2.2. Synthesis of DMA-MPC copolymer

Dopamine methacrylamide (DMA) was synthesized based on the following procedures. Dopamine hydrochloride (5 g), sodium tetraborate (10 g) and sodium bicarbonate (4 g) were dissolved in deionized water (100 mL) under N₂ atmosphere. Methacrylic anhydride (5 mL) was dissolved in tetrahydrofuran (25 mL) and then added dropwise to the above solution (pH = 8). The mixture was stirred overnight under N₂ atmosphere. Afterwards, the reacted mixture was adjusted to pH = 2 using hydrochloric acid (1 M), extracted with ethyl acetate (50 mL) and filtered with magnesium sulfate for purification. Subsequently, the product was collected by filtering after precipitation with mineral ether. DMA-MPC copolymer was synthesized by free radical polymerization using AIBN as the initiator. Briefly, DMA and MPC with different mass ratios (total weight: 1 g) were dissolved separately in N, N-dimethylformamide (50 mL) under N₂ atmosphere. Afterwards, AIBN (5 mg) was added and the solution was stirred at 68 °C for 24 h. Finally, the mixture was dialyzed against deionized water and freeze dried to obtain the DMA-MPC copolymer.