1 2 propanediol

Choline chloride > 98%, betaine 98%, D(+)-glucose 99.5%, D(-)-fructose, polyethyleneimine, branched (PEI), ethyl-4-hydroxy-3-methoxycinnamate (ethyl ferulate) 4-nitrophenyl butyrate (pNPB) > 98%, and p-nitrophenol (pNP) were obtained from Sigma-Aldrich, St. Louis, MI, USA. Choline dihydrogen phosphate >98% was bought from IOLITEC, (Heilbronn, Germany), ethylammonium chloride from Merck (Sigma-Aldrich, USA), urea > 99% from Fluka (Sigma-Aldrich, USA), glycerol 0.5% max water, and Glutaraldehyde 25% solution from Fisher Scientific (Hampton, NH, USA), ethylene glycol from AppliChem (Darmstadt, Germany), 1,2-butanediol > 98% from TCI (Japan), 1,2-propanediol 99% from Acros Organics (Waltham, MA, USA), and sodium hydroxide > 98% from Panreac (Barcelona, Spain). The HPLC solvents acetonitrile, methanol, and water were of HPLC grade and the water used was double distilled. The lipases from Candida antarctica Lipozyme CALB L (liquid) and Novozym 435 (immobilized) were kindly offered by Novozymes (Bagsværd, Denmark). PLA filament designed for use with FDM 3D printers (PrimaValue™) was purchased from Prima Creator (Malmö, Sweden). The 3D printer used was an Ender 5 from Creality 3D (Shenzhen, China).

l-Cysteine (Merck), d-cysteine
(Merck), 1,2-propanediol (Acros Organics), iridium chloride hydrate
(IrCl₃·xH₂O, Merck), cysteamine
(Merck), 3-mercaptopropionic acid (Merck), 37% hydrochloric acid (Fischer
Scientific), ethanol (99.5% purity, Honeywell), acetone (99.5% purity,
Acros Organics), and isopropyl alcohol (99.9% purity IPA, VWR).

For NADES preparation, chemicals choline chloride, 1,2-propanediol, DL-malic acid, malonic acid, D-sorbitol, urea (all Thermo Fisher Scientific, Waltham, MA, USA), citric acid monohydrate, glycerol, D(−)-fructose (all Carl Roth, Karlsruhe, Germany), D(+)-glucose (Merck, Darmstadt, Germany) and methylurea (Acros Organics, Geel, Belgium) were used. Methylurea had a specified purity of 97%, and all other reagents were at least 98% or higher. In HPLC mobile phases, ultrapure water prepared from deionized water with a Barnstead MicroPure system (Thermo Fisher Scientific, Waltham, MA, USA), HPLC-grade acetonitrile (VWR, Radnor, PA, USA) and formic acid (Honeywell, Charlotte, NC, USA) were used. The solvent for NMR analyses was chloroform-d₁ (VWR). Other solvents used in this study were partly denatured ethanol (96% v/v, AustrAlco, Spillern, Austria) methanol (≥99.9%, Carl Roth) and dichloromethane (≥99.5%, Carl Roth). Reference substance spilanthol was isolated in the course of this work with a purity of 97% as determined by NMR.

The methanol and acetonitrile used were HPLC (high-performance liquid chromatography) grade and purchased from Fisher Scientific, as well as the potassium sodium tartrate tetrahydrate used for reducing sugar determination and D-glucose standard (Madrid, Spain). Choline chloride, betaine, 1,2-propanediol, and albumin standard were from Thermo Fisher Scientific (Madrid, Spain), and triethylene glycol and Trolox standard were supplied by Acros Organics (Antwerp, Belgium). The HPLC standards, trifluoroacetic acid, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) were purchased from Sigma Aldrich (St. Louis, MO, USA)l; Folin-Ciocalteu reagent and ethanol were obtained from Scharlau (Barcelona, Spain); and 3,5-dinitrosalicylic acid was purchased from Alfa Aesar (Kandel, Germany). Mueller–Hinton Broth culture media and bacteriological agar for microbiological assays were supplied by Oxoid (Basingstoke, Hampshire, UK).