NUSNNI Seminar Series 2002 No.4

Title: Silicon Biotechnology Provides New Routes to Nanostructure-Directing Polycondensation of Silica, Silicones, Organometallics and Metalla-Oxanes
Speaker: Prof Daniel E. Morse (Chairman, Biomolecular Science & Engineering Program; California Nanosystems Institute & the Materials Research Laboratory, University of California)
Date: October 28, 2002
Time: 3.30 -4.30pm
Venue: LT31, Science Auditorium, S16 Level 3

Abstract:
With a precision of nanostructural control that exceeds present human capabilities, biological systems fabricate 3-dimensionally organized polysiloxane and other mineral-organic composites at low temperatures and near-neutral pH. Our analyses of the proteins, genes and molecular mechanisms governing the formation of these materials have revealed unique mechanisms of synthesis with industrial applicability. We found that the silica needles made by a marine sponge are inorganic-organic composites. Each contains an occluded axial filament of protein composed of repeating assemblies of three similar subunits we named “silicateins”. From this finding, we discovered that the silicatein filaments catalyze and spatially direct polycondensation to form silica, phenyl- and methyl-silsesquioxane from the corresponding alkoxides at neutral pH and low temperature. This counterintuitive discovery represents the first in which catalysis has been found to control the biofabrication of a mineral-organic composite. We now are exploring paths to harness the structure-directing activity of the silicateins to produce nanostructurally ordered, more coherent silsesquioxanes, metallo-oxanes and inorganic-organic hybrid materials with enhanced optoelectronic and other physical properties, and to write nanostructural features of these materials on silicon chips. We first called this new field "Silicon Biotechnology"; but now have discovered that it's applications extend far beyond silicon. Extensions of these findings now are under investigation with solution routes to nanostructurally controlled gallium oxide, gallium oxynitride, GaN, and structure-directed polycondensation of acid- or alkali-sensitive organofunctionalized siloxane and metallo-oxane precursors. Potential uses for sensors, pigments, cosmetics and pharmaceuticals are indicated.

About the Speaker:
Professor Morse received his PhD degree from Albert Einstein College of Medicine in 1967 and started his academic carrier as assistant professor at Harvard Medical School and became Silas Arnold Houghton Associate Professor of Microbiology & Molecular Genetics, Dept. Microbiology & Molecular Genetics, Harvard Medical School in 1971. He moved to University of California at Santa Barbara in 1973 and became a full Professor of Molecular Genetics & Biochemistry, Dept. Molecular, Cellular & Developmental Biology in 1975. From 1975 to date, he has been holding the position of chairman at various departments and directing a multidisciplinary research effort in materials science. He is also the founding director of Marine Biotechnology Center at University of California at Santa Barbara. During these years, he has received many awards and honors which include Smithsonian Inst. Regents Fellow, Fellow of AAAS, Burroughs-Wellcome Visiting Fellow, held numerous NRC, NSF, NIH councils & taskforces and given many key note lectures. His current research interests are in the areas of biotechnological approach to develop nanotechnology for advanced materials, biomaterials, biosensors, development of "silicon biotechnology“, proteins, genes and molecular mechanisms governing biomineralization with calcium and silicon, development of new low-temperature, environmentally benign routes for nanofabrication of high-performance composite materials, sensors, and nanoscale arrays of semiconductor and magnetic quantum dots.