The ability to observe cell adhesion
processes in real-time remains
a grand challenge in basic biology and medicine. Toward this goal,
we have developed a lateral optical microscope that allows direct
observation of cell–substrate interactions in real-time on
any substrateî—¸transparent, opaque, or coatedî—¸without
requiring labels or specialized optical components. We demonstrate
the use of our lateral microscope by quantifying dynamic changes in
cell morphology during the first 90 min of adhesion to various materials.
Specifically, we determined the rates of change in contact angle of
HeLa, 3T3, HEK293, and MDA-MB-231 cells on five different substrates:
glass, collagen-coated glass, Nylon, PTFE, and collagen-alginate hydrogels.
We used these rates of change to compare adhesion of different cell
lines on each surface, and to rank the adhesion-promoting capacities
of the five surfaces for each cell line. For HeLa, 3T3, and HEK293
cells, we observed maximal rates of change in contact angle (0.058
min–1) on collagen-coated glass substrates. All
five cell lines exhibited minimal rates of change (0.006 min–1) on PTFE. Lateral microscopy also revealed a unique morphology among
MDA-MB-231 breast cancer cells during initial adhesion, which we quantified
using measurements of changes in cell height. Our lateral microscope
will not only enable more comprehensive, quantitative studies of cell
adhesion to inform the development of biomaterials but will ultimately
assist in advancing our understanding of many important biological
processes and discovering new behaviors related to cell adhesion.