In the last decade, researchers are looking for platforms, methods, and techniques that mitigate all the problems that current cancer detection methods have; expensiveness, can not be use in a point of care location, do not detects early steps of the disease and are time consuming tests. Nowadays, various researchers have focused on the development of electrochemical devices that detect telomerase as a cancer biomarker. Using a Roche Diagnostics Accu-Chek Aviva® electrochemical platform and electrochemical impedance spectroscopy (EIS), as a sensing technique, telomerase activity in Acute T Cell Leukemia was detected. The detection limit was 0.980 cells/mL. X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were used to characterize the telomerase substrate DNA probe (TS) self assembled monolayer on the gold electrode surfaces. TS probe is rich in guanines thus form secondary structures know as G-quadruplex. Fluorescence spectra showed characteristic fluorescence of DNA G-quadruplex confirming its formation. Additionally, confocal microscope fluorescence images showed the formation of the DNA G-quadruplex as a result of the TS elongation on the electrode surface after been exposed to telomerase. Western blood and gel electrophoresis were used to confirm telomerase presence in Jurkat nuclear cell extracts and to study the DNA elongation process, respectively. The methods and equipment investigated by our group in this investigations will emerge in a development of an electrochemical label free telomerase biosensor and its implementation as a medical device.

This research work was supported by NSF-Chemistry Grant No. CHE-1152940.