Single enzyme nanoparticles in nanoporous silica: A hierarchical approach to enzyme stabilization and immobilization

Jungbae Kim, Hongfei Jia, Chang won Lee, Seung wook Chung, Ja Hun Kwak, Yongsoon Shin, Alice Dohnalkova, Byung Gee Kim, Ping Wang, Jay W. Grate

Research output: Contribution to journalArticlepeer-review

50 Scopus citations


Single enzyme nanoparticles of α-chymotrypsin (SEN-CT), in which each CT molecule is surrounded by a thin polymeric organic/inorganic network, stabilized the CT activity in a shaking condition as well as in a non-shaking condition. Since SEN-CT is soluble in a buffer solution and less than 10 nm in size, SEN-CT could be further immobilized in nanoporous silica with an average pore size of 29 nm. Free CT and SEN-CT were immobilized in nanoporous silica (NPS), and nanoporous silica that was first silanized with aminopropyltriethoxysilane (amino-NPS) to generate a positive surface charge. The SEN-CT adsorbed in amino-NPS was more stable than CT immobilized by either adsorption in NPS or covalent bonding to amino-NPS. In shaking conditions, nanoporous silica provided an additional stabilization by protecting SEN-CT from shear stresses. At 22 °C with harsh shaking, free, NPS-adsorbed and NPS-covalently attached CT showed half lives of 1, 62, and 80 h, respectively; whereas SEN-CT adsorbed in amino-NPS showed no activity loss within 12 days. The combination of SENs and nanoporous silica, which makes an active and stable immobilized enzyme system, represents a new structure for biocatalytic applications.

Original languageEnglish (US)
Pages (from-to)474-480
Number of pages7
JournalEnzyme and Microbial Technology
Issue number3
StatePublished - Jul 3 2006

Bibliographical note

Funding Information:
This work was supported by U.S. Department of Energy (DOE) LDRD funds administered by the Pacific Northwest National Laboratory, and the DOE Office of Biological and Environmental Research under the Environmental Management Science Program. The research was performed at the W. R. Wiley Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the U.S. Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. PNNL is operated for the Department of Energy by Battelle.


  • Enzyme immobilization
  • Enzyme stabilization
  • Mesocellular foams
  • Nanoporous silica
  • Single enzyme nanoparticles
  • α-Chymotrypsin

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