Functionalization of Nanotubes with Azoic O-glycoside Ivan Flores Rosales, Pamela Hurtado Ponce, Marco Brito-Arias* Biotechnology Unit National Polytechnic Institute of Mexico (UPIBI-IPN) Scheme Avenida Acueducto s/n, La Laguna Ticoman, Mexico City DF, 07340 Email: [email protected] O OH Keywords: Phenylazonaphtyl glycosides, nanotubes, TEM microscopy, azoic glycosides. Cl N OH + N O n O HO OH Abstract Text: This work describes the coupling reaction between an azoic O-glycoside with a single wall nanotube acyl chloride to generate the nanotube-azoic O-glycoside complex which was analyzed by TEM microscopy. The study showed the presence of nodules or aggregates along the cylindrical nanotube, suggesting the functionalization through a covalent interaction. Introduction Nanotubes are defined as coaxial cylindrical units nanoscale graphite (1 to 100 nm) with walls composed of carbon hexagonal mesh with both ends rounded. Nanotubes have had a major impact in biomedical areas such as molecules with potential use as drug carriers, biosensors, encapsulating enzymes, neuronal and bone growth among others. Because of the particular importance of the coupling of carbohydrates to nanotubes to improve solubility, increase the biocompatibility and specificity towards specific targets, we propose the synthesis of nanotubes (SWNT) linked to azoic O-glycosides using a covalent approach. The presence of the dye will also allow the detection of the nanotubes complex by spectroscopy or confocal microscopy which will allow us to find the nanotubes within cells.[1] N N O O O O OH n HO HO Scheme. Synthetic approach for the preparation of complex nanotube-azoic glycoside. Figure 1. Non functionalized single wall nanotube. Methodology The strategy employed for the preparation of the complex nanotube-azoic glycoside consisted in the coupling reaction between the nanotube acyl chloride with Sudan II-β-D-galactopyranoside as depicted in scheme. The reaction conditions used were sonication in THF at room temperature. The nanotube was centrifuged and washed (3 x 2 mL) with THF until the solution was colorless. The nanotubes obtained as pellet were dried in oven, suspended in isopropanol and analyzed by TEM microscopy. Results and Discussion The azoic glycoside was synthesized by direct coupling reaction between acetobromo glucose with Sudan II under the Koenigs-Knorr conditions, and deprotected under Zemplen conditios.[2] The resulting azoic glycoside was condensed with nanotube previously derivatized to the acyl chloride form. The reaction was repeatedly washed and centrifuged to assure that the nanotubes were free of unreacted glycoside. The suspended nanotubes were analyzed by TEM microscopy, observing for the unreacted nanotube a uniform surface without the presence of aggregates around the cylinder. On the other hand for the complex nanotube- azoic O-glycosides it was observed the presence of small bundles around the cylindrical nanotubes at different resolutions in agreement with those reported by Wu et al for the reaction with glycodendrimers [3] (figures 2 and 3). Figure 2. Functionalized nanotube with glycoside coating the SWNT. Figure 3. Functionalized nanotube. References [1] H. Sun, P. She, G. Lu, K. Xu, W. Zhang, Z. Liu. Recent advances in the development of functionalized carbon nanotubes: a versatile vector for drug delivery. J Mater Sci 2014 49:6845– 6854. [2] Marco Brito-Arias Synthesis and Characterization of Glycosides Ed Springer 2007, 73-74. [3] P. Wu, X. Chen, N. Hu, U. Tam, O. Blixt, Al. Zettl, and C. R. Bertozzi. Biocompatible Carbon Nanotubes Generated by Functionalizationwith Glycodendrimers. Angew. Chem. Int. Ed. 2008, 47, 5022 –5025.