2017-02, Correro, Maria Rita, Sykora, Sabine, Corvini, Philippe, Shahgaldian, Patrick

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.

2016, Correro, Maria Rita, Moridi, Negar, Schützinger, Hansjörg, Sykora, Sabine, Ammann, Erik, Peters, E. Henrik, Dudal, Yves, Corvini, Philippe, Shahgaldian, Patrick

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.

2017, Sykora, Sabine, Correro, Maria Rita, Moridi, Negar, Belliot, Gaël, Pothier, Pierre, Dudal, Yves, Corvini, Philippe, Shahgaldian, Patrick

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.

2015-01-05, Sykora, Sabine, Belliot, Gaël, Pothier, Pierre, Cumbo, Alessandro, Arnal, Charlotte, Dudal, Yves, Corvini, Philippe, Shahgaldian, Patrick

Functional recognition imprints of virus-like particles, at the surface of silica particles, were generated following a strategy based on protein-templated polycondensation of organosilanes.

2016-09, Correro, Maria Rita, Takacs, Michael, Sykora, Sabine, Corvini, Philippe, Shahgaldian, Patrick

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)​.