The AutoGlow quartz chamber plasma cleaning system was used in this paper to make the surface hydrophilic, principally through removal of organic contaminants from the nanopore surface. Other methods involve using wet chemistry (Piranha or Nanostrip wet chemistry). As stated in this paper: “Both of these approaches necessitate the use of extremely corrosive solutions, that introduce operational and disposal challenges. An alternative and effective approach is to use oxygen plasma. The standard approach used in these experiments was to use a Glow Research AutoGlow plasma cleaner to plasma clean the chip at 50 W for 1-3 minutes using O2 plasma at 0.8-1.0 Torr introduced into a chamber with a base pressure of 0.2 Torr.”
Tuning Intermolecular Interactions to Enhance Solid-State Nanopore Force Spectroscopy
Elaine Foun University of Rhode Island
http://digitalcommons.uri.edu/cgi/viewcontent.cgi?article=1048&context=theses
Surface modification of the pore or molecules is essential to prevent unwanted interfacial effects such as DNA sticking to solid-state nanopores. The development of surface functionalization methods to engineer a more robust version of NFS for DNA recognition is the focus of this study. By measuring the interaction time between a DNA probe and DNA analyte, NFS can allow for enhanced chemical selectivity in nanopore sensing to cope with the many molecules in blood and other human fluids. More generally, NFS will be a useful technique for single molecule sensing once fully optimized..
Excerpt from page 21:
CHARACTERIZING NANOPORE SENSING PERFORMANCE
2.1. Preparation of a Nanopore and Laboratory Set Up:
Before a nanopore can be mounted as detailed in chapter 1, the nanopore must be properly prepared. A variety of methods are available to make the surface hydrophilic, principally through removal of organic contaminants from the nanopore surface. Piranha solution cleaning is the most common approach in the semiconductor industry to clean silicon and silicon nitride surfaces. Since the solid-state nanopores used for this thesis are made in silicon nitride membranes on silicon wafers, they can be piranha cleaned.
Nanostrip (90% sulfuric acid, 5% peroxymonosulfuric acid, <1% hydrogen peroxide, and 5% water, OMG Cyantek #539200) is a stabilized alternative to piranha solution having a longer effective lifetime allowing extended cleaning
Both of these approaches necessitate the use of extremely corrosive solutions, that introduce operational and disposal challenges. An alternative and effective approach is to use oxygen plasma. The standard approach used in these experiments was to use a GlowResearch AutoGlow plasma cleaner to plasma clean the chip at 50 W for 1-3 minutes using O2 plasma at 0.8-1.0 Torr introduced into a chamber with a base pressure of 0.2 Torr.
