Auflistung nach Autor:in "Nazemi, Seyed Amirabbas"

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  • Vorschaubild
    Publikation
    Nanobiocatalysts with inbuilt cofactor recycling for oxidoreductase catalysis in organic solvents
    (Royal Society of Chemistry, 2023) Sahlin, Jenny; Wu, Congyu; Buscemi, Andrea; Schärer, Claude; Nazemi, Seyed Amirabbas; S. K., Rejaul; Herrera-Reinoza, Nataly; Jung, Thomas A.; Shahgaldian, Patrick
    The major stumbling block in the implementation of oxidoreductase enzymes in continuous processes is their stark dependence on costly cofactors that are insoluble in organic solvents. We describe a chemical strategy that allows producing nanobiocatalysts, based on an oxidoreductase enzyme, that performs biocatalytic reactions in hydrophobic organic solvents without external cofactors. The chemical design relies on the use of a silica-based carrier nanoparticle, of which the porosity can be exploited to create an aqueous reservoir containing the cofactor. The nanoparticle core, possessing radial-centred pore channels, serves as a cofactor reservoir. It is further covered with a layer of reduced porosity. This layer serves as a support for the immobilisation of the selected enzyme yet allowing the diffusion of the cofactor from the nanoparticle core. The immobilised enzyme is, in turn, shielded by an organosilica layer of controlled thickness fully covering the enzyme. Such produced nanobiocatalysts are shown to catalyse the reduction of a series of relevant ketones into the corresponding secondary alcohols, also in a continuous flow fashion. © 2023 RSC.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    Plasmonic photothermal activation of an organosilica shielded cold-adapted lipase co-immobilised with gold nanoparticles on silica particles
    (Royal Society of Chemistry, 01.01.2023) Giunta, Carolina; Nazemi, Seyed Amirabbas; Olesińska, Magdalena; Shahgaldian, Patrick
    Gold nanoparticles (AuNPs), owing to their intrinsic plasmonic properties, are widely used in applications ranging from nanotechnology and nanomedicine to catalysis and bioimaging. Capitalising on the ability of AuNPs to generate nanoscale heat upon optical excitation, we designed a nanobiocatalyst with enhanced cryophilic properties. It consists of gold nanoparticles and enzyme molecules, co-immobilised onto a silica scaffold, and shielded within a nanometre-thin organosilica layer. To produce such a hybrid system, we developed and optimized a synthetic method allowing efficient AuNP covalent immobilisation on the surface of silica particles (SPs). Our procedure allows to reach a dense and homogeneous AuNP surface coverage. After enzyme co-immobilisation, a nanometre-thin organosilica layer was grown on the surface of the SPs. This layer was designed to fulfil the dual function of protecting the enzyme from the surrounding environment and allowing the confinement, at the nanometre scale, of the heat diffusing from the AuNPs after surface plasmon resonance photothermal activation. To establish this proof of concept, we used an industrially relevant lipase enzyme, namely Lipase B from Candida Antarctica (CalB). Herein, we demonstrate the possibility to photothermally activate the so-engineered enzymes at temperatures as low as −10 °C.
    01A - Beitrag in wissenschaftlicher Zeitschrift