Characterization of an interstitial current model around a cancer nodule using optical tweezers.

Abstract

Currently, the process of diagnosis and treatment of a patient with metastatic cancer is highly inefficient due to the complexity of the disease (metastasis is the spread of cancer cells from a primary tumor to secondary tumors at distant sites [1]). However, recent studies have shown that shear stress, caused by natural microfluidic currents, causes cancer cells to break away, spreading them to secondary sites [2] and aggravating the disease. The extent of shear stress on nodules due to microfluidic currents has not been experimentally proven. In the present study, a methodology developed to induce local shear stresses on a cancer nodule model from velocity field measurements is presented. Such methodology is based on the use of the optical tweezers velocimetry technique reported by Eom, et al. [3] and Almendarez, et al. [4]. The methodology consists on using the holographic optical tweezers velocimetry technique (i.e. multiple trapping in one domain), in order to measure, in a discretized way, the flow field at different positions, and approximate through least squares the velocity profiles; with such information, the shear stresses on the surface of the nodule model will be approximated. The methodology contributes to the understanding of metastasis process and other applications, such as: the development of thrombosis, tumor formation, stopping bleeding, etc.