Minimum model of metallic nanoparticle surface and cluster for DNA nanosensors optimization

Abstract

Despite the synthesis techniques and characterization of nanoparticles have reached a ripening stage, with commercial applications, the validation of theoretical simulations of such systems is still a matter of debate. This reality is mainly attributed to the fact that modeling involves the need of neglecting controversial elements. The research presented in this project aims to contribute to the elucidation of these issues by proposing a protocol for modeling metallic nanoparticles surfaces in colloids, and another protocol for the establishment of a minimal model of DNA adsorbed nanoparticles agglomeration, both models in atomic scale and absent in the literature. In this study we use VASP and Gaussian programs which are based on Density Functional Theory. Once the protocols are established, they will be applied to support theoretically the experimental project developed at the Laboratory of Biomedical Vibrational Spectroscopy at University of Vale do Paraiba, with the aim of producing metallic nanoparticles functionalized with DNA oligonucleotides for Paracoccidioides Brasiliensis diagnosis (FAPESP-2009/09559-5). In this context, the study of the nanoparticle surface will provide the necessary theoretical support for the interpretations of data and details of the molecular interactions involved in nanoparticles stabilization and agglomeration, before and after the DNA detection. With the protocol, the DNA Nanosensor constituents will be changed in order to obtain an optimum detection prototype to be synthesized by other group members. The knowledge gained can be extended without difficulty to the study of nanosensors applied to the diagnosis of other diseases. (AU)