Resumen de Estudio de células cancerosas mediante métodos ópticos: polarimetría aplicada al análisis de la muerte celular inducida por quimioterapia
- español
La polarimetría es una herramienta muy útil en problemas de interacción luz-materia, con muchas aplicaciones exitosas en áreas tales como la biología y la medicina. Es razonable considerar que la polarimetría podría servir para la identificación de procesos celulares relacionados con el desarrollo de tumores, como la muerte celular, la adherencia a una superficie o la mitosis. Estos cambios se pueden analizar mediante la matriz de Mueller M, que describe la respuesta polarimétrica de un medio.
Esta tesis doctoral se centra en el estudio de diferentes procesos relacionados con cultivos de células mediante técnicas ópticas y, en particular, mediante técnicas polarimétricas de imagen. Se analizan muestras de células cancerosas siguiendo dos líneas principales. En primer lugar, un estudio experimental de la eficacia de la quimioterapia sobre varias líneas celulares cancerosas realizada en paralelo con un análisis polarimétrico. En segundo lugar, hemos desarrollado un modelo para comprender mejor la relación entre los procesos de adhesión de células a un sustrato y su imagen polarimétrica. En conjunto, se trata de una herramienta que podría ayudar a introducir procedimientos de evaluación y diagnóstico, ganando tanto velocidad como independencia del observador.
- English
Polarimetry has proven to be a very useful tool in problems that involve light-matter interaction, being a field of increasing activity with many successful applications in areas such as astronomy, agriculture, weather radar, environmental science, etc. Thanks to its non-destructive nature and its potential to identify local properties in media in which it propagates, nowadays imaging polarimetry is being used in biology and medicine, specifically, in the area of diagnosis. In this context, it is reasonable to consider that polarimetry could be used to identify cellular processes typically related to the development of tumors such as cell death, surface adhesion, mitosis, etc. These processes can alter locally the optical properties and, therefore, be detectable by the light that, when interacting with the biological system, changes its polarization.
These changes can be analysed using the Mueller matrix M, which describes the polarimetric response of the medium. An image of each element of this matrix provides spatially resolved local information about the polarimetric behaviour. Because this matrix is a complex object, a transformation is often required to interpret the information and obtain some physical insight.
This thesis focuses on the study of different processes related to cell cultures by means of optical techniques, mainly optical polarimetry. The approach chosen has been the analysis of several cancerous cell lines following two main approaches. First, an experimental study of the efficacy of chemotherapy on several cancer cell lines was carried out in parallel with a polarimetric analysis of the samples at different times with respect to the application of the therapy. This has involved a specific work in sample preparation and has allowed a comparison of the values provided by the polarimetric measurement and the efficacy of the therapy. Secondly, we have developed a model to better understand the relationship between the processes of adhesion and separation of cells to a substrate and their polarimetric image. In the first case, we propose that this could be used to develop new protocols that serve to quantify and asses, in an objective way, the effect of certain chemotherapy drugs and the mortality of different cell lines. In the second case, the practical objective would be the search for a tool that helps to quantify the degree of adhesion of a cell population, which in turn can be related to cell death. Together, it is a tool that could help introduce procedures for evaluation and diagnosis, gaining both speed and independence from the observer.
