KIST laser patterning promotes stent biocompatibility

31 Dec 2024

Textured surfaces limit the subsequent re-narrowing of arteries after surgery.

A project at the Korea Institute of Science and Technology (KIST) has developed a laser-based procedure intended to improve the successful use of stents in vascular surgery.

As the global population ages, so the incidence of vascular disease increases, with insertion of therapeutic stents to widen blood vessels remaining one of the primary remedies.

However, the re-narrowing of arteries after implantation, a process termed restenosis, is a frequent consequence. Caused by a complex interplay of cellular responses, restenosis is a significant concern for clinicians.

The project at KIST's Biomaterials Research Center investigated how the vascular cells reacted when the stent surface had been previously been laser-treated to create nano- or micro-scale wrinkles in the material. The results were reported in Bioactive Materials.

"Drug-eluting stents are widely used to mitigate restenosis, but often inhibit vascular re-endothelialization, increasing the risk of thrombosis and necessitating the use of anticoagulants," commented KIST.

"To overcome these limitations, research into coating stent surfaces with bioactive molecules like proteins or nucleic acids is ongoing. However, these coatings often serve limited functions, falling short in accelerating endothelial cell proliferation."

The KIST solution applied nanosecond laser texturing technology to create nano- and micro-scale wrinkle patterns on the nickel-titanium alloy surfaces of stent materials, to test if the patterns would inhibit the migration and morphological changes of smooth muscle cells caused by stent-induced vascular wall injury, a sign that they would then prevent subsequent restenosis.

Such patterns would also be expected to enhance cellular adhesion, promoting re-endothelialization and the restoration of the vascular lining.

Innovative advances in vascular care

In trials, a nanosecond-pulse 1064-nanometer source was used to pattern nickel-titanium surfaces, and the subsequent effect on surrounding cells was assessed through in vitro vascular cell studies and ex vivo angiogenesis assays using fetal animal bones.

"The laser-textured metal surfaces created favorable environments for endothelial cell proliferation while effectively suppressing smooth muscle cell dedifferentiation and excessive growth," noted KIST. "Notably, smooth muscle cell growth on the wrinkled surfaces was reduced by approximately 75 percent, while angiogenesis increased more than twofold."

KIST expects its surface patterning technology to be applicable not only to metal stents but also to biodegradable ones, in which the patterns can prevent restenosis and enhance endothelialization before the stents dissolve, improving treatment outcomes and reducing complication risks.

The research team is now planning to conduct animal tests and clinical trials to verify the long-term safety and efficacy of its laser patterning technology, seeing its research as a bridge between in vitro and in vivo studies of these metal-patterning approaches.

"This study demonstrates the potential of surface patterns to selectively control vascular cell responses without drugs," said Hojeong Jeon of KIST. "Using widely industrialized nanosecond lasers allows for precise and rapid stent surface processing, offering significant advantages for commercialization and process efficiency."