Controlled Scaffold Platform Designs on Nasopharyngeal Carcinoma Cell Separation

Nasopharyngeal carcinoma (NPC) is a highly invasive and metastatic disease occurring in the nasopharynx. For early diagnosis or treatment, it is helpful to separate invasive nasopharyngeal carcinoma (NPC43) cells from epithelial (NP460) cells. However, the lack of proper in vivo models significantly hinders the systematic study of NPC. In this study, an in vitro two-layer scaffold platform was developed to mimic the extracellular matrix of the tissue that allows the investigation of carcinoma and epithelial cell migration behaviors. Three precisely controlled factors were designed to investigate how topographic cues affected migration of NP460 and NPC43 cells: overlay angles between the top and bottom layers, top layer thicknesses, and surface topography of the bottom layer ridges. These designs offered different surface contact areas for cells to probe and form focal adhesions as they migrated on the platforms. As NP460 and NPC43 cells respond differently to the surrounding microenvironments, when the top layers were perpendicular to the bottom layers, 66.3% NPC43 cells could move into the $10~\mu \text{m}$ wide trenches compared to 5.5% for NP460 cells. However, NP460 and NPC43 cells migrating into top layer trenches were hindered when the top layer was too shallow or too thick. Moreover, the gratings added on the bottom layer ridges promoted cells to squeeze into the trenches. These results yielded over 92.3% separation efficiency on platforms with a 15- $\mu \text{m}$ thick top layer being perpendicular to the bottom layer and gratings on the bottom layer ridges.