Glucose Oxidase-Coated Calcium Peroxide Nanoparticles as an Innovative Catalyst for In Situ H2O2-Releasing Hydrogels.

In situ forming and hydrogen peroxide (H2O2)-releasing hydrogels have been considered as attractive matrices for various biomedical applications. Particularly, horseradish peroxidase (HRP)-catalyzed crosslinking reaction serves efficient method to create in situ forming hydrogels due to its advantageous features, such as mild reaction conditions, rapid gelation rate, tunable mechanical strength, and excellent biocompatibility. Herein, a novel HRP-crosslinked hydrogel system is reported that can produce H2O2 in situ for long-term applications, using glucose oxidase-coated calcium peroxide nanoparticles (CaO2@GOx NPs). In this system, CaO2 gradually produced H2O2 to support the HRP-mediated hydrogelation, while GOx further catalyzed the oxidation of glucose for in situ H2O2 generation. As the hydrogel is formed rapidly is expected and the H2O2 release behavior is prolonged up to 10 days. Interestingly, hydrogels formed by HRP/CaO2@GOx-mediated crosslinking reaction provided a favorable 3D microenvironment to support the viability and proliferation of fibroblasts, compared to that of hydrogels formed by either HRP/H2O2 or HRP/CaO2/GOx-mediated crosslinking reaction. Furthermore, HRP/CaO2@GOx-crosslinked hydrogel enhanced the angiogenic activities of endothelial cells, which is demonstrated by the in vitro tube formation test and in ovo chicken chorioallantoic membrane model. Therefore, HRP/CaO2@GOx-catalyzed hydrogels is suggested as potential in situ H2O2-releasing materials for a wide range of biomedical applications.

Synthesis, crystal structure and Hirshfeld surface analysis of diethyl 2,6-dimethyl-4-(thio-phen-3-yl)-1,4-di-hydro-pyridine-3,5-di-carboxyl-ate.

In the title compound, C17H21NO4S, the 1,4-di-hydro-pyridine ring has an envelope conformation with the Csp 3 atom at the flap. The thio-phene ring is nearly perpendicular to the best plane through the 1,4-di-hydro-pyridine ring, the dihedral angle being 82.19 (13)°. In the crystal, chains running along the b-axis direction are formed through N-H⋯O inter-actions between the 1,4-di-hydro-pyridine N atom and one of the O atoms of the ester groups. Neighbouring chains are linked by C-H⋯O and C-H⋯π inter-actions. A Hirshfeld surface analysis shows that the most prominent contributuion to the surface contacts are H⋯H contacts (55.1%).