In recent years, an increasing number of scientists have realized the potential of semiconductor nanomaterials in the biomedical field and begun to work on expanding their biological applications in areas such as biosensing, high throughput screening, and drug/gene delivery. Since the cytocompatibility of semiconductor nanomaterials can be influenced by various factors, including composition, size and morphology, cell type, specific bioassay, etc., any in vitro use of nanomaterials requires a comprehensive evaluation of toxicity in order to make full use of the material within a regulated safe range.\n Si nanowires (SiNWs) and Ge nanowires (GeNWs) have attracted more and more attention for possible use in biomedical applications due to advantages such as facile synthesis with tunable widths and lengths, high surface area, and distinct electronic, optical, chemical and thermal properties. Given the lack of useful cytotoxicity data of such nanowires that has emerged thus far, it is recognized that detailed cytocompatibility studies of exposure to SiNWs and GeNWs, and understanding of cytotoxicity mechanism are necessary before any applications can be put to real use. In this work, a detailed study of the synthesis and cytotoxicity of horizontal-oriented SiNWs and GeNWs grown from a Vapor-Liquid-Solid route is presented. Selected viability studies (MTT, Trypan Blue) were performed to evaluate the cytotoxicity of NWs on different types of cells, including HEK 293 and MCF-7. For the case of GeNWs, both Western Blot and Apo-ONE Homogenous Caspase 3/7 Assays were also performed to evaluate the mechanism of their cytotoxicity.\n The fundamental properties of other silicon-based structure related to their possible use in biotherapeutic platforms were also evaluated. These include measurements of the <italic>in vitro</italic> dissolution behavior of authentic amorphous silicon thin film transistors (a-Si TFTs), along with time-dependent stability and cytotoxicity of Fe<sub>3</sub>O<sub>4</sub> nanocrystals infiltrated into nanostructured mesoporous silicon.The latter system is of particular interest as a magnetic field-assisted drug delivery vehicle.\n In addition, another unique form of Si based nanomaterial, Si nanotubes (SiNT), were also investigated in this work. Different from SiNWs, SiNTs can dissolve in aqueous media and release Si(OH)<sub>4</sub>, which is nontoxic and readily eliminated from the kidneys. Because the dissolution behavior of SiNTs is solution-composition dependent and size-dependent, SiNTs are a candidate as a controlled release system for therapeutics. Initial cytocompatability assays and gene transfection experiments suggest that SiNTs can act as a non-toxic carrier for transfecting HEK 293 cells with a gene for green fluorescent protein (GFP) in a relatively efficient manner.
| Identifer | oai:union.ndltd.org:TCU/oai:etd.tcu.edu:etd-05132014-114706 |
| Date | 13 May 2014 |
| Creators | Tian, Yuan |
| Contributors | Jeffery L Coffer, Giridhar Akkaraju, Onofrio Annunziata, Kayla N Green |
| Publisher | Texas Christian University |
| Source Sets | Texas Christian University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf, application/octet-stream |
| Source | http://etd.tcu.edu/etdfiles/available/etd-05132014-114706/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to TCU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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