Electrochemical Nanobiosensors for Cancer Diagnosis

Cancer is one of the most leading cause of death worldwide and can take over 200 diverse forms, including lung, prostate, breast, cervical, ovarian, hematologic, colon cancer, and leukemia. It has been found that environmental factors (eg, alcohol, radiation, smoke, and carcinogenic chemical compounds) as well as genetic factors (eg, autoimmune dysfunction and hereditary mutations) are linked with an increased threat in the development and progression of cancer [1]. In addition microorganisms are also reported to be associated with some types of cancer (eg, stomach cancer and cervical cancer etc) [2]. In view of such an important medical condition, several methods have already been discovered to diagnose cancer and many more methods are in the process of development [3]. Conventional clinical approaches to detect cancers are based on biopsy followed by histopathology [4], biomarkers using protein levels or nucleic acid content and its expression in the cancer suspects [5]. Biopsy is the most widely used technique, however, it is an invasive technique and cannot always be used. Furthermore, it cannot be applied when cancer biomarkers are present in an extremely low concentrations in the body fluids and in malignant tissues. Thus, the development of highly sensitive and new techniques of cancer diagnosis is extremely interesting and significant in medical science. Due to high interest in interdisciplinary research in the last decade several nanobiosensors based on spectrophotometric or optical methods, fluorescence immunoassay, chemiluminescence analysis, electrochemistry, radioimmunoassay, capillary electrophoresis and chromatographic analysis have been developed to detect cancer biomarkers (proteomic and genetic markers) and cells [6,7]. The major issues in cancer diagnosis are sensitivity and to develop a miniaturized platforms that can be used as point-of-care medical device and can be applied in the remote areas. The development of electrochemical nanobiosensors composed of nanomaterials and biological receptors (antibody, aptamer, peptide etc) are likely the most encouraging approach to solve the problems related to sensitivity, rapidity, selectivity, and low cost [8-12]. This approach is expected to be very effective for cancer diagnosis due to the combination of conventional bioassay (antibody, aptamer, peptide etc) coupled with nanomaterials and electrochemical measurement. Another advantage of the electrochemical biosensor include its ability to be miniaturized as an onsite medical device, low cost, small, and handy size [13-17]. These features of electrochemical nanobiosensors may serve as a smart alternative to support fast cancer diagnosis, thereby designing better therapeutic strategies which will be extremely helpful in decreasing patient stress.