Patterned and switchable surfaces for biomaterial applications

Andrew Hook – Patterned and switchable surfaces for biomaterial applicationsThe adsorption and desorption of oligonucleotides and plasmid DNA to ALAPPwas manipulated by the application of an appropriate DC voltage to the semiconductingsilicon substrate in order to study the spatially controlled electrostimulatedmanipulation of DNA. Furthermore, the subsequent growth andtransfection of mammalian cells was conducted as depicted in Figure 2.1. Here, theenhancement of transfection efficiency by electro-stimulated DNA desorption was ofparticular interest.The unique combination of patterned and switchable components of this deviceallows unprecedented control over the behaviour of cells and DNA in fourdimensions. This approach is useful for overcoming the current limitations of TCMsand is promising for broader applications in advanced biodevices.2.2. Materials and methods2.2.1. Substrate preparationBoron doped p ++ silicon wafers (Virginia Semiconductors, Inc.) were cut intoapproximately 10 x 10 mm 2 pieces, cleaned by sonication for 30 min in a 5%surfactant (RBS 35, Pierce USA) solution and oxidised under UV light for 30 min.2.2.2. Plasma polymerisationPlasma polymerisation reactions were preformed in a custom-built reactordescribed elsewhere [182]. In short, the plasma reactor consisted of two circularelectrodes separated by 125 mm in a cylindrical reactor being 350 mm high with adiameter of 170 mm. Allylamine (Aldrich, 98% purity) was used as a monomer.2-67