Sintesis y derivatizacion de nanoparticulas de silicio con grupos tioles superficiales. Variacion en las propiedades luminiscentes.

CAREGNATO, PAULA; DELLARCIPRETE MARÍA LAURA; DANIEL MARTIRE; GONZALEZ, MÓNICA C.

Congreso; 21st I-APS Conference; 2011

Inter American Photochemical Society

Silicon nanoparticles of 1-5 nm size (NP-Si) have received a great attention, as they combine size-dependent photoluminescence, the capacity for singlet oxygen (1O2) generation and of reducing methyl viologen, and the richness of silicon surface chemistry [Llansola 2010]. Remarkable properties of silicon-based nanoparticles, when compared to other materials, are their biocompatibility, biodegradability and tunable surface derivatization for drug delivery and the fact that silicic acid administered to humans is efficiently excreted through the urine [Park 2009]. Thiols are extraordinarily efficient antioxidants. Humans and animals are continuously exposed to compounds with thiol and related disulfide groups, such as those present in garlic and fish. In vivo oxidation of thiols under conditions of oxidative stress, generate a group of redox-active molecules capable of oxidizing and inhibiting the biological activity of proteins and enzymes. To study the effect of surface antioxidants on the nanoparticle capacity of producing O2.- and 1O2 radicals by photolysis, 1-2 nm size NP-Si were synthesized and derivatized with thiol-terminated groups. The assembly method (Bottom-up) was used for the synthesis where the nucleation and growth of the particles were performed in the interior of inverse micelles [Rosso-Vasic 2008]. The chemisorption of organic thiols on NP-Si surface was developed according to [Xu 2003] and [Caregnato 2010]. The synthetic strategy involved the oxidiation of the particle surface and further silanization with a mercaptothiol. Besides, it is proposed to evaluate the efficiency of NP-SiSH to generate reactive species such as O2.-, 1O2 and organic radicals by photolysis of the particles. The comparison of these results with those of H-terminated nanoparticles it is possible to evaluate the effect of organic surface groups in the generation of ROS. [Llansola 2010] Llansola Portolés MJ, David Gara PM, Kotler ML, Bertolotti S, San Roman E, et al. (2010) Silicon Nanoparticle Photophysics and Singlet Oxygen Generation. Langmuir 26: 10953-10960. [Park 2009] Park J-H, Gu L, von Maltzahn G, Ruoslahti E, Bhatia SN, et al. (2009) Biodegradable luminescent porous silicon nanoparticles for in vivo applications. Nature Materials 8: 331-336. [Rosso-Vasic et al., 2008] Milena Rosso-Vasic, Evan Spruijt, Barend van Lagen, Luisa De Cola and Han Zuilhof , Small (2008) 10, 1835-1841. [Caregnato et al., 2010] Caregnato P, Forbes MDE, Soria DB, Mártire DO, Gonzalez MC, J. Phys. Chem. C. (2010), 114, 5080-5087. [Wu et al., 2003] Wu X, Liu H, Liu J, Haley KN, Treadway JA, Larson JP, Ge N, Peale F, Bruchez MP. Nat. Biotechnol (2003) 21, 41-46.