Sensing the dynamics of oxidative stress using enhanced absorption in protein-loaded random media

Abstract

Reactive oxygen species play a key role in cell signalling and oxidative stress mechanisms, therefore, sensing their production by living organisms is of fundamental interest. Here we describe a novel biosensing method for extracellular detection of endogenous hydrogen peroxide (H2O2). The method is based on the enhancement of the optical absorption spectrum of the hemoprotein cytochrome c when loaded into a highly scattering random medium. Such a configuration enables, in contrast to existing techniques, non-invasive and dynamic detection of the oxidation of cyt c in the presence of H2O2 with unprecedented sensitivity. Dynamic information on the modification of the cell oxidative status of Chlamydomonas reinhardtii, an aquatic green algae, was obtained under oxidative stress conditions induced by the presence of trace concentrations of Cd(II). Furthermore, the dynamics of H2O2 production was investigated under different lighting conditions confirming the impact of Cd(II) on the photosynthetic activity of those phytoplanktonic cells.

Non-invasive continuous monitoring of pro-oxidant effects of engineered nanoparticles on aquatic microorganisms

“…Most conventional ROS sensing methods rely on exogenous probes or resulting endogenous reaction products and molecular biomarkers reflecting oxidative damage and antioxidant status [13, 15–17]; they suffer one major technical drawback—the invasive nature of the detection method itself [18]. …”

Silver nanoparticle dissolution in the presence of ligands and of hydrogen peroxide

“…H 2 O 2 may be produced and released into solution by algae, in varying concentrations depending on the algae species and conditions (Palenik et al, 1987;Pospisil, 2012;He et al, 2012a;Suarez et al, 2013). The release of H 2 O 2 by algae in contact with AgNP would lead to a rapid release of Ag þ , as shown by the high reactivity reported here.…”

Portable oxidative stress sensor: Dynamic and non-invasive measurements of extracellular H 2 O 2 released by algae

“…In order to detect lower H 2 O 2 concentrations, the cyt c absorbance A must be amplified. Recently, we have proposed a multiscattering approach where cyt c is embedded in a highly scattering medium composed of polystyrene beads, leading to an enhanced A (Suarez et al, 2013). This configuration showed insufficient repeatability and reproducibility, since each polystyrene beads aggregate is different.…”

“…First, algae were exposed to 500 nM Cd(II), which is highly toxic and known to induce oxidative stress in algae (Suarez et al, 2013). Indeed, after 2 h of exposure, we measured a H 2 O 2 concentration of C 950 100 nM H O 2 2 = ± in the Cd/algae suspension (Fig.…”

“…Yet, these suffer from electrode fouling, lack of long-run stability, and poor selectivity with respect to the analytes (Putzbach and Ronkainen, 2013). Alternatively, we have recently developed a novel optical tool for continuous measurements (Suarez et al, 2012(Suarez et al, , 2013. A difficulty associated with this approach lies in the fabrication of the sensing elements in a controlled and repeatable manner and the bulky nature of the optical setup.…”