The hydrophobic properties of femtosecond laser fabricated spike structures and their effects on cell proliferation



Silicon (Si) spikes with an average tip surface of 1.4 μm2, an average depth 5.9 μm and a spike-to-spike distance of 4.8 μm have been produced with a commercial laser system which delivers sub-30-fs pulses at 800 nm and a repetition rate of 1 kHz. The fabricated spikes can be used for the generation of negative replica in soft material such as silicone elastomer. Since the Si spikes were not destroyed during the replication process, it is possible to reproduce ad libitum soft material with the same spike configuration rendering comparison possible. The analysis of the wettability of the surfaces revealed that the structuring induced an increase in hydrophobic character of Si as well as of silicone elastomer. This effect is related to the presence of air trapped in the microstructured surface. Analysis of the effect of the structuring on the proliferation activity of fibroblasts and SH-SY5Y neuroblastoma cells showed that the spike structures and its negative replicas in silicone elastomer are able to suppress the proliferation of the fibroblasts for 48 h but did not affect the neuroblastoma cells. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)