Intracellular Implantation of Enzymes in Hollow Silica Nanospheres for Protein Therapy: Cascade System of Superoxide Dismutase and Catalase

Abstract

An approach for enzyme therapeutics is elaborated with cell-implanted nanoreactors that are based on multiple enzymes encapsulated in hollow silica nanospheres (HSNs). The synthesis of HSNs is carried out by silica sol-gel templating of water-in-oil microemulsions so that polyethyleneimine (PEI) modified enzymes in aqueous phase are encapsulated inside the HSNs. PEI-grafted superoxide dismutase (PEI-SOD) and catalase (PEI-CAT) encapsulated in HSNs are prepared with quantitative control of the enzyme loadings. Excellent activities of superoxide dismutation by PEI-SOD@HSN are found and transformation of H2 O2 to water by PEI-CAT@HSN. When PEI-SOD and PEI-CAT are co-encapsulated, cascade transformation of superoxide through hydrogen peroxide to water was facile. Substantial fractions of HSNs exhibit endosome escape to cytosol after their delivery to cells. The production of downstream reactive oxygen species (ROS) and COX-2/p-p38 expression show that co-encapsulated SOD/CAT inside the HSNs renders the highest cell protection against the toxicant N,N'-dimethyl-4,4'-bipyridinium dichloride (paraquat). The rapid cell uptake and strong detoxification effect on superoxide radicals by the SOD/CAT-encapsulated hollow mesoporous silica nanoparticles demonstrate the general concept of implanting catalytic nanoreactors in biological cells with designed functions.

Robust glucose oxidase with a Fe3O4@C-silica nanohybrid structure

“…35 The protein was dissolved in 50 mM sodium phosphate buffer (pH of 7.4) with a concentration of 10 mg mL À1 NHS and EDCÁHCl prepared in sodium phosphate buffer (50 mM, pH of 7.4) was added to the GOD solution. 35 The protein was dissolved in 50 mM sodium phosphate buffer (pH of 7.4) with a concentration of 10 mg mL À1 NHS and EDCÁHCl prepared in sodium phosphate buffer (50 mM, pH of 7.4) was added to the GOD solution.…”

Immobilization of Superoxide Dismutase on Polyelectrolyte‐Functionalized Titania Nanosheets

“…Besides,apromising way to improve the sensitivity and recyclability of SOD is to immobilize it on solid supports, such as inorganic particles, [19][20][21][22][23] polymers, [24,25] or other hybrid mate-rials. [26] In addition, enzyme cascades containing SOD, catalase, or other peroxidase enzymes have been prepared, for which these natural biocatalysts were confined in silica nanoparticles, [27,28] polymericv esicles, [29][30][31] or nanocontainers [32] to mimic the cellulare nvironmenta nd to achieve complete decomposition of ROS into molecular oxygen and water.A ntioxidant enzymes have also been covalently linked to polymeric chains to obtain such antioxidant cascades. [33,34] Titania materials are of great potential in enzyme immobilization owing to their advantageous surfacep roperties as well as their chemical and thermal stability.…”

Membrane Fusion Mediated Intracellular Delivery of Lipid Bilayer Coated Mesoporous Silica Nanoparticles

“…[4] However, therapeutic proteins are susceptible to proteolysis and denaturation, limiting their efficacy in the body. [5,6] To solve the delivery problem, protein delivery systems based on for instance polymeric nanoparticles, [7] hydrogels, [8,9] or lipid-based nanoparticles [10,11] have been developed.…”