Department of Biomaterials and Biotechnology, University of Groningen, University Medical Center Groningen, Groningen 9713 AV, The Netherlands.
Laboratory of Genomic of Germ Cells, Biomedical Sciences Institute, Faculty of Medicine, University of Chile, Independencia Santiago 1027, Chile.
Proc Natl Acad Sci U S A. 2024 Oct 22;121(43):e2317921121. doi: 10.1073/pnas.2317921121. Epub 2024 Oct 14.
Free radical generation plays a key role in many biological processes including cell communication, maturation, and aging. In addition, free radical generation is usually elevated in cells under stress as is the case for many different pathological conditions. In liver tissue, cells produce radicals when exposed to toxic substances but also, for instance, in cancer, alcoholic liver disease and liver cirrhosis. However, free radicals are small, short-lived, and occur in low abundance making them challenging to detect and especially to time resolve, leading to a lack of nanoscale information. Recently, our group has demonstrated that diamond-based quantum sensing offers a solution to measure free radical generation in single living cells. The method is based on defects in diamonds, the so-called nitrogen-vacancy centers, which change their optical properties based on their magnetic surrounding. As a result, this technique reveals magnetic resonance signals by optical means offering high sensitivity. However, compared to cells, there are several challenges that we resolved here: Tissues are more fragile, have a higher background fluorescence, have less particle uptake, and do not adhere to microscopy slides. Here, we overcame those challenges and adapted the method to perform measurements in living tissues. More specifically, we used precision-cut liver slices and were able to detect free radical generation during a stress response to ethanol, as well as the reduction in the radical load after adding an antioxidant.
自由基的产生在许多生物学过程中起着关键作用，包括细胞通讯、成熟和衰老。此外，自由基的产生通常在应激状态下的细胞中升高，如许多不同的病理情况。在肝组织中，细胞在暴露于有毒物质时会产生自由基，但在癌症、酒精性肝病和肝硬化等情况下也是如此。然而，自由基体积小、寿命短且丰度低，这使得它们难以检测，尤其是难以实时解析，从而导致缺乏纳米级信息。最近，我们小组已经证明，基于金刚石的量子传感为测量单个活细胞中的自由基生成提供了一种解决方案。该方法基于金刚石中的缺陷，即所谓的氮空位中心，它们的光学性质基于其周围的磁场而发生变化。因此，这种技术通过光学手段揭示磁共振信号，具有高灵敏度。然而，与细胞相比，我们在这里解决了几个挑战：组织更脆弱，背景荧光更高，颗粒摄取较少，并且不附着在显微镜载玻片上。在这里，我们克服了这些挑战，并调整了该方法以在活组织中进行测量。更具体地说，我们使用了精密切割的肝切片，能够在乙醇应激反应期间检测到自由基的产生，以及在添加抗氧化剂后自由基负荷的减少。
