Text

ETD_2838

http://hdl.rutgers.edu/1782.1/rucore10001600001.ETD.000056809

theses

A central effort in biomedical research concerns the development of materials for sustaining and controlling cell growth. Carbon nanotube based substrates have been shown to support the growth of different kinds of cells. However the underlying molecular mechanisms remain poorly defined. To address the fundamental question of mechanisms by which nanotubes promote bone mitosis and histogenesis, primary calvariae osteoblastic cells were grown on single walled carbon nanotube (SWNT) network substrates. Using a combination of biochemical and optical techniques, we demonstrate here that SWNT networks promote cell development through two distinct steps. Initially, SWNTs are absorbed in a process that resembles endocytosis, inducing acute toxicity. Nanotube mediated cell destruction, however, induces a release of endogenous factors that act to boost the activity of the surviving cells by stimulating the synthesis of extracellular matrix. In the second part of the research, minimally invasive SWNT matrices were used to further investigate network properties for biomedical applications without extensive presence of cytotoxicity. In the literature, carbon nanotube based substrates have been shown to support the growth of different cell types and, as such, have raised considerable interest in view of their possible use in biomedical applications. Nanotube matrices that are embedded in polymers cause inherent changes in nanotube chemical and physical film properties. Thus, it is critical to understand how the physical properties of the pristine networks affect the biology of the host tissue. Here, we investigated how the physical and chemical properties of SWNT networks impact the response of MC3T3-E1 bone osteoblasts. We found that two fundamental steps in cell growth: initial attachment to the substrate and proliferation, are strongly dependent on the energy and roughness of the surface, respectively. Thus, fine-tuning the properties of the film may represent a strategy to optimize the response of the biological host. Outlined above results led to a next set of experiments in which in-situ, real time cell interactions with SWNT films were investigated. Direct electrical measurements on SWNT thin films on changing osteoblastic cell growth were conducted. The experiments indicated that in fact the nanotube films have capability of hosting and sensing initial cell material interactions.

Ph.D.

Includes bibliographical references

Includes vita

by Wojtek Tutak

doi:10.7282/T3ST7PK2

ETD doctoral

The author owns the copyright to this work.

ETD

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