Biomedical Technology: Hierarchically ordered scaffolds for nerve repair

The purpose of this research is to develop technology for repairing spinal cord and peripheral nerve injuries. The approach involves the development of functionalized, hierarchically-ordered pore networks in hydrogels that simultaneously provide biological cues for axonal growth and physical confinement for axonal guidance. The two levels of porosity consist of close-packed arrays of channels in the 100 micron diameter/centimeter long range to guide axonal growth and nanometer-scale pores to provide encapsulation of nerve growth factors. The nanometer scale pores are functionalized with biodegradable polymers films impregnated with nerve growth factors (NGF) that, when biodegraded in the body, initiate or sustain axonal growth. This work is a collaborative effort between MSU and the Neuroscience Department at UC San Diego.

Electrochemical Energy Storage

Lithium batteries have the highest energy density of all batteries making them attractive for hybrid electric vehicles, powering microelectronics and space exploration. The energy delivered, however, tends to diminish at low temperatures or at high discharge rates. This research is focused on tailoring electrode design and materials by investigating hierarchically-ordered pore networks with the intent of improving ionic and electronic transport to address kinetic limitations. Specifically, the work I am currently pursuing involves sol-gel derived metal oxide and carbonaceous nanocomposite materials, templating highly-ordered, hierarchical pore networks using dissolvable templates and electrical wiring using novel conductive additives.

Thermoelectric power generation

Thermoelectric technology is based on semiconductor-like materials that convert heat into electrical power without the use of moving parts, liquids or gases. Simplicity and myriad sources of wasted heat make thermoelectric an attractive technology for meeting today’s growing electrical power needs. My research is focused on the development of high efficiency thermoelectric materials and materials device technology. Specifically, nanomaterials synthesis, segmenting, metalizing and cast-in-place aerogel insulation are at the center of my effort to develop thermoelectric technology capable of operating at >15% efficiency. Realizing this goal could result in vehicles with improved fuel efficiency, viable solar-heat electrical power generation, and more on board electrical power for future NASA missions. This research is currently supported by the Department of Energy, NASA and the Michigan University Research Corridor Program is focused on the development of high-efficiency thermoelectric power generation.

Reviewed Journal Publications

Mehrotra, S.; Lynam, D.; Maloney, R.; Pawelec, K. M.; Tuszynski, M.; Lee, I.; Chan, C.; Sakamoto, J.; "Time controlled protein release from layer-by-layer assembled multilayers functionalized agarose hydrogels", Advanced Functional Materials, in press (2009).

El Genk, M.S., Saber H. H., Caillat T., Sakamoto J., "Test results and performance comparisons of coated and un-coated skutterudite based segmented unicouples," Energy Conv. and Management 47, 2, 174-200, (2006).

S. Stokols, J. Sakamoto, D. Welker, T. Holt, J. Weiss and M. Tuszynski, "Templated Agarose Scaffolds Support Linear Axonal Regeneration," Tissue Engineering, 12, 10, 2777-2778 (2006).

Paul E. Tang, Jeff S. Sakamoto, Emmanuel Baudrin and Bruce Dunn, "V2O5 aerogel as a versatile host for metal ions," J. of Non Crystalline Solids, 350 (2004) 67-72

W. Dong, J. Sakamoto and B. Dunn, "Electrochemical Properties of Vanadium Oxide Aerogels and Aerogel Nanocomposites," J. Sol-Gel Science and Technology, 26, 1-4, (2003)

W. Dong, J. Sakamoto and B. Dunn, "Electrochemical Properties of Vanadium Oxide Aerogel," Science and Technology of Advanced Materials, 4, 1, 3-11 (2003)

J. H. Harreld, J. Sakamoto and B. Dunn, "Non-hydrolytic sol-gel synthesis and electrochemical characterization of tin-based oxide aerogels," J. Power Sources 115, 19-26 (2003)

J. Sakamoto and B. Dunn, "Vanadium Oxide-Carbon Nanotube Composite Electrodes for use in Secondary Lithium Batteries," Journal of the Electrochemical Society, 149, A26-30 (2002)

J. Sakamoto and B. Dunn, "Hierarchical battery electrodes based on inverted opal structures," J. Mater. Chem., 1, 12 (2002)

J. Sakamoto, F. Wudl and B. Dunn, "Passivating Lithium Electrodes with Trimethylsilylacetylene," Solid State Ionics, 144, 295-8 (2001)

Books, Chapters, Monographs

T. Caillat and J. Sakamoto, Chapter 4 in, The New Edition of Thermoelectric Energy Conversion Systems,"High Efficiency Segmented Thermoelectric Materials and Unicouples for Power Generation Applications", Published by Realize Science and Technology, Japan, ISBN4-89808-049-9 (2004).

Other Works

J. Sakamoto, T. Caillat, J. -P. Fleurial and J. Snyder, California Institute of Technology, US patent application 10/977,276, "System and Method for Suppressing Sublimation using Opacified Aerogel" 2007

J. Sakamoto, S. Jones, B. Nesmith, and J. Paik, National Aeronautics and Space Administration, US patent application 12/114,993, "Hybrid Multifoil Aerogel Thermal Insulation (HyMATI)", 2008

J. Sakamoto, T. Caillat, J. -P. Fleurial, S. Jones and J. Snyder, National Aeronautics and Space Administration, US patent application 10/863,835, "Method of Suppressing Sublimation in Advanced Thermoelectric Devices and Resulting Apparatus" 2006

J. Sakamoto, S. Stokols, J. Weiss, T. Holt, D. Welker, C. B. Breckon, A. Kisor and M. Tuszynski, California Institute of Technology, US patent application 11/200,982, "High Aspect Ratio Template and Method for Producing the Same" 2005

J. Sakamoto, T. Caillat, J.-P. Fleurial, S. Jones and S. -P. Yen, California Institute of Technology, US patent application 11/300,632, "System and Method for Fabrication of High-Efficiency Durable Thermoelectric Devices" 2005

J. Harreld, N. Mitchell, G. Stucky, J. Sakamoto, University of California, US patent application 10/341,671, "Colloidal Sphere Templates", 2002