Recent investigations have demonstrated that polydopamine (PDA)-modified surfaces were beneficial to the proliferation of endothelial cells (ECs). In this work, PDA coated 316L stainless steels (316L SS) were thermally treated at 50, 100, and 150 °C respectively (hereafter designated as Th50, Th100, and Th150) and consequently produced diverse surface chemical components. In vitro hemocompatibility and vascular cell-material interactions with ECs and smooth muscle cells (SMCs) affected by surface characteristics have been investigated. The Th150, rich in quinone, showed the best hemocompatibility and could effectively inhibit platelet adhesion, activation, and fibrinogen conformation transition. The polydopamine-modified surfaces were found to induce dramatic cell-material interaction with enhanced ECs proliferation, viability and migration, release of nitric oxide (NO), and reduced SMCs proliferation. The inhibitory effect of SMCs proliferation might be associated with the surface catechol content. The coating on Th150 showed a good resistance to the deformation of compression and expansion of vascular stents. These results effectively suggested that the Th150 coating might be promising when served as a stent coating platform.

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A one-step method to deposit a functional amine-rich coating in dopamine and hexamethylendiamine mixed solution through simple dip-coating of objects.

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Polydopamine (PDAM), a mussel adhesive protein inspired coating that can be easily deposited onto a wide range of metallic, inorganic, and organic materials, gains interest also in the field of biomaterials. In this work, PDAM is applied as coating on 316L stainless steel (SS) stents and the response of cells of the blood vessel wall, human umbilical vein endothelial cell (HUVEC), and human umbilical artery smooth muscle cell (HUASMC) as predictors for re‐endothelialization is tested. It is found that the PDAM‐modified surface significantly enhances HUVEC adhesion, proliferation, and migration, release of nitric oxide (NO), and secretion of prostaglandin I2 (PGI2). Additionally, the PDAM‐modified surface shows a remarkable ability to decrease the adhesion and proliferation of HUASMCs. As a blood‐contacting material, the PDAM tends to improve the hemocompatibility compared with the substrate 316L SS. It is noteworthy that the PDAM coating shows good resistance to the deformation behavior of compression and expansion of a stent. These data suggest the potential of PDAM as a blood‐contacting material for the application in vascular stents or grafts.

Heparin, an important polysaccharide, has been widely used for coatings of cardiovascular devices because of its multiple biological functions including anticoagulation and inhibition of intimal hyperplasia. In this study, surface heparinization of a commonly used 316L stainless steel (SS) was explored for preparation of a multifunctional vascular stent. Dip-coating of the stents in an aqueous solution of dopamine and hexamethylendiamine (HD) (PDAM/HD) was presented as a facile method to form an adhesive coating rich in primary amine groups, which was used for covalent heparin immobilization via active ester chemistry. A heparin grafting density of about 900 ng/cm(2) was achieved with this method. The retained bioactivity of the immobilized heparin was confirmed by a remarkable prolongation of the activated partial thromboplastin time (APTT) for about 15 s, suppression of platelet adhesion, and prevention of the denaturation of adsorbed fibrinogen. The Hep-PDAM/HD also presented a favorable microenvironment for selectively enhancing endothelial cell (EC) adhesion, proliferation, migration and release of nitric oxide (NO), and at the same time inhibiting smooth muscle cell (SMC) adhesion and proliferation. Upon subcutaneous implantation, the Hep-PDAM/HD exhibited mitigated tissue response, with thinner fibrous capsule and less granulation formation compared to the control 316L SS. This number of unique functions qualifies the heparinized coating as an attractive alternative for the design of a new generation of stents.

Thrombogenic reaction, aggressive smooth muscle cell (SMC) proliferation, and sluggish endothelial cell (EC) migration onto bioinert metal vascular stents make poststenting reendothelialization a dilemma. Here, we report an easy to perform, biomimetic surface engineering strategy for multiple functionalization of metal vascular stents. We first design and graft a clickable mussel-inspired peptide onto the stent surface via mussel-inspired adhesion. Then, two vasoactive moieties [i.e., the nitric-oxide (NO)-generating organoselenium (SeCA) and the endothelial progenitor cell (EPC)-targeting peptide (TPS)] are clicked onto the grafted surfaces via bioorthogonal conjugation. We optimize the blood and vascular cell compatibilities of the grafted surfaces through changing the SeCA/TPS feeding ratios. At the optimal ratio of 2:2, the surface-engineered stents demonstrate superior inhibition of thrombosis and SMC migration and proliferation, promotion of EPC recruitment, adhesion, and proliferation, as well as prevention of in-stent restenosis (ISR). Overall, our biomimetic surface engineering strategy represents a promising solution to address clinical complications of cardiovascular stents and other blood-contacting metal materials.