Trifluoroacetic acid

1-[Bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxid hexafluorophosphate (HATU), 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium fluorophosphate (HBTU) and N-Fmoc-protected amino acids were obtained from Iris Biotech GmbH. Piperidine, diisopropylcarbodiimide (DIC), N-hydroxybenzotriazole (HOBt), MPAA (97%, MPAA), 3-mercaptopropionic acid (MPA), tris(2-carboxyethyl)phosphine hydrochloride (≥98%, TCEP·HCl), thiophenol, triisopropylsilane (TIS), guanidine hydrochloride (≥99%, Gn·HCl), hydrochloric acid (reagent grade, 37%), and sodium hydroxide (pellets, 97%) as well as other reagents were purchased from Sigma Aldrich, Acros Organics or Merck and were of the purest grade available. Peptide synthesis grade N,N-dimethylformamide (DMF), dichloromethane, diethyl ether, acetonitrile, heptane, LC-MS-grade acetonitrile (0.1% TFA), LC-MS grade water (0.1% TFA), N,N-diisopropylethylamine (DIEA), acetic anhydride (Ac₂O), and trifluoroacetic acid (TFA) were purchased from Biosolve and Fisher-Chemical. NovaSyn TGR solid support was purchased from Sigma Aldrich. Bis(2-sulfenylethyl)amino trityl 1% divinylbenzene cross-linked polystyrene solid support (SEA PS) was produced on demand by Roowin. Solvents and reagents were used as received.

High-purity chemicals from various suppliers were purchased for the different experiments and used as received without any further modifications. Acetonitrile (ACN) HPLC grade, Ethanol HPLC grade, Methanol LC-MS grade, and Isopropyl alcohol LC-MS were purchased from CARLO ERBA Reagents SAS (Val de Reuil, France). Water UHPLC-MS was supplied by Fisher Scientific (Illkirch, France). Trifluoroacetic acid and Formic Acid (FA) were obtained from Biosolve B.V. (Valkenswaard, the Netherlands). Additionally, alpha-Cyano-4-hydroxycinnamic acid (4-HCCA), Aniline (ANI), and Glycerol were sourced from Sigma Aldrich (Saint-Quentin-Fallavier, France).

Water (H²O), formic acid (FA), acetonitrile (ACN), and trifluoroacetic acid (TFA) were obtained from Biosolve B. V. (Valkenswaard, Netherlands). DL-dithiothreitol (DTT), Hydrochloric acid (HCl), and Triton X-114 were purchased from Sigma-Aldrich (Saint-Quentin Fallavier, France). Trypsin was purchased from Promega (Charbonnieres, France). Tris was purchased from Interchim (Montluçon, France). EZ-Link Sulfo-NHS-SS-Biotin, Streptavidin UltraLink Resin (Pierce), Sodium chloride (NaCl), Dulbecco’s Modified Eagle’s Medium (DMEM), DMEM high glucose GlutaMAX™ Supplement, heat-inactivated fetal bovine serum (FBS), Trypsin, phosphate buffer saline (PBS), penicillin and streptomycin were purchased from Thermo Fisher Scientific (Massachusetts, USA). U-87 MG (ATCC^® HTB-14™) cell lines were purchased from ATTC (Manassas, Virginia, USA). Immortalized Human Astrocytes (Ref: P10251-IM) and astrocyte medium were obtained from Innoprot (Derio, Spain). Human NCH82 stage IV glioma cells were obtained from Dr Regnier-Vigouroux.

Sodium alginate (M.W. 200 kDa), calcium chloride dihydrate, gentamicin sulfate (GM), citric acid (CA), and chitosan (75–85% degree of deacetylation, M.W. 50–190 kDa) were obtained from Sigma-Aldrich (St. Louis, MO, USA). Phosphate buffer saline (PBS) was purchased from Gibco (Carlsbad, CA, USA). Acetonitrile and trifluoroacetic acid were purchased from Biosolve (Valkenvaard, The Netherlands), and formic acid was obtained from Merck (Darmstadt, Germany).