Phase contrast microscopy of cultured endothelial cells on day 4. A – tissue culture plastic, B – Polymethylpentene, C – Polypropylene, D – Polydimethylsiloxane. Scale 100 μm. All materials except A are coated with fibronectin. Endothelial cells form confluent monolayers after 4 days of culture on tissue culture plastic (A) and PDMS (D) but neither on TPX (B) nor on PP (C).