title: Enzyme-carbon nanotube conjugates in room-temperature ionic liquids.
abstract: Room-temperature ionic liquids (RTILs) are intriguing solvents, which are recognized as "green" alternatives to volatile organics. Although RTILs are nonvolatile and can dissolve a wide range of charged, polar, and nonpolar organic and inorganic molecules, there remain substantial challenges in their use, not the least of which is the solvents' high viscosity that leads to potential mass transfer limitations. In the course of this work, we discovered that the simple adsorption of the bacterial protease, proteinase K, onto single-walled carbon nanotubes (SWNTs) results in intrinsically high catalytic turnover. The high surface area and the nanoscopic dimensions of SWNTs offered high enzyme loading and low mass transfer resistance. Furthermore, the enzyme-SWNT conjugates displayed enhanced thermal stability in RTILs over the native suspended enzyme counterpart and allowed facile reuse. These enzyme-SWNT conjugates may therefore provide a way to overcome key operational limitations of RTIL systems.
authors.affiliation: Department of Chemical and Biological Engineering, Rensselaer Nanotechnology Center, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
authors.forename: Bilge
authors.initials: B
authors.lastname: Eker
authors.forename: Prashanth
authors.initials: P
authors.lastname: Asuri
authors.forename: Saravanababu
authors.initials: S
authors.lastname: Murugesan
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Linhardt
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Dordick
mesh_terms: D000327:Adsorption; D019286:Endopeptidase K / Q000737:chemistry / Q000378:metabolism; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism; D052578:Ionic Liquids / Q000737:chemistry*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D013696:Temperature
chemical_list: D004800:Enzymes, Immobilized; D052578:Ionic Liquids; D037742:Nanotubes, Carbon; D019286:Endopeptidase K