| Biomaterials / BioMEMS | |
| Overview | |
| Nitinol’s (NiTi) shape memory, superelastic, and biocompatible
properties are desirable for many medical applications. Phase transformations
between NiTi’s low temperature martensite phase and its high temperature
austenite structure give rise to NiTi’s shape memory capabilities
and superelastic properties. These characteristics make Nitinol devices
useable for interventional procedures require devices that possess the ability
to be compressed into small diameter catheters and to revert back to an
original size or shape upon deployment. Catheter based procedures are associated
with less trauma, shorter recovery times, and lower costs than their surgical
counterparts. Nitinol is also biocompatible due to a native titanium oxide
layer that forms on NiTi’s surface to prevent corrosion and thrombosis.
In the medical field, NiTi is commonly used in stents, AAA devices, ASD
closure devices, guidewires, surgical tools, and orthodontic applications.
Although NiTi in the bulk form has been used in several types of medical
devices, researchers have yet to study thin film NiTi for medical implants.
Thin film NiTi is on the order of 5-10 microns thick (i.e. orders of magnitude
smaller than bulk NiTi) and is fabricated using DC magnetron sputter deposition.
NiTi in the thin film form allows for the use of MEMS fabrication, slimmer
catheter profiles, and possibly the enhancement of NiTi’s biocompatible
properties. |
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| Current Research Projects | ||
| Development of a Thin Film Nitinol Heart Valve | ||
| Lenka Stepan | ||
| The goal of this research is to test the feasibility of using thin film nitinol as a heart valve leaflet. Current heart valves are surgically placed and require anticoagulants (mechanical) or are plagued by degenerative calcification (bioprosthetic). Thin film nitinol’s biocompatibility properties would alleviate these concerns while its shape memory properties would allow for the development of a percutaneously placed valve. A percutaneous heart valve could be loaded into a catheter, guided through the vasculature and deployed in a precise location thereby eliminating the need for traumatic open heart surgery. Several valve designs incorporating thin film nitinol have been manufactured and tested. Pulsatile flow tests, durability, and biocompatibility of the thin film nitinol valves are being investigated. | ||
| Development of a Thin-Film Nitinol Covered Stent | ||
| Jasen Liu | ||
| Several designs of covered drug-eluting stents are currently undergoing trials for FDA approval; these stents are designed to reduce the occurrence of restenosis seen in patients who receive angioplasty-stent therapies. Restenosis—the reoccurrence of occlusive plaque buildup in a treated blood vessel—is a major limitation to the popular angioplasty-stent procedure. The excellent biocompatibility and non-thrombogeneity of thin-film NiTi has led to this current study which is attempting to develop a novel thin-film NiTi covered stent. It is the ultimate goal of this investigation to develop a stent that would take advantage of NiTi’s unique shape memory properties, in addition to its biocompatibility, to develop a device that could be introduced through catheters into a patient’s body to treat atherosclerosis of arteries, carotid artery disease, aortic aneurysms, and other cardiovascular diseases. | ||
| Thin Film Shape Memory Alloy Micropump for Drug Delivery Application | ||
| Motoki Ujihara | ||
| The purpose of this reaserch is to design an implantable micrpump for drug delivery application such as insulin, cancer drugs, and morphine. This will improve the patients' daily experiecnes, since it will offer a finer dose adjustment and a quicker drug absorption. The technologies used in this pump consist of MEMS fabricatoin and sputtered NiTi thin film. Current research is focused on parameter study of fatigue life and power consumption. | ||
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