Physico-chemical Evaluation of Antiatherosclerotic Coronary Stent Coatings Based on Poly(lactic acid) Doped with Functionalized Fe@C Nanoparticles

High mortality associated with atherosclerosis necessitates the development of novel strategies for its treatment. Despite the widespread use and success of lipid-reducing drugs in therapy, they often come with unwanted side effects. One of the modern approaches for atherosclerosis treatment is using coronary stents with polymer coating and antiatherosclerotic agent, which can be released locally. Previously, our team demonstrated the benefits of composite coatings based on poly(lactic acid) (PLA) doped with Fe@C nanoparticles functionalized with C18 hydrophobic groups (C18-NPs). The presence of hydrophobic groups on the nanoparticles surface allows them to interact effectively with atherosclerotic plaque leading to its structural changes and destruction. Herein, the effect of functionalized nanoparticle content (from 0 to 10 wt.%) on the physicochemical properties of the composite PLA-based coatings (particularly, morphology, elemental composition, hydrophilicity, crystal structure, and adhesion to the substrate) is reported. It is demonstrated that the deposited coatings uniformly cover the surface of the model AISI 321H steel substrates with oxynitride layer regardless of the nanoparticle content. It was found that nanoparticle content had no effect on the PLA crystal structure. The formation of nanoparticle agglomerates and surface hydrophobization was observed for coatings with a nanoparticle content greater than 1 wt.%. The reported findings indicate that a nanoparticle content of 5 wt.% is optimal in terms of achieving a desirable combination of physicochemical characteristics and the ability to degrade atherosclerotic plaques.