Label-free mechanoelectrical investigation of single cancer cells by dielectrophoretic-induced stretch assay

Abstract

It is well-known that cancerous transformation induces many disruptions in the chemical, mechanical, and electrical functions of cells. However, limited data have been reported on their correlative behavior, such as mechanoelectrical responses. In this work, we have applied dielectrophoretic stimulation using transparent Indium Tin Oxide (ITO) microelectrodes to analyze the mechanical deformation of the cells. Our studies have shown high electrodeformation response in non-cancer cells (e.g., for the breast cell line (MCF-10A) ∼21 %). In contrast, the stretch response to the same applied dielectrophoretic stimulation was extremely weak in malignant cells (breast cell line (MDA-MB-231) ∼6 %). This observation points to a new cancer investigation technique based on the real-time correlation between dielectric properties and mechanical behaviors of single cells. Using the smaller electro-deformative ability of cancer cells compared to healthy ones, we have designed and proposed a label-free mechanoelectrical chip to detect metastatic cancer cells in unprocessed tumor samples. The methods of conventional pathology and immunofluorescence assays confirmed the results obtained from our "Dielectrophoretic Stretch Assay" (DSA). This method could help develop protocols for detecting micro invasions in small samples of suspicious masses or cytological samples diagnosis without requirement to pretreatment or labeling and in single-cell resolutions.