title: Real-time in-situ Simultaneous Monitoring of Dissolved Oxygen and Materials Movements at a Vicinity of Micrometers from an Aquatic Plant by Combining Deflection of a Probe Beam and Fluorescence Quenching.
abstract: It is desirable to be able to monitor the intake or release of the components at different organs of aquatic plants in real time and in-situ. Here, we report a novel optical detection system that allows for real-time in-situ simultaneous monitoring of the dissolved oxygen and material movements at a vicinity of micrometers from the aquatic plant surface. A blue semiconductor diode-laser was used as the light source of both the probe beam and excitation light for fluorescence. The laser light reflected by a dichroic mirror was focused to a vicinity of the plant/water interface in a culture dish by an objective lens. The distance between the focused laser beam and the plant surface was adjusted by an X-Y-Z micro-stage. Deflection of the probe beam was detected by a position sensor, and fluorescence from the vicinity was monitored by a PMT. A commercial fluorescent DO sensor, which simultaneously monitored temperature, was immersed into the culture dish at about 1 cm away from the aquatic plants. A white-light LED was used to illuminate the aquatic plants in the dish in photosynthesis process. A Ru-complex (tris (2,2'-bipyridyl)ruthenium(II) chloride) was used as a fluorescent probe, and Egeria densa Planch. was used as a model aquatic plant. The DO-quenched fluorescence and material movement-induced deflection signals are compared at different distances from the aquatic plant surface. The results show that the optical detection system can monitor DO and the material movements at a vicinity of the aquatic plants not only much more sensitively, but also much more closely to real time than analytical methods that monitor concentration changes at a bulk solution.
authors.affiliation: Department of Life, Environment and Materials Science, Fukuoka Institute of Technology.
authors.forename: Xing-Zheng
authors.initials: XZ
authors.lastname: Wu
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Wu
authors.forename: Tomomi
authors.initials: T
authors.lastname: Inoue
mesh_terms: D005456:Fluorescent Dyes / Q000737:chemistry*; D031321:Hydrocharitaceae / Q000737:chemistry*; D061848:Optical Imaging; D009942:Organometallic Compounds / Q000737:chemistry*; D010100:Oxygen / Q000032:analysis*; D013499:Surface Properties; D013997:Time Factors
chemical_list: D005456:Fluorescent Dyes; D009942:Organometallic Compounds; C415768:tris(2,2'-bipyridyl)ruthenium(II); D010100:Oxygen