Drug resistance is a characteristic of tumor initiat-
ing cells that can give rise to metastatic disease. In this work
we demonstrate the use of microbubble well arrays as a cell
culture platform to enumerate and characterize drug resistant
cells in a human derived tumorigenic squamous cell carcino-
ma cell line. The spherical architecture and compliant hydro-
phobic composition of the microbubble well favors single cell
survival, clonal proliferation and formation of spheres that do
not grow on standard tissue culture plastic and are resistant to
cisplatin. Spheres form in isolation and in microbubble wells
containing proliferating cells and to some degree they stain
positive for common stem cell markers CD44 and CD133.
Spheres are also observed in cellularized primary human
tumors cultured in microbubble arrays. This proof-
of-concept study illustrates the potential for microbubble array
technology to enumerate cancer cells resistant to standard care
drugs with the ability to test alternative drug combinations.
This capability can be developed for designing patient
specific treatment strategies. Recovery of drug-resistant cells
will allow a more full characterization of their gene
expression profile thereby expanding our fundamental
knowledge and ability to develop new targets to fight
metastatic disease.

• Identifying drug resistant cancer cells using microbubble well arraysIdentifying drug resistant cancer cells using microbubble well arrays