Resumen en inglés

ABSTRACT: Colorectal cancer is the third most frequent type of cancer in the world and in Colombia. According to the World Health Organization (WHO), in 2021 approximately 2 million people were reported with this condition, and, in Colombia, the figure rises to 2,000 new cases per year. Despite being a disease with high prevalence, the treatments that have been developed to combat it are not very effective, generating the need to explore new alternatives, such as nanotechnology that has allowed advances, however, the search for materials and techniques that allow an effective performance in the treatment of colorectal cancer continues. In this work the use of chitosan nanoparticles was proposed because they have advantages in stability, biodegradability, and biocompatibility, besides they can be crossed with other molecules to improve their properties. Therefore, the objective of this project was to establish a protocol to evaluate chitosan-based nanoparticles in a culture of colorectal cancer cells for their possible application as a treatment for this disease. To carry out the project, a methodology divided into two stages was proposed, the first stage consisted of obtaining and analyzing the stability of the nanoparticles, and the second stage consisted of evaluating the nanoparticles in two cell line cultures (Caco-2 cancer cell line and the NIH-3T3 mouse fibroblast cell line). The evaluation was performed at different concentrations of nanoparticles in a range between 0 - 100 µg/mL to establish the experimental conditions for the study of the effect of these nanoparticles on the cell lines mentioned, and thus contribute to the development of the project entitled "Chitosan - Fe (III) nanocomplexes modified with folic acid for targeted therapy in colon cancer" of the research group GIBEC of the EIA University. The results obtained showed that the ionotropic gelation method used to synthesize chitosan nanoparticles allows obtaining particles with an average size of 188.3 nm. However, when in contact with the protein-free cell culture medium, an increase in size was observed, reaching approximately 902.2 nm, with an average ζ-potential value of 10.79 mV. Furthermore, upon evaluating these nanoparticles in the cell cultures mentioned previously, it was possible to verify that they do not exert cytotoxicity on the cell lines studied, since in all the tests performed, the cell viability results were never lower than 70%.