Biomedical Engineering Reference
In-Depth Information
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Figure 3.15
(A) Engineered networks of different cell geometries with PDL (poly-
D
-lysine) templates on glass (B-E). Low magnification image of illustrating
interconnected ordered cell clusters designed lattices with (B) triangular
lattice, (C) a single and row lattice, (D) square lattices and (E) circular
arrangement. Adhesive sites were 100 mm in diameter and 'neuronal
wiring' was achieved almost exclusively between neighboring islands.
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(Reprinted by kind permission of the Institute of Physics Publishing.)
micropipettes. The smaller the electrodes, the higher the impedance, and so
platinum-black electroplating lowers this electrode impedance to acceptable value
levels of mega ohms. To improve the electrical resistance between neurons and
electrodes, a cellular matrix (that promotes adhesion) is required.
Even so, some neurons will grow at a large distance from the recording
electrodes and measurements will not feasible. To overcome this particular
problem, electrode wells (to trap the somata of the cells) can be designed so that
the neurons form a network by extending neuritis and connecting outside the
wells, while the cell body remains in contact with the electrode at the bottom of
the well. In order to guide the growing of the neurons on or around specific
electrodes, some cells can be removed using a precise laser or employing