Abstract

Introduction: Gastric cancer (GC) is the third cause of death by cancer in the world and its rapid progression and lack of specific symptoms make it necessary to find new methods of detection and prevention. Gold nanoparticles have been of great scientific interest because of the many applications, especially in the area of human diseases, for its optoelectronic properties that make them useful for the development of biosensors. We have a new biomarker, Reprimo, which is inactivated at early stages of GC by methylation of promoter region. Unfortunately, current detection techniques have low sensitivity, and are useless for the diagnosis. We therefore propose the use of metal nanoparticles functionalized with oligonucleotides as a tool for early diagnostic of GC. Methodology: Gold nanoparticles of different sizes were synthesized by reduction method with citrate. They were functionalized with α-HS-PEG-ω-COOH and amino-oligonucleotides. All were characterized by UV-Vis, DLS, zeta potential, IR spectroscopy and TEM. Hybridization assays incubating various mixtures of nanoparticles with Reprimo DNA were performed and characterized by UVVis spectroscopy and TEM. Results: All nanoparticles maintain their optoelectronic properties after modification. The results show changes in the zeta potential as the surface oligonucleotide molecules were added. TEM analysis reveals an increase of size, attributable to the functionalization, corroborating those obtained by zeta potential. Hybridization assays demonstrate the formation of a nano-DNA hybrid by increasing the absorption intensity of the plasmonic band due to a coupling of nanoparticles plasmon. Conclusions: Our results demonstrate the potential of these systems as diagnostic tools in GC.