ABSTRACT:
A stent is typically a scaffold device fabricated from metals, alloys, or polymers having the surface treated or covered with materials that reduce the rejection mechanisms. It is usually delivered into the body lumen in reduced size form using a catheter. The stent is expanded and released from the catheter, so that it engages the lumen wall when it reaches the desired location. Coronary artery stents coated with a variety of pharmacologic agents are used to prevent restenosis. Unlike earlier pharmacologic trials in which systemic agents were administered during/after percutaneous treatment to prevent restenosis, drug-eluting stents allow controlled local release of a drug directly to the injured endothelium, avoiding systemic side effects. The stents are coated with a polymer that acts as a drug reservoir and allows for the gradual elution of the drug. The mock-up stents were coated by moving the stent in a coordinated fashion under the inkjet micro dispenser. Printing was done "on-the-fly" by moving the stent continuously (rotation and axial movement) and generating drops based on the desired spot to spot spacing. The figure to the right was captured during coating. The fluid that was deposited just on the struts can be barely observed as a protrusion on the top strut surface to the right of the ink-jet micro dispenser.