Hfe 7500 fluorinated oil

Devices were produced using soft photolithography for which the photomasks were ordered from CAD/Art Services, Inc. (Bandon, Oregon). The PDMS molds were made on silicon wafers by spin coating with SU-8 3000 or SU-8 3050 photoresist (both Microresist Technologies) to obtain 30 or 70 µm of channel height, respectively. Our 3-inlet PDMS devices were fabricated by pouring a 10:1 mix of SYLGARD^® 184 PDMS and SYLGARD^® 184 curing agent (both from Merck) onto the silicon wafers and curing for 2 hours at 65°C. Using a 1.2 mm biopsy puncher holes for the inlets and outlet were punched. The devices were bonded to glass slides using a plasma asher (Emitech, K1050X). After which, the channels were treated with 5% perfluorooctyltriethoxysilane in HFE-7500 fluorinated oil (both from Fluorochem), to make the channels hydrophobic. After 1 hour incubation at 65°C, and flushing with HFE-7500, the devices were incubated overnight at 65°C for thermal bonding and drying.

Droplet microfluidics devices were produced using soft lithography. Photomasks were ordered from CAD/Art Services, Inc. (Bandon, OR, USA). PDMS molds were produced by spin-coating wafers with SU-8 3000 photoresist (Microresist Technology, Berlin, Germany) according to manufacturer’s protocol to obtain 30 µm of channel height. PDMS devices were fabricated by mixing SYLGARD^® 184 PDMS with SYLGARD^® 184 curing agent (both from Merck) at 10:1 w/w before pouring the mixture onto the PDMS molds and curing for 2 h at 65 °C. Using a 1 mm biopsy puncher, holes for the inlets and outlet were punched. The obtained PDMS devices were bonded to glass slides using a plasma asher (Emitech, K1050X, Montigny-le-Bretonneux, France). After bonding, the channels were treated with 5% perfluorooctyltriethoxysilane in HFE-7500 fluorinated oil (both from Fluorochem, Hadfield, United Kingdom) in order to make channel walls hydrofobic, incubated for 1 h at 65 °C, flushed again with HFE-7500, and incubated overnight at 65 °C for thermal bonding.