Nanophotonics and Metrology Laboratory (NAM), Swiss Federal Institute of Technology (EPFL), 1015 Lausanne, Switzerland.
Nanophotonics and Metrology Laboratory (NAM), Swiss Federal Institute of Technology (EPFL), 1015 Lausanne, Switzerland.
Biosens Bioelectron. 2015 Jun 15;68:245-252. doi: 10.1016/j.bios.2014.12.044. Epub 2014 Dec 23.
Reactive oxygen species (ROS) generated by aerobic organisms are essential for physiological processes such as cell signaling, apoptosis, immune defense and oxidative stress mechanisms. Unbalanced oxidant/antioxidant budgets are involved in many diseases and, therefore, the sensitive measurement of ROS is of great interest. Here, we present a new device for the real-time monitoring of oxidative stress by measuring one of the most stable ROS, namely hydrogen peroxide (H2O2). This portable oxidative stress sensor contains the heme protein cytochrome c (cyt c) as sensing element whose spectral response enables the detection of H2O2 down to a detection limit of 40 nM. This low detection limit is achieved by introducing cyt c in a random medium, enabling multiscattering that enhances the optical trajectory through the cyt c spot. A contact microspotting technique is used to produce reproducible and reusable cyt c spots which are stable for several days. Experiments in static and microfluidic regimes, as well as numerical simulations demonstrate the suitability of the cyt c/H2O2 reaction system for the real-time sensing of the kinetics of biological processes without H2O2 depletion in the measurement chamber. As an example, we detect the release of H2O2 from the green alga Chlamydomonas reinhardtii exposed to either 180 nM functionalized CdSe/ZnS core shell quantum dots, or to 10 mg/l TiO2 nanoparticles. The continuous measurement of extracellular H2O2 by this optical sensor with high sensitivity is a promising new means for real-time cytotoxicity tests, the investigation of oxidative stress and other physiological cell processes.
需氧生物产生的活性氧（ROS）对于细胞信号转导、细胞凋亡、免疫防御和氧化应激机制等生理过程至关重要。氧化剂/抗氧化剂平衡失调与许多疾病有关，因此，ROS 的敏感测量具有重要意义。在这里，我们提出了一种新的设备，用于通过测量最稳定的 ROS 之一过氧化氢（H2O2）来实时监测氧化应激。这种便携式氧化应激传感器包含血红素蛋白细胞色素 c（cyt c）作为传感元件，其光谱响应能够检测到 H2O2，检测限低至 40 nM。通过将 cyt c 引入随机介质中，可以实现低检测限，从而实现多散射，增强通过 cyt c 点的光轨迹。采用接触微点胶技术来产生可重复使用的 cyt c 斑点，这些斑点稳定数天。静态和微流控条件下的实验以及数值模拟表明，cyt c/H2O2 反应体系适用于实时感测生物过程的动力学，而不会在测量室中耗尽 H2O2。作为一个例子，我们检测到暴露于 180 nM 功能化 CdSe/ZnS 核壳量子点或 10 mg/l TiO2 纳米颗粒的绿藻莱茵衣藻中 H2O2 的释放。这种光学传感器对细胞外 H2O2 的连续高灵敏度测量是实时细胞毒性测试、氧化应激和其他生理细胞过程研究的一种有前途的新方法。
