Biomedical Engineering Reference
In-Depth Information
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Figure 2.9
Optical micrograph of mouse N-38 hypothalamic neurons cultured on
TSM electrode.
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Figure 2.10
Basic repeat unit of PLL.
as glucagon and nanoparticles. As was the case for ASMCs, results for the bare
surface were compared with coated devices. The results of this work centered
on neurons are discussed in more detail later.
2.5.3 Polypeptide Coating
As implied in the previous section, a myriad of different coatings and films
imposed on surfaces have been employed to attempt enhanced adhesion of cells
to a substrate with varying degrees of success. By far the most prevalent
molecule that has a long history of such use is poly-
L
-lysine (PLL), a homo-
polypeptide of some 30 residues (
L
-lysine). Not only has the molecule been
applied to the area of cell surface attachment, but it also appears to figure
prominently in DNA and protein microarray technology for the glass surface
binding of protein and nucleic acid probes for multiplexed assay of biochemical
interaction.
32,33
The use of PLL is so ubiquitous that a number of commercial
preparations are available.
The molecule is positively charged (Figure 2.10) and is considered to bind to
surfaces via electrostatic chemisorptive forces. Over 30 years ago it was
suggested that various cells could be attached to a PLL-coated substrate via the
polyanionic functional groups present at the cell surface. The specific appli-
cation at that time was connected to sample preparation prior to study by
