Quantitative Local Photosynthetic Flux Measurements at Isolated Chloroplasts and Thylakoid Membranes Using Scanning Electrochemical Microscopy (SECM)

Abstract

Quantitative local photosynthetic flux measurements at isolated chloroplasts and thylakoid membranes using scanning electrochemical microscopy (SECM). Copies of full items can be used for personal research or study, educational, or not-forprofit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. Publisher's statement:This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Physical Chemistry Part B, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://dx.doi.org/10.1021/jp403048fThe version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP url' above for details on accessing the published version and note that access may require a subscription. (CN) 6 4-), from the artificial electron acceptor ferricyanide (Fe(CN) 6 3-), using a stationary ultramicroelectrode at chloroplasts and thylakoid membranes (sourced from chloroplasts). Oxygen generation at films of chloroplasts and thylakoid membranes was detected directly during photosynthesis, but in the case of thylakoid membranes this switched to sustained oxygen consumption at longer illumination times. An initial oxygen concentration spike was detected over both chloroplast and thylakoid membrane films, and the kinetics of the oxygen generation were extracted by fitting the experimental data to a finite element method (FEM) simulation. In contrast to previous work, the oxygen generation spike was attributed to the limited size of the plastoquinone pool, a key component in the linear electron transport pathway and a contributing factor in photoinhibition. Finally, the mobile nature of the SECM probe, and its high spatial resolution, also allowed us to detect ferrocyanide produced from a single thylakoid membrane. These results further demonstrate the power of SECM for localized flux measurements in biological processes, in this case photosynthesis, and, that the high time resolution, combined with FEM simulations, allows the elucidation of quantitative kinetic information.

Understanding the interaction of thiosulfate with Alloy 800 in aqueous chloride solutions using SECM

“…An advantage of SECM is its capability to probe charge transfer occurring nonuniformly at interfaces [13,14]. Scanning reference electrode technique (SRET) has been used for determination of the potential distribution on corroding surfaces [15][16][17][18][19][20] and scanning tunneling microscope (STM) is a technique to study corrosion at micro-and nano-scale [21][22][23][24].…”

Biological imaging with scanning electrochemical microscopy

“…In the context of the development of biofuel cells, the transmembrane charge transfer ability of eukaryotic yeast cells was, for instance, assessed by means of G/C SECM [65,66] colonies [67], quorum sensing of aggregates of Pseudomonas aeruginosa [68] and metabolite production of Pseudomonas aeruginosa during proliferation [69] are examples of G/C-SECM studies with bacterial prokaryotes. Exotic targets for biological SECM studies were salt glands on the leaf of the halophyte Cynodon dactylon (L.) [70] and chloroplasts and their thylakoid membranes for which local photosynthetic flux measurements have been attempted [71]. SECM study entries into the literature databases that underline well the wide applicability of scanning electrochemical probe-based cellular analysis are examinations of the differentiation status of embryonic stem cells [72], evaluation of the respiration activity of blastocysts [73], monitoring intracellular enzyme activity of HeLa cells [74], analysis of beat fluctuations and oxygen consumption of cardiomyocytes [75], characterization of Ag + toxicity on fibroblast cells [76], inspection of the multi-drug resistance of adenocarcinoma cervical cancer cells [77], the detection of reactive oxygen species in prostate cancer cells [78], the creation of insulin release profiles of single pancreatic islets [79] and the disclosure of Cd 2+ -induced variability in the permeation properties of human bladder cancer cells [80,81].…”

Applications of scanning electrochemical microscopy in photoelectrochemistry

“…(E) (a) 应用SECM研究植物叶片中提取叶绿体的光合作用过程示意图; (b) SECM在含有铁氰化物溶液中扫描类囊体膜的光 生电流结果 [12] [38] . 2001年, Bard等 [39] [8] .…”

“…如图1所示, 从最初观察植物细胞的光合作用 [12] 、研 究电致发光反应过程 [13] 、光诱导电荷转移反应 [8] , 到 近些年对太阳能电池材料的筛选 [7,14,15] [16] . 在光电化学体系研究 中, 在原有SECM系统上组装光源(如氙灯)和光学通路 图 1 SECM在光电化学研究领域的应用示例(光合作用 [12] 、光诱导电荷转移 [8] 、电致化学发光 [13] 、光解水 [7] 、染料敏化太 阳能电池 [14] 、钙钛矿太阳能电池 [15] ) (网络版彩图) http://engine.scichina.com/doi/10.1360/N032017-00013 1~100 μm不同种类和形貌的超微电极为常用的SECM 探针, 其中以圆盘形微米电极为代表(图2B(a)). 常用 的探针材料包括铂 [18] 、金 [19] 、碳纤维等 [7] .…”