Polymeric Tissue Culture Substrates patterned by UV Irradiation
- PDF / 433,398 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 89 Downloads / 210 Views
Polymeric Tissue Culture Substrates patterned by UV Irradiation
Alexander Welle, Eric Gottwald, Karl-Friedrich Weibezahn, and Herman Dertinger Forschungszentrum Karlsruhe GmbH, Institute for Medical Engineering and Biophysics P.O. Box 3640, 76021 Karlsruhe, GERMANY ABSTRACT We studied the physico/chemical effects of deep UV irradiation of polystyrene, PMMA and polycarbonate with respect to cell adhesion and protein immobilization. Photochemical modifications of the polymer surfaces yielded unstable peroxides and carboxylic acid groups. Patterned protein adsorbates were realized by coupling via carbodiimid activation of the COOH moieties. We have immobilized enzymes and antibodies. It was observed that hepatoma cells (HepG2) and fibroblasts (L929) adhered in the presence of serum proteins in the culture medium on the irradiated regions of the substrate without any further treatment.
INTRODUCTION Today, some in vitro cell culture systems have reached a high complexity. However, also the demands for more realistic in vitro tissue models grew strongly in order to get closer to the in vivo situation. The in vivo performance of an organ is related to the extracellular matrix surrounding the cells, homologous and heterologous intercellular communication and a precisely determined super cellular architecture. This has been demonstrated for instance in comparative cell cultures using monolayers, multicellular spheroids [1] and co-cultures [2]. Structured cocultures of hepatocytes and fibroblasts on µ-patterned surfaces precisely defining the contact areas between cells and the substrate lead to the concept of tissue engineering [3, 4]. The presented masked UV irradiations of polymeric cell culture substrates open a simple, fast, and economical route to obtain chemically patterned substrates applicable as basic tissue engineering modules. This procedure is advantageous as compared to silane or thiol based patterning by micro-contact printing or other techniques due to the availability and versatility of the polymeric substrates, the elimination of any wet chemical treatment, the clean room compatibility of the process and the small size of achieved structures.
EXPERIMENTAL Materials and surface modifications Polystyrene (PS) was used in the form of sterile, untreated (bacteria) petri dishes. Tissue culture dishes (pre-treated polystyrene) were used as cell adhesive reference substrates. Polystyrene surfaces were exposed to UV irradiation in air using a low pressure mercury lamp (Heraeus Noblelight GmbH, Kleinostheim, Germany, NNQ lamp, λ= 185 and 253 nm, quartz tube, 15 W) together with a reflector at 10 cm distance to the polymer sample. For patterned exposure a chromium mask on quartz was placed in contact to the polymer surface. GG1.6.1
Diazomethane esterification of surface carboxyl groups was performed according to [5]. Surface analysis Advancing (θa) and receding (θr) contact angles of buffered solutions from pH 2 to pH 12 determined the pKa of surface groups (contact angle titrations, [6]). Ionic dye binding [7] w
Data Loading...
