewandte Chemie: International Edition]
    The fragile nature of most enzymes is a major hindrance to their use in industrial processes. Herein, we describe a synthetic chem. strategy to produce hybrid org.​/inorg. nanobiocatalysts; it exploits the self-​assembly of silane building blocks at the surface of enzymes to grow an organosilica layer, of controlled thickness, that fully shields the enzyme. Remarkably, the enzyme triggers a rearrangement of this organosilica layer into a significantly soft structure. We demonstrate that this change in stiffness correlates with the biocatalytic turnover rate, and that the organosilica layer shields the enzyme in a soft environment with a markedly enhanced resistance to denaturing stresses.
    01A - Beitrag in wissenschaftlicher Zeitschrift