Immobilization of Agaricus bisporus Polyphenol Oxidase 4 on mesoporous silica : Towards mimicking key enzymatic processes in peat soils

Hypothesis: The use of immobilized enzyme-type biocatalysts to mimic specific processes in soil can be considered one of the most promising alternatives to overcome the difficulties behind the structural elucidation of riverine humic-derived iron-complexes. Herein, we propose that the immobilization of the functional mushroom tyrosinase, Agaricus bisporus Polyphenol Oxidase 4 (AbPPO4) on mesoporous SBA-15-type silica could contribute to the study of small aquatic humic ligands such as phenols. Experiments: The silica support was functionalized with amino-groups in order to investigate the impact of surface charge on the tyrosinase loading efficiency as well as on the catalytic performance of adsorbed AbPPO4. The oxidation of various phenols was catalyzed by the AbPPO4-loaded bioconjugates, yielding high levels of conversion and confirming the retention of enzyme activity after immobilization. The structures of the oxidized products were elucidated by integrating chromatographic and spectroscopic techniques. We also evaluated the stability of the immobilized enzyme over a wide range of pH values, temperatures, storage-times and sequential catalytic cycles. Findings: This is the first report where the latent AbPPO4 is confined within silica mesopores. The improved catalytic performance of the adsorbed AbPPO4 shows the potential use of these silica-based mesoporous biocatalysts for the preparation of a column-type bioreactor for in situ identification of soil samples

Immobilization of Agaricus bisporus Polyphenol Oxidase 4 on mesoporous silica: Towards mimicking key enzymatic processes in peat soils

The use of immobilized enzyme-type biocatalysts to mimic specific processes in soil can be considered one of the most promising alternatives to overcome the difficulties behind the structural elucidation of riverine humic-derived iron-complexes. Herein, we propose that the immobilization of the functional mushroom tyrosinase, Agaricus bisporus Polyphenol Oxidase 4 (AbPPO4) on mesoporous SBA-15-type silica could contribute to the study of small aquatic humic ligands such as phenols.The authors thank the University of Vienna (Austria) and the Austrian Science Research Fund (FWF, P32326 to A.R.) for financial support.Peer reviewe

Morphology-Dependent Interaction of Silica Nanoparticles with Intestinal Cells: Connecting Shape to Barrier Function

The intestinal compartment ensures nutrient absorptionand barrierfunction against pathogens. Despite decades of research on the complexityof the gut, the adaptive potential to physical cues, such as thosederived from interaction with particles of different shapes, remainsless understood. Taking advantage of the technological versatilityof silica nanoparticles, spherical, rod-shaped, and virus-like materialswere synthesized. Morphology-dependent interactions were studied ondifferentiated Caco-2/HT29-MTX-E12 cells. Contributions of shape,aspect ratio, surface roughness, and size were evaluated consideringthe influence of the mucus layer and intracellular uptake pathways.Small particle size and surface roughness favored the highest penetrationthrough the mucus but limited interaction with the cell monolayerand efficient internalization. Particles of a larger aspect ratio(rod-shaped) seemed to privilege paracellular permeation and increasedcell-cell distances, albeit without hampering barrier integrity.Inhibition of clathrin-mediated endocytosis and chemical modulationof cell junctions effectively tuned these responses, confirming morphology-specificinteractions elicited by bioinspired silica nanomaterials.11Nsciescopu

Novel iron oxide nanoparticles induce ferroptosis in a panel of cancer cell lines

The use of nanomaterials rationally engineered to treat cancer is a burgeoning field that has reported great medical achievements. Iron-based polymeric nano-formulations with precisely tuned physicochemical properties are an expanding and versatile therapeutic strategy for tumor treatment. Recently, a peculiar type of regulated necrosis named ferroptosis has gained increased attention as a target for cancer therapy. Here, we show for the first time that novel iron oxide nanoparticles coated with gallic acid and polyacrylic acid (IONP-GA/PAA) possess intrinsic cytotoxic activity on various cancer cell lines. Indeed, IONP-GA/PAA treatment efficiently induces ferroptosis in glioblastoma, neuroblastoma, and fibrosarcoma cells. IONP-GA/PAA-induced ferroptosis was blocked by the canonical ferroptosis inhibitors, including deferoxamine and ciclopirox olamine (iron chelators), and ferrostatin-1, the lipophilic radical trap. These ferroptosis inhibitors also prevented the lipid hydroperoxide generation promoted by the nanoparticles. Altogether, we report on novel ferroptosis-inducing iron encapsulated nanoparticles with potent anti-cancer properties, which has promising potential for further in vivo validation

Novel iron oxide nanoparticles induce ferroptosis in a panel of cancer cell lines

The use of nanomaterials rationally engineered to treat cancer is a burgeoning field that has reported great medical achievements. Iron-based polymeric nano-formulations with precisely tuned physicochemical properties are an expanding and versatile therapeutic strategy for tumor treatment. Recently, a peculiar type of regulated necrosis named ferroptosis has gained increased attention as a target for cancer therapy. Here, we show for the first time that novel iron oxide nanoparticles coated with gallic acid and polyacrylic acid (IONP–GA/PAA) possess intrinsic cytotoxic activity on various cancer cell lines. Indeed, IONP–GA/PAA treatment efficiently induces ferroptosis in glioblastoma, neuroblastoma, and fibrosarcoma cells. IONP–GA/PAA-induced ferroptosis was blocked by the canonical ferroptosis inhibitors, including deferoxamine and ciclopirox olamine (iron chelators), and ferrostatin-1, the lipophilic radical trap. These ferroptosis inhibitors also prevented the lipid hydroperoxide generation promoted by the nanoparticles. Altogether, we report on novel ferroptosis-inducing iron encapsulated nanoparticles with potent anti-cancer properties, which has promising potential for further in vivo validation