Development of an elastic cell culture substrate for a novel uniaxial tensile strain bioreactor

Abstract

Bioreactors can be used for mechanical conditioning and to investigate the mechanobiology of cells in vitro. In this study a polyurethane (PU), Chronoflex AL, was evaluated for use as a flexible cell culture substrate in a novel bioreactor capable of imparting cyclic uniaxial tensile strain to cells. PU membranes were plasma etched, across a range of operating parameters, in oxygen. Contact angle analysis and X-ray photoelectron spectroscopy showed increases in wettability and surface oxygen were related to both etching power and duration. Atomic force microscopy demonstrated that surface roughness decreased after etching at 20 W but was increased at higher powers. The etching parameters, 20 W 40 s, produced membranes with high surface oxygen content (21%), a contact angle of 66° ± 7° and reduced topographical features. Etching and protein conditioning membranes facilitated attachment, and growth to confluence within 3 days, of MG-63 osteoblasts. After 2 days with uniaxial strain (1%, 30 cycles/min, 1500 cycles/day), cellular alignment was observed perpendicular to the principal strain axis, and found to increase after 24 h. The results indicate that the membrane supports culture and strain transmission to adhered cells. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 2356–2364, 2014.

VUV treatment combined with mechanical strain of stretchable polymer foils resulting in cell alignment

“…A similar effect is described for PU after UV irradiation in [29] and is attributed to photo-reactions. Also the XPS results showed for the PU samples irradiated by the VUV light in a N 2 or NH 3 Fig. 2 shows XPS high-resolution spectra of the C 1s level for all three cases.…”

“…The cell-substrate interaction under mechanical strain or compression is not only influenced by the adhesion-strength of the cell-contact to the surface, which is assumed to depend mainly on the chemistry and the micro-or nanotopography of the interface, but also directly on the rigidity of the substrate material itself [23][24][25][26]. For a systematic study of the response of cells to mechanical stimulation in vitro, cell-stretchers and adequate substrates are needed that can model the complexity of the in vivo environment and provide opportunities for examining in vitro how cells respond to different kinds of mechanical stimuli [3,18,27,28].…”

“…Elastic polyurethanes (PU) and PU-composites are of interest as flexible and stretchable cell-culture substrates and scaffolds [1][2][3]. PU is widely used in industry, especially also in the field of medicine and biotechnology [4,5], due to its good mechanical characteristics, high chemical stability, low electrical conductivity, thermal stability and low wettability.…”

Oxidation State of a Polyurethane Membrane after Plasma Etching

“…Previously, a stable biocompatible polyurethane (PU), Chronoflex AL 80A (AdvanSource Biomaterials, Wilmington, MA), was tested as a low modulus candidate substrate for a bioreactor capable of subjecting cells to a dynamic mechanical environment [2]. PU was selected as it is more resilient [3] and has a better cell response than similar polymers [4].…”

“…PU was selected as it is more resilient [3] and has a better cell response than similar polymers [4]. It was shown that plasma etching is a key factor to the success of cell adhesion and normal cell growth: the wettability was found to be dependent on etching power and duration, while roughness was more affected by the duration [2]. Therefore the state of oxidation of the PU membrane has been examined, in order to understand the effects of plasma etching on protein and cell adhesion.…”