Lysozyme-mediated formation of protein-silica nano-composites for biosensing applications

Madhumati Ramanathan, Heather R. Luckarift, Ainur Sarsenova, James R. Wild, Erlan K. Ramanculov, Eric V. Olsen, Aleksandr L. Simonian

Research output: Contribution to journalArticlepeer-review

48 Citations (Scopus)


We demonstrate a rapid method for enzyme immobilization directly on a waveguide surface by encapsulation in a silica matrix. Organophosphate hydrolase (OPH), an enzyme that catalytically hydrolyzes organophosphates, was used as a model enzyme to demonstrate the utility of lysozyme-mediated silica formation for enzyme stabilization. Silica morphology and the efficiency of OPH encapsulation were directly influenced by the precursor choice used in silica formation. Covalent attachment of the lysozyme template directly to the waveguide surface provided a stable basis for silica formation and significantly increased the surface area for OPH encapsulation. OPH conjugated to a pH-responsive fluorophore was encapsulated in silica and patterned to a waveguide surface to demonstrate the immobilization strategy for the development of an organophosphate array biodetector. Silica-encapsulated OPH retained its catalytic activity for nearly 60 days with a detection limit of paraoxon of ∼35 μM. The encapsulation technique provides a potentially versatile tool with specific application to biosensor development.

Original languageEnglish
Pages (from-to)58-64
Number of pages7
JournalColloids and Surfaces B: Biointerfaces
Issue number1
Publication statusPublished - Oct 1 2009
Externally publishedYes


  • Array biosensor
  • Lysozyme
  • OPH
  • Paraoxon
  • Silica
  • Silicification

ASJC Scopus subject areas

  • Biotechnology
  • Surfaces and Interfaces
  • Physical and Theoretical Chemistry
  • Colloid and Surface Chemistry


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