Molecular Assembly Patterning by Lift-off at the Micro- and Nanoscale 
for Applications in the Biosciences

Didier Falconnet
University of British Columbia


A number of applications in the biosciences such as DNA-chips, protein
microarrays and cell-based sensors rely on chemically patterned surfaces.
Such surfaces are essentially characterized by bio-interactive and 
non-interactive areas. The ability to host single cells or ensembles of
 few cells in well controlled surface-microenvironments has proven to be
 useful to study the fundamental mechanisms involved in cell-substrate 
interactions. Several surface cues are known to steer cellular 
development into a particular phenotype, namely, the type and density of 
cell-binding ligands, the substrate stiffness, the topography/roughness 
and the cell spreading. The desire to unravel the complex interplay 
between these different factors has created a substantial need for 
improved surface and interface modification tools that allow a 
quantitative and precise control of individual surface cues as well as 
their combination.

I will present the development and characterization of a novel, 
reproducible and cost effective patterning process named Molecular 
Assembly Patterning by Lift-off (MAPL). The attractive features of the 
MAPL technique are its ability: to quantitatively control type and 
surface density of the biointeractive ligands within the adhesive 
patches; to elicit highly specific and quantitative interactions with 
the biological medium while inhibiting non-specific interactions; to 
control the pattern geometry/size independently of the bioligand surface 
density; and to produce complex pattern geometries of dimensions ranging 
from hundreds of microns to 100 nm.

The culture, in serum-containing media, of small cell populations as well 
as single cells in a predefined shape and location demonstrates that 
MAPL is suitable in the context of studying independently the effect of 
ligand surface density and cell-surface contact area ("footprint"). 
Finally, the versatility of the MAPL platform for “non-cell related” 
experiments/applications will also be discussed, for example, patterning 
of colloidal particles and arraying of lipid vesicles for transmembrane 
protein chips.