Oxidative Stress in Cardiovascular Disease
Oxidative stress, marked by an imbalance of reactive oxygen species (ROS) and reactive nitrogen species (RNS), is a pivotal pathological mechanism across numerous cardiovascular diseases (CVD), including atherosclerosis, heart failure, and ischemia/reperfusion injury. This disturbed redox balance is not merely a consequence but a fundamental aspect of cardiovascular pathophysiology, driving cellular damage, remodelling, and functional decline. Accurate, real-time, and localized detection of these highly reactive, fleeting free radicals is critically required but remains a challenge.
Given the central and pervasive role of free radicals, the ability to accurately, precisely, and dynamically detect and quantify these species in situ is a critical prerequisite for advancing cardiovascular research and clinical practice. However, free radicals are characterized by exceptionally high reactivity and fleeting times, for instance ion superoxide (O2·–) lasts about 2 microseconds.
Conventional Methods for Free Radical Detection
Traditional methods, such as conventional fluorescent dyes and spin-trapping Electron Paramagnetic Resonance (EPR) are commonly used to measure ROS/RNS in biological samples, nevertheless these techniques have significant limitations:
- Conventional fluorescent dyes are consumed irreversibly by the target molecule, preventing continuous measurement and providing only a static snapshot. They also suffer from severe photobleaching and lack specificity, reacting with multiple species.
- EPR, while direct, is often relatively insensitive, requires large concentrations of radicals, and typically lacks the nanoscale spatial resolution needed for subcellular studies.
These limitations make it hard to find out exactly where and when these radicals are generated. This hides their specific role in the complex communication paths inside cells and their correlation with CVD.
Quantum Nuova: Live Cell Assay Platform for Free Radical Quantification
Quantum Nuova, developed by QT Sense, is a breakthrough live-cell assay platform that uses quantum sensing fluorescent nanodiamonds to map oxidative stress and free radical activity in real time and at subcellular location. It offers a non-destructive, high-resolution window into mitochondrial and cellular health, solving the spatiotemporal limitation of standard methods for free radical measurement, improving the understanding of critical pathways and disease mechanisms related with CVD and providing insights for drug development and efficacy.
Translational impact of quantum Nuova in CVD research
Fluorescent nanodiamonds (FNDs) based quantum sensing offers unparalleled advantages that directly support translational CVD research in three main ways:
- Exceptional Sensitivity and Spatial Resolution: FNDs achieve detection limits down to the nanomolar range (1 -10nM). More importantly, they provide nanoscale resolution at the single-cell level, allowing to target FNDs to specific subcellular compartments (i.e mitochondria, endoplasmic reticulum, nuclei), measuring the radical load in those distinct organelles (1). This is critical since oxidative stress is often highly compartmentalized.
- Mechanism of Action (MoA): The spatial and temporal data generated is essential for elucidating CVD mechanisms. For instance, FNDs have been used to precisely monitor real-time free radical production near mitochondria in heart cells during hypoxia and reoxygenation (2), providing crucial insights into myocardial ischemia/reperfusion injury pathogenesis. The ability to precisely monitor endothelial cells under shear stress provides insight into the early events of atherosclerosis and hypertension (3).
- Drug Testing and Therapeutics: The non-destructive nature and long-term photostability of FNDs enable the continuous assessment of a drug’s effect on radical generation. This facilitates the rational design and evaluation of novel therapeutic strategies aimed at modulating oxidative stress, ensuring that interventions can be precisely timed and localized for maximum efficacy and safety over CVD progression. FNDs even allow for direct quantification of ROS in complex fluids like whole blood, opening new ways for clinical diagnostics.
In Summary
Quantum Nuova and FND-based quantum sensing could reduce cycle times, improve prediction accuracy to revolutionize our understanding of redox biology, providing a powerful, quantum-enabled platform to accelerate the development of highly targeted diagnostics and therapies for CVDs.
References
- Sharmin et al. Intracellular Quantum Sensing of Free-Radical Generation Induced by Acetaminophen (APAP) in the Cytosol, in Mitochondria and the Nucleus of Macrophages. ACS Sensors. 2022. Volume 7 Issue 11.
- Fan et al. Quantum Sensing of Free Radical Generation in Mitochondria of Single Heart Muscle Cells during Hypoxia and Reoxygenation. ACS 2024 Jan 18;18(4):2982-2991
- Sharmin et al. Fluorescent Nanodiamonds for Detecting Free-Radical Generation in Real Time during Shear Stress in Human Umbilical Vein Endothelial Cells. ACS 2021 Vol 6. Issue 12.
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