Diamond sensor for Reactive Oxygen Species (ROS)

Reactive Oxygen Species (ROS), and radicals in general, play a fundamental role in a broad range of chemical and biological processes, usually as catalysts and mediators of various reactions. For example, ROS are crucial as catalysts in clean energy production, such as batteries and light-harvesting complexes, and are instrumental in cellular and inter-cellular disease processes, such as inflammation. Detecting and quantifying ROS dynamics is a challenging task, as these molecules are usually short-lived due to their catalytic behavior. This is usually achieved by using spin traps or modified fluorescence markers, which act as indirect indications of ROS activity. However, due to the need to introduce them into the biological system and since they are essentially side-effects of the reactive process, the resulting measurements can affect the process itself, and their quantitative analysis is limited. The proposed project is based on the fact these radicals have free spins, and therefore introduce magnetic noise into the environment. Such noise can be detected and characterized by the diamond-NV platform, through various control schemes referred to as noise spectroscopy.

Figure 3: Schematic for noise spectroscopy schemes based on CPMG and DYSCO: green indicates a laser pulse, orange indicates a π or π/2 pulse, while yellow and blue indicate microwave-pulse blocks composed of 4π pulses with the denoted phases (in which ϕ is a function of the block number).

In this project we will realize a biologically compatible noise spectroscopy system for studying ROS dynamics:

• Develop and optimize noise spectroscopy schemes relevant for ROS measurements, such as we have demonstrated recently using continuous and pulsed control. For this purpose, we will benefit from a collaboration with Uri Banin of the Chemistry Dept. at HUJI, who provides us with specifically designed nano-particles that controllably create ROS as a function of optical illumination (using 405nm light).

• Optimize diamond substrate for these measurements in terms of various parameters, including diamond structure and nanofabrication, NV integration, optical coupling.

• Construct an integrated, biologically compatible ROS sensor, and demonstrate measurements of ROS concentration as a function of controlled stimuli. The proposed project will combine the expertise of the Prawer group in terms of the diamond structure and NV integration, with the noise spectroscopy expertise of the BarGill group (including the collaboration with the Banin group).


Joint Supervision

UoM Prof Steven Prawer – School of Physics, Faculty of Science, The University of Melbourne

Website: https://physics.unimelb.edu.au/home

HUJI Prof Nir Bar-Gill – The Racah Institute of Physics, Faculty of Science, Hebrew University of Jerusalem

Website: https://bargill.phys.huji.ac.il/

HUJI co-supervisor Prof Alex Retzker – The Racah Institute of Physics, Faculty of Science, Hebrew University of Jerusalem