Researchers at University of California, Irvine (UCI), along with collaborators at Harvard University and the University of Pennsylvania, have created a graphene-based electronic method of monitoring changes in the cell's mitochondria that could indicate the start of the cell's self-annihilation process that may open the door to new ways of treating and destroying cancer cells.

The mitochondria, known as the cells' power plants, metabolize energy from carbohydrates and fats to create energy that the cells can use and store it as voltage across their surfaces. Their secondary role, however, is regulating a cell's life-death pathway. The researchers attached about 10,000 purified mitochondria, separated from their cells, to a graphene sensor via antibodies capable of recognizing a protein in their outer membranes. The graphene's qualities allowed it to function as a dual-mode sensor; its electrical sensitivity let researchers gauge fluctuations in the acidity levels surrounding the mitochondria, while its optical transparency enabled the use of fluorescent dyes for the staining and visualization of voltage across the inner mitochondrial membranes.

This ability to measure acidity levels and membrane voltages independently led to two important conclusions. The researchers showed that the inner and outer membranes of the mitochondria are linked to each other's processes; In addition, they identified two separate and independent electrochemical gradients where only one had been thought to exist. This discovery alters scientific understanding of the conversion of chemical nutrients into electrical energy that enables the cells in living organisms to function.

Furthermore, the researchers connected these two electrochemical gradients with the regulation of apoptosis, or programmed cell death, noting changes in mitochondrial function that can influence the life-or-death decision-making pathways. "It shows that there is a relationship between the energy and the apoptosis," the researchers said. The understanding of the mitochondrial pathway of apoptosis may prove important for manipulating various diseases, including cancer. Still, many questions remain open and more work will be required.



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