Sylgard 184 elastomer kit

An economic soft lithography variant fabricated a microfluidic reactor. First, a mold was produced with laser engraving on a 3 mm PMMA plaque. Then, a second mold was created with polydimethylsiloxane (PDMS). Then, a replicate from the PDMS mold was done with PDMS to get the shape of a serpentine and then functionalized by laccase on its inner walls (details in SI). In general, The immobilization process was tested for duplicate with three different methods -ethyl-3-(3-dimethylamino propyl) carbodiimide (EDC), Glutaraldehyde (GA), and passive adhesion (PA). The laccase enzymatic activity was measured through the oxidation reaction for the substrate 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) by absorbance measurement. Similarly, the BPA transformation was measured by absorbance with a wavelength of 228 nm.
Poly (methyl methacrylate) (PMMA) was acquired from Polymershapes, Chihuahua, Mexico, and polydimethylsiloxane (PDMS) Sylgard 184 elastomer Kit, absolute ethanol, phosphate citrate buffer pH 3, ABTS pills of 5 mg, Dichlorodimethylsilane (99.5 %), 1-ethyl-3-(3-dimethylamino propyl) carbodiimide (EDC), and Glutaraldehyde (GA) were acquired from Sigma Aldrich, San Louis, USA. The laccase enzyme was produced by the Sustainable and Applied Biotechnology Group from Tecnológico de Monterrey using the fungus Pycnoporus sanguineus CS43.

Planar alginate layers were used as scaffolds positioned on round standard cell culture treated polystyrene‐based coverslips (Thermanox™, Ø 13 mm, Thermo Fisher Scientific, Dreieich, Germany) and dishes (Ø 35 mm, Corning, New York, NY) treated with poly‐l‐lysine (pLL; Sigma‐Aldrich, Taufkirchen, Germany) in phosphate‐buffered saline (PBS; Gibco, Thermo Fisher Scientific, Darmstadt, Germany) for 30 min at 37°C. The alginate solution (LN/LT 1:1, 0.7% [wt %/vol %]) were placed on the treated, dried plastic surfaces and gelled with 20 mM barium chloride solution (BaCl₂) for 20 min at room temperature (RT). The obtained alginate layers were washed three times with NaCl and stored at 4°C until usage.
Structured, planar alginate surfaces were manufactured using a μ‐contact printer (GeSiM mbH, Rossendorf, Germany; see Supporting Information, Fig. 1). The alginate solution was placed on an agarose gel (4% [wt/vol %]; Sigma‐Aldrich, Taufkirchen, Germany) containing 100 mM BaCl₂ and structured for 3 min by a stamp based on polydimethylsiloxane (PDMS; Sylgard 184 elastomer kit, Sigma‐Aldrich, Taufkirchen, Germany). The structured hydrogel was transferred to a pLL‐treated plastic dish, post‐cross‐linked with 20 mM BaCl₂ for 10 min, washed three times with NaCl, and stored at 4°C until usage.