Temporal Changes in the Surface Chemistry and Topography of Reactive Ion Plasma-Treated Poly(vinyl alcohol) Alter Endothelialization Potential

Synthetic small-diameter vascular grafts (<6 mm) are used in the treatment of cardiovascular diseases, including coronary artery disease, but fail much more readily than similar grafts made from autologous vascular tissue. A promising approach to improve the patency rates of synthetic vascular grafts is to promote the adhesion of endothelial cells to the luminal surface of the graft. In this study, we characterized the surface chemical and topographic changes imparted on poly(vinyl alcohol) (PVA), an emerging hydrogel vascular graft material, after exposure to various reactive ion plasma (RIP) surface treatments, how these changes dissipate after storage in a sealed environment at standard temperature and pressure, and the effect of these changes on the adhesion of endothelial colony-forming cells (ECFCs). We showed that RIP treatments including O2, N2, or Ar at two radiofrequency powers, 50 and 100 W, improved ECFC adhesion compared to untreated PVA and to different degrees for each RIP treatment, but that the topographic and chemical changes responsible for the increased cell affinity dissipate in samples treated and allowed to age for 230 days. We characterized the effect of aging on RIP-treated PVA using an assay to quantify ECFCs on RIP-treated PVA 48 h after seeding, atomic force microscopy to probe surface topography, scanning electron microscopy to visualize surface modifications, and X-ray photoelectron spectroscopy to investigate surface chemistry. Our results show that after treatment at higher RF powers, the surface exhibits increased roughness and greater levels of charged nitrogen species across all precursor gases and that these surface modifications are beneficial for the attachment of ECFCs. This study is important for our understanding of the stability of surface modifications used to promote the adhesion of vascular cells such as ECFCs.

Copper and Zinc Co-doped Titanium Dioxide Nanotubes Arrays on Controlling Nitric Oxide Releasing and Regulating the Inflammatory Responses for Cardiovascular Biomaterials

BACKGROUND

Titanium dioxide (TiO₂) nanotubes arrays have shown tremendous application foreground due to their unique characters of structure and performance. However, the single bio-function is still the limit on cardiovascular biomaterials.

METHODS

The loadability function provides the possibility for the TiO₂ nanotubes arrays to realize composite multifunction. The copper can catalyze the release of nitric oxide to promote the proliferation of endothelium cells and improve the anticoagulant. Also, zinc can adjust the inflammatory responses to improve anti-inflammation.

RESULTS

In this patent work, we co-doped the copper and zinc onto TiO₂ nanotubes arrays to estimate the hemocompatibility, cytocompatibility and responses of inflammation. The results showed that copper and zinc could introduce better multi-biofunctions to the TiO₂ nanotubes arrays for the application in cardiovascular biomaterials.

CONCLUSION

In summary, the NTs@Cu/Zn sample as a new composite material in this study had significant biocompatibility in vascular implantation and can be used as a potential material for polymer- free drug-eluting stents.

Recent advances in the design of cardiovascular materials for biomedical applications

Biomaterials dominate the field of cardiovascular therapeutics, a multitude of which have been used to repair and replace injured heart tissue. This field has evolved beyond the simple selection of compatible materials and now focuses on the rational design of controlled structures that integrate with the cardiovascular system. However, the compatibility of these materials with the blood presents a major limitation to their clinical application. In this context, surface modification strategies can enhance blood compatibility and several recent advances in this area have emerged. This review summarizes the recent applications of biomaterials in cardiovascular therapies, the improvements in their biocompatibility and the surface modification technologies that have the potential to improve clinical outcomes.

Controlling Molecular Weight of Hyaluronic Acid Conjugated on Amine-rich Surface: Toward Better Multifunctional Biomaterials for Cardiovascular Implants

The molecular weights (MWs) of hyaluronic acid (HA) in extracellular matrix secreted from both vascular endothelial cells (VECs) and vascular smooth muscle cells (VSMCs) play crucial roles in the cardiovascular physiology, as HA with appropriate MW influences important pathways of cardiovascular homeostasis, inhibits VSMC synthetic phenotype change and proliferation, inhibits platelet activation and aggregation, promotes endothelial monolayer repair and functionalization, and prevents inflammation and atherosclerosis. In this study, HA samples with gradients of MW (4 × 10³, 1 × 10⁵, and 5 × 10⁵ Da) were prepared by covalent conjugation to a copolymerized film of polydopamine and hexamethylendiamine (PDA/HD) as multifunctional coatings (PDA/HD-HA) with potential to improve the biocompatibility of cardiovascular biomaterials. The coatings immobilized with high-MW-HA (PDA/HD-HA-2: 1 × 10⁵ Da; PDA/HD-HA-3: 5 × 10⁵ Da) exhibited a remarkable suppression of platelet activation/aggregation and thrombosis under 15 dyn/cm² blood flow and simultaneously suppressed the adhesion and proliferation of VSMC and the adhesion, activation, and inflammatory cytokine release of macrophages. In particular, PDA/HD-HA-2 significantly enhanced VEC adhesion, proliferation, migration, and functional factors release, as well as the captured number of endothelial progenitor cells under dynamic condition. The in vivo results indicated that the multifunctional surface (PDA/HD-HA-2) created a favorable microenvironment of endothelial monolayer formation and functionalization for promoting reendothelialization and reducing restenosis of cardiovascular biomaterials.

Multifaceted prospects of nanocomposites for cardiovascular grafts and stents

Cardiovascular disease is the leading cause of death across the globe. The use of synthetic materials is indispensable in the treatment of cardiovascular disease. Major drawbacks related to the use of biomaterials are their mechanical properties and biocompatibility, and these have to be circumvented before promoting the material to the market or clinical setting. Revolutionary advancements in nanotechnology have introduced a novel class of materials called nanocomposites which have superior properties for biomedical applications. Recently, there has been a widespread recognition of the nanocomposites utilizing polyhedral oligomeric silsesquioxane, bacterial cellulose, silk fibroin, iron oxide magnetic nanoparticles, and carbon nanotubes in cardiovascular grafts and stents. The unique characteristics of these nanocomposites have led to the development of a wide range of nanostructured copolymers with appreciably enhanced properties, such as improved mechanical, chemical, and physical characteristics suitable for cardiovascular implants. The incorporation of advanced nanocomposite materials in cardiovascular grafts and stents improves hemocompatibility, enhances antithrombogenicity, improves mechanical and surface properties, and decreases the microbial response to the cardiovascular implants. A thorough attempt is made to summarize the various applications of nanocomposites for cardiovascular graft and stent applications. This review will highlight the recent advances in nanocomposites and also address the need of future research in promoting nanocomposites as plausible candidates in a campaign against cardiovascular disease.