Table 4.
Functional coatings directly used for Mg alloy stents.
| Mat. | Coa. | Th. (μm) | Sol. |
Ecorr (V/SCE) |
icorr (μA/cm2) |
Cor.(mm/a) |
Im. (d) | Res. Ref. | |||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Sub. | Coa. | Sub. | Coa. | Sub. | Coa. | ||||||
| MgZnMn | PEO | 0.15 | PBS | −1.457 | −1.342 | 12.979 | 2.039 | 0.296 | 0.046 | 10 | PEO had an excellent anti-corrosion effect, and there was no cracking or peeling after balloon dilatation [100]. |
| JDBM | MgF2 | 0.8 | Artificial plasma | −1.70 | −1.66 | 1.91 | 1.58 | 0.043 | 0.036 | – | MgF2 film with a nanoscale reduced the degradation rates of JDBM substrate. MgF2 offered a much more favorable surface for ECs adhesion, proliferation, and alignment. JDBM stent coated with MgF2 film confirmed excellent tissue compatibility of the well re-endothelialized stent with no sign of thrombogenesis and restenosis in the stent-supported vessel in vivo implantation test [124]. |
| MgZnMn | PPAam | 0.25 | PBS | −1.60 | −1.30 | 51.28 | 8.3176 | 1.24 | 0.190 | – | PPAam coating not only provided an endothelium-friendly microenvironment (enhancing the ECs attachment, spreading, and proliferation) but also exhibited good corrosion resistance [219]. |
| AZ31 | MgF2/PLLA | – | E-MEM | – | – | – | – | – | – | 14 | The Mg stents coated by polymer coating maintained the high corrosion resistance after balloon expansion; moreover, it dramatically accelerated ECs adhesion compared with stents [231]. |
| AZ31 | PCUU/PTX | – | DMEM | – | – | – | – | – | – | 28 | PCUU/PTX coating slowed Mg alloy corrosion and reduced platelet adhesion, and the release of PTX from PCUU coatings effectively impeded SMCs proliferation [203]. |
| WE43 | PEI/PLGA/SRL | 0.85 | Artificial plasma | −1.612 | −1.542 | 62.24 | 3.00 | 1.422 | 0.068 | 14 | By introducing the PEI coating, the coating showed super adhesion force to the WE43 stent and greatly improved corrosion resistance after stent expansion. Interestingly, only SMCs were directly influenced by SRL because of the asymmetric geometry of PLGA/PEI double coating, which had a satisfactory anti-proliferation effect [159]. |
| ZE21B | APTES/PLGA/SRL | 9.60 | Hank's | −1.626 | −0.401 | 3.223 | 0.141 | 0.073 | 0.0016 | 30 | APTES/PLGA/SRL coating improved anti-corrosion ability and biocompatibility in vitro experiments. Furthermore, ZE21B stents treated with coating were implanted in the porcine coronary artery of minipigs, confirming superb tissue compatibility and re-endothelialization capacity without a severe sign of injury, thrombosis, or restenosis of the vascular wall for as long as 6 months [75]. |
| AZ31 | MgF2/SF/SRL | – | PBS | – | – | – | – | – | – | 14 | The outer SF coating restrained local and deep corrosion of HF-treated Mg stents. MgF2/SF/SRL composite coating allowed outstanding HUVECs adhesion and minimal platelet adhesion on its surface [211]. |
| JDBM | MgF2/PLLA/SRL | 6.0 | – | – | – | – | 0.039 | – | 0.0009 | 30 | MgF2/PLLA/SRL coated Mg-based stent showed favorable safety compared with non-degradable commercial DESs, with no signs of in-stent thrombus and restenosis [247]. |
*E-MEM = Eagle's minimum essential medium, PEO = Polyethylene oxide, PEI = Poly (ether imide), PTX = Paclitaxel, SRL = Sirolimus or Rapamycin, DESs = Drug-eluting stents.