Preparing the device’s surface is essential for obtaining good adhesion of the coating or of the implantable device. We implement the following pre-treatment surface techniques:
Grit-blasting: By forcibly propelling a stream of sand at high pressure against the stent’s metallic surface, the smooth surface becomes porous, which improves the adhesion of the coating to the surface.
Corona treatment (Air plasma): When utilizing this technique, a low-temperature, high-voltage electrical discharge is applied to an electrode that has a sharp tip, causing corona plasma to form at the tip. A linear array of electrodes is used to create a curtain of corona plasma, which modifies the stent’s surface.
Chemical treatment: This highly-effective method uses strong acids, alkalis, or mixtures of oxidants which remove thin layers of the surface, resulting in roughening of the surface, as well as causing surface porosity, which facilitates adhesion of the coatings.
Bonding molecules: In this technique, a base coating layer is created from bonding molecules, which one side adheres to the substrate, while the other side adheres to the coating.
Electrospinning is a fiber production method which uses electric force to draw charged threads of polymer solutions to fiber diameters.
The electrospinning manufacturing process comprises of surface treatment sequence that enables strong adhesion forces between the substrate and the coating layer.
The end result is a fully encapsulated cover without any exposed metal surfaces.
- Fiber diameter range: 2 – 300 [nm]
- Porosity definition: 2-40 [nm]
Differentiations in pore size can impact :
- Tissue regrowth
- Cell adhesion
The main clinical application for this technology are in structural heart and peripheral angioplasty.