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Proceedings Paper

Encapsulation of enzymes and cells in sol-gel matrices for biosensor applications
Author(s): Anup K. Singh; Alok Gupta; Ashok Mulchandani; Wilfred Chen; Rimple B. Bhatia; Joseph S. Schoeniger; Carol S. Ashley; C. Jeffrey Brinker
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Paper Abstract

Porous silicate materials made by low temperature sol-gel process are promising host matrices for encapsulation of biomolecules. Their mechanical strength, chemical inertness, hydrophilic nature, and above all, their optical transparency makes them an exciting platform for development of biosensors. To date, researchers have focused on sol-gel routes using alkoxides for encapsulation of biomolecules. However, formation of alcohol as a byproduct is an undesired complication as it can have detrimental effect on the activity of entrapped biomolecules. We have developed a novel sol-gel process to encapsulate biological molecules (such as enzymes, antibodies and cells) that uses neutral pH, room temperature, and does not generate alcohol as a byproduct. The process uses sodium silicate as precursor and is carried out in two steps--preparation of a low pH silicate sol followed by gelation at neutral pH in a buffer containing biomolecules. We developed a novel homogeneous immunoassay for 2,4,6-trinitrotoluene (TNT), and have encapsulated the immunoassay reagents in sol-gel matrices to product dispersible biosensors for the detection of TNT. Using the sol-gel doped with immunoassay reagents, we can detect TNT at low ppm levels. We also report encapsulation of E. Coli cells expressing the enzyme organophosphorus hydrolase on the cell surface in sol-gel matrices. The cell- doped sol-gel material can be used to develop biosensors for detection of organophosphates.

Paper Details

Date Published: 15 December 1999
PDF: 7 pages
Proc. SPIE 3858, Advanced Materials and Optical Systems for Chemical and Biological Detection, (15 December 1999); doi: 10.1117/12.372912
Show Author Affiliations
Anup K. Singh, Sandia National Labs. (United States)
Alok Gupta, Sandia National Labs. (United States)
Ashok Mulchandani, Univ. of California/Riverside (United States)
Wilfred Chen, Univ. of California/Riverside (United States)
Rimple B. Bhatia, Univ. of New Mexico (United States)
Joseph S. Schoeniger, Sandia National Labs. (United States)
Carol S. Ashley, Sandia National Labs. (United States)
C. Jeffrey Brinker, Univ. of New Mexico and Sandia National Labs. (United States)

Published in SPIE Proceedings Vol. 3858:
Advanced Materials and Optical Systems for Chemical and Biological Detection
Mahmoud Fallahi; Basil I. Swanson, Editor(s)

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