Vascular Stents with Rationally-Designed Sub-Micrometer Scale Surface Patterning

Shannon Gott, PhD Student, ME

Drug-eluting stents have revolutionized the field of interventional cardiology by reducing incidence of restenosis through local delivery of drugs that inhibit inflammation caused by implantation-induced injury. However, growing evidence suggests that this may also inhibit reestablishment  of  the  endothelium,  thus  delaying  healing  and  increasing  potential  for thrombogenic  stimulus.  Herein,  we  discuss  our  recent  progress  towards  realization  of next-generation titanium (Ti) stents that seek to mitigate adverse physiological responses to stenting via rational design of stent surface topography at the micro- and nanoscale.

Specifically, we discuss: 1) advances which now allow patterning of features in Ti substrates down to 150 nm, which represents the smallest features achieved to date using our novel Ti deep  reactive  ion  etching  (Ti  DRIE)  technique;  2)  creation  and  evaluation  of  balloon-deployable, cylindrical, surface-patterned stents from micromachined planar Ti substrates; and 3) integration of these processes to produce a device platform that allows, for the first time, evaluation of surface patterning in more physiologically relevant contexts, e.g. in vitro organ culture. Using elasto-plastic finite element analysis, we also explore the feasibility of planar stents with novel locking mechanisms intended to address radial stiffness deficiencies observed in our earlier studies. Collectively, these efforts represent key steps towards our long-term goal of developing a new paradigm for stents in which rationally-designed surface patterning  provides  a  physical  means  for  complementing,  or  replacing,  current pharmacological interventions.

Shannon Gott graduated from Walla Walla University in 2009 with a Bachelor’s Degree in mechanical engineering and is currently pursuing a PhD in mechanical engineering from the University of California, Riverside as an NSF Fellow. Seeking to overcome some of the current limitations with cardiovascular stents, her current focus is on the design, fabrication, and mechanical testing of a novel, titanium-based stent.