The development of a new technology to measure single-cell mitochondrial respiration

Over the last 20 years there has been an explosion of research into the role of the mitochondria in health and disease. Once regarded as merely the "powerhouse" of the cell, we now know that mitochondria are involved in numerous cellular processes beyond energy production, including inflammation, oxidative stress, and programmed cell death. Due to these diverse roles, mitochondrial dysfunction can impact multiple aspects of cellular function, often leading to pathological conditions, such as neurodegenerative disorders, cancer, and cardiovascular disease1. On the other hand, modifications in mitochondrial pathways can be adaptive, allowing humans and other animals to inhabit hostile habitats, such as high altitude or high temperature environments2. Consequently, understanding mitochondrial physiology has far-reaching implications for a variety of disciplines, including medicine, ecology and conservation.

The gold standard for investigating mitochondrial physiology is microrespirometry using a Clark-type electrode or fluorescent probe. In this classic technique, mitochondrial respiration is measured with pharmacological protocols to investigate different aspects of the electron transfer system3. However, commercially available microrespirometry systems are only capable of measuring bulk oxygen consumption in large populations of cells, rather than single cells. This caveat greatly limits the diagnostic value of our measurements and reduces our experimental control. Furthermore, multicellular preparations limit our ability to make parallel integrative measurements of other intracellular variables (e.g. calcium and pH), and current systems are inappropriate for dynamic cell types that engage in mechanical work, such as heart cells. For these reasons, there is great interest in developing a new system for measuring mitochondrial respiration in single cells4.

The successful development of new technologies requires a broad cross-disciplinary and inter-institutional research effort. To this end, this project brings together a diverse team of cellular physiologists, biochemists and electrochemists to develop a new microelectrode system for measuring single-cell respiration. The electrodes will be developed in collaboration with the Department of Chemistry on the basis of recent advances in scanning electrochemical microscopy5. The system will be optimised in cardiomyocytes at The Division of Cardiovascular Sciences with a view to diagnosing metabolic dysfunction in cardiac diseases. Once optimised, our industry partner Dr Andrew Allan at Cairn Research, and our biochemical consultant, Dr Javier Iglesias, will translate the academic design into a functional commercial prototype that can be used on standard laboratory microscopes. The student will be trained in a wide variety of cross-cutting research skills including; microelectrode fabrication, cell isolation, epifluorescent microscopy, product design and rapid prototyping.