Surface microarchitectural design in biomedical applications: in vivo analysis of tissue ingrowth in excimer laser-directed micropored scaffold for cardiovascular tissue engineering.
A micropatterned microporous segmented polyurethane film (20 x 12 mm in size, 30 micrometer thick) with four regions was prepared by excimer laser microprocessing to provide an in vivo model of transmural tissue ingrowth in an open cell-structured scaffold specially designed for cardiovascular tissue engineering. Three microporous regions had the same circular micropores (30 micrometer diameter) but different pore density arrangements (percentage of total pore area against unit area was 0.3%, 1.1%, and 4.5%), and the other region remained nonporous. The covered stent, prepared by wrapping the regionally different density-microporous film on an expandable metallic stent (approximately 3.1 mm in diameter), was delivered to the luminal surface of canine common carotid arteries and placed after expansion of the stent to a diameter of approximately 8 mm using a balloon catheter. At 4 weeks of implantation, all the covered stents (n = 10) were patent. The luminal surfaces of the covered stents were almost confluently endothelialized both in nonporous and microporous regions. Histological examination showed that the neointimal wall was formed by tissue ingrowth from host through micropores (transmural) and anastomotic sites. Thrombus formation occurred frequently in the lowest density porous region and nonporous region. With an increase in pore density, the thickness of the neointimal wall decreased. This study demonstrated how the micropore density of implanted devices influences tissue ingrowth in arterial implantation.
Nakayama
Y
Y
Department of Bioengineering, National Cardiovascular Center Research Institute, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565, Japan.
Nishi
S
S
Ishibashi-Ueda
H
H
Matsuda
T
T
D000800:Angioplasty, Balloon; D000818:Animals; D001672:Biocompatible Materials; D001698:Biomedical Engineering; D002320:Cardiovascular Physiological Phenomena; D017536:Carotid Artery, Common / Q000502:physiology / Q000648:ultrastructure; D016893:Carotid Stenosis / Q000473:pathology / Q000503:physiopathology / Q000628:therapy; D004285:Dogs; D007834:Lasers; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D011140:Polyurethanes; D012038:Regeneration; D015607:Stents; D013499:Surface Properties
D001672:Biocompatible Materials; D011140:Polyurethanes