Elsevier

Biomaterials

Volume 24, Issue 15, July 2003, Pages 2605-2610
Biomaterials

Hepatocyte performance on different crystallographic faces of rutile

https://doi.org/10.1016/S0142-9612(03)00064-4Get rights and content

Abstract

The influence of crystallographic orientation of polished rutile single crystal surfaces of the (1 0 0), (1 1 0) and (1 1 1) orientation on hepatocyte performance was tested in cell culture over 3 days. Cell adhesion was observed on the titanium dioxide surfaces and their performance was measured by means of cell number attached (protein mass), cell viability (neutral red assays) and metabolic activity (thiazolyl tetrazolium bromide assay).

Titanium dioxide displays no cytotoxic effects on hepatocytes, and shows a performance in the range of standard collagen-coated tissue culture polystyrene dish. The number of hepatocytes adhered on the different rutile surfaces were not significantly different to those on dense rutile polycrystalline ceramic.

These findings suggest that hepatocytes do not recognize the specific differences of differently orientated rutile crystal surfaces.

Introduction

To provide long-term liver-specific functions in vitro, culture systems are needed which mimic the microstructure of liver tissue and allow the conservation of highly differentiated cells [1], [2]. The cell-carrier material used in cell culture systems is of major importance for a differentiated cell performance. Substrate materials investigated so far include materials as e.g. glass [3], polystyrene, polyethylene-terphtalate, polylactic acid–polylactico glycolic acid [4], collagen and alginate. Titanium dioxide ceramics have been demonstrated to be useful as porous cell substrate materials whose properties serve to sustain the viability of cells [5]. In contrast to many materials investigated so far like polystyrene, collagen or alginate, these porous ceramics consist of crystallites exhibiting distinct crystallographic faces.

It was reported, that the differences in atom arrangement can lead to distinct protein adsorption and thus influence cell attachment to the surface. The identification of the optimum crystallographic face(s) for hepatocyte performance could lead to improved hepatocyte cell carrier material. An influence of the crystallinity of a substrate on cell performance is reported for chondrocytes on TiO2 surfaces [6], and for osteoblasts on Ti [7]. Hanein et al. showed that epithelial cells adhere differently to different crystallographic faces of calcium tartrate crystal surfaces [8], [9].

In this work hepatocyte adhesion as well as hepatocyte viability and metabolic activity on three different rutile single crystal faces ((1 0 0), (1 1 0) and (1 1 1)) were characterized. They differ in their surface symmetry and their Ti:O configuration. The goal was to investigate a dependence of cell growth on the crystallographic orientation of this material.

Section snippets

Materials

Rutile single crystal discs with three crystallographic orientations (1 0 0), (1 1 0), (1 1 1), grown by the Verneuil method (DJEVA, Monthey, Switzerland) were investigated. The crystals were round, 12 mm in diameter, 2 mm thick and optically polished. Deviation from the ideal axis determined by Laue diffraction varied between 1.2° (1 0 0) and 2.7° (1 1 0).

Dense rutile ceramic samples were produced by sintering pressed anatase titanium dioxide powders (Kronos 1171, Germany) at 1450°C for 1 h.

All cell

Surface characterization

Surface composition of all titania surfaces showed high concentration of carbon (Table 1). The carbon concentration varied between 22.7 and 53.9 at% on the different oriented crystal surfaces and was found to be lowest on the ceramic sample with only 14.5 at%. Minor traces of Na, Ca, Al, Si, N, Cl and F could be found. Al (5.6 at%) was only found on the ceramic samples.

Cell adherence

Cell adhesion could be observed on all rutile surfaces and the collagen-coated tissue culture polystyrene (CC TCPS). The observed

Discussion

It has been shown that freshly isolated rat hepatocytes adhere to flat single crystal rutile surfaces as well as rutile ceramic surfaces. No cytotoxic effect of titanium dioxide substrate material on hepatocytes could be found. Furthermore it could be shown, that hepatocytes have no significant preference for adhesion to crystallographic surfaces of rutile with orientations, (1 0 0), (1 1 0) and (1 1 1) after incubation for 3 days. In contrast to data presented by Hanein et al. [9], who found largest

Acknowledgments

We are thankful to Ms. Gersbach-Fey for excellent technical assistance and Dr. Gilbert Francz for XPS analysis. Funding by ETH Zürich and SNF 31-51172.97 is gratefully acknowledged.

References (19)

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