Imagine being able to accurately detect the existence and type of cancer at its earliest stages by a simple blood test. Thanks to nanotechnology, that may be possible in the future. In the December 2014 issue of Nature Nanotechnology, researchers affiliated with the Universidade de Sao Paulo and the IMM-Instituto de Microelectronica de Madrid report on their work with a biosensor using nanotechnology that “allows for ultralow concentrations of cancer biomarkers to be detected in blood.”
Cancer is the uncontrolled growth of abnormal cells. To turn into a cancer, normal cells must undergo a multistep process that makes permanent changes to the cell and its progeny. Those good-cells-gone-bad must acquire various traits to allow them to evade the body’s defense mechanisms and thrive. Those acquired physiological changes include being able to divide on their own, resist anti-growth signals, evade apoptosis, immortalization, angiogenesis, and the ability to invade and metastasize. For more see “Rules for Making Human Tumor Cells,” W. Hahn, M.D., Ph.D., and R.A. Weinberg, Ph.D., N Engl J Med 2002; 347:1593-1603.
Cancer cells are, however, still cells. And every cell of the body, through direct secretion or intermediate signaling between neighboring cells, adds to the protein composition of blood. Those protein biomarkers provide a sort of signature or footprint that could, theoretically, lead to the detection of cancer at very early stages. But, protein biomarkers from the early tumors are in extremely low concentrations set against a background of “high biological noise.” Filtering out that noise and finding those low concentrations of biomarkers is exceedingly difficult.
Detection of Cancer Biomarkers in Serum
In their article, “Detection of cancer biomarkers in serum using a hybrid mechanical and optoplasmonic nanosensor,”P.M. Kosaka, V. Pini, J.J. Ruz, R.A. da Silva, M.U. Gonzalez, M. Calleja, and J. Tamayo describe a “sandwich assay” biosensor based on a silicon cantilever and gold nanoparticles that essentially filters out the “biological noise,” captures, and tags the relevant biomarkers. The cantilever is functionalized with “capture” antibodies and immersed in the serum sample allowing for an immunoreaction between the antibodies and protein biomarkers. Next, a “recognition” antibody tethered to a gold nanoparticle attaches to the biomarker.
[The] technique allows for ultralow concentrations of cancer biomarkers to be detected in blood.
The technique is somewhat similar to current conventional diagnostic technology such as enzyme-linked immunosorbent assay, but it also allows for nanomechanical quantification of the biomarkers. This nanomechanical plus optoplasmonic detection creates a “duel nanosensor” that increases the detection sensitivity. The researchers reported that they successfully detected ultralow concentrations of cancer biomarkers for colon (CEA) and prostate (PSA) cancer using their technique. The approach reportedly achieved a detection limit several orders of magnitude lower than achieved in current clinical practice. While acknowledging the limitations of their work, and the challenges that lie ahead, the authors conclude that hybrid mechanical and optoplasmonic devices “could be useful in the development of technologies capable of early-cancer detection through routine blood tests.”
Developments in nanotechnology and cancer research will obviously impact the public health, academic, medical and scientific communities. They will also have an impact on private industry and the legal community. A link to the article “Detection of cancer biomarkers in serum using a hybrid mechanical and optoplasmonic nanosensor,” by P.M. Kosaka, et al., Nature Nanotechnology 9, 1047–1053 (2014) can be found here.