Browsing by Author "Osorio Román, Igor"

Now showing 1 - 7 of 7
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    Capping biological quantum dots with the peptide CLPFFD to increase stability and to reduce effects on cell viability
    (2016) Riveros, A. L.; Astudillo, J.; Vásquez, C. C.; Jara, Danilo H.; Guerrero, Ariel R.; Guzmán, F.; Osorio Román, Igor; Kogan, M. J.
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    Enhancement of Peroxidase Stability Against Oxidative Self-Inactivation by Co-immobilization with a Redox-Active Protein in Mesoporous Silicon and Silica Microparticles
    (2016) Sahare, P.; Osorio Román, Igor; Ayala, M.; Vazquez-Duhalt, R.; Pal, U.; Loni, A.; Canham, L. T.; Agarwal, V.
    Abstract The study of the stability enhancement of a peroxidase immobilized onto mesoporous silicon/silica microparticles is presented. Peroxidases tend to get inactivated in the presence of hydrogen peroxide, their essential co-substrate, following an auto-inactivation mechanism. In order to minimize this inactivation, a second protein was co-immobilized to act as an electron acceptor and thus increase the stability against self-oxidation of peroxidase. Two heme proteins were immobilized into the microparticles: a fungal commercial peroxidase and cytochrome c from equine heart. Two types of biocatalysts were prepared: one with only covalently immobilized peroxidase (one-protein system) and another based on covalent co-immobilization of peroxidase and cytochrome c (two-protein system), both immobilized by using carbodiimide chemistry. The amount of immobilized protein was estimated spectrophotometrically, and the characterization of the biocatalyst support matrix was performed using Brunauer–Emmett–Teller (BET), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), and Fourier transform infrared (FTIR) analyses. Stability studies show that co-immobilization with the two-protein system enhances the oxidative stability of peroxidase almost four times with respect to the one-protein system. Thermal stability analysis shows that the immobilization of peroxidase in derivatized porous silicon microparticles does not protect the protein from thermal denaturation, whereas biogenic silica microparticles confer significant thermal stabilization.Abstract The study of the stability enhancement of a peroxidase immobilized onto mesoporous silicon/silica microparticles is presented. Peroxidases tend to get inactivated in the presence of hydrogen peroxide, their essential co-substrate, following an auto-inactivation mechanism. In order to minimize this inactivation, a second protein was co-immobilized to act as an electron acceptor and thus increase the stability against self-oxidation of peroxidase. Two heme proteins were immobilized into the microparticles: a fungal commercial peroxidase and cytochrome c from equine heart. Two types of biocatalysts were prepared: one with only covalently immobilized peroxidase (one-protein system) and another based on covalent co-immobilization of peroxidase and cytochrome c (two-protein system), both immobilized by using carbodiimide chemistry. The amount of immobilized protein was estimated spectrophotometrically, and the characterization of the biocatalyst support matrix was performed using Brunauer–Emmett–Teller (BET), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), and Fourier transform infrared (FTIR) analyses. Stability studies show that co-immobilization with the two-protein system enhances the oxidative stability of peroxidase almost four times with respect to the one-protein system. Thermal stability analysis shows that the immobilization of peroxidase in derivatized porous silicon microparticles does not protect the protein from thermal denaturation, whereas biogenic silica microparticles confer significant thermal stabilization.
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    Photoelectrochemical Reduction of Carbon Dioxide on Quantum-Dot-Modified Electrodes by Electric Field Directed Layer-by-Layer Assembly Methodology
    (2015) Guzmán, Diego; Isaacs Casanova, Mauricio; Osorio Román, Igor; García, Macarena; Astudillo, Jason; Ohlbaum, Macarena
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    Plasmon Enhanced Fluorescence with Aggregated Shell-Isolated Nanoparticles
    (2014) Osorio Román, Igor; Guerrero V., Claudio; Albella, P.; Aroca, R.
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    Shell-isolated nanoparticle-enhanced fluorescence (SHINEF) of CdTe quantum dots
    (2015) Ramírez Maureira, Mónica; Vargas, Víctor C.; Riveros, Ana; Goulet, Paul, J. G.; Osorio Román, Igor
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    Surface characterization of GSH-CdTe quantum dots
    (2013) Gautier, J.; Monras, J.; Osorio Román, Igor; Vásquez, C.; Bravo, D.; Herranz, T.; Marco, J.; Pérez Donoso, J.
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    Synthesis of gold nanoparticles using Coffea Arabica fruit extract
    (2017) Reddy Bogireddy, Naveen; Martinez Gomez, L.; Osorio Román, Igor; Agarwal, V.