Construction Of Copper Mediated In Situ Nitric Oxide-generating Coating For Cardiovascular Interventional Devices

Nitric Oxide (NO), originally known as the endothelin-derived relaxating factor (EDRF), which is released from healthy endothelial cells (ECs), plays an extremely important role in maintaining the balance of blood flow and pressure and influences the cellular activities of platelats and smooth muscle cells. Cardiovascular disease and interventional operation often causes vascular endothelial cell dysfunctions, resulting in the lack of exogenous NO expressing. In the light of the pathobiology, local administration of human endogenous NO donor (RSNO) instead of adding exogenous NO provides a promising approach to achieve safe and continuous treatment of cardiovascular disease. The present study has focused on the surface modification of vascular materials in terms of in-situ generating NO via decomposing RSNO by constructing a Cu(Ⅰ)-loading coating, where Cu (Ⅰ) is the catalyst adopted in this study. Polydopamine (PDA) coating in the presence of large amounts of pyrocatechin can chelate Cu (Ⅰ) on the material surface and thus performed as a targeted investigated carrier for Cu(Ⅰ) loading and releasing.In this paper,a different PDA coating formation time of 24 h,48 h and 72 h was performed, in order to obtained diverse catechol densities, followed with a simple dip-coating of CuCl2 solution (copper reduction and chelation process). The chemical characterization of the coatings was investigated by Micro-BCA assay, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). Ellipsometry, Actomic Force Microscope(AFM), Water Contact Angle(WCA)were utilized to study the coating thickness, surface morphology and hydrophilicity. Results showed that the reaction time could regulate the thickness and functional groups density of catechol on PDA coating from 0.12 nmol/cm2 to 0.22 nmol/cm2. Density of the catechol influenced the corresponding loading amount of copper. Griess assay and chemiluminescence NO analyzer were adopted to investigate the NO releasing behavior toward PBS. More Cu (Ⅰ) were incorporated into the larger catechol-containing PDA coatings and thus induced long-time NO catalyzing/releasing. In vitro Platelet adhesion and whole blood circulating test showed that copper incorporated PDA coating could effectively inhibitd platelet activation and thrombus formation. Interestingly, longer PDA deposition time (higher density of catechols) caused the decreased cell density and activity. With SNAP addition, Cu incorporated PDA is more friendly for the cell adhesion and proliferation. Moreover, macrophage cells culture showed that longer deposition time also decreased the cell activity and TNF-α and IL-1 expression per unit area. Compared to PDA coating, Cu incorporated sample would not lead to the inflammatory of macrophage cells.In conclusion, this study has demonstrated a successfully construction of copper incorporated PDA coating. The coating contained an immobilized catalyst Cu(I) can generate NO in physiological condition. In vitro results indicated the coating had an anticlotting effect, was ECs friendly and showed no inflammatory response of macrophage cells. Current data indicated the potential of copper-incorporated PDA coating to be a applied for modifying blood-contacting materials.