(147f) Interference-Based Label-Free Probe of Cancer Cells

Cancer diagnostics and treatment requires identification of tumor cancer cells and determination of their metastatic potential. Current standard methods make cancer cell identification time-consuming and costly, since they involve the use of specific antibodies and biomarkers for immuno-histochemical staining. Here, we describe work aimed at overcoming these barriers. Interference-based techniques have demonstrated great spatial and temporal resolution capabilities in the study of microscopic objects near surfaces, with reflection interference contrast microscopy (RICM) offering a unique non-invasive â??view from belowâ? perspective. Therefore, to identify cancer cells and determine their metastatic potential, cells are studied using RICM, where images captured in just microseconds contain interferograms that embed detailed topographical information of the cells, down to the nanometer-scale. The computational analysis of RICM interferograms, using fast custom-developed algorithms, facilitates label-free quantification of cell adhesion, deformability, and membrane fluctuations. Direct observation of cell adhesion by RICM enables both static and dynamic determination of the contact boundary fractal dimension, measurement of the size and distribution of adhesion patches within the contact area, and evaluation of adhesion strength. In addition, interference fringes can be conveniently analyzed for fast reconstruction of the cellâ??s surface contour with unprecedented nanometer-scale resolution, while fringe visibility analysis allows quantification of nanometer-scale cell membrane undulations or roughness. These static and dynamic measurements using RICM produce valuable information that could reveal characteristic cell signatures and open new possibilities for identification of tumor cancer cells and determination of their metastatic potential.