Agarose powder

Methacrylic acid (MAA), N-vinylpyrrolidone (VP), dimethyl sulfoxide (DMSO), potassium chloride (KCl), and agarose powder were purchased from VWR International (Vienna, Austria); N,N′-(1,2-dihydroxyethylene)bisacrylamide (DHEBA), 2,2′-azobis(isobutyronitrile) (AIBN), sodium bromide (NaBr), and Sudan Black B were from Sigma-Aldrich (Steinheim, Germany). Tris(hydroxymethyl)-aminomethane (Tris), ethylenediamine tetraAcetic acid (EDTA), calcium chloride (CaCl₂), magnesium chloride (MgCl₂), urea (CH₄N₂O), and (D+)-glucose monohydrate were purchased from Merck (Darmstadt, Germany). Sodium chloride (NaCl) was obtained from Applichem (Darmstadt, Germany). Acetic acid was purchased from Carl Roth (Karlsruhe, Germany). 4-(2-Hydroxyethyl)piperazine-1-ethanesulfonic acid (HEPES) was obtained from Alfa Aesar (Karlsruhe, Germany). HSA was purchased from Millipore (MA, USA). Brilliant gold paste (gold colloid, 12% gold content) was purchased from Heraeus, Germany. All reagents were of analytical or highest synthetic grade commercially available.

Stainless steel grade 304 plates (2 mm thick) and grade 303 rods (50 mm diameter) were acquired from Dejond (Antwerp, Belgium). Milling and chamfer tools were obtained from DIXI Polytool (Le Locle, Switzerland), with a detailed tool list in Table S1 of the Supplementary Information. Acetone was obtained from Acros Organics (Geel, Belgium). PVC plastic films of 180 and 300 μm thickness were bought from Delbo (Maldegem, Belgium). Double-sided pressure-sensitive adhesive (PSA) tapes 200 MP types 7956 MP (153 μm thick) and 7945 MP (127 μm thick) and transfer tape type 467 MP (58 μm thick) were acquired from 3M (Maplewood, MN, USA). Sigma-Aldrich (Overijse, Belgium) delivered Whatman quantitative filter paper grades 40, 43, and 598. Aquapel hydrophobic agent was obtained from Aquapel (Butler County, PA ,USA). Aqueous dye was obtained from Darwin Microfluidics (Paris, France). Agarose powder and glycerol bidistilled 99.5% were obtained from, respectively, Melford (Ipswich, UK) and VWR (Leuven, Belgium).