Project Reference: TRG27-MED-DT1

Project title: Quantum sensing of spatiotemporal reactive oxygen species, temperature and pH dynamics during the phagocyte respiratory burst using NV-centre nanodiamonds

Project outline

This project leverages the expertise of the Thomas lab (medicine) in reactive species (ROS) biology which is essential for immune function and those of the Knowles lab (physics) in using fluorescent nanodiamond quantum sensing to understand cell biology at the nanoscale. 

Background

Reactive oxygen species (ROS) generated by the phagocyte NADPH oxidase (NOX2) are essential for antimicrobial defence and immune regulation. The membrane-bound NOX2 complex transfers electrons from NADPH to molecular oxygen, producing superoxide that is converted to H₂O₂, HOCl and peroxynitrite among other ROS. These reactions create localised changes in temperature, pH and oxidative stress. Inability to generate ROS leads to susceptibility to infection and autoinflammation. Conversely too much ROS can damage host tissues. Traditional fluorescent probes suffer from bleaching, invasiveness and limited spatial resolution. Thus, the exquisite spatiotemporal control of this process and its sequelae remain undefined. Fluorescent nanodiamonds offer a solution. 

Aims & Approach

This project will exploit nitrogen-vacancy (NV) centres in fluorescent nanodiamonds as a multimodal quantum sensing platform, applying the Knowles laboratory’s simultaneous ODMR nanothermometry (~0.1 °C resolution) and T₁ relaxometry protocols. Differentiated PLB-985 cells (neutrophil model) and primary human neutrophils/macrophages will be used. Genetic controls include gp91phox and p22phox- ( unable to produce superoxide) plus MPO- and iNOS-deficient lines (deficient in HOCl or nitric oxide). Pharmacological inhibitors will provide complementary perturbation.

Questions:

Where exactly is ROS made, how does local temperature change and what  local pH changes occur at the 10–20 nm scale during the burst ?

What is the ability of nano-ESR/NMR modalities to discriminate specific radical species?

How does ROS production by the oxidative burst influence mitochondrial function, temperature, metabolism - all tractable.

Principal Supervisor

Professor David Thomas

Email address: tdct2@cam.ac.uk

Department / Partner Institute: Medicine / Cambridge Institute for Therapeutic Immunology and Infectious Disease (CITIID)

Website: https://www.immunology.cam.ac.uk/Networkdirectory/thomas

BBSRC strategic theme

Understanding the rules of life