PDMS Surface Modification activation

Fig. 5 Schematic representation of the surface modification steps used by Ganger et al. to produce a biologically active surface in a microreactor. Biotin-labeled human anti- 5-integrin (HAI) was bound to modified PDMS and used to study cell surface receptor activity. (From Ref.. ) (View this art in color at www.dekker.com.)...

Plasma treatment of microchannels can be useful for improving the functionality of microdevices. For example, previous studies have shown that PDMS microchannels can be made hydrophilic by the addition of silane molecules with polar head groups [6]. In this process (3-mercaptopropyl)trimethoxysilane (3-MPS) was absorbed to PDMS to increase the hydrophilic properties of microchannels. Additionally, plasma polymerization has been used to induce in the long-term hydrophilic surface modification by covalently bonding a polymer layer to the surface. Barbier et al. [7] describe a method based on plasma polymerization modification with acrylic acid coatings. First, argon plasma pretreatment was used to activate trace oxygen molecules in the chamber, which partially oxidize the top layer of the substrate. This step cross-linked the surface to reduce ablation of silicon... 

As mentioned earlier, the magnitude of EOF on PT devices is 10 times lower than that in common microfabrication substrates such as glass, quartz, and PDMS. While the EOF in these popular materials can be raised by chemical or physical modification of the surface (activation by oxygen plasma or sodium hydroxide), similar treatment of PT chips does not yield the same enhancement. The use of sodium hydroxide is not recommended because it attacks the toner surface rapidly (in a few minutes), even at low concentration. However, the low EOF can certainly be an advantage for the analysis of analytes with similar electrophoretic mobilities. One strategy to obtain a simple microdevice but with greater EOF is the fabrication of glass-toner microchips. ... 

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