TY - JOUR
T1 - Diamond Relaxometry as a Tool to Investigate the Free Radical Dialogue between Macrophages and Bacteria
AU - Wu, Kaiqi
AU - Nie, Linyan
AU - Nusantara, Anggrek C.
AU - Woudstra, Willem
AU - Vedelaar, Thea
AU - Sigaeva, Alina
AU - Schirhagl, Romana
N1 - Funding Information:
This work was financially supported by an ERC starting grant, (ERC-2016-STG Stress Imaging 714289). The authors would also thank the China Scholarships Council for supporting us with a scholarship (No.201706170089) for L.N. and (No.201808320450) for K.W. A.C.N. acknowledges the Kolff Institute for her PhD scholarship. Confocal images shown in this paper were acquired from UMCG Imaging and Microscopy Center (UMIC) under NWO grant 175-010-2009-023 for imaging work in the paper. The authors thank Gert ten Brink from the Department of Nanostructured Materials and Interfaces Zernike Institute for Advanced Materials (University of Groningen) for help with S/TEM samples on FEI Helios G4 CX.
Publisher Copyright:
© 2023 The Authors. Published by American Chemical Society.
PY - 2023/1/11
Y1 - 2023/1/11
N2 - Although free radicals, which are generated by macrophages play a key role in antimicrobial activities, macrophages sometimes fail to kill Staphylococcus aureus (S. aureus) as bacteria have evolved mechanisms to withstand oxidative stress. In the past decades, several ROS-related staphylococcal proteins and enzymes were characterized to explain the microorganism's antioxidative defense system. Yet, time-resolved and site-specific free radical/ROS detection in bacterial infection were full of challenges. In this work, we utilize diamond-based quantum sensing for studying alterations of the free radical response near S. aureus in macrophages. To achieve this goal we used S. aureus-fluorescent nanodiamond conjugates and measured the spin-lattice relaxation (T1) of NV defects embedded in nanodiamonds. We observed an increase of intracellular free radical generation when macrophages were challenged with S. aureus. However, under a high intracellular oxidative stress environment elicited by lipopolysaccharides, a lower radical load was recorded on the bacteria surfaces. Moreover, by performing T1 measurements on the same particles at different times postinfection, we found that radicals were dominantly scavenged by S. aureus from 80 min postinfection under a high intracellular oxidative stress environment.
AB - Although free radicals, which are generated by macrophages play a key role in antimicrobial activities, macrophages sometimes fail to kill Staphylococcus aureus (S. aureus) as bacteria have evolved mechanisms to withstand oxidative stress. In the past decades, several ROS-related staphylococcal proteins and enzymes were characterized to explain the microorganism's antioxidative defense system. Yet, time-resolved and site-specific free radical/ROS detection in bacterial infection were full of challenges. In this work, we utilize diamond-based quantum sensing for studying alterations of the free radical response near S. aureus in macrophages. To achieve this goal we used S. aureus-fluorescent nanodiamond conjugates and measured the spin-lattice relaxation (T1) of NV defects embedded in nanodiamonds. We observed an increase of intracellular free radical generation when macrophages were challenged with S. aureus. However, under a high intracellular oxidative stress environment elicited by lipopolysaccharides, a lower radical load was recorded on the bacteria surfaces. Moreover, by performing T1 measurements on the same particles at different times postinfection, we found that radicals were dominantly scavenged by S. aureus from 80 min postinfection under a high intracellular oxidative stress environment.
KW - bacterial infections
KW - diamond magnetometry
KW - fluorescent nanodiamonds
KW - free radicals
KW - microorganism antioxidative defense
KW - S. aureus
U2 - 10.1021/acsnano.2c08190
DO - 10.1021/acsnano.2c08190
M3 - Article
AN - SCOPUS:85146350422
SN - 1936-0851
VL - 17
SP - 1100
EP - 1111
JO - Acs Nano
JF - Acs Nano
IS - 2
ER -