Biomedical Engineering Reference
In-Depth Information
3D radial cell migration
This approach is a 3D generalization of the two-dimensional (2D) microcar-
rier bead or fence-type assays where a cell carrier that concentrates the cells
is embedded in a gel such as collagen, fi brin or Matrigel (Reed
et al.
, 2007;
Vernon and Gooden, 2002; Vernon and Sage, 1999). After a set experimen-
tal culture period, the radial distance of cell migration is evaluated. Usually
the carriers are imbedded in thin gels, and thus the cell positions are only
measured on the horizontal projections. However, migration in this type of
assay can be fully characterized by 3D cell tracking methods which requires
a fully automated translation (X, Y, Z) microscope stage or confocal micros-
copy (Adanja
et al.
, 2010; Mandeville
et al.
, 1997).
Trans-fi lter assay
A variety of culture inserts based on the original Boyden chamber are avail-
able commercially for characterizing population motility, including invasion
and chemoattraction (Boyden, 1962; Kioka
et al.
, 2010). The trans-fi lter
confi guration consists of a porous fi lter that separates two compartments.
Cells are placed in the upper chamber and the chemoattractant in the lower
chamber. The attractant diffuses up through the pores of the fi lter, forming
a concentration gradient. The pores must be small enough that the cells do
not fall through, but large enough to permit them to crawl through if they
respond to the attractant. After a specifi ed period of time, the cells that
have migrated to the bottom surface of the fi lter are counted. Trans-fi lter
assays have been used extensively to investigate chemotaxis; however, this
assay can also been used to measure chemokinesis by placing the same con-
centration of chemoattractant in the top and bottom compartments. This
design has limitations, including the inability to generate more than a single
chemotactic gradient in each experiment and the gradients that are gener-
ated are very sharp. The biggest limitation of this confi guration, however, is
the inability to visualize the motility of cells as they move through the fi lter
into the lower chamber precluding the ability to characterize the path or
speed of the cells.
Collagen gel invasion
This assay quantifi es the depth of migration of cells into a collagen gel. The
cells are seeded on the surface of the gel and the invasion progress is moni-
tored by phase contrast with a stage positioned by a stepper motor which
enables the capture of a depth profi le in the gel (De Wever
et al.
, 2010).
This assay is primarily employed in the study of tumor cell invasion. Similar
assays have been developed to quantify the invasion of cells into organ or
