Biomedical Engineering Reference
In-Depth Information
The LAPS system can be used in monitoring the K
1
induced preconditioning
in cultured neurons to assess the role of N-methyl-
D
-aspartate (NMDA) and
alpha-7-nicotinic acetylcholine receptors.
d
n
4
t
3
n
g
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2
5.2.5 Acoustic Wave Detection
The thickness shear mode (TSM) device was introduced in Chapter 1. Briefly, a
resonant shear wave is produced in a piezoelectric material such as quartz by
electrodes (usually gold) placed on each face of the sensor. When operated in a
liquid environment, a portion of the acoustic energy is not reflected at the
interface but is dissipated into the liquid. The propagation of the acoustic shear
into the liquid and resultant energy dissipation is detected via variations in the
motional resistance (Rm) and series resonant frequency (fs) parameters of an
impedance analyzer attached to the system. A typical experiment involving
study of neurons to the gold electrode of a 9MHz TSM is depicted in
Figure 5.11. The sensor system is incorporated into a temperature-controlled
static or flow-through confutation which allows the introduction of various
reagents in order to detect response of the cells. The latter are kept in a CO
2
environment.
One of the first TSM studies of neuron behavior involved immortalized
hypothalamic mouse cells (N-38) in terms of their response to various known
neurotrophic factors such as forskolin, betaferon and cerebrolysin.
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Betaferon
has been used in the treatment of relapsing forms of multiple sclerosis to reduce
the frequency of exacerbations. It is believed that the molecule acts by inter-
acting with specific receptors found on the surface of cells. The binding of
betaferon to these receptors induces the expression of a number of gene
products and markers, including 29,59-oligoadenylate synthetase, protein
kinase, beta 2-microglobulins, neopterins, and indoleamine 2,3-dioxygenase.
n
3
.
Figure 5.11
Schematic of a TSM system for the study of neurons. Cells are constantly
bathed in a fresh supply of Dulbecco's modified eagle medium (DMEM)
supplemented with 5% fetal bovine serum (FBS). All test solutions being
made up using either 5% FBS DMEM or DMEM as the solvent to
prevent adverse effects to cells.
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(Reprinted by kind permission of the Royal Society of Chemistry.)
