Heptadecafluoro 1 1 2 2 tetrahydrodecyltrichlorosilane

Bare silicon wafers were obtained from University Wafers (Boston, MA). 1.5 mm and 2 mm thick poly (methyl methacrylate), PMMA, sheets were purchased from Evonik (Sanford, ME). 1 mm and 2 mm thick cyclic olefin polymer, COP, ZEONOR 1060 R sheets were purchased from Zeon Specialty Materials (San Jose, CA). Fluorinert FC 40, optiprep density gradient medium, 10-μm size streptavidin-functionalized magnetic beads, and biotin-β-Galactosidase were purchased from Sigma Aldrich (Milwaukee, WI). Novec 7500 Engineered Fluid was from 3M (Maplewood, MN). Fluorosurfactant-008 for droplet stabilization was purchased from RAN Biotechnologies (Beverly, MA). Potassium hydroxide pellets and resorufin-β-D-galactopyranoside were from Thermo Fisher Scientific (Waltham, MA). Food coloring dyes were obtained from McCormick (Baltimore, MD). Heptadecafluoro-1,1,2,2-tetrahydrodecyltrichlorosilane used for PMMA and COP channel surface modification was purchased from Gelest (Morrisville, PA). All solutions were passed through Nylon syringe filters (0.2 μm pore size) from VWR International (Radnor, PA) to remove particulates. NdFeB permanent magnets were purchased from K&J Magnetics, Inc. (Pipersville, PA). All aqueous solutions were prepared in 18 MΩ deionized water purified using a Barnstead GenPure water purifying system from Thermo Scientific (Waltham, MA).

A TCA arranged in a U shape (for droplet gripper and sequential droplet manipulation) or an elliptical shape (for simultaneous droplet manipulation) was sandwiched between two layers of soft adhesive tape (3M Inc., VHB tape 4905). To create asymmetric stiffness, a soft elastomer layer fabricated by folding a self-fusing silicone tape (Loctite Inc., Go2 wrap) was attached to one side of the soft body. The two ends of the TCA were connected to copper wires that acted as electrical leads. The surface of the manipulator was rendered superomniphobic by spray-coating with fluorinated fumed silica particles. The fluorinated particles were fabricated through liquid phase silanization of 500 mg of 7 nm fumed silica particles (Sigma-Aldrich) in 20 ml hexane containing 0.5 ml heptadecafluoro-1,1,2,2-tetrahydrodecyl trichlorosilane (Gelest Inc.) for three days. Our biofluid manipulators can easily handle liquid volumes from 5 μl to 5 ml.