title: Determination of nanomolar levels of reactive oxygen species in microorganisms and aquatic environments using a single nanoparticle-based optical sensor.
abstract: Reactive oxygen species (ROS) are strong oxidants, and have attracted considerable attention in both biological and environmental fields. Although various methods for ROS detection, including optical and electrochemical techniques, have been developed, they still face challenging issues in terms of poor sensitivity, reproducibility, stability, and in vivo applicability. Here, we present a sensitive and selective optical sensor for ROS detection, based on single plasmonic nanoprobes and redox-active cytochrome c (Cyt c)-mediated plasmon resonance energy transfer. By measuring the spectral changes of plasmonic nanoprobes, derived from the unique molecular absorption of Cyt c in accordance with the redox state, calibration curves for H2O2, a representative ROS, in various media were obtained over a wide concentration range from 100 mM to 1 nM. Limit of detection and limit of quantification in accordance with the used medium were determined from 8.3 to 12.8 nM and from 27.6 to 42.7 nM, respectively. Selectivity coefficients for major interfering solutes were much lower than 0.1 indicating a good selectivity for ROS. From the dynamic spectral changes, we sensitively monitored ROS generated in Caenorhabditis elegans (C. elegans) exposed to graphene oxide. Based on the calibration curves, we also determined ROS levels in various aquatic environments, such as river streams and a small pond, as a way of environmental monitoring. We believe that our approach could provide an avenue for achieving dynamic and sensitive monitoring of ROS in toxicological, biological, and environmental fields in the future.
authors.affiliation: Department of Life Science, University of Seoul, Seoul 130-743, Republic of Korea.
authors.forename: Yura
authors.initials: Y
authors.lastname: Kim
authors.affiliation: School of Environmental Engineering, Graduate School of Energy and Environmental System Engineering, University of Seoul, Seoul 130-743, Republic of Korea.
authors.forename: Youngho
authors.initials: Y
authors.lastname: Kim
authors.affiliation: School of Environmental Engineering, Graduate School of Energy and Environmental System Engineering, University of Seoul, Seoul 130-743, Republic of Korea.
authors.forename: Jinhee
authors.initials: J
authors.lastname: Choi
authors.affiliation: Department of Chemical and Biomolecular Engineering, Sogang University, Seoul 121-742, Republic of Korea. Electronic address: twkang@sogang.ac.kr.
authors.forename: Taewook
authors.initials: T
authors.lastname: Kang
authors.affiliation: Department of Life Science, University of Seoul, Seoul 130-743, Republic of Korea. Electronic address: inheechoi1@uos.ac.kr.
authors.forename: Inhee
authors.initials: I
authors.lastname: Choi
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000378:metabolism; D004784:Environmental Monitoring; D006861:Hydrogen Peroxide; D053758:Nanoparticles; D061005:Ponds; D017382:Reactive Oxygen Species / Q000032:analysis*; D015203:Reproducibility of Results; D045483:Rivers
chemical_list: D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide
keywords: Cytochrome c; Hydrogen peroxide; Optical sensor; Plasmon resonance energy transfer; Plasmonic nanoparticles; Reactive oxygen species