Obtención de nanosistemas biogénicos para aplicaciones en SERS

Abstract

Nanotechnology as a field of great relevance at present has focused its efforts in the controlled obtaining of nanosystems of different shape, size, dispersion and chemical composition, as well as its different applications; Furthermore, the field of nanobiotechnology investigates the use of a biological material to manufacture nanosystems, which can improve the biocompatibility of the nanomaterial, which generates widely dispersed systems in size and morphology. For this reason, in the present research, the synthesis and characterization of three different nanosystems are presented: obtaining of silver and gold nanoparticles using Anemopsis californica extract as a reducing and stabilizing agent; generation of nanocomposites of biosynthesized graphene oxide functionalized with silver and gold nanoparticles; and obtaining of hybrid nano/microstructures of silver and gold nanoparticles using pollen grains of Dimorphotheca ecklonis as a template. In addition to the synthesis and characterization of the nanosystems, its evaluation was carried out as substrates for surface enhanced Raman spectroscopy (SERS) effect, occupying methylene blue as the signal molecule. Gold and silver nanoparticles with A. californica extract were obtained, using different solvents in the preparation of the extract (water, methanol and isopropanol), which shows significant differences in morphology depending on the type of metal of the nanoparticles and dependent of the kind of solvent used, likewise considering only hemispheric nanoparticles, significant differences were found depending on the solvent occupied for the preparation of the extract.

The second system, graphene oxide synthesis is obtained by graphite exfoliation in an aqueous/surfactant system supported by A. californica extract, which adds functional groups to the 2D material surface, inducing the possibility of functionalization. Such material was functionalized by the biosynthesis of silver and gold nanoparticles, which adhered to the surface of the material, thus generating AgNPs/GO and AuNPs/GO nanocomposites. The third nanosystem evaluates the obtaining of hybrid nano/microstructures, in which pollen grains of Dimorphotheca ecklonis are used as a reducing and stabilizing agent in the synthesis of silver and gold nanoparticles, working at the same time as a biteplate for the adhesion of these, thus generating the hybrid nano/microstructures AgNPs/PG and AuNPs/PG. Finally, we report the evaluation of all the systems as substrates for the application in SERS, occupying methylene blue as a signal molecule. In the same way all the systems exhibited such property of application of the Raman signal, with special preference silver nanostructures, due to the predominant anisotropic morphology; the AuNPs/OG nanocomposites associated with the conglomeration of the particles and the properties of the template, and the nano/microstructures AgNPs/GP due to the agglomeration of the particles and the morphology of the template.