"This dissertation deals with gold nanoparticle green synthesis in aqueous solution using heparin, as a reducing and stabilizing agent, without other reagents through photochemistry, and their usage as surface enhanced Raman colloidal substrates. This work is divided in four parts: The first one is about proposing the photochemical synthesis method used to prepare the heparinbased gold nanoparticles in aqueous solution using UVA light (λ=366 nm). Two types of experiments were carried out: The nanoparticles were synthesized using reactive and pharmaceutical-grade heparins. Nanoparticle characterization was carried out with UV-Vis spectroscopy and Scanning Electron Microscopy. In the second one, a nanoparticle formation mechanism is proposed with the aid of UV-Vis and FTIR spectroscopies and pH measurements. In the third part, surface enhanced Raman activity is investigated, finding that reactive-grade heparin gold nanoparticles yield good Raman signals and the pharmaceutical-grade ones do not. The probe molecules used were differently charged dyes: Methylene Blue (-), Rosebengal (+) and Neutral Red (+-); as well as proteins (GP120 and Bovine Serum Albumin). There are no reports on heparin-gold nanoparticles being used for this purpose to our knowledge. In the final section, this dissertation´s contributions are presented as a closure to the research that was performed."