Immobilized Growth Factor and peptide on indium tin oxide (ITO) scaffold for long-term hepatocyte culture towards developing a hepatotoxicity bioreactor

Abstract

The overarching goal of this work is to design and develop organic self-assembled monolayer (SAM) based cell culture platforms (SCCPs) to provide an appropriate microenvironment that promotes cell attachment, growth and functionality with the ultimate goal of developing cell-based bioreactors for rapid drug toxicity screening. We describe proliferation of a model cell line, HepG2, and primary rat hepatocytes for culture periods up to 3 days, on a model peptide, Gastrin Releasing Peptide (GRP), and a Growth Factor, Epidermal Growth Factor (EGF), that is covalently coupled to the amine end group of 3-aminopropyl triethoxysilane (APTES)-Self-Assembled Monolayer (SAM) on conducting indium tin oxide (ITO) substrates. The scaffolds were characterized using contact angle and surface-IR techniques. The cells, HepG2 or primary hepatocytes, were cultured on GRP- and EGF-immobilized scaffolds for 24, 48, and 72 hrs. MTT (3-methyltetrazoliumbromide) cell proliferation and Lactose Dehydrogenase (LDH) cytotoxicity assays were performed on HepG2 cells and primary hepatocytes cultures on peptide and growth factor modified scaffolds to evaluate cellular heath and toxicity. Cell proliferation analysis indicated that the HepG2 cells cultured on EGF- and GRP-immobilized substrates showed increased cell viability with time from 24 to 72 hours. The LDH production after 48 hours was reduced in cells cultured on GRP and EGF immobilized surfaces in comparison to the cells cultured on ITO and ITO-APTES substrates. The results overall showed that cell viability increased and cytotoxicity decreased for both HepG2 cells and primary hepatocytes cultured on GRP- and EGF-modified scaffolds. Furthermore, the increase of cell viability with reduced cytotoxicity is extended to 72 hrs with good biocompatibility.