Three types of clay were supplied from the Clay Mineral Society Source Clays Repository: kaolinite, Warren County, Georgia, USA (KGa-2); Na-rich montmorillonite, Crook County, Wyoming, USA (SWy-2); and Ca-rich montmorillonite, Gonzales County, Texas, USA (STx-1b). NX-illite was obtained from Arginotec, NX Nanopowder, B + M Notenkämper, Munich, Germany. NX-Illite is composed of illite, illite-smectite mixed layer, feldspar, kaolinite, quartz and carbonate52 (link).
PEG 8 kDa, dextran 10 kDa, 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), HEPES sodium salt, sodium bicarbonate, o-phenylenediamine tablets, hydrogen peroxide and 2,3-diaminophenazine were purchased from Sigma-Aldrich (St. Louis, MO). Labeled polymer mPEG-NH2 MW 5000 was purchased from Shearwater Polymers. Alexa Fluor 647-dextran 10 kDa, Alexa Fluor 488 labeling kits and 20 mm diameter by 0.5 mm deep press-to-seal silicone isolators were obtained from Life Technologies (Carlsbad, CA). Water was deionized to a resistance of 18.2 MΩ with Barnstead NANOpure Diamond water purification system (Van Nuys, CA) and used for all experiments.
PEG 8 kDa, dextran 10 kDa, 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), HEPES sodium salt, sodium bicarbonate, o-phenylenediamine tablets, hydrogen peroxide and 2,3-diaminophenazine were purchased from Sigma-Aldrich (St. Louis, MO). Labeled polymer mPEG-NH2 MW 5000 was purchased from Shearwater Polymers. Alexa Fluor 647-dextran 10 kDa, Alexa Fluor 488 labeling kits and 20 mm diameter by 0.5 mm deep press-to-seal silicone isolators were obtained from Life Technologies (Carlsbad, CA). Water was deionized to a resistance of 18.2 MΩ with Barnstead NANOpure Diamond water purification system (Van Nuys, CA) and used for all experiments.