Coronary stents are mesh tubes placed in arteries to prevent their collapse andmaintain continuous blood supply to heart muscles. Despite the clinical success of metal stents based onstainless steel and cobalt-chromium, they continue to present a risk of blood clots and overgrowth ofundesirable smooth muscle cells, resulting in vessel blockage in the long run. The concept of drug-elutingstents was introduced to circumvent these problems; wherein metallic stents were coated with a polymerloaded with drugs such as sirolimus and paclitaxel. These drugs prevent the excessive growth of smoothmuscle cells and improve clinical efficacy. However, the drugs released from the polymer-coated stentdelay healing by averting endothelial cells' growth. These cells play a protective role by preventing bloodclot formation. Additionally, the polymeric coatings on stents were susceptible to nonuniformities on thesurfaces and delamination, which affect their long-term stability and integrity. Therefore, there is anunmet need to develop a new type of stent to address these problems.

We present a novel approach to nanotexture the surface of metallic stents, mainly titanium,thereby regulating cellular behavior with the stents. Architecture in the form of a nanoscale leaf wasengineered on the stent surface that remained stable under blood flow and upon mechanical crimping andexpansion, which is experienced by the stent during implantation. The nanomodified stent surfacepromotes endothelial cell growth while simultaneously inhibiting the excessive proliferation of smoothcells, resulting in faster blood vessel healing. Our research demonstrated stable and uniform nanotexturedtitania surface on metallic titanium through a facile hydrothermal processing technique that exhibitedexcellent vascular cell response and hemocompatibility in a rabbit model for two months, compared tobare metal stents and drug-eluting stents. In addition, surface modification of stents did not elicit anyinflammatory response.

Background Information

More than 600,000 coronary stents are implanted in the United States annually. Our newtechnology has the potential to improve the therapeutic outcome by a simple modification of metal stentswith titanium nanostructures, a prospective method to circumvent the current limitations of commercialstents. Notably, these characteristics are observed in the absence of any drug or polymer as in commercialdrug-eluting stent, making our technology a more promising approach for clinical translation. This studyalso indicates the effectiveness of surface modification and the likelihood of bringing low-priced materialback to clinics.

Cherian AM, Joseph J, Nair MB, Nair S V., Maniyal V, Menon D. Successful Reduction of Neointimal Hyperplasia on Stainless Steel Coronary Stents by Titania Nanotexturing. ACS Omega. 2020;

Anitha A, Joseph J, Menon D, Nair S V, Nair MB. Electrospun Yarn Reinforced NanoHA Composite Matrix as a Potential Bone Substitute for Enhanced Regeneration of Segmental Defects. Tissue Eng

Mohan CC, Cherian AM, Kurup S, Joseph J, Nair MB, Vijayakumar M, et al. Stable Titania Nanostructures on Stainless Steel Coronary Stent Surface for Enhanced Corrosion Resistance andEndothelialization. Adv Healthc Mater 2017;6:1601353.