Background:

• Postdoctoral Associate, University of Florida, 2004-2006
• National Research Council Postdoctoral Associate, Naval Research Laboratory, 2001-2004

Mother Nature is the preeminent practitioner of nanotechnology. From genetic expression, to photosynthesis, to enzymatic processes, the chemistry of life demonstrates the elegance and efficiency of well-designed (evolved) systems. A recurrent motif in Nature is the transmembrane channel. These biological nanopores are integral to the function of living organisms, controlling transport in and out of cells, often in response to an external stimulus. In general, we are interested in mimicking biological archetypes using components or principles from biological systems in combination with synthetic platforms at the nanometer scale. Our research program uses the design principles of biological transmembrane channels in combination with nanofabricated pores to create bio/nano systems for bio/chem sensors and for separations.

The synthetic nanopores fabricated are comparable in diameter to biological nanopores. By functionalizing these pores with recognition chemistries (e.g. antibodies, aptamers, DNA complements), sensitivity and selectivity can be imparted. Measurements of ionic current and permeation rates are used to monitor the response of our systems. Our studies expand current applications of such biomimetic nanopores to microfluidic and scanned probe platforms. Electroanalytical and spectroscopic techniques are also commonly used to address our systems.

This research addresses a focus of modern analytical chemistry - the accurate, rapid, and sensitive detection or separation of bio-relevant species. For instance, the development of sensors for protein toxins (e.g. Ricin) and other biological agents (e.g. Anthrax) has become a necessity. Also, the development of ultra-sensitive assays for biological markers for diseases (e.g. cancer, Alzheimer's disease, Creutzfeldt-Jakob disease) offers the possibility of early diagnosis and treatment. Finally, separation of biologically active species (e.g. drugs) is relevant to pharmaceutical applications in enantiomeric separations and drug delivery.

Selected Publications:

Heins, E. S.; Baker, L. A.; Siwy, Z. S.; Mota, M. O.; Martin, C. R. The Effect of Crown Ether on Ion Currents through Synthetic Membranes Containing a Single Conically Shaped Nanopore. J. Phys. Chem. B. 2005, 109, 18400-18407.

Odom, D. J.; Baker, L. A.; Martin, C. R. Solvent-Extraction and Langmuir-Adsorption-Based Transport in Chemically Functionalized Nanopore Membranes. J. Phys. Chem. B. 2005, 109, 20887-20894.

Heins, E. S.; Siwy, Z. S.; Baker, L. A.; Martin, C. R. Detecting Single Porphyrin Molecules in a Conically Shaped Synthetic Nanopore. Nano Lett. 2005, 5, 1824-1829.

Ervin, E. N.; White, H. S.; Baker, L. A. A.C. Impedance Imaging of Membranes Pores Using Scanning Electrochemical Microscopy. Anal. Chem. 2005; 77, 5564-5569.

Martin, C. R.; Baker, L. A. Expanding the Molecular Electronics Toolbox. Science 2005, 309, 67-68 (invited commentary).

Baker, L. A.; Jin, P.; Martin, C. R. Biomaterials and Biotechnologies Based on Nanotube Membranes. Crit. Rev. Solid State Mater. Sci. 2005, 30, 1-22.

Baker, L. A.; Laracuente, A. R.; Whitman, L. J. Hydrogen-termination of the Cu/Si(001) Interface. Phys. Rev. B 2005, 73, 153302.

Siwy, Z.; Trofin, L.; Kohli, P.; Baker, L. A.; Trautmann, C.; Martin, C. R. Protein Biosensors Based on Biofunctionalized Conical Gold Nanotubes. J. Am. Chem. Soc. 2005, 127, 5000-5001.

Kooi, S. E.; Baker, L. A.; Sheehan, P. E.; Whitman, L. J. Dip-Pen Nanolithography of Chemical Templates on Silicon Oxide. Adv. Mater. 2004, 16, 1013-1016.