Diethylene glycol dimethacrylate

Urethane dimethacrylate (UDMA), triethylene glycol dimethacrylate (TEGDMA), diethylene glycol dimethacrylate (DEGDMA) and ethylene glycol dimethacrylate (EGDMA) were purchased from Sigma Aldrich (Gillingham, UK) (Fig. 1). Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) was purchased from Tokyo Chemical Industry Co., Ltd. (Tokyo, Japan). Isopropyl alcohol (IPA) was purchased from Sigma-Aldrich (St. Louis, MO, USA). NIH 3T3 embryonic mouse fibroblasts (ATCC-CRL-1658), Dulbecco’s modified Eagle’s medium (DMEM) and calf bovine serum (CBS) were purchased from ATCC (LGC, UK).Fig. 1

Chemical structures of Urethane dimethacrylate, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate and triethylene glycol dimethacrylate

HEMA, supplied from Merk Company KGaA (Darmstadt, Germany), was purified by vacuum distillation immediately prior to use. Poly(4-vinylpiridine) (M_W = 60,000 g/mol), dimethacrylic monomers: ethylene glycol dimethacrylate (EGDMA), diethylene glycol dimethacrylate (DEGDMA) and triethylene glycol dimethacrylate (TEGDMA), N,N,N′N′-tetramethylethylenediamine (TEMED), ammonium persulfate (APS), sodium bicarbonate, tetracycline (M = 444.43 g/mol), methanol and ethanol were purchased from Sigma-Aldrich and were used as received.
The synthesis of poly(betaines) derived from P4VP has already been presented in other works [36 ,37 (link)]. Poly(betaines) were obtained via polymer-analogous reactions, the betainization agents being sodium monochloroacetate (P4VPB-1) and acrylic acid (P4VPB-2). The chemical structures of P4VP, P4VPB-1 and P4VPB-2 are presented in Scheme 1. Polybetaines were obtained with different degrees of betainization, as follows: 95% for P4VPB-1 and 96% for P4VPB-2.

All chemicals were purchased from Sigma-Aldrich (Overijse, Belgium), Acros (Geel, Belgium) and TCI (Zwijndrecht, Belgium). 2,2,6,6-Tetramethyl-1-piperidyl methacrylate (TMPM, 98%, TCI), oligo(ethylene glycol) methyl ether methacrylate (OEGMA, average molar mass of 300 g/mol, Sigma-Aldrich) and di(ethylene glycol) dimethacrylate (OEGMA₂, 98%, Sigma-Aldrich) were purified on a AlO_x-filtration column prior use in order to remove the inhibitor. The 2,2′-azobisisobutyronitrile (AIBN, 98% purity, Sigma Aldrich) initiator was recrystallized twice from methanol (Acros, 99%) prior use. Acetylsalicylic acid (ASA, 99.9%, Sigma-Aldrich), isopropanol (IPA, Acros, 99.5%), methanol (Acros, 99.8%), diethyl ether (Acros, 99%), NaHCO₃ (Sigma Aldrich, 99%), Na₂WO₄.2H₂O (Sigma-Aldrich, 99%), H₂O₂ (Sigma-Aldrich, 30 wt% solution in water), ethylene diamine tetraacetic acid disodium salt dihydrate (EDTA, Sigma Aldrich, 99%), NaClO (Sigma Aldrich, 99%), HBF₄ (Sigma Aldrich, 48 wt% solution in water), NaClO₄ (Sigma Aldrich, 98%), acetonitrile (ACN, 99.9%, Sigma Aldrich), formic acid (98%, Sigma Aldrich), benzylic alcohol (Sigma Aldrich, 99%) and tert-butyl nitrite (Sigma Aldrich, 90%) were used as received.