Date of Award

2012

Document Type

Thesis

First Advisor

Kuila, Debasish

Abstract

Artificial juxtacrine stimulation arises from the covalent attachment of growth factors onto biomaterials. Incorporation of growth factors onto cell culture substrates has been found to enhance the functionality of cells in vitro. In this study, we describe how the immobilization of Gastrin Releasing Peptide (GRP) enhances the viability of hepatocarcinoma cell line, HepG2 up to 4 days. The biomaterial for immobilization of GRP was prepared using indium tin oxide (ITO) sputtered on polyethylene terephthalate (PET). A self-assembled monolayer (SAM) of 3-aminopropyl triethoxysilane (3-APTES) on ITO was covalently attached to GRP. Characterization of the substrates before and after immobilization of GRP was carried out using contact angle measurements, FTIR and AFM techniques. HepG2 cells were cultured on immobilized GRP-SAM-ITO substrate for 24, 48, 72 and 96 hours and compared to cell viability of soluble GRP under similar conditions. The cell viability on immobilized GRP-SAM-ITO after 48 hours was less than that of soluble GRP by 19%. Lactate dehydrogenase (LDH) production after 48 hours was significantly reduced by 44% for immobilized GRP when compared to that with soluble GRP. After 96 hours, cell viability increased and cytotoxicity decreased for HepG2 cells on GRP-SAM-ITO substrates, suggesting viability was successfully extended. A similar experiment (LDH assay) with immobilized epidermal growth facor (EGF), obtained by covalent attachment of EGF shows that the cell viability can be extended to 5 days. These data may provide insight towards the development of bioreactors for drug toxicity screening.

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