Table 1.

Materials.

Reagents	Manufacturer
Fmoc-L-Lys (Boc; 99.23%) and 2-hydroxyethyl methacrylate (HEMA, 97%)	Bidepharm, Shanghai, China
2,3-dihydroxybenzoic acid	Yuanye, Shanghai, China
Hydroxybenzotriazole (HOBt, >99%) and N-(3-dimethylaminopropyl)-N-ethylcarbodiimide hydrochloride (EDC–HCl, >99%)	D&B, Shanghai, China
N, N-diisopropylethylamine (DIPEA, 99%), diethylamine (DEA, >99%), and triethylamine (TEA, 99%)	Aladdin, Shanghai, China
Sodium bicarbonate (NaHCO3, >99.5%) and sodium chloride (NaCl, >99.5%)	KESHI, Chengdu, China
Methanol (>99.5%)	Hushi, Shanghai, China
Dichloromethane (DCM, >99.5%), anhydrous sodium sulfate (Na2SO4, >99%), tetrahydrofuran (THF, >99.5%), and 1,4-dioxane (>99.5)	N&S, Nanjing, China
Bisphenol-A glycol dimethacrylate (Bis-GMA), triethylene glycol dimethacrylate (TEGDMA), and diurethane dimethacrylate (UDMA)	MilliporeSigma, St. Louis, MI, USA