Cu, Zn complexes inserted in mesoporous silica as biomimetic catalysts for superoxide dismutation

PATRIARCA MATIAS; SIGNORELLA, SANDRA; DAIER, VERÓNICA

Congreso; VII Latin American Meeting on Biological Inorganic Chemistry.; 2021

UNIVERSIDAD DE LA REPUBLICA

Superoxide dismutase enzymes (SODs) are a group of metalloenzymes which constitute the main biological defense against O2?− in aerobic, aero-tolerant organisms and some obligate anaerobes. These enzymes convert O2?− into O2 and H2O2. Exogenous SOD enzymes have been tested as therapeutic agents to reduce oxidative stress damage with limited success. Therefore, efforts have been focused on the design of low molecular-weight antioxidant catalysts (SOD-mimics) as potential therapeutic agents with better bioavailability than exogenously administered SOD enzymes. The use of mesoporous silicas (MPS) as support for bioinorganic complexes is of great interest because of its large surface area, controllable mesostructure, good mechanical and chemical stability and easily modifiable surface.1,2 In this work a CuZn-superoxide dismutase (SOD) functional mimic, [CuZn(dien)2(μ-Im)](ClO4)3, (Im=imidazole, dien=diethylenetriamine) was successfully inserted into the nanochannels of four type of MPS : SBA15, MCM41, MSP and MSSP with retention of the silica mesostructure. The characterization of the compounds was carried out: SEM, TEM, to observe the morphology of materials; N2 Adsorption-Desorption; TGA, EPR, XANES, UV-Vis, IR and EPR spectra were also performed. Finally, the catalytic activity of the SOD type was measured with an indirect method of photoreduction of NBT as an indicator. Pore sizes between 0?4 nm were obtained for MCM-41, MSN and MSSP, while for SBA-15 between 6-9 nm. Confinement imposed by the silica nanochannels upon encapsulation of complexes leads to stable hybrid materials at physiological pH with enhanced SOD activity relative to the free complexes. Finally, the SOD-type catalytic activity was similar between the complex adsorbed on SBA15 and MCM41 and improved with MSN and MSSP. This makes this work strategy very promising for the design of possible therapeutic agents and / or catalysts.References: 1- M. Patriarca, V. Daier, G. Camí, N. Pellegri, E. Rivière, C. Hureau, S. Signorella. Microporous and Mesoporous Materials 279 (2019) 13.2- M. Patriarca, V. Daier, G. Camí, E. Rivière, C. Hureau, S. Signorella. Journal of Inorganic Biochemistry 207 (2020) 111050