NIRT: Developing a Nanoscale Sensing Device for Measuring the Supply of Iron to Phytoplankton in Marine Systems

0304523 Wells建议活动的智力价值：本建议是响应NSE NSF-02- 148而收到的。越来越多的证据表明，铁在海洋生态系统中具有独特的作用，既调节世界上高硝酸盐、低叶绿素地区的浮游植物总产量，又影响其他地区浮游植物组合的主要组成。值得注意的是，与常量营养素氮、磷或硅相比，关于如何定义生物可利用的铁没有达成一致。 目前试图获得预测性的见解，海洋生态系统将如何影响气候变化的幅度在很大程度上被这个问题所阻碍，沿着的数据在海洋中的铁分布的极端短缺。 最近有证据表明，铁的可用性可以调节散装海水培养的真菌铁载体desferrioximine B（DFB）的小补充。 铁-DFB复合物是不容易获得的真核浮游植物，因此，如果铁的量络合的DFB被测量和校准的浮游植物的铁吸收，它可以产生一个新的一阶措施的铁的可用性。 从我们目前的研究中，我们已经开发出脂质体，专门从溶液中获得DFB结合的铁。 这些直径为100 nm的器件为应用纳米技术在海洋沃茨中创建新型Fe生物传感器开辟了道路。该项目的目标是1）通过提高其物理稳健性，确定尺寸/功能关系，并检查其他DFB-Fe转运分子的功效来优化这些纳米器件，2）开发用于量化这些纳米器件的Fe吸收的自我报告能力，以及3）校准这些纳米器件对Fe的捕获，以适应各种浮游植物物种的Fe吸收。 预期的最终产品将是一个校准的纳米级生物传感器，用于实验室规模的使用，然后可以适用于远程车辆上的部署。拟议活动产生的更广泛影响：参与该项目的两个机构（美国）。缅因州和科尔比学院）在让本科生和研究生参与海洋科学和化学前沿研究方面有着良好的记录，本项目将继续这一进程。

0304523WellsIntellectual Merit of the Proposed Activity: This proposal was received in response to NSE NSF-02-148.There is increasing evidence that Fe has a singularly unique role in marine ecosystems, both regulating total phytoplankton production in high nitrate, low chlorophyll regions of the world, and influencing the predominant composition of the phytoplankton assemblages found in others. It is remarkable then that there is no agreement about how to define biologically available Fe, in contrast to the macronutrients nitrogen, phosphorous or silicon. Current attempts to attain predictive insights to how ocean ecosystems will influence the magnitude of climate change are blocked in large part by this question, along with an extreme shortage of data on Fe distributions in the oceans. There is recent evidence that Fe availability can be regulated in bulk seawater incubations by small additions of the fungal siderophore desferrioximine B (DFB). The Fe-DFB complex is not readily available to eukaryotic phytoplankton, so that if the quantity of Fe complexed by DFB were measured and calibrated to Fe uptake by phytoplankton it could yield a novel first order measure of Fe availability. Building from our current research we have developed liposomes that specifically acquire DFB-bound Fe from solution. These devices, 100 nm in diameter, open the way to applying nanotechnology to create a new breed of Fe biosensors in marine waters. The project goals are to 1) optimize these nanodevices by improving their physical robustness, identifying the size/functionality relationship, and examining the efficacy of other DFB-Fe transporter molecules, 2) develop self-reporting capabilities for quantifying Fe uptake by these nanodevices, and 3) to calibrate the capture of Fe by these nanodevices to the Fe uptake by various phytoplankton species. The anticipated final product will be a calibrated nanoscale biosensor for laboratory-scale use that could then be adapted for deploying on remote vehicles. Broader Impacts Resulting from the Proposed Activity: The two institutions involved in this project (U. Maine and Colby College) have a strong track record for involving undergraduate and graduate students in cutting edge research in marine science and chemistry, and this project will continue this process.