Despite significant medical advancements, doctors still rely on extracellular indicators, such as tumor growth or the symptoms a patient exhibits, to assess cellular health. In a new study published last month in the ACS journal Nano by doctors at the University of Edinburgh, scientists revealed a new method for monitoring electronic activity from inside the cell, allowing doctors to evaluate intracellular redox (short for reduction-oxidation) potential, which has implications for many aspects of cellular health.

Cellular signaling pathways elicit a variety of responses, such as cell proliferation and differentiation; these pathways are regulated by the intracellular redox state of the cell. Redox homeostasis and signaling are critically important to the regulation of cell function. In the past, measuring intracellular redox potentials has proven very difficult, but this newly published method presents a novel, effective method for doing so. Cellular electronic activity runs like clockwork and, thus, any irregularity may be an indication of damage to the cell by toxicity, inflammation or disease.

The study - the result of three years’ work - utilizes microscopic gold nanoshells, functionalized with redox-active molecules. These nanosensors are delivered into the cytoplasm of tissue cells in the laboratory and then subjected to a 785 nm laser. Surface Enhanced Raman Spectroscopy (SERS) measures the laser projections to analyze the intracellular redox potential. The laser light interacts with the molecular vibrations or other excitations in the cell, resulting in an upward or downward shift in energy in the laser photons. These shifts can be graphed and analyzed to measure the cell’s electronic signals, thus providing a clear indication of the cell’s health.

Cancerous tumors, depending on their size, may consist of millions or even billions of cells. The human body itself is comprised of an estimated fifty to seventy-five trillion cells. One might wonder, then, how a doctor would go about selecting the individual cells into which these nanosensors are injected. Depositing the nanoshells into tumor cells may assist doctors in monitoring the tumor’s progress, but other technology already exists for doing so, and, thus, the need for this new technology is not readily apparent. However, the scientists behind these sensors have expressed the hope of using this technology to boost drug development by offering insight into how cells respond to particular drug therapy. This usage seems more efficacious than that of diagnosing cancer, as it may provide a greater understanding of how drugs are affecting patients on a cellular level. With this information, doctors may better utilize drug treatments in patients suffering from a host of diseases and conditions.