عنوان

Formulation and Testing of Biodegradable Polymeric Coating on Zinc Wires in Cardiovascular Stent Application

شماره

TL49394

زبان متن نوشتاري يا گفتاري و مانند آن

انگلیسی

عنوان اصلي

Formulation and Testing of Biodegradable Polymeric Coating on Zinc Wires in Cardiovascular Stent Application

نام عام مواد

[Thesis]

نام نخستين پديدآور

Avishan  Arab Shomali

نام ساير پديدآوران

Drelich, Jaroslaw W.

نام ناشر، پخش کننده و غيره

Michigan Technological University

تاریخ نشرو بخش و غیره

2017

نام خاص و کميت اثر

78

متن يادداشت

Committee members: Goldman, Jeremy; Seguin, Daniel

متن يادداشت

Place of publication: United States, Ann Arbor; ISBN=978-1-369-82043-0

جزئيات پايان نامه و نوع درجه آن

M.S.

نظم درجات

Materials Science and Engineering

کسي که مدرک را اعطا کرده

Michigan Technological University

امتياز متن

2017

متن يادداشت

Biodegradable and biocompatible poly (L-lactic-acid) (PLLA) coating was applied on a modified zinc (Zn) substrate by dip coating, with the intent to delay the bio-corrosion and slow the degradation rate of zinc substrate. 3-(Trimethoxysilyl) propyl methacrylate (MPS) was used for modification of the zinc substrate for promoting the adhesion between the metallic substrate and the polymer coating. It is hypothesized that the delay in Zn biodegradation could be useful in the first several weeks to prevent the early loss of mechanical integrity of the endovascular stent and to improve the healing process of the diseased vascular site. The PLLA coating was used in this study because of its biodegradability, favorable degradation rate, hydrophobicity and favorable mechanical properties. Static immersion, electrochemical and inductively coupled plasma (ICP) tests were used to investigate the degradation behavior of a polymer coated modified Zn substrate. Two uniform polymer layers with thickness of 1 and 3 μm were coated on the Zn substrate. The potentiodynamic polarization test indicated that the 1 μm polymer coated specimen has higher corrosion potentials (E_corr) and lower corrosion cur rents (i_corr) in the simulated body fluid (SBF) compared to the uncoated Zn. AC impedance measurement in EIS test also demonstrated a significant improvement in the impedance and polarization resistance of the coated Zn substrate. However, after 10 days of immersion in the SBF, the impedance reduced drastically which is indicative of a coating degradation and penetration of the electrolyte to the zinc substrate. Immersion degradation studies showed that the cross-sectional area (CSA) reduction and penetration rate (PR) for polymer coated samples are 5 times smaller than for uncoated samples after 14 days of immersion in SBF solution. Results of the ICP method indicated an increase in the release of the Zn²⁺ to the solution for the uncoated Zn, while the 1 μm PLLA coated sample demonstrated much slower release rate of Zn²⁺ and the concentration of Zn ion during the 14 days' immersion in SBF was almost the same. In in vivo studies, the polymer-coated Zn and uncoated Zn samples were implanted into the abdominal aorta of the rats and then directed into the lumen. The explants were extracted after 0.5 to 6 months. The results of in vivo study indicated that the uncoated samples have approximately two times higher CSA reduction and PR in comparison to the coated samples during first 4.5 months. After 4.5 months, the CSA reduction and PR increased significantly. However, the histological analysis of the biological tissue surrounding samples showed a reduction in biocompatibility of the polymer coated samples indicated by increasing cell toxicity and neointimal hyperplasia.

موضوع مستند نشده

Biomedical engineering; Materials science

اصطلاح موضوعی

Applied sciences;Arterial implant;Biodegradable;Poly (L-lactic-acid);Polymer coating;Stent material

مستند نام اشخاص تاييد نشده

Belt, David Douglas

مستند نام اشخاص تاييد نشده

Drelich, Jaroslaw W.

تقسيم فرعي

Materials Science and Engineering

مستند نام تنالگان تاييد نشده

Michigan Technological University

شماره بازیابی

1911315344; 10266577

نام الکترونيکي

فرمت انتشار

p

نوع ماده

[Thesis]

کد کاربرگه

276903

سطح دسترسي

a

تكميل شده

Y