Award Abstract #0102334
NER: Exploratory Research on Developing a Nanoscale Sensing Device for Measuring the Supply of Iron to Eukaryotic Phytoplankton in Natural Seawater

NSF Org:	OCE Division of Ocean Sciences
Initial Amendment Date:	May 30, 2001
Latest Amendment Date:	May 30, 2001
Award Number:	0102334
Award Instrument:	Standard Grant
Program Manager:	Simone Metz OCE Division of Ocean Sciences GEO Directorate for Geosciences
Start Date:	September 1, 2001
Expires:	August 31, 2003 (Estimated)
Awarded Amount to Date:	$99330
Investigator(s):	Mark Wells mlwells@maine.edu (Principal Investigator)
Sponsor:	University of Maine 5717 Corbett Hall ORONO, ME 04469 207/581-1484
NSF Program(s):	NANOSCALE: EXPLORATORY RSRCH
Field Application(s):	0204000 Oceanography
Program Reference Code(s):	OTHR, 9150, 1676, 0000
Program Element Code(s):	1676

ABSTRACT



This proposal was received in response to NSE, NSF-0019.

The long delay in recognizing the potentially key role of Fe in coastal marine systems has been in large part because of the complexity of microbial:Fe interactions in seawater. There still is no analytical method for determining biologically available Fe for either prokaryotic or eukaryotic phytoplankton. However, there is evidence that Fe availability to eukaryotic phytoplankton can be regulated by additions of the fungal siderophore desferrioxamine B (DFB) to coastal waters. The DFB-Fe complex not only is unavailable for uptake at significant rates, but also outcompetes the natural organic ligand classes in seawater for Fe. Measurement of DFB-Fe concentrations in a titration series should therefore provide a first order measure of the Fe supply to phytoplankton.

This project will investigate the feasibility of miniaturizing a current bulk liquid membrane system that can actively isolate and concentrate 59Fe-DFB from aqueous solutions by constructing liposomes with the needed transport characteristics. The high surface area and optimal diffusional aspects of these nanodevices will enable efficient 59Fe-DFB accumulations at the extremely low dissolved Fe concentrations (<1 nM) encountered in coastal waters. The transport characteristics of these nanodevices will be measured as a function of liposome compositions and fabrication conditions to optimize the active transport of 59Fe-DFB from a seawater matrix. If progress permits, the relationship between 59Fe accumulated by these nanodevices and cellular 59Fe uptake and growth of natural population cultures will be explored. The immediate goal of this exploratory project is to demonstrate the feasibility of developing nanoscale sensors for quantifying the supply of Fe to eukaryotic phytoplankton in coastal seawaters. The broader goal is to establish the viability of nanotechnology for sensing bioactive substrates in the marine realm.

Please report errors in award information by writing to: awardsearch@nsf.gov.