Nanotube Devices for Digital Profiling: A focus on cancer biomarkers and circulating tumor cells.

Circulating tumor cells (CTCs) were first discovered in 1869 in the blood of patients suffering from metastatic disease by an Australian physician, Thomas Ashworth, using optical microscopy [1]. The current understanding is that these CTCs mediate the spread of cancer at distant sites, including the lungs, liver, bones, and brain. CTCs are shed by primary and metastatic cancers in the range of 1-77,200/ml [2], [3]. Recent clinically approved techniques for CTC detection include Veridex from Cell Search [4], the CTC chip [5], and the ADNA test [6], [7], to name a few. Table 1 presents a list of CTC detection methodologies and their U.S. Food and Drug Administration (FDA) approval stages. Although these methods are impressive, none are handheld point-of-care devices; the test cannot be administered in the clinic, with results available in a few minutes both for CTCs and cancer biomarkers. Therefore, with this objective in mind, we present our results on the development of nanotube devices for detection of both protein biomarkers and CTCs using nanotube devices.