Professor Seong H. Kim | Research
9. Bio-catalytic nanofibers
Nanofibers are an ideal support material for enzyme immobilization and biocatalytic engineering due to their high surface-to-mass ratios. Non-woven, entangled nanofiber mats can easily be retrieved from the reaction media and recycled, allowing easy separation and recovery of the enzyme. In these developments, the most challenging problem is how to maintain the enzyme activity over an extended period of time. In collaboration with Dr. Jungbae Kim at Korea University, we have developed unique and efficient ways of anchoring and stabilizing enzymes on nanofiber surfaces and dispersing hydrophobic nanofibers in aqueous solutions.∗
Schematic illustration of three different approaches to GOx immobilization on nanofibers, together with SEM images of (A) covalent attachment (CA-GOx), (B) enzyme coating (EC-GOx), and (C) enzyme precipitate coating (EPC-GOx). The scale bar in each SEM image denotes 10μm, while that in the inset of (C) denotes 1μm.
Application of the electro-spinning technique, a most widely used method for production of polymeric nanofibers, to hydrogels and conducting polymers has been difficult since these materials cannot be dissolved in solution for electro-spinning. Our group developed "reactive electro-spinning" processes to fabricate functional nanofibers of hydrogels and conducting polymers.∗∗ We are currently investigating enzyme immobilization and stabilization on these nanofibers for biocatalysis and biosensing applications.
The poly(3,4-ethylenedioxythiophene) conducting polymer was grown via a vapor-phase polymerization on a nonwoven porous mat of polystyrene nanofibers containing ferric p-toluenesulfonate. The fibers in the mat could be melt-welded by condensing the monomer vapor on the PS template fiber during the polymerization.
- ∗ B. C. Kim, X. Zhao, H.-K. Ahn, J. H. Kim, H.-J. Lee, K. W. Kim, S. Nair, E. Hsiao, H. Jia, M.-K. Oh, B. I. Sang, B.-S. Kim, S. H. Kim, Y. Kwon, S. Ha, M. B. Gu, P. Wang, J. Kim "Highly stable enzyme precipitate coatings and their electrochemical applications" Biosens. Bioelectron. 2011, 26, 1980–1986;
- ∗S. Nair, J. Kim, B. Crawford, and S. H. Kim, "Improving Biocatalytic Activity of Enzyme-Loaded Nanofibers by Dispersing Entangled Nanofiber Structure" Biomacromolecules 2007, 8, 1266-1270.
- ∗∗ S. Nair, E. Hsaio, and S. H. Kim "Melt-Welding and Improved Electrical Conductivity of Nonwoven Porous Nanofiber Mats of Poly(3,4-ethylenedioxythiophene) Grown on Electrospun Polystyrene Fiber Template" Chem. Mater., 2009, 21, 115-121.