Micropatterning of Substrates and Cells - Introduction to BioMEMS - page 95

seeded, producing a micropatterned coculture. Another variant is to form electroactive SAMs
of cell-adhesion peptides (instead of SAMs of nonadhesive EG 3 -C 11 ), and cells detach when the
cell-adhesion peptides are electrically desorbed. his work represents probably the most exqui-
site spatiotemporal and molecular control over cell-substrate interactions.
In 2007, Muhammad Yousaf (formerly a student of the Mrksich laboratory) and colleagues
from the University of North Carolina at Chapel Hill were able to bring photochemistry into
play, to generate…gradients of electroactive SAMs ( Figure 2.51 )! In addition, the cells can be
released from the substrate ater attachment. Such dynamic surface gradients will no doubt
become invaluable tools in studies of cell polarization and cell migration.
2.7 Summary
his chapter has reviewed the application of the techniques covered in Chapter 1 for pattern-
ing biological material such as proteins and cells, as well as other materials that are used for
cell and protein patterning (such as SAMs and polymers). Cells are exquisitely sensitive to the
physicochemical properties of the substrate to which they attach. Chemists have spent great
eforts to engineer the surface of materials with SAMs and polymers to modulate (prevent as
well as enhance) cell adhesion with nanometer precision and, occasionally, with temporal con-
trol. Using simple microluidic devices, it is now possible to create micropatterns of cells on
templates made of physisorbed ECM proteins (on a variety of biocompatible polymers); or to
pattern cells on electroactive cell-adhesion RGD peptides simply by applying a small voltage
pulse—the spectrum of existing techniques is very wide and the dilemma of choosing the best
one is application-dependent (and expertise-dependent).
Further Reading
Baneyx, F., and Schwartz, D.T. “Selection and analysis of solid-binding peptides,” Current Opinion in
Biotechnology 18 , 312-317 (2007).
Falconnet, D., Csucs, G., Michelle Grandin, H., and Textor, M. “Surface engineering approaches to micropat-
tern surfaces for cell-based assays,” Biomaterials 27 , 3044-3063 (2006).
Folch, A., and Toner, M. “Microengineering of Cellular Interactions,” Annual Review of Biomedical
Engineering 2 , 227-256 (2000).
Lim, J.Y., and Donahue, H.J. “Cell sensing and response to micro- and nanostructured surfaces produced by
chemical and topographic patterning,” Tissue Engineering 13 , 1879-1891 (2007).
Madou, M. Fundamentals of Microfabrication . CRC Press (2002).
Mrksich, M. “Using self-assembled monolayers to model the extracellular matrix,” Acta Biomaterialia 5 ,
832-841 (2009).
Nie, Z., and Kumacheva, E. “Patterning surfaces with functional polymers,” Nature Materials 7 , 277-290
(2008).
Smith, R.K., Lewis, P.A., and Weiss, P.S. “Patterning self-assembled monolayers,” Progress in Surface Science
75 , 1-68 (2004).
Stevens, M.M., and George, J.H. “Exploring and engineering the cell surface interface,” Science 310 , 1135-
1138 (2005).