Plasma lithography for probing cell mechanoregulation

Mechanical and physical cues in the cellular microenvironment are important factors in the regulation of cellular activities, such as proliferation, apoptosis, differentiation, migration and adhesion. For instance, cells are known to respond dynamically to different topographical cues and biophysical structures, such as surface roughness, fiber diameters, and micro/nano scale patterns. Nevertheless, little is known about the fundamental physical mechanisms that govern the cell-substrate interactions and their roles in the 'regulation of physiological processes. This presents a major hurdle toward the realization of nanoengineered medicine. Herein, we report a plasma lithography technique to elucidate the influences of biophysical cues on different cellular activities. The plasma lithography technique selectively functionalizes polymeric and other biologically relevant surfaces, such as PDMS, glass and polystyrene, at scales ranging from millimeters to hundreds of nanometers. We applied this method to cellular patterning and examined the response of human mammary gland epithelial cells and mouse embryo fibroblasts to patterns of hydrophobic and hydrophilic areas towards the elucidation of the mechanoregulation of cellular processes. The technique enables us to systematically investigate the essential role of physical cues on cell migration, proliferation, and morphology. Collectively, these activities are not only fundamental in cell biology but also essential to the creation of novel tissue engineering constructs and medical implants. This study will shed light on how cells interact with their microenvironment as well as demonstrate a means to exercise control over cellular processes for future nanoengineered medical applications.