Stent Coating

Coating of Drug Eluting Stents

The GeSiM Nano-PlotterTM has been extended by a motor controlled rotor for the application of Micrograms of solved polymer on cylindrical microstructures. This application notice shows how to dispense Nanoliter amounts on stain less steel made coronar stents. Basically a “stent” is a tiny mesh or scaffold for insertion into coronar vessels of the human body. Orginally stents were developed to prevent blood vessels from collapsing after ballon angioplasty. A resistent problem was that bar metal stents still experienced reblocking as a body’s response to the “controlled injury” of arterial vessels during insertion of the stent. The controlled drug release requires to embed the drug into a soluble polymer. For a reproducible release rate an exact amount of drug solution has to be applied to the scaffold structure of the stent. Dipping the stent into a reservoir is no appropriated approach. The rather high viscous drug solution simply bridges meshes of the stent structure which leads to an unpredictable amount of remaining drug after levering the stent out of the reservoir. Placing the stent onboard of the micropipetting system Nano-Plotter brings up several advantages:

  • Less waste of material by controlled aspiration of sample into the dispenser nozzle
  • Applying of single drops below one Nanoliter avoids bridges between and tears on the stent structure
  • The programmable number of microdrops ensures exact and reproducible drug deposition solely on the stent structure
  • The camera based alignment of the dispenser above the stent ensures that no stent will be missed
  • The rotating stent holder allows homogenous coating of all sides of the cylindrical stent
The rotating stent holder can be moved to any position between 0° and 360°

The rotating stent holder can be moved to any position between 0° and 360°

A single drop volume is about 250 Pikolitres

A single drop volume is about 250 Pikolitres

 

The GeSiM Nano-PlotterTM has been extended by a motor controlled rotor for the application of Micrograms of the operation software of the Nano-Plotter allows two different modes for dispensing on the stent structure: a) Continuous line dispensing emitting drops at a fixed frequency (faster) b) Step-by-step dispensing, the nozzle stops before ejecting a drop (more accurate).


The development of the rotating stent holder was initiated by

UoG-logo.gifUniversity of Greenwich, School of Sciences, Medway Campus, Central Avenue
Chatham Maritime, Kent, ME4 4TB, UK
We thank Dr. Dionysios Douroumis and his group