Materials for medical vascular stents
Metal Alloys
Medical-grade stainless steel: Primarily the 316L grade; it was the mainstream material for early stents, offering high mechanical strength and good corrosion resistance.
Cobalt-chromium alloy: Currently the most widely used mainstream material in clinical practice; it allows for thinner strut walls, offers strong corrosion resistance, and provides excellent deliverability within blood vessels.
Nickel-titanium alloy (Nitinol):Possesses unique shape-memory and superelastic properties; it can be deformed at low temperatures and automatically returns to its preset shape after implantation, making it ideal for self-expanding stents.
Platinum-chromium alloy: Offers excellent radiopacity (visibility under X-ray), allowing doctors to clearly locate the stent and perform procedures with greater precision.
Biodegradable Materials
Polylactic acid (PLA): A mainstream base material for biodegradable stents; it is gradually metabolized and absorbed by the body within 2–3 years after implantation, avoiding the long-term retention of foreign metal objects.
Magnesium alloy: Features good biocompatibility, with degradation products (magnesium ions) that the body can utilize; the degradation rate is currently being optimized to match the vascular healing cycle.
Functional Coatings
Surfaces are coated with anti-proliferative drugs-such as sirolimus or paclitaxel-combined with sustained-release carriers like polyurethane; this inhibits excessive intimal hyperplasia and reduces the risk of restenosis.