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The effect of salt and phage concentrations on the binding sensitivity of magnetoelastic biosensors for Bacillus anthracis detection
Author(s) -
Huang S.,
Yang H.,
Lakshmanan R.S.,
Johnson M.L.,
Chen I.,
Wan J.,
Wikle H.C.,
Petrenko V.A.,
Barbaree J.M.,
Cheng Z.Y.,
Chin B.A.
Publication year - 2008
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.21995
Subject(s) - bacillus anthracis , biosensor , spore , chemistry , salt (chemistry) , chromatography , microbiology and biotechnology , bacteria , biology , biochemistry , organic chemistry , genetics
This article presents an investigation of the effect of salt and phage concentrations on the binding affinity of magnetoelastic (ME) biosensors. The sensors were fabricated by immobilizing filamentous phage on the ME platform surface for the detection of Bacillus anthracis spores. In response to the binding of spores to the phage on the ME biosensor, a corresponding decrease occurs in resonance frequency. Transmission electron microscopy (TEM) was used to verify the structure of phage under different combinations of salt/phage concentration. The chemistry of the phage solution alters phage bundling characteristics and, hence, influences both the sensitivity and detection limit of the ME biosensors. The frequency responses of the sensors were measured to determine the effects of salt concentration on the sensors' performance. Scanning electron microscopy (SEM) was used to confirm and quantify the binding of spores to the sensor surface. This showed that 420 mM salt at a phage concentration of 1 × 10 11 vir/mL results in an optimal distribution of immobilized phages on the sensor surface, consequently promoting better binding of spores to the biosensor's surface. Additionally, the sensors immobilized with phage under this condition were exposed to B. anthracis spores in different concentrations ranging from 5 × 10 1 to 5 × 10 8 cfu/mL in a flowing system. The results showed that the sensitivity of this ME biosensor was 202 Hz/decade. Biotechnol. Bioeng. © 2008 Wiley Periodicals, Inc.